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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
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
PMCID:3432952
PMID: 12851554
ISSN: 1531-7129
CID: 67958

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
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
PMID: 14696993
ISSN: 1092-4388
CID: 67956

Language development in deaf infants following cochlear implantation

Miyamoto, Richard T; Houston, Derek M; Kirk, Karen Iler; Perdew, Amy E; Svirsky, Mario A
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
PMID: 12701749
ISSN: 0001-6489
CID: 67959

Untitled [Editorial]

Svirsky, MA
ISI:000186787300001
ISSN: 0196-0202
CID: 97892

Deriving the loudness exponent from categorical judgments

Norwich, Kenneth H; Sagi, Elad
The power function exponent for loudness is traditionally determined by means of a process of magnitude estimation. It is demonstrated in this paper that the exponent can also be obtained by using the procedure of absolute identification of sound intensity. It has been shown that subjects' responses to tones of a given intensity are distributed in a normal distribution whose variance depends on the range, R, over which the tones are distributed. By means of a standard statistical transformation, the normal density in log space is converted to the corresponding probability density in linear space. The power function exponent can then be obtained directly from the linear probability density. We also suggest that there is a direct relationship between the information calculated from experiments on absolute identification of sound intensity and the neurophysiological, poststimulus histogram measured in a nerve fiber in the auditory nerve
PMID: 12201339
ISSN: 0031-5117
CID: 147977

Untitled [Editorial]

Svirsky, MA
ISI:000176192600001
ISSN: 0196-0202
CID: 97895

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
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. $$:
PMID: 12018335
ISSN: 0096-8056
CID: 97896

Physiologically based analysis of cochlear implant representations [Meeting Abstract]

Laflen, JB; Talavage, TM; Thirukkonda, PM; Svirsky, MA
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.
ISI:000180194801019
ISSN: 1094-687x
CID: 2392132

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
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
ISI:000180105900006
ISSN: 0042-8639
CID: 55595

Efecto del implante coclear en el desarrollo linguistico de ninos con hipoacuasia profunda prelocutiva

Chapter by: Svirsky MA
in: Implantes cocleares by Rodriguez MJM; Irujo AH [Eds]
Barcelona : Masson, 2002
pp. ?-?
ISBN: 8445811495
CID: 5000