Mario A. Svirsky, Ph.D.

A mathematical model of medial consonant identification by cochlear implant users
Svirsky, Mario A; Sagi, Elad; Meyer, Ted A; Kaiser, Adam R; Teoh, Su Wooi
2011 Apr;129(4):2191-2191, Journal of the Acoustical Society of America
The multidimensional phoneme identification model is applied to consonant confusion matrices obtained from 28 postlingually deafened cochlear implant users. This model predicts consonant matrices based on these subjects' ability to discriminate a set of postulated spectral, temporal, and amplitude speech cues as presented to them by their device. The model produced confusion matrices that matched many aspects of individual subjects' consonant matrices, including information transfer for the voicing, manner, and place features, despite individual differences in age at implantation, implant experience, device and stimulation strategy used, as well as overall consonant identification level. The model was able to match the general pattern of errors between consonants, but not the full complexity of all consonant errors made by each individual. The present study represents an important first step in developing a model that can be used to test specific hypotheses about the mechanisms cochlear implant users employ to understand speech
— id: 130913, year: 2011, vol: 129, page: 2191, stat: Journal Article,

Speech production intelligibility of early implanted pediatric cochlear implant users
Habib, Mirette G; Waltzman, Susan B; Tajudeen, Bobby; Svirsky, Mario A
2010 Aug;74(8):855-859, International journal of pediatric otorhinolaryngology
OBJECTIVES: To investigate the influence of age, and age-at-implantation, on speech production intelligibility in prelingually deaf pediatric cochlear implant recipients. METHODS: Forty prelingually, profoundly deaf children who received cochlear implants between 8 and 40 months of age. Their age at testing ranged between 2.5 and 18 years. Children were recorded repeating the 10 sentences in the Beginner's Intelligibility Test. These recordings were played back to normal-hearing listeners who were unfamiliar with deaf speech and who were instructed to write down what they heard. They also rated each subject for the intelligibility of their speech production on a 5-point rating-scale. The main outcome measures were the percentage of target words correctly transcribed, and the intelligibility ratings, in both cases averaged across 3 normal-hearing listeners. RESULTS: The data showed a strong effect of age at testing, with older children being more intelligible. This effect was particularly pronounced for children implanted in the first 24 months of life, all of whom had speech production intelligibility scores of 80% or higher when they were tested at age 5.5 years or older. This was true for only 5 out of 9 children implanted at age 25-36 months. CONCLUSIONS: Profoundly deaf children who receive cochlear implants in the first 2 years of life produce highly intelligible speech before the age of 6. This is also true for most, but not all children implanted in their third year
— id: 110684, year: 2010, vol: 74, page: 855, stat: Journal Article,

A new software tool to optimize frequency table selection for cochlear implants
Jethanamest, Daniel; Tan, Chin-Tuan; Fitzgerald, Matthew B; Svirsky, Mario A
2010 Oct;31(8):1242-1247, Otology & neurotology
HYPOTHESIS: When cochlear implant (CI) users are allowed to self-select the 'most intelligible' frequency-to-electrode table, some of them choose one that differs from the default frequency table that is normally used in clinical practice. BACKGROUND: CIs reproduce the tonotopicity of normal cochleas using frequency-to-electrode tables that assign stimulation of more basal electrodes to higher frequencies and more apical electrodes to lower frequency sounds. Current audiologic practice uses a default frequency-to-electrode table for most patients. However, individual differences in cochlear size, neural survival, and electrode positioning may result in different tables sounding most intelligible to different patients. No clinical tools currently exist to facilitate this fitting. METHODS: A software tool was designed that enables CI users to self-select a most intelligible frequency table. Users explore a 2-dimensional space that represents a range of different frequency tables. Unlike existing tools, this software enables users to interactively audition speech processed by different frequency tables and quickly identify a preferred one. Pilot testing was performed in 11 long-term, postlingually deaf CI users. RESULTS: The software tool was designed, developed, tested, and debugged. Patients successfully used the tool to sample frequency tables and to self-select tables deemed most intelligible, which for approximately half of the users differed from the clinical default. CONCLUSION: A software tool allowing CI users to self-select frequency-to-electrode tables may help in fitting postlingually deaf users. This novel approach may transform current methods of CI fitting
— id: 113658, year: 2010, vol: 31, page: 1242, stat: Journal Article,

Effects of semantic context and feedback on perceptual learning of speech processed through an acoustic simulation of a cochlear implant
Loebach, Jeremy L; Pisoni, David B; Svirsky, Mario A
2010 Feb;36(1):224-234, Journal of experimental psychology: human perception & performance
The effect of feedback and materials on perceptual learning was examined in listeners with normal hearing who were exposed to cochlear implant simulations. Generalization was most robust when feedback paired the spectrally degraded sentences with their written transcriptions, promoting mapping between the degraded signal and its acoustic-phonetic representation. Transfer-appropriate processing theory suggests that such feedback was most successful because the original learning conditions were reinstated at testing: Performance was facilitated when both training and testing contained degraded stimuli. In addition, the effect of semantic context on generalization was assessed by training listeners on meaningful or anomalous sentences. Training with anomalous sentences was as effective as that with meaningful sentences, suggesting that listeners were encouraged to use acoustic-phonetic information to identify speech than to make predictions from semantic context
— id: 114806, year: 2010, vol: 36, page: 224, stat: Journal Article,

A Model of Incomplete Adaptation to a Severely Shifted Frequency-to-Electrode Mapping by Cochlear Implant Users
Sagi, Elad; Fu, Qian-Jie; Galvin, John J 3rd; Svirsky, Mario A
2010 Mar;11(1):69-78, Journal of the Association for Research in Otolaryngology : JARO
In the present study, a computational model of phoneme identification was applied to data from a previous study, wherein cochlear implant (CI) users' adaption to a severely shifted frequency allocation map was assessed regularly over 3 months of continual use. This map provided more input filters below 1 kHz, but at the expense of introducing a downwards frequency shift of up to one octave in relation to the CI subjects' clinical maps. At the end of the 3-month study period, it was unclear whether subjects' asymptotic speech recognition performance represented a complete or partial adaptation. To clarify the matter, the computational model was applied to the CI subjects' vowel identification data in order to estimate the degree of adaptation, and to predict performance levels with complete adaptation to the frequency shift. Two model parameters were used to quantify this adaptation; one representing the listener's ability to shift their internal representation of how vowels should sound, and the other representing the listener's uncertainty in consistently recalling these representations. Two of the three CI users could shift their internal representations towards the new stimulation pattern within 1 week, whereas one could not do so completely even after 3 months. Subjects' uncertainty for recalling these representations increased substantially with the frequency-shifted map. Although this uncertainty decreased after 3 months, it remained much larger than subjects' uncertainty with their clinically assigned maps. This result suggests that subjects could not completely remap their phoneme labels, stored in long-term memory, towards the frequency-shifted vowels. The model also predicted that even with complete adaptation, the frequency-shifted map would not have resulted in improved speech understanding. Hence, the model presented here can be used to assess adaptation, and the anticipated gains in speech perception expected from changing a given CI device parameter
— id: 106591, year: 2010, vol: 11, page: 69, stat: Journal Article,

A mathematical model of vowel identification by users of cochlear implants
Sagi, Elad; Meyer, Ted A; Kaiser, Adam R; Teoh, Su Wooi; Svirsky, Mario A
2010 Feb;127(2):1069-1069, Journal of the Acoustical Society of America
A simple mathematical model is presented that predicts vowel identification by cochlear implant users based on these listeners' resolving power for the mean locations of first, second, and/or third formant energies along the implanted electrode array. This psychophysically based model provides hypotheses about the mechanism cochlear implant users employ to encode and process the input auditory signal to extract information relevant for identifying steady-state vowels. Using one free parameter, the model predicts most of the patterns of vowel confusions made by users of different cochlear implant devices and stimulation strategies, and who show widely different levels of speech perception (from near chance to near perfect). Furthermore, the model can predict results from the literature, such as Skinner, et al. [(1995). Ann. Otol. Rhinol. Laryngol. 104, 307-311] frequency mapping study, and the general trend in the vowel results of Zeng and Galvin's [(1999). Ear Hear. 20, 60-74] studies of output electrical dynamic range reduction. The implementation of the model presented here is specific to vowel identification by cochlear implant users, but the framework of the model is more general. Computational models such as the one presented here can be useful for advancing knowledge about speech perception in hearing impaired populations, and for providing a guide for clinical research and clinical practice
— id: 106597, year: 2010, vol: 127, page: 1069, stat: Journal Article,

Speech perception in congenitally deaf children receiving cochlear implants in the first year of life
Tajudeen, Bobby A; Waltzman, Susan B; Jethanamest, Daniel; Svirsky, Mario A
2010 Oct;31(8):1254-1260, Otology & neurotology
OBJECTIVE: To investigate whether children implanted in the first year of life show higher levels of speech perception than later-implanted children, when compared at the same ages and to investigate the time course of sensitive periods for developing speech perception skills. More specifically, to determine whether faster gains in speech perception are made by children implanted before 1 year old relative to those implanted at 2 or 3 years. STUDY DESIGN: Retrospective cohort study. SETTING: Tertiary academic referral center. PATIENTS: 117 children with congenital profound bilateral sensorineural hearing loss, with no additional identified disabilities. INTERVENTION: Cochlear implantation in the first, second, or third year of life. MAIN OUTCOME MEASURE: Development curves showing Lexical Neighborhood Test (LNT) word identification scores as a function of age. RESULTS: Children implanted within the first year of life have a mean advantage of 8.2% LNT-easy word scores over those implanted in the second year (p < 0.001) and a 16.8% advantage in LNT-easy word scores over those implanted in the third year of life (p < 0.001). These advantages remained statistically significant after accounting for sex, residual hearing, and bilateral cochlear implant use. When speech perception scores were expressed as a function of 'hearing age' rather than chronological age, however, there were no significant differences among the 3 groups. CONCLUSION: There is a clear speech perception advantage for earlier-implanted children over later-implanted children when compared at the same age but not when compared at the same time after implantation. Thus, the sensitive period for developing word identification seems to extend at least until age 3 years
— id: 113659, year: 2010, vol: 31, page: 1254, stat: Journal Article,

Transfer of auditory perceptual learning with spectrally reduced speech to speech and nonspeech tasks: implications for cochlear implants
Loebach, Jeremy L; Pisoni, David B; Svirsky, Mario A
2009 Dec;30(6):662-674, Ear & hearing
OBJECTIVE: The objective of this study was to assess whether training on speech processed with an eight-channel noise vocoder to simulate the output of a cochlear implant would produce transfer of auditory perceptual learning to the recognition of nonspeech environmental sounds, the identification of speaker gender, and the discrimination of talkers by voice. DESIGN: Twenty-four normal-hearing subjects were trained to transcribe meaningful English sentences processed with a noise vocoder simulation of a cochlear implant. An additional 24 subjects served as an untrained control group and transcribed the same sentences in their unprocessed form. All subjects completed pre- and post-test sessions in which they transcribed vocoded sentences to provide an assessment of training efficacy. Transfer of perceptual learning was assessed using a series of closed set, nonlinguistic tasks: subjects identified talker gender, discriminated the identity of pairs of talkers, and identified ecologically significant environmental sounds from a closed set of alternatives. RESULTS: Although both groups of subjects showed significant pre- to post-test improvements, subjects who transcribed vocoded sentences during training performed significantly better at post-test than those in the control group. Both groups performed equally well on gender identification and talker discrimination. Subjects who received explicit training on the vocoded sentences, however, performed significantly better on environmental sound identification than the untrained subjects. Moreover, across both groups, pre-test speech performance and, to a higher degree, post-test speech performance, were significantly correlated with environmental sound identification. For both groups, environmental sounds that were characterized as having more salient temporal information were identified more often than environmental sounds that were characterized as having more salient spectral information. CONCLUSIONS: Listeners trained to identify noise-vocoded sentences showed evidence of transfer of perceptual learning to the identification of environmental sounds. In addition, the correlation between environmental sound identification and sentence transcription indicates that subjects who were better able to use the degraded acoustic information to identify the environmental sounds were also better able to transcribe the linguistic content of novel sentences. Both trained and untrained groups performed equally well ( approximately 75% correct) on the gender-identification task, indicating that training did not have an effect on the ability to identify the gender of talkers. Although better than chance, performance on the talker discrimination task was poor overall ( approximately 55%), suggesting that either explicit training is required to discriminate talkers' voices reliably or that additional information (perhaps spectral in nature) not present in the vocoded speech is required to excel in such tasks. Taken together, the results suggest that although transfer of auditory perceptual learning with spectrally degraded speech does occur, explicit task-specific training may be necessary for tasks that cannot rely on temporal information alone
— id: 114807, year: 2009, vol: 30, page: 662, stat: Journal Article,

The effect of temporal gap identification on speech perception by users of cochlear implants
Sagi, Elad; Kaiser, Adam R; Meyer, Ted A; Svirsky, Mario A
2009 Apr;52(2):385-395, Journal of speech, language, & hearing research
PURPOSE: This study examined the ability of listeners using cochlear implants (CIs) and listeners with normal-hearing (NH) to identify silent gaps of different duration, and the relation of this ability to speech understanding in CI users. METHOD: Sixteen NH adults and eleven postlingually deafened adults with CIs identified synthetic vowel-like stimuli that were either continuous or contained an intervening silent gap ranging from 15 to 90 ms. Cumulative d', an index of discriminability, was calculated for each participant. Consonant and CNC word identification tasks were administered to the CI group. RESULTS: Overall, the ability to identify stimuli with gaps of different duration was better for the NH group than for the CI group. Seven CI users had cumulative d' scores that were no higher than those of any NH listener, and their CNC word scores ranged from 0 to 30%. The other four CI users had cumulative d' scores within the range of the NH group, and their CNC word scores ranged from 46% to 68%. For the CI group, cumulative d' scores were significantly correlated with their speech testing scores. CONCLUSIONS: The ability to identify silent gap duration may help explain individual differences in speech perception by CI users
— id: 94927, year: 2009, vol: 52, page: 385, stat: Journal Article,

Reimplantation of hybrid cochlear implant users with a full-length electrode after loss of residual hearing
Fitzgerald, Matthew B; Sagi, Elad; Jackson, Michael; Shapiro, William H; Roland, J Thomas Jr; Waltzman, Susan B; Svirsky, Mario A
2008 Feb;29(2):168-173, Otology & neurotology
OBJECTIVE: To assess word recognition and pitch-scaling abilities of cochlear implant users first implanted with a Nucleus 10-mm Hybrid electrode array and then reimplanted with a full length Nucleus Freedom array after loss of residual hearing. BACKGROUND: Although electroacoustic stimulation is a promising treatment for patients with residual low-frequency hearing,a small subset of them lose that residual hearing. It is not clear whether these patients would be better served by leaving in the 10-mm array and providing electric stimulation through it, or by replacing it with a standard full-length array. METHODS: Word recognition and pitch-scaling abilities were measured in 2 users of hybrid cochlear implants who lost their residual hearing in the implanted ear after a few months. Tests were repeated over several months, first with a 10-mm array, and after, these patients were reimplanted with a full array. The word recognition task consisted of 2 50-word consonant nucleus consonant (CNC) lists. In the pitch-scaling task, 6 electrodes were stimulated in pseudorandom order, and patients assigned a pitch value to the sensation elicited by each electrode. RESULTS: Shortly after reimplantation with the full electrode array, speech understanding was much better than with the 10-mm array. Patients improved their ability to perform the pitch-scaling task over time with the full array, although their performance on that task was variable, and the improvements were often small. CONCLUSION: 1) Short electrode arrays may help preserve residual hearing but may also provide less benefit than traditional cochlear implants for some patients. 2) Pitch percepts in response to electric stimulation may be modified by experience
— id: 76765, year: 2008, vol: 29, page: 168, stat: Journal Article,

Speech perception and insertion trauma in hybrid cochlear implant users: A response to Gstottner and Arnolder
Fitzgerald, MB; Sagi, E; Jackson, M; Shapiro, WH; Roland, JT; Waltzman, SB; Svirsky, MA
2008 SEP ;29(6):881-882, Otology & neurotology
— id: 86665, year: 2008, vol: 29, page: 881, stat: Journal Article,

An exploratory look at pediatric cochlear implantation: is earliest always best?
Holt, Rachael Frush; Svirsky, Mario A
2008 Aug;29(4):492-511, Ear & hearing
OBJECTIVES: Since the advent of cochlear implants, age at implantation has declined as investigators report greater benefit the younger a child is implanted. Infants younger than 12 mos currently are excluded from Food and Drug Administration clinical trials, but have been implanted with Food and Drug Administration-approved devices. With a chance that an infant without profound hearing loss could be implanted because of the limitations of the diagnostic measures used with this population and the potential for additional anesthetic risks to infants younger than 1-yr-old, it is prudent to evaluate benefit in the youngest cochlear implant recipients. The goals of this research were to investigate whether significant gains are made by children implanted before 1-yr-old relative to those implanted at later ages, while controlling for potential covariates, and whether there is behavioral evidence for sensitive periods in spoken language development. It was expected that children implanted before age 1 yr would have more advanced spoken language skills than children implanted at later ages; there would be a negative relationship between age at implantation and rate of spoken language development, allowing for an examination of the effects of sensitive periods in spoken language development; and these trends would remain despite accounting for participant characteristics and experiences that might influence spoken language outcomes. DESIGN: Ninety-six children with congenital profound sensorineural hearing loss bilaterally and no additional identified disabilities who were implanted before the age of 4 yrs were stratified into four groups based on age at implantation. Children's spoken language development was followed for at least 2 yrs after device activation. Spoken language scores and rate of development were evaluated along with four covariates (unaided pure-tone average, communication mode, gender, and estimated family income) as a function of age at implantation. RESULTS: In general, the developmental trajectories of children implanted earlier were significantly better than those of children implanted later. However, the advantage of implanting children before 1-yr old versus waiting until the child was between 1 and 2 yrs was small and only was evident in receptive language development, not expressive language or word recognition development. Age at implantation did not significantly influence the rate of the word recognition development, but did influence the rate of both receptive and expressive language acquisition: children implanted earlier in life had faster rates of spoken language acquisition than children implanted later in life. CONCLUSIONS: Although in general earlier cochlear implantation led to better outcomes, there were few differences in outcome between the small sample of six children implanted before 12 mos of age and those implanted at 13 to 24 mos. Significant performance differences remained among the other age groups despite accounting for potential confounds. Further, oral language development progressed faster in children implanted earlier rather than later in of life (up to age 4 yrs), whereas the rate of open-set speech recognition development was similar. Together, the results suggest that there is a sensitive period for spoken language during the first 4 yrs of life, but not necessarily for word recognition development during the same period
— id: 94929, year: 2008, vol: 29, page: 492, stat: Journal Article,

Regarding sufficiency of authors' disclosures: Hearing levels of firefighters: risk of occupational noise-induced hearing loss assessed by cross-sectional and longitudinal data [Ear Hear 2005;26(3):327-340]
Ryals, Brenda M; Svirsky, Mario A
2008 Oct;29(5):815-816, Ear & hearing
— id: 94928, year: 2008, vol: 29, page: 815, stat: Journal Article,

Information transfer analysis: a first look at estimation bias
Sagi, Elad; Svirsky, Mario A
2008 May;123(5):2848-2857, Journal of the Acoustical Society of America
Information transfer analysis [G. A. Miller and P. E. Nicely, J. Acoust. Soc. Am. 27, 338-352 (1955)] is a tool used to measure the extent to which speech features are transmitted to a listener, e.g., duration or formant frequencies for vowels; voicing, place and manner of articulation for consonants. An information transfer of 100% occurs when no confusions arise between phonemes belonging to different feature categories, e.g., between voiced and voiceless consonants. Conversely, an information transfer of 0% occurs when performance is purely random. As asserted by Miller and Nicely, the maximum-likelihood estimate for information transfer is biased to overestimate its true value when the number of stimulus presentations is small. This small-sample bias is examined here for three cases: a model of random performance with pseudorandom data, a data set drawn from Miller and Nicely, and reported data from three studies of speech perception by hearing impaired listeners. The amount of overestimation can be substantial, depending on the number of samples, the size of the confusion matrix analyzed, as well as the manner in which data are partitioned therein
— id: 81060, year: 2008, vol: 123, page: 2848, stat: Journal Article,

Speech perception benefits of sequential bilateral cochlear implantation in children and adults: a retrospective analysis
Zeitler, Daniel M; Kessler, Megan A; Terushkin, Vitaly; Roland, Thomas J Jr; Svirsky, Mario A; Lalwani, Anil K; Waltzman, Susan B
2008 Apr;29(3):314-325, Otology & neurotology
Objective: To examine speech perception outcomes and determine the impact of length of deafness and time between implants on performance in the sequentially bilateral implanted population. STUDY DESIGN: Retrospective review. SETTING: Tertiary academic referral center. PATIENTS: Forty-three children (age, <18 yr) and 22 adults underwent sequential bilateral implantation with at least 6 months between surgeries. The mean age at the time of the second implant in children was 7.83 years, and mean time between implants was 5.16 years. Five children received the first side implant (C1) below 12 months of age; 16, at 12 to 23 months; 9, between the ages of 24 and 35 months; and 11, at 36 to 59 months; 2 were implanted above the age of 5 years. In adults, mean age at second implant was 46.6 years, and mean time between implants was 5.6 years. INTERVENTION: Sequential implantation with 6 months or more between implantations. MAIN OUTCOME MEASURES: Speech perception tests were performed preoperatively before the second implantation and at 3 months postoperatively. RESULTS: Results revealed significant improvement in the second implanted ear and in the bilateral condition, despite time between implantations or length of deafness; however, age of first-side implantation was a contributing factor to second ear outcome in the pediatric population. CONCLUSION: Sequential bilateral implantation leads to significantly better speech understanding. On average, patients improved, despite length of deafness, time between implants, or age at implantation
— id: 79563, year: 2008, vol: 29, page: 314, stat: Journal Article,

The effect of perimodiolar placement on speech perception and frequency discrimination by cochlear implant users
Fitzgerald, Matthew B; Shapiro, William H; McDonald, Paulette D; Neuburger, Heidi S; Ashburn-Reed, Sara; Immerman, Sara; Jethanamest, Daniel; Roland, J Thomas; Svirsky, Mario A
2007 Apr;127(4):378-383, Acta oto-laryngologica
CONCLUSION: Neither speech understanding nor frequency discrimination ability was better in Nucleus Contour users than in Nucleus 24 straight electrode users. Furthermore, perimodiolar electrode placement does not result in better frequency discrimination. OBJECTIVES: We addressed three questions related to perimodiolar electrode placement. First, do patients implanted with the Contour electrode understand speech better than with an otherwise identical device that has a straight electrode? Second, do these groups have different frequency discrimination abilities? Third, is the distance of the electrode from the modiolus related to frequency discrimination ability? SUBJECTS AND METHODS: Contour and straight electrode users were matched on four important variables. We then tested these listeners on CNC word and HINT sentence identification tasks, and on a formant frequency discrimination task. We also examined X-rays and measured the distance of the electrodes from the modiolus to determine whether there is a relationship between this factor and frequency discrimination ability. RESULTS: Both speech understanding and frequency discrimination abilities were similar for listeners implanted with the Contour vs a straight electrode. Furthermore, there was no linear relationship between electrode-modiolus distance and frequency discrimination ability. However, we did note a second-order relationship between these variables, suggesting that frequency discrimination is worse when the electrodes are either too close or too far away from the modiolus
— id: 73408, year: 2007, vol: 127, page: 378, stat: Journal Article,

What matched comparisons can and cannot tell us: the case of cochlear implants
Sagi, Elad; Fitzgerald, Matthew B; Svirsky, Mario A
2007 Aug;28(4):571-579, Ear & hearing
OBJECTIVES: To examine the conclusions and possible misinterpretations that may or may not be drawn from the 'outcome-matching method,' a study design recently used in the cochlear implant literature. In this method, subject groups are matched not only on potentially confounding variables but also on an outcome measure that is closely related to the outcome measure under analysis. For example, subjects may be matched according to their speech perception scores in quiet, and their speech perception in noise is compared. DESIGN: The present study includes two components, a simulation study and a questionnaire. In the simulation study, the outcome-matching method was applied to pseudo-randomly generated data. Simulated speech perception scores in quiet and in noise were generated for two comparison groups, in two imaginary worlds. In both worlds, comparison group A performed only slightly worse in noise than in quiet, whereas comparison group B performed significantly worse in noise than in quiet. In Imaginary World 1, comparison group A had better speech perception scores than comparison group B. In Imaginary World 2, comparison group B had better speech perception scores than comparison group A. The outcome-matching method was applied to these data twice in each imaginary world: 1) matching scores in quiet and comparing in noise, and 2) matching scores in noise and comparing in quiet. This procedure was repeated 10,000 times. The second part of the study was conducted to address the level of misinterpretation that could arise from the outcome-matching method. A questionnaire was administered to 54 students in a senior level course on speech and hearing to assess their opinions about speech perception with two different models of cochlear implant devices. The students were instructed to fill out the questionnaire before and after reading a paper that used the outcome-matching method to examine speech perception in noise and in quiet with those two cochlear implant devices. RESULTS: When pseudorandom scores were matched in quiet, comparison group A's scores in noise were significantly better than comparison group B's scores. Results were different when scores were matched in noise: in this case, comparison group B's scores in quiet were significantly better than comparison group A's scores. Thus, the choice of outcome measure used for matching determined the result of the comparison. Additionally, results of the comparisons were identical regardless of whether they were conducted using data from Imaginary World 1 (where comparison group A is better) or from Imaginary World 2 (where comparison group B is better). After reading the paper that used the outcome-matching method, students' opinions about the two cochlear implants underwent a significant change even though, according to the simulation study, this opinion change was not warranted by the data. CONCLUSIONS: The outcome-matching method can provide important information about differences within a comparison group, but it cannot be used to determine whether a given device or clinical intervention is better than another one. Care must be used when interpreting the results of a study using the outcome-matching method
— id: 73808, year: 2007, vol: 28, page: 571, stat: Journal Article,

Implantes cocleares
Svirsky MA; Suarez H
Ingenieria biomedica, perspectivas desde el Uruguay Montevideo : Publications de la Universidad de la Republica, 2007,
— id: 5004, year: 2007, vol: , page: 283, stat: Chapter,

The effects of age at implantation on speech intelligibility in pediatric cochlear implant users: Clinical outcomes and sensitive periods
Svirsky, Mario A; Chin, Steven B; Jester, Andrea
2007 ;5(4):293-306 May, Audiological Medicine
This study assessed the effects of age at implantation on the speech intelligibility of congenitally, profoundly deaf pediatric cochlear implant users. The children received implants during the first eight years of life and were divided into subgroups based on their age at implantation. The children's tape recordings of standard sentences were digitized and played back to normal-hearing listeners who were unfamiliar with deaf speech. Intelligibility was measured as the number of words correctly identified averaged across all listeners. The data showed that earlier implantation had a positive and significant effect on the speech intelligibility of cochlear implant users. The results also suggested that a gradual decline in the ability to acquire spoken language skills may occur over time and, furthermore, cochlear implantation before the age of two years may yield significantly better speech intelligibility outcomes than later implantation. (journal abstract)
— id: 76395, year: 2007, vol: 5, page: 293, stat: Journal Article,

Customized selection of frequency maps in an acoustic simulation of a cochlear implant
Fitzgerald, Matthew B; Morbiwala, Tasnim A; Svirsky, Mario A
2006 ;1:3596-3599, Conference Proceedings (IEEE Engineering in Medicine & Biology Society)
Cochlear implants can restore hearing to deaf individuals by electrically stimulating the auditory nerve. They do so by assigning different frequencies to different stimulating electrodes via a frequency map. We have developed a device that enables us to change the frequency map in real time. Here, in normal-hearing adults listening to an acoustic simulation of a cochlear implant, we investigate what frequency maps are initially preferred, and how the ability to understand speech with that preferred map compares with two other maps. We show that naive listeners prefer a map that balances the need for low-frequency information with the desire for a naturally-sounding stimulus, and that initial performance with this listener-selected map is better than that with a map that distorts the signal to provide low-frequency information
— id: 94930, year: 2006, vol: 1, page: 3596, stat: Journal Article,

Speech production
Svirsky MA; Chin SB
Cochlear implants New York, Thieme, 2006,
— id: 5003, year: 2006, vol: , page: 167, stat: Chapter,

Effects of a cochlear implant simulation on immediate memory in normal-hearing adults
Burkholder, Rose A; Pisoni, David B; Svirsky, Mario A
2005 Oct;44(10):551-558, International Journal of Audiology
This study assessed the effects of stimulus misidentification and memory processing errors on immediate memory span in 25 normal-hearing adults exposed to degraded auditory input simulating signals provided by a cochlear implant. The identification accuracy of degraded digits in isolation was measured before digit span testing. Forward and backward digit spans were shorter when digits were degraded than when they were normal. Participants' normal digit spans and their accuracy in identifying isolated digits were used to predict digit spans in the degraded speech condition. The observed digit spans in degraded conditions did not differ significantly from predicted digit spans. This suggests that the decrease in memory span is related primarily to misidentification of digits rather than memory processing errors related to cognitive load. These findings provide complementary information to earlier research on auditory memory span of listeners exposed to degraded speech either experimentally or as a consequence of a hearing-impairment
— id: 67953, year: 2005, vol: 44, page: 551, stat: Journal Article,

A PC-based speech processor for cochlear implant fitting that can be adjusted in real-time
Morbiwala, T.A.; Svirsky, M.; El-Sharkway, M.; Rizkalla, M.
2005 ;44(10):1310-1313, Midwest Symposium on Circuits & Systems conference proceedings : MWSCAS
Cochlear implants are electrical prostheses that partially replace the functions of the human ear. They bypass normal hearing operation to directly simulate the auditory nerve with electric current. The input acoustic signal passes through a filter bank and the output of each filter modulates the energy of a stimulation waveform delivered to a different intra-cochlear electrode. This approach attempts to mimic the signal processing that takes place in a normal ear. When fitting a cochlear implant to a patient who has lost his hearing after learning language, one important problem is how to optimize the frequency range of the filter bank This optimization seeks a tradeoff between maximum speech perception and the patient\\\\\\\'s subjective preference. Unfortunately, currently available tools to change the frequency-to-electrode mapping (i.e., the frequencies of the filter bank) are cumbersome to use. In a previous project we developed a real time speech processor for the Nucleus-22 and Nucleus-24 cochlear implants, based on a common PC and additional hardware drivers. The present project involves the development of a similar system that is adjustable in real time. In other words, the patient can modify the frequency-to-electrode map using computer keystrokes, and a visual representation of the frequency range employed by the filter bank is displayed on the monitor. The patient adjusts the frequency range interactively and selects the preferred setting in a much faster way than can be accomplished with commercially available hardware. If successful, this approach may be implemented in the next generation of hardware used to program cochlear implants in the clinic
— id: 97890, year: 2005, vol: 44, page: 1310, stat: Journal Article,

Perceptual learning and nonword repetition using a cochlear implant simulation
Burkholder R; Pisoni D; Svirsky M
2004 Jan 1;1273(10):208-211, International congress series
This study examined the effects of perceptual learning on nonword repetition performance of normal-hearing listeners who were exposed to severely degraded auditory conditions that were designed to simulate the auditory input of a cochlear implant. Twenty normal-hearing adult listeners completed a nonword repetition task using an eight-band, frequency-shifted cochlear implant simulation strategy both before and after training on open- and closed-set word recognition tasks. Feedback was provided during training. The nonword responses obtained from each participant were digitally recorded and played back to normal-hearing listeners. These listeners rated the nonword repetition accuracy in comparison to the original unprocessed target stimuli using a seven-point scale. The mean nonword accuracy ratings were significantly higher for the non words repeated after training than for non words repeated prior to training. These results suggest that the word recognition training tasks encouraged auditory perceptual learning that generalized to novel, nonword auditory stimuli. The present findings also suggest that adaptation and learning from the degraded auditory stimuli produced by a cochlear implant simulation can be achieved even in a difficult perceptual-motor task such as nonword repetition which involves both speech perception and production of an auditory stimulus that lacks any lexical or semantic representation
— id: 133309, year: 2004, vol: 1273, page: 208, stat: Journal Article,

Age at implantation and communicative outcome in pediatric cochlear implant users: Is younger always better?
Holt, RF; Svirsky, MA; Neuburger, H; Miyamoto, RT
2004 ;1273(10):368-371, International congress series
As with any surgery requiring anesthesia, cochlear implantation in the first few years of life carries potential risks, which makes it especially important to assess potential benefits. In this study, we compared speech perception outcomes in children who received cochlear implants in the first, second, third, or fourth year of life. Among the latter three groups of age at implantation, it was found that earlier implantation resulted in spoken word recognition advantages. Speech perception performance of children implanted during the first year of life was similar to that of the children implanted in the second year of life. (c) 2004 Elsevier B.V. All rights reserved
— id: 97891, year: 2004, vol: 1273, page: 368, stat: Journal Article,

Long-term auditory adaptation to a modified peripheral frequency map
Neuburger, H; Silveira, A; Svirsky, M A; Suarez, H; Teoh, Su-Wooi
2004 May;124(4):381-386, Acta oto-laryngologica
OBJECTIVE: Cochlear implants (CIs) attempt to mimic the tonotopicity of the normal ear by stimulating more basal regions of the cochlea in response to higher frequencies. However, there may be a mismatch between the normal place-frequency map and that implemented by a CI. MATERIAL AND METHODS: Aiming to measure this potential mismatch and its changes over time, the present study used a method-of-adjustment procedure where CI users and normal-hearing listeners selected synthetic vowels to match prespecified vowel targets. Data from CI users were obtained longitudinally, starting on the day of initial stimulation and continuing for 2 years. RESULTS: CI users showed a significant amount of initial mismatch with respect to the normal-hearing listeners, but they also showed significant learning and adaptation over time and achieved nearly normal performance after some experience with the CI. CONCLUSION: In general, the adaptation process took several months, suggesting that some CI users may benefit from alternative signal processing or rehabilitation procedures designed to facilitate perceptual learning after cochlear implantation
— id: 67960, year: 2004, vol: 124, page: 381, stat: Journal Article,

New policies aim to minimize potential or actual conflicts of interest
Svirsky, Mario A
2004 Apr;25(2):85-85, Ear & hearing
— id: 67955, year: 2004, vol: 25, page: 85, stat: Journal Article,

Development of language and speech perception in congenitally, profoundly deaf children as a function of age at cochlear implantation
Svirsky, Mario A; Teoh, Su-Wooi; Neuburger, Heidi
2004 Jul-Aug;9(4):224-233, Audiology & neuro-otology
Like any other surgery requiring anesthesia, cochlear implantation in the first few years of life carries potential risks, which makes it important to assess the potential benefits. This study introduces a new method to assess the effect of age at implantation on cochlear implant outcomes: developmental trajectory analysis (DTA). DTA compares curves representing change in an outcome measure over time (i.e. developmental trajectories) for two groups of children that differ along a potentially important independent variable (e.g. age at intervention). This method was used to compare language development and speech perception outcomes in children who received cochlear implants in the second, third or fourth year of life. Within this range of age at implantation, it was found that implantation before the age of 2 resulted in speech perception and language advantages that were significant both from a statistical and a practical point of view. Additionally, the present results are consistent with the existence of a 'sensitive period' for language development, a gradual decline in language acquisition skills as a function of age
— id: 67954, year: 2004, vol: 9, page: 224, stat: Journal Article,

The effect of short-term auditory deprivation on the control of intraoral pressure in pediatric cochlear implant users
Jones, David L; Gao, Sujuan; Svirsky, Mario A
2003 Jun;46(3):658-669, Journal of speech, language, & hearing research
The purpose of this study was to determine whether 2 speech measures (peak intraoral air pressure [IOP] and IOP duration) obtained during the production of intervocalic stops would be altered as a function of the presence or absence of auditory stimulation provided by a cochlear implant (CI). Five pediatric CI users were required to produce repetitions of the words puppy and baby with their CIs turned on. The CIs were then turned off for 1 hr, at which time the speech sample was repeated with the CI still turned off. Seven children with normal hearing formed a comparison group. They were also tested twice, with a 1-hr intermediate interval. IOP and IOP duration were measured for the medial consonant in both auditory conditions. The results show that auditory condition affected peak IOP more so than IOP duration. Peak IOP was greater for /p/ than /b/ with the CI off, but some participants reduced or reversed this contrast when the CI was on. The findings suggest that different speakers with CIs may use different speech production strategies as they learn to use the auditory signal for speech
— id: 67956, year: 2003, vol: 46, page: 658, stat: Journal Article,

Modeling open-set spoken word recognition in postlingually deafened adults after cochlear implantation: some preliminary results with the neighborhood activation model
Meyer, Ted A; Frisch, Stefan A; Pisoni, David B; Miyamoto, Richard T; Svirsky, Mario A
2003 Jul;24(4):612-620, Otology & neurotology
HYPOTHESES: Do cochlear implants provide enough information to allow adult cochlear implant users to understand words in ways that are similar to listeners with acoustic hearing? Can we use a computational model to gain insight into the underlying mechanisms used by cochlear implant users to recognize spoken words? BACKGROUND: The Neighborhood Activation Model has been shown to be a reasonable model of word recognition for listeners with normal hearing. The Neighborhood Activation Model assumes that words are recognized in relation to other similar-sounding words in a listener's lexicon. The probability of correctly identifying a word is based on the phoneme perception probabilities from a listener's closed-set consonant and vowel confusion matrices modified by the relative frequency of occurrence of the target word compared with similar-sounding words (neighbors). Common words with few similar-sounding neighbors are more likely to be selected as responses than less common words with many similar-sounding neighbors. Recent studies have shown that several of the assumptions of the Neighborhood Activation Model also hold true for cochlear implant users. METHODS: Closed-set consonant and vowel confusion matrices were obtained from 26 postlingually deafened adults who use cochlear implants. Confusion matrices were used to represent input errors to the Neighborhood Activation Model. Responses to the different stimuli were then generated by the Neighborhood Activation Model after incorporating the frequency of occurrence counts of the stimuli and their neighbors. Model outputs were compared with obtained performance measures on the Consonant-Vowel Nucleus-Consonant word test. Information transmission analysis was used to assess whether the Neighborhood Activation Model was able to successfully generate and predict word and individual phoneme recognition by cochlear implant users. RESULTS: The Neighborhood Activation Model predicted Consonant-Vowel Nucleus-Consonant test words at levels similar to those correctly identified by the cochlear implant users. The Neighborhood Activation Model also predicted phoneme feature information well. CONCLUSION: The results obtained suggest that the Neighborhood Activation Model provides a reasonable explanation of word recognition by postlingually deafened adults after cochlear implantation. It appears that multichannel cochlear implants give cochlear implant users access to their mental lexicons in a manner that is similar to listeners with acoustic hearing. The lexical properties of the test stimuli used to assess performance are important to spoken-word recognition and should be included in further models of the word recognition process
— id: 67958, year: 2003, vol: 24, page: 612, stat: Journal Article,

Language development in deaf infants following cochlear implantation
Miyamoto, Richard T; Houston, Derek M; Kirk, Karen Iler; Perdew, Amy E; Svirsky, Mario A
2003 Jan;123(2):241-244, Acta oto-laryngologica
OBJECTIVE: To evaluate the benefits of cochlear implantation in infancy and compare them to those obtained in children implanted at a slightly older age. MATERIAL AND METHODS: Using standard language measurement tools, including the Grammatical Analysis of Elicited Language--Presentence Level (GAEL-P) and the Reynell Developmental Language Scales, progress was documented in a child who received a cochlear implant in infancy and compared to that achieved in children implanted at older ages. A new measurement tool, the Visual Habituation Procedure, was used to document early skills and the results were compared to those obtained in normal-hearing infants. RESULTS: By the age of 2 years the subject implanted in infancy achieved scores on the GAEL-P which were nearly equivalent to those achieved at the age of 5 1/2 years by children implanted at later ages. Age-equivalent scores on the Reynell Developmental Language Scales were achieved by the subject implanted in infancy and the ability to discriminate speech patterns was demonstrated using the Visual Habituation Procedure. CONCLUSION: This report demonstrates enhanced language development in an infant who received a cochlear implant at the age of 6 months
— id: 67959, year: 2003, vol: 123, page: 241, stat: Journal Article,

Untitled
Svirsky, MA
2003 ;24(5):351-351, Ear & hearing
— id: 97893, year: 2003, vol: 24, page: 351, stat: Journal Article,

Untitled
Svirsky, MA
2003 ;24(4):259-259, Ear & hearing
— id: 97892, year: 2003, vol: 24, page: 259, stat: Journal Article,

Acoustic and electrical pattern analysis of consonant perceptual cues used by cochlear implant users
Teoh, Su Wooi; Neuburger, Heidi S; Svirsky, Mario A
2003 Sep-Oct;8(5):269-285, Audiology & neuro-otology
It is hypothesized that for postlingually deafened adult cochlear implant (CI) users, a significant source of their perceptual performance variability is attributable to differences in their ability to discriminate the basic perceptual cues that are important in speech recognition. Previous research on 'electric hearing' has identified consistent perceptual cues for vowel recognition. However, the results on consonant perception by CI users are less clear. The primary purpose of this study is to present a quantitative method of evaluating potential 'electric cues' used by CI users in consonant identification. Since the actual input signals to the auditory periphery of CI users are electric in nature, we elected to measure the CI electric discharge patterns in addition to the original acoustic waveforms. The characteristics of the electric discharge patterns in response to intervocalic consonants were quantified and correlated with the dimensions of CI patients' perceptual spaces, which were computed from multidimensional scaling analyses of their consonant confusion matrices. The results agree with most, but not all, commonly accepted acoustic cues used by normal-hearing listeners. The correlation findings also suggest that CI users employ different sets of 'electric cues' in perceiving consonants that differ in their manner of articulation. Specifically, spectral and temporal cues associated with slowly changing formant structures and transitions, and features associated with frication and high-frequency noise, are all highly correlated with the perceptual dimensions of all CI users. However, rapidly changing formant transitions, such as those present in stop consonants, did not appear to play a significant role in consonant recognition by more poorly performing CI subjects. The perceptual results were consistent with our physical findings that the SPEAK coding strategy partially degraded the rapidly changing formant transitions
— id: 67957, year: 2003, vol: 8, page: 269, stat: Journal Article,

Physiologically based analysis of cochlear implant representations
Laflen, J.B.; Talavaoe, T.M.; Thirukkonda, P.M.; Svirsky, M.A.
2002 ;8(5):2078-2079, Proceedings of the Annual International Conference of the IEEE Engineering in Medicine & Biology Society
A method is presented for analyzing cochlear implant stimulations and typical representations used in simulations. Filtered \'white-noise\' bands are modulated using sinusoids, representing differing stimulation channels. These representations, along with their corresponding envelopes, are used to generate neural activation patterns (NAPs), which represent \'normal-hearing\' responses In the auditory nerve to these stimuli. Additionally, NAPs are generated to represent the neural activity induced by cochlear implant stimulation strategies, assuming exponential rolloff from the electrodes. The mean squared error is measured between NAPs both directly, and after compensation for perceptual resolution. Results suggest that the noise-band approximation of the CIS implant signal actually has more in common with the original source than with the implant stimulation patterns
— id: 97894, year: 2002, vol: 8, page: 2078, stat: Journal Article,

Rationale for early cochlear implanation in congenitally deaf children
Miyamoto RT; Kirk KI; Svirsky MA
Cochlear implants : an update The Hague : Kugler, 2002,
— id: 5001, year: 2002, vol: , page: 329, stat: Chapter,

Efecto del implante coclear en el desarrollo linguistico de ninos con hipoacuasia profunda prelocutiva
Svirsky MA
Implantes cocleares Barcelona : Masson, 2002,
— id: 5000, year: 2002, vol: , page: ?, stat: Chapter,

The multidimensional phoneme identification (MPI) model : a new quantitative framework to explain the perception of speech sounds by cochlear implant users
Svirsky MA
Methodes d'evaluation des performances de l'implant cochleaire Bruxelles : Universite libre de Bruxelles. Institut des langues vivantes et de phonetique, 2002,
— id: 5002, year: 2002, vol: , page: 143, stat: Chapter,

Untitled
Svirsky, MA
2002 ;23(3):169-169, Ear & hearing
— id: 97895, year: 2002, vol: 23, page: 169, stat: Journal Article,

Language development in children who are prelingually deaf who have used the SPEAK or CIS stimulation strategies since initial stimulation
Svirsky, MA; Chute, PM; Green, J; Bollard, P; Miyamoto, RT
2002 JAN ;102(4):199-213, Volta review
Children with profound congenital or prelingual deafness encounter significant difficulties in the development of skills in an oral language such as English. Their language development, however, can be accelerated if they receive a cochlear implant-a sensory aid that facilitates language acquisition by providing important auditory information. The present study used the Reynell Developmental Language Scales (RDLS) to assess language skills pre- and postimplant in 44 pediatric cochlear implant users. All users were profoundly to totally deaf, either at birth or before the age of 3 years. They all received cochlear implants before the age of 6 and were programmed with state-of-the-art stimulation strategies (CIS or SPEAK) since the day of initial stimulation. The main finding was that postimplantation language development proceeded at a pace that was not significantly different from normal. Thus, the language gap present at implantation did not increase after children started using the device, as it would if they had not received cochlear implants. Nevertheless, it is important to conduct further studies to determine whether these conclusions apply when other language skills, such as the use of grammar, are measured
— id: 55595, year: 2002, vol: 102, page: 199, stat: Journal Article,

Grammatical morphologic development in pediatric cochlear implant users may be affected by the perceptual prominence of the relevant markers
Svirsky, Mario A; Stallings, Lynne M; Lento, Cara L; Ying, Elizabeth; Leonard, Laurence B
2002 ;189(3):109-12, Annals of otology rhinology & laryngology. Supplement
The goal of this study was to test 2 hypotheses about language development in pediatric cochlear implant (CI) users. The 'language instinct' hypothesis states that children with CIs will develop language in the same sequence as children with normal hearing, but in a delayed fashion. In other words, noun plurals will develop first, and the use of the uncontractible copula and regular past tense will follow. An alternative hypothesis (the 'perceptual prominence' hypothesis) is that the pattern of language development in CI users will be strongly affected by the perceptual prominence of the relevant morphological markers. This hypothesis predicts that the uncontractible copula will develop first, followed by noun plurals, and then by regular past tense. A sentence completion task was used to measure the performance of 9 pediatric CI users and compare it to that of several groups of children with normal hearing. The results from the CI users were consistent with the perceptual prominence hypothesis. In particular, the scores for the copula probe were higher than those for the noun plural probe for 8 of the 9 CI users. This result represents a rather striking inversion with respect to the usual development pattern in children with normal hearing and even in children with specific language impairment. If the perceptual prominence hypothesis receives further support in future studies, clinicians who work in language rehabilitation of CI users may choose to target those aspects of grammar that are less acoustically prominent to these children. In addition, and from a theoretical standpoint, these results suggest that although there may well be an innate language acquisition mechanism, patterns of language development can be strongly affected by the acoustic input. $$:
— id: 97896, year: 2002, vol: 189, page: 109, stat: Journal Article,

Protesis cocleares
Svirsky MA; Loizou PC
La coclea : fisiologica y patologia Montevideo : Ediciones Trilce, 2001,
— id: 5005, year: 2001, vol: , page: 271, stat: Chapter,

Perceptual "vowel spaces" of cochlear implant users: implications for the study of auditory adaptation to spectral shift
Svirsky, M A; Harnsberger, J D; Meyer, T A; Wright, R; Pisoni, D B; Kaiser, A R
2001 May;109(5 Pt 1):2135-2145, Journal of the Acoustical Society of America
Cochlear implant (CI) users differ in their ability to perceive and recognize speech sounds. Two possible reasons for such individual differences may lie in their ability to discriminate formant frequencies or to adapt to the spectrally shifted information presented by cochlear implants, a basalward shift related to the implant's depth of insertion in the cochlea. In the present study, we examined these two alternatives using a method-of-adjustment (MOA) procedure with 330 synthetic vowel stimuli varying in F1 and F2 that were arranged in a two-dimensional grid. Subjects were asked to label the synthetic stimuli that matched ten monophthongal vowels in visually presented words. Subjects then provided goodness ratings for the stimuli they had chosen. The subjects' responses to all ten vowels were used to construct individual perceptual 'vowel spaces.' If CI users fail to adapt completely to the basalward spectral shift, then the formant frequencies of their vowel categories should be shifted lower in both F1 and F2. However, with one exception, no systematic shifts were observed in the vowel spaces of CI users. Instead, the vowel spaces differed from one another in the relative size of their vowel categories. The results suggest that differences in formant frequency discrimination may account for the individual differences in vowel perception observed in cochlear implant users
— id: 67961, year: 2001, vol: 109, page: 2135, stat: Journal Article,

Auditory learning and adaptation after cochlear implantation: a preliminary study of discrimination and labeling of vowel sounds by cochlear implant users
Svirsky, M A; Silveira, A; Suarez, H; Neuburger, H; Lai, T T; Simmons, P M
2001 Jan;121(2):262-265, Acta oto-laryngologica
This study examined two possible reasons underlying longitudinal increases in vowel identification by cochlear implant users: improved labeling of vowel sounds and improved electrode discrimination. The Multidimensional Phoneme Identification (MPI) model was used to obtain ceiling estimates of vowel identification for each subject, given his/her electrode discrimination skills. Vowel identification scores were initially lower than the ceiling estimates, but they gradually approached them over the first few months post-implant. Taken together, the present results suggest that improved labeling is the main mechanism explaining post-implant increases in vowel identification
— id: 67962, year: 2001, vol: 121, page: 262, stat: Journal Article,

Application of the multidimentional phoneme identification (MPI) model to vowel identification in cochlear implant users
Walsh, W.; Svirsky, M.; Kaiser, A.; Neuberger, H.
2001 ;49(1):63A-265, Journal of investigative medicine
— id: 97897, year: 2001, vol: 49, page: 63A, stat: Journal Article,

Using behavioral data to model open-set word recognition and lexical organization by pediatric cochlear implant users
Frisch, S; Meyer, T A; Pisoni, D B; Svirsky, M A; Kirk, K I
2000 Dec;185:60-62, Annals of otology rhinology & laryngology. Supplement
— id: 67964, year: 2000, vol: 185, page: 60, stat: Journal Article,

Using a personal computer to perform real-time signal processing in cochlear implant research
Kaiser AR; Svirsky MA
2000 ;?:?-?, IEEE digital signal processing workshop
— id: 97957, year: 2000, vol: ?, page: ?, stat: Journal Article,

Modeling phoneme and open-set word recognition by cochlear implant users: a preliminary report
Meyer, T A; Frisch, S; Svirsky, M A; Pisoni, D B
2000 ;185(3):68-70, Annals of otology rhinology & laryngology. Supplement
On the basis of the good predictions for phonemes correct, we conclude that closed-set feature identification may successfully predict phoneme identification in an open-set word recognition task. For word recognition, however, the PCM model underpredicted observed performance, and the addition of a mental lexicon (ie, the SPAMR model) was needed for a good match to data averaged across 7 adults with CIs. The predictions for words correct improved with the addition of a lexicon, providing support for the hypothesis that lexical information is used in open-set spoken word recognition by CI users. The perception of words more complex than CNCs is also likely to require lexical knowledge (Frisch et al, this supplement, pp 60-62) In the future, we will use the performance off individual CI users on psychophysical tasks to generate predicted vowel and consonant confusion matrices to be used to predict open-set spoken word recognition. $$:
— id: 97901, year: 2000, vol: 185, page: 68, stat: Journal Article,

Speech perception by children with the Clarion (CIs) or nucleus 22 (SPEAK) cochlear implant or hearing aids
Meyer, T A; Svirsky, M A
2000 ;185(3):49-51, Annals of otology rhinology & laryngology. Supplement
— id: 97900, year: 2000, vol: 185, page: 49, stat: Journal Article,

Longitudinal communication skill acquisition in pediatric cochlear implant recipients
Miyamoto, R T; Kirk, K I; Svirsky, M; Seghal, S
2000 ;57:212-214, Advances in oto-rhino-laryngology
— id: 133308, year: 2000, vol: 57, page: 212, stat: Journal Article,

Aspects of linguistic development affected by cochlear implantation
Robbins AM; Svirsky MA; Miyamoto RT
Cochlear implants New York : Thieme, 2000,
— id: 4997, year: 2000, vol: , page: 284, stat: Chapter,

Assessing the language abilities of pediatric cochlear implant users across a broad range of ages and performance abilities
Stallings, LM; Gao, SJ; Svirsky, MA
2000 ;102(4):215-235, Volta review
This study considers the validity of the Words and Gestures and Words and Sentences portions of the MacArthur Communicative Development Inventories (MCDI) for pediatric cochlear implant users who exceed the age ranges for which these inventories were normed. In Experiment 1, scores on the Words and Gestures measures were compared with scores on behavioral receptive and expressive vocabulary and language measures at preimplantation and again at 6 months postimplantation. Children ranged in age from 17 to 72 months, and results revealed significant correlations (r-values:.38-.80), with the strongest correlations resulting between MCDI measures and raw scores derived using the Reynell Developmental Language Scales (RDLS). Correlations also obtained between the number of words produced reported on the MCDI Words and Gestures inventory and the Peabody Picture Vocabulary Test-Third Edition (PPVT-III). Experiment 2 compared scores on the Words and Sentences measures with the same behavioral receptive and expressive vocabulary and language measures at 12 and 18 months postimplantation. Children ranged in age from 38 months to 67 months, and significant correlations obtained between behavioral measures and Words and Sentences measures assessing word production as well as grammatical ability (r-values:.60-.90). The strong validity findings motivated Experiment 3, in which predictive formulas were developed to predict scores on the RDLS based on scores from the MCDI. These models will allow researchers and clinicians to use a single index to assess the language abilities of a broad range of ages and performance abilities within the pediatric cochlear implant population. $$:
— id: 97898, year: 2000, vol: 102, page: 215, stat: Journal Article,

Speech intelligibility of pediatric cochlear implant users and hearing aid users
Svirsky MA
Cochlear implants New York : Thieme, 2000,
— id: 4998, year: 2000, vol: , page: 312, stat: Chapter,

Speech production
Svirsky MA; Chin SB
Cochlear implants New York : Thieme, 2000,
— id: 4999, year: 2000, vol: , page: 293, stat: Chapter,

A computational model of the identification of speech sounds by cochlear implant users
Svirsky MA; Kaiser AR; Neuberger H; Meyer TA
2000 ;?:?-?, Proceedings of the World Congress on Medical Physics & Biomedical Engineering
— id: 97956, year: 2000, vol: ?, page: ?, stat: Journal Article,

Consonant recognition with the CIS and SPEAK strategies by users of the Nucleus-22 cochlear implant : preliminary results
Svirsky MA; Meyer TA; Basalo S; Simmons PM; Suarez H; Miyamoto RT
2000 ;45(4):146-157, Anales de otorrinolaringologia mexicana
— id: 97949, year: 2000, vol: 45, page: 146, stat: Journal Article,

Commentary on monaural and binaural loudness measures in cochlear implant users with contralateral residual hearing by P. Blamey, G. Dooley, C. James, and E. Parisi
Svirsky, M A
2000 Feb;21(1):5-5, Ear & hearing
— id: 67968, year: 2000, vol: 21, page: 5, stat: Journal Article,

Language development in children with profound and prelingual hearing loss, without cochlear implants
Svirsky, M A
2000 ;185(3):99-100, Annals of otology rhinology & laryngology. Supplement
— id: 97902, year: 2000, vol: 185, page: 99, stat: Journal Article,

Mathematical modeling of vowel perception by users of analog multichannel cochlear implants: temporal and channel-amplitude cues
Svirsky, M A
2000 Mar;107(3):1521-1529, Journal of the Acoustical Society of America
A 'multidimensional phoneme identification' (MPI) model is proposed to account for vowel perception by cochlear implant users. A multidimensional extension of the Durlach-Braida model of intensity perception, this model incorporates an internal noise model and a decision model to account separately for errors due to poor sensitivity and response bias. The MPI model provides a complete quantitative description of how listeners encode and combine acoustic cues, and how they use this information to determine which sound they heard. Thus, it allows for testing specific hypotheses about phoneme identification in a very stringent fashion. As an example of the model's application, vowel identification matrices obtained with synthetic speech stimuli (including 'conflicting cue' conditions [Dorman et al., J. Acoust. Soc. Am. 92, 3428-3432 (1992)] were examined. The listeners were users of the 'compressed-analog' stimulation strategy, which filters the speech spectrum into four partly overlapping frequency bands and delivers each signal to one of four electrodes in the cochlea. It was found that a simple model incorporating one temporal cue (i.e., an acoustic cue based only on the time waveforms delivered to the most basal channel) and spectral cues (based on the distribution of amplitudes among channels) can be quite successful in explaining listener responses. The new approach represented by the MPI model may be used to obtain useful insights about speech perception by cochlear implant users in particular, and by all kinds of listeners in general
— id: 67967, year: 2000, vol: 107, page: 1521, stat: Journal Article,

The cochlear implant field is slowly approaching the time when electrophysiologic measures will be widely used in cochlear implant fitting
Svirsky, M A
2000 Apr;21(2):84-84, Ear & hearing
— id: 67966, year: 2000, vol: 21, page: 84, stat: Journal Article,

Language development in profoundly deaf children with cochlear implants
Svirsky, M A; Robbins, A M; Kirk, K I; Pisoni, D B; Miyamoto, R T
2000 Mar;11(2):153-158, Psychological science
Although cochlear implants improve the ability of profoundly deaf children to understand speech, critics claim that the published literature does not document even a single case of a child who has developed a linguistic system based on input from an implant. Thus, it is of clinical and scientific importance to determine whether cochlear implants facilitate the development of English language skills. The English language skills of prelingually deaf children with cochlear implants were measured before and after implantation. We found that the rate of language development after implantation exceeded that expected from unimplanted deaf children (p < .001) and was similar to that of children with normal hearing. Despite a large amount of individual variability, the best performers in the implanted group seem to be developing an oral linguistic system based largely on auditory input obtained from a cochlear implant
— id: 67963, year: 2000, vol: 11, page: 153, stat: Journal Article,

Speech intelligibility of prelingually deaf children with multichannel cochlear implants
Svirsky, M A; Sloan, R B; Caldwell, M; Miyamoto, R T
2000 Dec;185:123-125, Annals of otology rhinology & laryngology. Supplement
— id: 67965, year: 2000, vol: 185, page: 123, stat: Journal Article,

Speech intelligibility of profoundly deaf pediatric hearing aid users
Svirsky, MA; Chin, SB; Miyamoto, RT; Sloan, RB; Caldwell, MD
2000 ;102(4):175-198, Volta review
This study examined the speech intelligibility of profoundly, prelingually or congenitally deaf children who use hearing aids. Children were 1-15 years old and they were classified into subgroups according to residual hearing (pure-tone averages [PTAs] between 90 and 100 dB HL, 100 and 110 dB HL, or greater than 110 dB HL) and communication mode (either oral or Total Communication [TC]). They read lists of standard sentences which were played back to panels of three naive listeners who were not familiar with the speech of the deaf and who did not know to which subgroup the children belonged. The data revealed a strong significant trend toward higher intelligibility for children with more residual hearing, and a significant trend toward higher intelligibility for users of oral communication than for those who used Total Communication. However, the latter trend was much more pronounced for some ranges of residual hearing than for others, and it may have been partly due to a sampling effect. A third trend showed significantly higher intelligibility levels at older ages, but this was particularly pronounced for children with PTAs between 90 and 100 dB HL, and for the majority of oral communication users (and only a few Total Communication users) with PTAs between 100 and 110 dB HL. These results suggest that the amount of residual hearing (possibly in interaction with the communication mode used by the child) may be an important factor in the development of intelligible speech. $$:
— id: 97899, year: 2000, vol: 102, page: 175, stat: Journal Article,

Vowel identification and pitch perception by cochlear implant users
Lai, TT; Svirsky, MA; Meyer, TA; Kaiser, AR; Basalo, S; Silveira, A; Suarez, H; Simmons, PM; Miyamoto, RT
1999 ;47(2):79A-79A, Journal of investigative medicine
— id: 97903, year: 1999, vol: 47, page: 79A, stat: Journal Article,

Communication skills in pediatric cochlear implant recipients
Miyamoto, R T; Kirk, K I; Svirsky, M A; Sehgal, S T
1999 Mar;119(2):219-224, Acta oto-laryngologica
Detailed longitudinal studies of speech perception, speech production and language acquisition have justified a significant change in the demographics of congenitally and prelingually deaf children who receive cochlear implants. A trend toward earlier cochlear implantation has been justified by improvements in measures assessing these areas. To assess the influence of age at implantation on performance, age 5 years was used as a benchmark. Thirty-one children who received a Nucleus cochlear implant and use the SPEAK speech processing strategy and two children who received a Clarion cochlear implant and use the CIS strategy served as subjects. The subjects were divided into three groups based on age at implantation. The groups comprised children implanted before the age of 3 years (n = 14), children implanted between 3 years and 3 years 11 months (n = 11) and those implanted between 4 years and 5 years 3 months (n = 8). The children were further divided according to whether they used oral or total communication. The earlier-implanted groups demonstrated statistically significant improvements on measures of speech perception. Improvements in speech intelligibility as a function of age at implant were seen but did not reach statistical significance. The results of the present study demonstrate that early implantation promotes the acquisition of speaking and listening skills
— id: 67969, year: 1999, vol: 119, page: 219, stat: Journal Article,

Enhancement of language performance in children with cochlear implants
Robbins AM; Svirsky MA; Kirk KI; Miyamoto RT; Bollard P; Green J
Reports from the International Conference on Language Development in Cochlear Implanted Children : Lyon, France, December 8 - 9, 1996 Amsterdam : Elsevier, 1999,
— id: 5012, year: 1999, vol: , page: ?, stat: Chapter,

Changes in the cerebral blood flow in postlingual cochlear implant users
Suarez, H; Mut, F; Lago, G; Silveira, A; De Bellis, C; Velluti, R; Pedemonte, M; Svirsky, M
1999 ;119(2):239-243, Acta oto-laryngologica
Five postlingually deaf patients (age range 28-58 years) with multichannel cochlear implants were examined with single photon emission tomography (SPECT) (triple-head rotating gamma camera). Changes in the regional cerebral blood how (rCBF) after intravenous administration of technetium-99m ethyl cysteinate dimer (Tc-99m ECD) were assessed through a stimulation paradigm, consisting of. ij click stimuli (75 dB SPL) in the ear that was to be implanted, 2 weeks before surgery; iii stimulation with the same click, one month after initial fitting. iii) stimulation with hearing sequential Spanish sentences one month after initial fitting. The results showed a significant increase in the rCBF in the primary left auditory area and in the right auditory cortex, in conditions iii and iii). The rCBF also showed a significant asymmetrical increase in the frontal lobes when the patient was hearing sequential sentences (condition iiii) with asymmetrical distribution among patients. These results are discussed, principally the correlation between speech discrimination scores and the rCBF distribution in the frontal and temporal lobes. $$:
— id: 97904, year: 1999, vol: 119, page: 239, stat: Journal Article,

Comparison of speech perception in pediatric CLARION cochlear implant and hearing aid users
Svirsky, M A; Meyer, T A
1999 Apr;177:104-109, Annals of otology rhinology & laryngology. Supplement
Multichannel cochlear implants (CIs) allow many profoundly deaf children to achieve high levels of speech perception. In order to develop optimal criteria for implantation, it is crucial to test representative samples (or, if possible, full populations) of CI users and compare their results to those of hearing aid (HA) users of the same age and communication mode (oral or total communication) to determine which subgroups of HA users may obtain more perceptual benefit from a CI than from an HA. Word and phoneme identification skills of deaf children who use either HAs or CIs were evaluated and compared. The CI group included all of the prelingually deaf children in the United States who were implanted with the CLARION Multi-Strategy Cochlear Implant during the clinical trial (as of January 1998). Before implantation, the mean scores on the PB-K test (scored phonemically) were lower for prospective CI users than for HA users. However, by 12 to 18 months postimplantation, the average scores for the CI users were higher than those of HA users with residual hearing in the 101- to 110-dB hearing level (HL) range. The CI scores were similar to those of HA users with residual hearing in the 90- to 100-dB HL range
— id: 67970, year: 1999, vol: 177, page: 104, stat: Journal Article,

Improvements in speech perception by children with profound prelingual hearing loss: effects of device, communication mode, and chronological age
Meyer, T A; Svirsky, M A; Kirk, K I; Miyamoto, R T
1998 Aug;41(4):846-858, Journal of speech, language, & hearing research
The present investigation expanded on an earlier study by Miyamoto, Osberger, Todd, Robbins, Karasek, et al. (1994) who compared the speech perception skills of two groups of children with profound prelingual hearing loss. The first group had received the Nucleus multichannel cochlear implant and was tested longitudinally. The second group, who were not implanted and used conventional hearing aids, was tested at a single point in time. In the present study, speech perception scores were examined over time for both groups of children as a function of communication mode of the child. Separate linear regressions of speech perception scores as a function of age were computed to estimate the rate of improvement in speech perception abilities that might be expected due to maturation for the hearing aid users (n=58) within each communication mode. The resulting regression lines were used to compare the estimated rate of speech perception growth for each hearing aid group to the observed gains in speech perception made by the children with multichannel cochlear implants. A large number of children using cochlear implants (n=74) were tested over a long period of implant use (m=3.5 years) that ranged from zero to 8.5 years. In general, speech perception scores for the children using cochlear implants were higher than those predicted for a group of children with 101-110 dB HL of hearing loss using hearing aids, and they approached the scores predicted for a group of children with 90-100 dB HL of hearing loss using hearing aids
— id: 67972, year: 1998, vol: 41, page: 846, stat: Journal Article,

Beyond the audiogram : the role of functional assessments
Robbins AM; Svirsky MA; Osberger MJ; Pisoni DB
Children with hearing impairment : contemporary trends Nashville TN : Vanderbilt Bill Wilkerson Center Press, 1998,
— id: 5006, year: 1998, vol: , page: 105, stat: Chapter,

Imitative consonant feature production by children with multichannel sensory aids
Sehgal, ST; Kirk, KI; Svirsky, M; Ertmer, DJ; Osberger, MJ
1998 ;19(1):72-84, Ear & hearing
Objective: To examine changes over time in consonant feature production by children with profound hearing impairments who used either the Nucleus multichannel cochlear implant or the multichannel vibrotactile aid, Tactaid 7. Design: Imitative consonant productions of children with prelingual deafness were elicited and transcribed at two intervals: 1) before receiving their respective devices (predevice interval), and 2) after an average of 1.5 yr of device use (postdevice interval), The consonant productions were analyzed in terms of the percentage of consonant features (manner, place, and voicing) produced by the child that matched the features of the examiner's target, The percentage of features produced correctly was then averaged across repetitions, vowel environments, and participants within each group. Results: At the predevice interval, the cochlear implant and Tactaid 7 participants demonstrated similar imitative consonant production abilities After an average of 1.5 yr of device use, the cochlear implant participants demonstrated significantly greater gains than did the Tactaid 7 participants for the features of voicing and place of articulation, Although the cochlear implant participants showed a trend towards better production of the consonant manner features, this difference failed to reach significance, Conclusions: The current results suggest that the use of a multichannel sensory aid yields improvements in consonant feature production. Furthermore, use of a cochlear implant appears to promote the production of consonant voicing and place features to a greater degree than does time use of a multichannel tactile aid. $$:
— id: 97905, year: 1998, vol: 19, page: 72, stat: Journal Article,

The effects of processor strategy on the speech perception performance of pediatric nucleus multichannel cochlear implant users
Sehgal, ST; Kirk, KI; Svirsky, M; Miyamoto, RT
1998 ;19(2):149-161, Ear & hearing
Objective: The present investigation examined the speech perception skills of pediatric cochlear implant users who changed from their original speech processors and strategies to the Spectral Peak (SPEAK) strategy. Design: A within-subjects design was used to compare individual subject's performance using the SPEAK strategy with that obtained with their previous speech strategy (FOF1F2 or Multipeak) in this retrospective study. The subjects demonstrated a wide range of perceptual abilities and had used a cochlear implant for varying lengths of time before converting to the SPEAK. strategy. Results: Nine of the 11 subjects showed significant improvement on at least one of the open-set word recognition measures, whereas two subjects showed no change on any of the open-set measures when using the SPEAK strategy. Conclusions: The present results suggest that the majority of pediatric cochlear implant users are likely to show improved speech perception performance when converting to the new SPEAK processing strategy. $$:
— id: 97906, year: 1998, vol: 19, page: 149, stat: Journal Article,

Sprachverstandlichkeit von Kindern mit Cochlear-Implantaten under Horgeraten
Svirsky MA
Horen, Verstehen, Kommunizieren. Friedberger Cochlear-Implant Symposium, Friedberg/Hessen, 4.-6. Juni 1998 [S.l.] : Niddatal Verein zur Forderung Horgeschadigter, 1998,
— id: 5009, year: 1998, vol: , page: 350, stat: Chapter,

A mathematical model of consonant perception in adult cochlear implant users with the SPEAK strategy
Svirsky MA; Meyer TA
16th International Congress on Acoustics and 135th Meeting Acoustical Society of America : the sound of the future : a global view of acoustics in the 21st century Woodbury NY : Acoustical Society of America, 1998,
— id: 5007, year: 1998, vol: 3, page: 1981, stat: Chapter,

The effect of auditory feedback on the control of oral-nasal balance by pediatric cochlear implant users
Svirsky, M A; Jones, D; Osberger, M J; Miyamoto, R T
1998 Oct;19(5):385-393, Ear & hearing
OBJECTIVE: This study examined the control of oral-nasal balance by pediatric cochlear implant (CI) users, with and without auditory feedback. DESIGN: Five CI users read lists of sentences in two conditions: with their devices on and with their devices off. Their oral-nasal balance (ratio of energy radiated from the oral and nasal cavities) was measured in both conditions and compared with values obtained from children with normal hearing. RESULTS: CI users showed different patterns of abnormal oral-nasal balance with their devices off, but they generally achieved values that were closer to normal when their devices were on. CONCLUSIONS: The results suggest that children with CIs use the auditory signal provided by their device to improve their control of nasalization. It is also possible that at least part of the changes in oral-nasal balance were driven by changes in related articulatory parameters
— id: 67971, year: 1998, vol: 19, page: 385, stat: Journal Article,

Changes in sound pressure and fundamental frequency contours following changes in hearing status
Lane, H; Wozniak, J; Matthies, M; Svirsky, M; Perkell, J; O'Connell, M; Manzella, J
1997 Apr;101(4):2244-2252, Journal of the Acoustical Society of America
Sound-pressure level (SPL) and fundamental frequency (F0) contours were obtained from four postlingually deafened adults who received cochlear implants and from a subject with Neurofibromatosis-2 (NF2) who had her hearing severely reduced following surgery to remove an auditory-nerve tumor and to implant an auditory brainstem implant. SPL and F0 contours for each phrase in passages read before and after changes in hearing were averaged over repeated readings and then normalized with respect to the highest SPL or F0 value in the contour. The regularity of each average contour was measured by calculating differences between successive syllable means and averaging the absolute values of these differences. With auditory feedback made available, the cochlear implant user with the least contour variation preimplant showed no change but all of the remaining speakers produced less variable F0 contours and three also produced less variable SPL contours. In complementary fashion, when the NF2 speaker had her auditory feedback severely reduced, she produced more variable F0 and SPL contours. The results are interpreted as supporting a dual-process theory of the role of auditory feedback in speech production, according to which one role of self-hearing is to monitor transmission conditions, leading the speaker to make changes in speech postures aimed at maintaining intelligibility
— id: 97942, year: 1997, vol: 101, page: 2244, stat: Journal Article,

Cochlear implant reimplantation
Miyamoto, R T; Svirsky, M A; Myres, W A; Kirk, K I; Schulte, J
1997 Nov;18(6 Suppl):S60-S61, American journal of otology
The objective of this study was to determine whether insertion length and number of active channels remained the same after reimplantation of a cochlear implant. A retrospective case review of 170 consecutively implanted multichannedl cochlear implants was conducted. Seventeen of these devices had to be replaced. Data were analyzed for the Nucleus cochlear implant users who were reimplanted in the same ear. For most subjects, insertion length and number of channels remained unchanged, but a few subjects experienced substantial decreases. When the whole group was considered, a small but statistically significant drop was noted for both parameters. In conclusion, although reimplantation is technically possible, the first procedure provides the optimal surgical environment
— id: 67973, year: 1997, vol: 18, page: S60, stat: Journal Article,

Enhancement of expressive language in prelingually deaf children with cochlear implants
Miyamoto, R T; Svirsky, M A; Robbins, A M
1997 Mar;117(2):154-157, Acta oto-laryngologica
Expressive language skills were assessed in two groups of prelingually-deafened children using the Reynell Developmental Language Scales (RDLS). Results from a group of 89 unimplanted subjects provided cross-sectional data which suggested that profoundly deaf children without implants, on average, could only be expected to make 5 months of expressive language growth in one year. Twenty-three children who received cochlear implants made up the second group of subjects and were administered the RDLS at three intervals: preimplant, 6-, and 12-months postimplant. The scores obtained at the post-implant intervals were then compared to scores that would be predicted on the basis of maturation alone, without the implant (these predictions were formulated based on the data obtained from the unimplanted subjects). At the 12-month postimplant interval, the observed mean language score was significantly higher than the predicted score. Although the mean group data were extremely encouraging, wide inter- subject variability was observed. Although the implant subjects, as a group, were substantially delayed compared with their normal hearing peers, their rate of language growth was found to match that of hearing peers, following implantation. Thus, the gap between chronological age and language age, which normally widens over time in deaf children, remained constant. Preliminary analyses over the first 2.5 years post-implant are consistent with this trend. These results suggest that early implantation (before age 3) might be beneficial to profoundly deaf children because the language delays at the time of implantation would be much smaller
— id: 67975, year: 1997, vol: 117, page: 154, stat: Journal Article,

Speech intelligibility of children with multichannel cochlear implants
Miyamoto, R T; Svirsky, M; Kirk, K I; Robbins, A M; Todd, S; Riley, A
1997 ;168(5):35-6, Annals of otology rhinology & laryngology. Supplement
The purpose of this longitudinal study is to document improvements in speech intelligibility in children who have received multichannel cochlear implants, to compare their performance to that of a matched group of children with different levels of hearing loss who use conventional hearing aids. Speech intelligibility was measured by panels of listeners who analyzed recorded speech samples preimplant and at 6-month intervals following implantation. The results of this study demonstrate that prelingually deafened children with the Nucleus multichannel cochlear implant achieved significant improvements in speech intelligibility. By the 4.5- to 7.5-year intervals, the speech intelligibility exceeded 40%. $$:
— id: 97907, year: 1997, vol: 168, page: 35, stat: Journal Article,

Der verlauf der Sprachentwicklung bei Kindern mit einem Cochlear-Implant
Robbins AM; Svirsky MA; Miyamoto RT
Aktuelle Aspekte der Indikation, Rehabilitation und Technik : 3. Friderger Cochlear-Implant-Symposium, Friedberg/Hessen 13.-14. Juni 1997 [S.l.] : Niddatal Verein zur Forderung Horgeschadigter e.V., 1997,
— id: 5008, year: 1997, vol: , page: 126, stat: Chapter,

Children with implants can speak, but can they communicate?
Robbins, A M; Svirsky, M; Kirk, K I
1997 Sep;117(3 Pt 1):155-160, Otolaryngology, head & neck surgery
English-language skills were evaluated in two groups of profoundly hearing-impaired children with the Reynell Developmental Language Scales, Revised. The first group consisted of 89 deaf children who had not received cochlear implants. The second group consisted of 23 children wearing Nucleus multichannel cochlear implants. The subjects without implants provided cross-sectional language data used to estimate the amount of language gains expected on the basis of maturation. The Reynell data from the group without implants were subjected to a regression by age. On the basis of this analysis, deaf children were predicted to make half or less of the language gains of their peers with normal hearing. Predicted language scores were then generated for the subjects with implants by using the children's preimplant Reynell Developmental Language Scale scores. The predicted scores were then compared with actual scores achieved by the subjects with implants 6 and 12 months after implantation. Twelve months after implantation, the subjects demonstrated gains in receptive and expressive language skills that exceeded by 7 months the predictions made on the basis of maturation alone. Moreover, the average language-development rate of the subjects with implants in the first year of device use was equivalent to that of children with normal hearing. These effects were observed for children with implants using both the oral and total-communication methods
— id: 97941, year: 1997, vol: 117, page: 155, stat: Journal Article,

Vibrotactile aid and brain cortical activity
Suarez, H; Cibils, D; Caffa, C; Silveira, A; Basalo, S; Svirsky, M
1997 ;117(2):208-210, Acta oto-laryngologica
Six profoundly deaf patients were studied with mapping evoked potentials (MEP) using an acoustic signal passed through the vibrotactile prosthesis. This stimulus produced an activation of the central sulcus brain cortex. When the prothesis was placed in the presternal area it showed N1 P1 potentials with higher voltage and a more defined cortical dipole inversion than when the prosthesis was placed in the arm or abdomen: thus the presternal stimulation is considered an adequate place for the use of vibrotactile stimulation. The MEP were recorded in 2 patients after a period of audiological training and they showed new earlier potentials. These suggest plastic changes in the processing of an acoustic signal sent from the presternal skin by the somatosensory pathway after training and involving learning procedures. $$:
— id: 97908, year: 1997, vol: 117, page: 208, stat: Journal Article,

Tongue surface displacement during bilabial stops
Svirsky, M A; Stevens, K N; Matthies, M L; Manzella, J; Perkell, J S; Wilhelms-Tricarico, R
1997 Jul;102(1):562-571, Journal of the Acoustical Society of America
The goals of this study were to characterize tongue surface displacement during production of bilabial stops and to refine current estimates of vocal-tract wall impedance using direct measurements of displacement in the vocal tract during closure. In addition, evidence was obtained to test the competing claims of passive and active enlargement of the vocal tract during voicing. Tongue displacement was measured and tongue compliance was estimated in four subjects during production of /aba/ and /apa/. All subjects showed more tongue displacement during /aba/ than during /apa/, even though peak intraoral pressure is lower for /aba/. In consequence, compliance estimates were much higher for /aba/, ranging from 5.1 to 8.5 x 10(-5) cm3/dyn. Compliance values for /apa/ ranged from 0.8 to 2.3 x 10(-5) cm3/dyn for the tongue body, and 0.52 x 10(-5) for the single tongue tip point that was measured. From combined analyses of tongue displacement and intraoral pressure waveforms for one subject, it was concluded that smaller tongue displacements for /p/ than for /b/ may be due to active stiffening of the tongue during /p/, or to intentional relaxation of tongue muscles during /b/ (in conjunction with active tongue displacement during /b/)
— id: 67974, year: 1997, vol: 102, page: 562, stat: Journal Article,

Acoustic and articulatory measures of sibilant production with and without auditory feedback from a cochlear implant
Matthies, M L; Svirsky, M; Perkell, J; Lane, H
1996 Oct;39(5):936-946, Journal of speech & hearing research
The articulator positions of a subject with a cochlear implant were measured with an electromagnetic midsagittal articulometer (EMMA) system with and without auditory feedback available to the subject via his implant. Acoustic analysis of sibilant productions included specific measures of their spectral properties as well as the F3 formant amplitude. More general postural characteristics of the utterances, such as speech rate and sound level, were measured as well. Because of the mechanical and aerodynamic interdependence of the articulators, the postural variables must be considered before attributing speech improvement to the selective correction of a phonemic target with the use of auditory feedback. The tongue blade position was related to the shape and central tendency of the /integral of/ spectra; however, changes in the spectral contrast between /s/ and /integral of/ were not related to changes in the more general postural variables of rate and sound level. These findings suggest that the cochlear implant is providing this subject with important auditory cues that he can use to monitor his speech and maintain the phonemic contrast between /s/ and /integral of/
— id: 97943, year: 1996, vol: 39, page: 936, stat: Journal Article,

Goal-based speech motor control : a theoretical framework and some preliminary data
Perkell JS; Matthies ML; Svirsky MA; Jordan MI
Disorders of motor speech : assessment, treatment, and clinical characterization Baltimore : Brookes Pub, 1996,
— id: 4996, year: 1996, vol: , page: 27, stat: Chapter,

Phonemic resetting versus postural adjustments in the speech of cochlear implant users: an exploration of voice-onset time
Lane, H; Wozniak, J; Matthies, M; Svirsky, M; Perkell, J
1995 Dec;98(6):3096-3106, Journal of the Acoustical Society of America
Voice-onset time (VOT) was measured in plosive-initial syllables uttered by five cochlear implant users prior to and repeatedly at intervals after activation of their speech processors. In 'short-term' experiments, the elicitation set was read after the subject's processor has been off for 24 h, then turned on them off again. Four out of five implant users increased voiceless and/or voiced VOTc (VOT corrected for changes in syllable duration) from preimplant baselines to final recordings made 1-3 years later. Measured acoustic correlates of speech 'posture' (average SPL, F0, and low-frequency spectral slope) changed concurrently. Results in the short-term study were largely consistent with the long term. Significant multiple regressions relating changes in VOTc to accompanying changes in postural correlates were found in both studies. This outcome is consistent with hypotheses that predict changes in both VOTc and in postural correlates with the restoration of some hearing and that allow for linkages between the two. Some of the reliable VOTc increases obtained over the long term that were not correlated with postural changes may have been caused directly by auditory validation of articulatory/acoustic relations that underlie synergisms for phoneme production
— id: 97944, year: 1995, vol: 98, page: 3096, stat: Journal Article,

Changes in speech production following hearing loss due to bilateral acoutic neuromas
Perkell JS; Manzella J; Wozniak J; Mathies M; Lane H; Svirsky M; Guiod P; Delhorne L; Short P; MacCollin M; Mitchell C
Proceedings of the XIIIth International Congress of Phonetic Sciences : ICPhS 95 ; Stockholm, Sweden, 13-19 August 1995 Stockholm : Published by the Congress organisers at KTH and Stockholm University, 1995,
— id: 5011, year: 1995, vol: 3, page: 194, stat: Chapter,

GOAL-BASED SPEECH MOTOR CONTROL - A THEORETICAL FRAMEWORK AND SOME PRELIMINARY DATA
PERKELL, JS; MATTHIES, ML; SVIRSKY, MA; JORDAN, MI
1995 ;23(1-2):23-35, Journal of phonetics
A theoretical framework for the segmental component of speech production is outlined and some preliminary supporting data are reviewed. According to the framework, articulatory movements are programmed to achieve sequences of goals that are defined in terms of articulatory and acoustic parameters. The goals are correlates of distinctive features. Some feature correlates are determined by quantal (non-linear) relations between articulation and sound. Goals may also be influenced by other principles, such as a compromise between sufficient perceptual contrast and economy of articulatory effort, which leads to the prediction that the goal definitions correspond to regions (as opposed to points) in acoustic and articulatory space. Thus the goals are characterized by some parameter variation, which is possible partly because listeners can understand variable speech. Before utterances are produced, goal specifications are modified by prosodic influences and reduction. The sequence of modified goal specifications is converted to smooth, appropriately-timed articulatory movements by the speech motor control system. This control and the resulting kinematics are constrained in part by the biomechanical properties of the articulators. To help keep acoustic variability within perceptually-acceptable limits, speech motor control mechanisms may include a strategy by which different parts of the vocal-tract area function are adjusted in a complementary (''motor equivalent'') manner. The strategy takes advantage of the fact that for some sounds, a similar acoustic transfer function can be achieved with somewhat different area functions. The existence of such a strategy and the idea that speech motor programming is based in part on acoustic goals are supported by data that show trading relations between lip rounding and tongue-body raising in production of the vowel /u/. $$:
— id: 97909, year: 1995, vol: 23, page: 23, stat: Journal Article,

A preliminary study of the effects of cochlear implants on the production of sibilants
Matthies, M L; Svirsky, M A; Lane, H L; Perkell, J S
1994 Sep;96(3):1367-1373, Journal of the Acoustical Society of America
The potential influence of auditory information in the production of /s/ and /integral of/ was explored for postlingually deafened adults with four-channel Ineraid cochlear implants. Analyses of the spectra of the sibilant sounds were compared for speech obtained prior to implant activation, after early implant use and after 6 months of use. In addition, the output of the Ineraid device (measured at each of the four electrodes) was analyzed with pre- and postactivation speech samples to explore whether the speech production changes were potentially audible to the cochlear-implant user. Results indicated that subjects who showed abnormally low or incorrect contrast between /s/ and /integral of/ preactivation, and who received significant auditory benefit from their implants were able to increase the distinctiveness of their productions of the two speech sounds
— id: 67976, year: 1994, vol: 96, page: 1367, stat: Journal Article,

On the use of electro-magnetic midsagittal anticulometer (EMMA) systems
Perkell JM; Svirsky MA; Matthies M; Manzella J
1993 ;31:29-42, Forschungsberichte (Universistat Munchen. Institut for Phonetik & Sprachliche Kommmunikation)
— id: 97948, year: 1993, vol: 31, page: 29, stat: Journal Article,

Trading relations between tongue-body raising and lip rounding in production of the vowel /u/: a pilot "motor equivalence" study
Perkell, J S; Matthies, M L; Svirsky, M A; Jordan, M I
1993 May;93(5):2948-2961, Journal of the Acoustical Society of America
Articulatory and acoustic data were used to explore the following hypothesis for the vowel /u/: The objective of articulatory movements is an acoustic goal; varying and reciprocal contributions of different articulators may help to constrain acoustic variation in achieving the goal. Previous articulatory studies of similar hypotheses, expressed entirely in articulatory terms, have been confounded by interdependencies of the variables being studied (e.g., lip and mandible displacements). One case in which this problem may be minimized is that of lip rounding and tongue-body raising (formation of a velo-palatal constriction) for the vowel /u/. Lip rounding and tongue-body raising should have similar acoustic effects for /u/, mainly to lower F2. In multiple repetitions, reciprocal contributions of lip rounding and tongue-body raising could help limit F2 variability for /u/; thus this experiment looked for complementary covariation (negative correlations) in measures of these two parameters. An electro-magnetic midsagittal articulometer (EMMA) was used to track movements of midsagittal points on the tongue body, upper and lower lips, and mandible for large numbers of repetitions of utterances containing /u/. (Interpretation of the data was aided by results from area-function-to-formant modeling.) Three of four subjects showed weak negative correlations, tentatively supporting the hypothesis; a fourth showed the opposite pattern: positive correlations of lip rounding and tongue raising. The results are discussed with respect to ideas about motor equivalence, the nature of speech motor programming, and potential improvements to the paradigm
— id: 67977, year: 1993, vol: 93, page: 2948, stat: Journal Article,

Measuring articulatory movements with an electromagnetic midsagittal articulometer (EMMA) system
Svirsky MA
Measuring speech production Woodbury NY : Acoustical Society of America, 1993,
— id: 5013, year: 1993, vol: , page: ?, stat: Chapter,

Electromagnetic midsagittal articulometer systems for transducing speech articulatory movements
Perkell, J S; Cohen, M H; Svirsky, M A; Matthies, M L; Garabieta, I; Jackson, M T
1992 Dec;92(6):3078-3096, Journal of the Acoustical Society of America
This paper describes two electromagnetic midsagittal articulometer (EMMA) systems that were developed for transducing articulatory movements during speech production. Alternating magnetic fields are generated by transmitter coils that are mounted in an assembly that fits on the head of a speaker. The fields induce alternating voltages in a number of small transducer coils that are attached to articulators in the midline plane, inside and outside the vocal tract. The transducers are connected by fine lead wires to receiver electronics whose output voltages are processed to yield measures of transducer locations as a function of time. Measurement error can arise with this method, because as the articulators move and change shape, the transducers can undergo a varying amount of rotational misalignment with respect to the transmitter axes; both systems are designed to correct for transducer misalignment. For this purpose, one system uses two transmitters and biaxial transducers; the other uses three transmitters and single-axis transducers. The systems have been compared with one another in terms of their performance, human subjects compatibility, and ease of use. Both systems can produce useful midsagittal-plane data on articular movement, and each one has a specific set of advantages and limitations. (Two commercially available systems are also described briefly for comparison purposes). If appropriate experimental controls are used, the three-transmitter system is preferable for practical reasons
— id: 67978, year: 1992, vol: 92, page: 3078, stat: Journal Article,

Speech of cochlear implant patients: a longitudinal study of vowel production
Perkell, J; Lane, H; Svirsky, M; Webster, J
1992 May;91(5):2961-2978, Journal of the Acoustical Society of America
Acoustic parameters were measured for vowels spoken in /hVd/ context by four postlingually deafened recipients of multichannel (Ineraid) cochlear implants. Three of the subjects became totally deaf in adulthood after varying periods of partial hearing loss; the fourth became totally deaf at age four. The subjects received different degrees of perceptual benefit from the prosthesis. Recordings were made before, and at intervals following speech processor activation. The measured parameters included F1, F2, F0, SPL, duration, and amplitude difference between the first two harmonic peaks in the log magnitude spectrum (H 1-H2). Numerous changes in parameter values were observed from pre- to post-implant, with differences among subjects. Many changes, but not all, were in the direction of normative data, and most changes were consistent with hypotheses about relations among the parameters. Some of the changes tended to enhance phonemic contrasts; others had the opposite effect. For three subjects, H 1-H2 changed in a direction consistent with measurements of their average air flow when reading; that relation was more complex for the fourth subject. The results are interpreted with respect to: characteristics of the individual subjects, including vowel identification scores; mechanical interactions among glottal and supraglottal articulations; and hypotheses about the role of auditory feedback in the control of speech production. Almost all the observed differences could be attributed to changes in the average settings of speaking rate, F0 and SPL, which presumably can be perceived without the need for spectral place information. Some observed F2 realignment may be attributable to the reception of spectral cues
— id: 97945, year: 1992, vol: 91, page: 2961, stat: Journal Article,

Propuesta de norma de almacenamiento de senales
Simini F; Handler P; Puchet J; Basalo S; Echague JV; Svirsky MA
1992 ;8(2):29-44, Revista brasileira de engenharia. Caderno de engenharia biomedica
— id: 97947, year: 1992, vol: 8, page: 29, stat: Journal Article,

Effects of short-term auditory deprivation on speech production in adult cochlear implant users
Svirsky, M A; Lane, H; Perkell, J S; Wozniak, J
1992 Sep;92(3):1284-1300, Journal of the Acoustical Society of America
Speech production parameters of three postlingually deafened adults who use cochlear implants were measured: after 24 h of auditory deprivation (which was achieved by turning the subject's speech processor off); after turning the speech processor back on; and after turning the speech processor off again. The measured parameters included vowel acoustics [F1, F2, F0, sound-pressure level (SPL), duration and H1-H2, the amplitude difference between the first two spectral harmonics, a correlate of breathiness] while reading word lists, and average airflow during the reading of passages. Changes in speech processor state (on-to-off or vice versa) were accompanied by numerous changes in speech production parameters. Many changes were in the direction of normalcy, and most were consistent with long-term speech production changes in the same subjects following activation of the processors of their cochlear implants [Perkell et al., J. Acoust. Soc. Am. 91, 2961-2978 (1992)]. Changes in mean airflow were always accompanied by H1-H2 (breathiness) changes in the same direction, probably due to underlying changes in laryngeal posture. Some parameters (different combinations of SPL, F0, H1-H2 and formants for different subjects) showed very rapid changes when turning the speech processor on or off. Parameter changes were faster and more pronounced, however, when the speech processor was turned on than when it was turned off. The picture that emerges from the present study is consistent with a dual role for auditory feedback in speech production: long-term calibration of articulatory parameters as well as feedback mechanisms with relatively short time constants
— id: 67979, year: 1992, vol: 92, page: 1284, stat: Journal Article,

Changes in speech breathing following cochlear implant in postlingually deafened adults
Lane, H; Perkell, J; Svirsky, M; Webster, J
1991 Jun;34(3):526-533, Journal of speech & hearing research
Three postlingually deafened adults who received cochlear implants read passages before and after their prostheses were activated while their lung volumes were measured with an inductive plethysmograph that transduced the cross-sectional areas of the speaker's chest and abdomen. Lung volumes at the initiation and termination of the speakers' expiratory limbs, their average air flow, and the volume of air they expended per syllable were derived from tracings of calibrated lung volume displayed by computer. The activation of the speakers' cochlear prostheses was followed in every case by a significant change in average airflow, which rose for two subjects with initially low flow rates and fell for one subject who had a much higher average preimplant flow rate. These changes in average flow rate were accompanied by corresponding changes in volume of air expended per syllable, statistically reliable in two of the three cases. There were no significant changes in the levels at which speakers initiated their expiratory limbs, but one speaker, after his prosthesis was activated, reliably increased the level of air in his lungs at the end of expiratory limbs to an average value that no longer required him to draw on expiratory reserve volume
— id: 97946, year: 1991, vol: 34, page: 526, stat: Journal Article,

Effect of different types of auditory stimulation on vowel formant frequencies in multichannel cochlear implant users
Svirsky, M A; Tobey, E A
1991 Jun;89(6):2895-2904, Journal of the Acoustical Society of America
Two experiments investigating the effects of auditory stimulation delivered via a Nucleus multichannel cochlear implant upon vowel production in adventitiously deafened adult speakers are reported. The first experiment contrasts vowel formant frequencies produced without auditory stimulation (implant processor OFF) to those produced with auditory stimulation (processor ON). Significant shifts in second formant frequencies were observed for intermediate vowels produced without auditory stimulation; however, no significant shifts were observed for the point vowels. Higher first formant frequencies occurred in five of eight vowels when the processor was turned ON versus OFF. A second experiment contrasted productions of the word 'head' produced with a FULL map, OFF condition, and a SINGLE channel condition that restricted the amount of auditory information received by the subjects. This experiment revealed significant shifts in second formant frequencies between FULL map utterances and the other conditions. No significant differences in second formant frequencies were observed between SINGLE channel and OFF conditions. These data suggest auditory feedback information may be used to adjust the articulation of some speech sounds
— id: 67980, year: 1991, vol: 89, page: 2895, stat: Journal Article,

Cochlear implants
Svirsky MA; Cullen JK; Walker CF
Bioinstrumentation : research, developments, and applications Boston : Butterworths, 1990,
— id: 5010, year: 1990, vol: , page: 1161, stat: Chapter,

AN ALTERNATIVE WAY TO ENCODE VOICING IN MULTICHANNEL COCHLEAR IMPLANTS
SVIRSKY, MA; FEINMAN, GR; CULLEN, JK; WALKER, CF
1988 ;89(6):1541-1542, Proceedings of the Annual International Conference of the IEEE Engineering in Medicine & Biology Society
Voicing is the feature that indicates whether a speech sound is quasiperiodic or aperiodic. It is used perceptually to discriminate pairs of sound such as /s,z/,/p,b/,f,v/, etc. The nucleus WSP-III multichannel speech processor uses a stimulation rate equal to the fundamental frequency of the input speech signal: two pulses are sent in rapid sequence during each fundamental period. When speech is unvoiced and a fundamental frequency cannot be determined, a random stimulation rate of approximately 100 Hz is used. Therefore the processor uses the stimulation rate to encode voicing: unvoiced sounds are delivered using a random rate while voiced sounds are delivered using a more stable rate. The author's compare this voicing encoding strategy to a novel one which uses an extra pulse per period when voicing is present in the input signal. Results were encouraging: one subject achieved 100% discrimination with the new strategy (after very limited training), compared to 85% obtained using the old strategy
— id: 97910, year: 1988, vol: 89, page: 1541, stat: Journal Article,

DISCRIMINATION OF COMPLEX SPEECH-RELATED SIGNALS WITH A MULTICHANNEL ELECTRONIC COCHLEAR IMPLANT AS MEASURED BY ADAPTIVE PROCEDURES
HOOD, LJ; SVIRSKY, MA; CULLEN, JK
1987 ;96(1):38-41, Annals of otology rhinology & laryngology
— id: 97911, year: 1987, vol: 96, page: 38, stat: Journal Article,

Matching acoustical properties of speech with electrical stimulation frequency boundaries in cochlear implant patients
Svirsky, M.A.; Cullen, J.K.; Walker, C.F.
1986 ;14(1-2):1906-1910, Proceedings (IEEE Engineering in Medicine & Biology Society)
Cochlear implant patients implanted with a programmable, 21-channel stimulator receive information about the dominant spectral peak in the midfrequency range (800-4000 Hz) encoded as electrode position. Three frequency-to-electrode position maps were tried, including one map where frequency-band boundaries were those frequencies that are midfrequency spectral peak boundaries between vowels, in an effort to increase vowel discrimination. Identification tests were not conclusive with respect to one map being better than the others for the three patients, but the two maps which had more electrodes representing lower frequencies were significantly better than the other map, when measured by discrimination tests
— id: 97913, year: 1986, vol: 14, page: 1906, stat: Journal Article,

MULTICHANNEL COCHLEAR IMPLANTS AS TREATMENT FOR THE PROFOUNDLY DEAF - A REPORT
SVIRSKY, MA; JENISON, V; CULLEN, JK; WALKER, CF
1986 ;14(1-2):40-40, Biomaterials, medical devices, & artificial organs
— id: 97912, year: 1986, vol: 14, page: 40, stat: Journal Article,