The Korean Version of the Theory of Mind Test and the Early Development of the Theory of Mind in Children with Cochlear Implant / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Theory of Mind (ToM) refers to the ability humans have for recognizing the mental states of others and for predicting or explaining other people’s behavior. ToM is an essential ability people have for living with other people because it influences social relations, and the deaf children have been reported to have problems in ToM. As there are no ToM assessment tools in Korea, the purpose of this study was to establish such a version and to examine the early development of ToM of children with cochlear implant (CI). SUBJECTS AND METHOD: The original tools for ToM assessment were translated in Korean and the reliability and validity of the Korean version of ToM assessment tools were investigated with fifty normal hearing (NH) children. The early development of ToM of sixteen children with CI was compared with that of age-matched children with NH. RESULTS: The reliability of Korean version of ToM assessment tools was determined by tests for internal consistency and test-retest reliability. The validity of the tools was also evaluated by the tests for criterion-related validity and concurrent validity. There was no significant difference in ToM between children with CI and those with NH. CONCLUSION: The Korean version of ToM assessment tools was established and the assessment showed that the early development of ToM of deaf children, who received early intervention using CI, was comparable to that of NH children.

The Korean Version of the Theory of Mind Test and the Early Development of the Theory of Mind in Children with Cochlear Implant / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES@#Theory of Mind (ToM) refers to the ability humans have for recognizing the mental states of others and for predicting or explaining other people’s behavior. ToM is an essential ability people have for living with other people because it influences social relations, and the deaf children have been reported to have problems in ToM. As there are no ToM assessment tools in Korea, the purpose of this study was to establish such a version and to examine the early development of ToM of children with cochlear implant (CI).SUBJECTS AND METHOD: The original tools for ToM assessment were translated in Korean and the reliability and validity of the Korean version of ToM assessment tools were investigated with fifty normal hearing (NH) children. The early development of ToM of sixteen children with CI was compared with that of age-matched children with NH.@*RESULTS@#The reliability of Korean version of ToM assessment tools was determined by tests for internal consistency and test-retest reliability. The validity of the tools was also evaluated by the tests for criterion-related validity and concurrent validity. There was no significant difference in ToM between children with CI and those with NH.@*CONCLUSION@#The Korean version of ToM assessment tools was established and the assessment showed that the early development of ToM of deaf children, who received early intervention using CI, was comparable to that of NH children.

Speech Perception and Language Outcome in Congenitally Deaf Children Receiving Cochlear Implants in the First Year of Life / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: The objective of this study was to examine the effect of early cochlear implantation (CI) performed in infants less than 12 months of age. SUBJECTS AND METHOD: Twenty-five children who received their first CI before 12 months of age were included in this study (infant group). The speech perception and language outcomes of these children were compared with those of 14 children who received their first CI between 13 and 24 months of age (older group). All children received sequential bilateral CI with the inter-stage interval of less than 2 years. Speech perception was measured using Categories of Auditory Performance, monosyllabic word test and sentence test, and language ability was measured using Sequenced Language Scale for Infants, Preschool Receptive-Expressive Language Scale, or Receptive & Expressive Vocavulary Test, depending on the age at the time of testing. RESULTS: There were no significant differences in speech perception abilities between the infant group and the older group. The mean expressive language score of infant group was higher than that of the older group, but the difference was not statistically significant. However, the receptive language score of infant group was significantly higher than that of the older group. CONCLUSION: Children who received CI before 12 months of age achieved better receptive language ability than those who received it after 12 months of age. Thus CI should be performed as early as before 12 months of age to achieve better language ability.

Association between Frontal-Executive Dysfunction and Speech-in-Noise Perception Deficits in Mild Cognitive Impairment

BACKGROUND AND PURPOSE: Speech-in-noise perception deficits have been demonstrated in patients with mild cognitive impairment (MCI). However, it remains unclear whether the impairment of speech perception varies between MCI subtypes. The purpose of this study was twofold: 1) to compare speech perception performance among MCI subgroups, and 2) to identify the cognitive domains specifically related to speech-in-noise perception. METHODS: We studied 46 patients with MCI and 39 hearing-threshold-matched cognitively normal elderly (CNE) subjects. Two different patient classifications were used: 1) patients with amnestic mild cognitive impairment (aMCI) (n=21) or nonamnestic mild cognitive impairment (naMCI) (n=25), and 2) patients with frontal-executive dysfunction (FED) (n=16) or without FED (n=30). All of the subjects underwent audiometric, neuropsychological, and speech perception assessments. Speech-in-noise perception was measured using sentence recognition tests in the presence of two types of background noise at four levels. RESULTS: First, as the level of background noise increased, the MCI with FED group scored lower than both the MCI without FED and CNE groups under both types of noise. Second, both the naMCI and aMCI groups scored lower than the CNE group, but there were no differences between the naMCI and aMCI groups in sentence recognition under any noise conditions. Third, significant correlations were found between sentence recognition and executive function scores both in the MCI groups and in the CNE group. CONCLUSIONS: Our findings suggest that frontal-executive function is strongly related to speech-in-noise perception and that MCI patients with FED have greater deficits in speech-in-noise perception compared to other subgroups of MCI.

Peer Relations in Children with Cochlear Implants / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Children who received cochlear implants (CIs) in early age can achieve age-appropriate language ability and can be educated in the classroom alongside normal hearing (NH) peers. However, what is rarely investigated is their relations with NH peers in the classroom. The purpose of this study was to examine the peer relations of children with CIs. SUBJECTS AND METHOD: Peer relations were examined using a peer relation scale test that included support, intimacy, recognition, conflict, and competition. Participants were 25 children who received their first CI before 3.5 years of age. Their peer relations were compared with those of 129 children with NH. RESULTS: Children with CIs evaluated themselves as having good peer relations, but their perception of peer relations varied according to gender and language ability. CI boys with language delay perceived lack of support and intimacy, whereas CI girls with language delay perceived more conflict than NH children. On the other hand, CI children with normal language ability showed no differences in their peer relations from NH children. CONCLUSION: Early CI surgery and intensive language rehabilitation can prevent peer problems and promote adjustment in school life for children with CI.

Interpersonal Competence in College Students with Cochlear Implants: A Preliminary Study / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: ObjectivesZZAlthough many studies have shown that cochlear implantation promotes restoration of adequate hearing and verbal ability, there is little research showing whether patients with cochlear implants (CI) adapted well to the society by forming a good interpersonal relationship. The purpose of this study was to investigate the interpersonal competence of college students who acquired good verbal ability through CI. SUBJECTS AND METHOD: Interpersonal competence was examined using the Korean version of interpersonal competence questionnaire. Participants were 23 college students with CI who had good verbal communication abilities. Their interpersonal competence was compared to that of 28 college students with normal hearing (NH). To identify the factors contributing to the interpersonal competence, regression analysis was performed using speech perception, vocabulary and speech intelligibility as independent variables. RESULTS: College students with CI showed significantly weaker interpersonal competence than those with NH. Among 5 sub-factors of interpersonal competence, assertion and conflict management were not significantly different between two groups and initiation, caring others, and appropriate disclosure of CI group were significantly weaker than NH group. But college students with CI who had normal vocabulary and Speech Intelligibility Ratings score of 5 showed good interpersonal competence, which was comparable to those with NH. CONCLUSION: College students with CI who acquired good verbal communication ability demonstrates lower interpersonal competence than those with NH. Therefore, it is necessary to support them to improve interpersonal competence as well as speech-language ability.

A Case of Auditory Neuropathy Caused by Pontine Hemorrhage in an Adult

A pontine hemorrhage can evoke several neurological symptoms because the pons contains various nuclei and nerve fibers. Hearing loss can develop as a result of a pontine hemorrhage because there is an auditory conduction pathway in the cochlear nucleus of the pons. However, very few cases of hearing loss caused by pontine lesions have been reported, and there have been no reports of auditory neuropathy that developed following a pontine hemorrhage. Recently we had a patient who experienced a nontraumatic pontine hemorrhage who was diagnosed with auditory neuropathy. The 34-year-old male patient was admitted to the emergency department with sudden alteration of mental status. His brain computed tomographic imaging revealed a hemorrhage in the central pons. He complained of hearing difficulties after his mental status recovered through conservative treatment, but a pure-tone audiogram showed very mild hearing loss in both ears. Further hearing tests using otoacoustic emissions, which showed normal responses, and auditory brainstem responses, which showed no waveforms at maximum stimulus intensity, revealed that his hearing difficulties were caused by auditory neuropathy. This case implies that the threshold of sound detection can be preserved in patients with pontine hemorrhage who complain of hearing difficulties. Auditory neuropathy should be considered as a possible cause of hearing difficulties in these patients and appropriate hearing tests should be performed.

Management of Pediatric Unilateral Sensorineural Hearing Loss / 대한이비인후과학회지

Every one of a thousand of neonates is born with unilateral sensorineural hearing loss (UHL) and the prevalence of UHL increases in school aged children due to delayed-onset or acquired HL. Some studies showed that UHL impacted on speech-language development and school performance adversely. Therefore, appropriate intervention for UHL children may be needed. Treatment approach for UHL children can be chosen depending on the degree of HL. Cochlear implantation (CI) provides benefits of binaural hearing including better speech perception in noise and sound localization to children with acquired severe-to-profound UHL. However, children with congenital severe-to-profound UHL and long duration of HL gain the unfavorable benefit from CI. Contralateral routing of signal hearing aid and bone anchored hearing device should not be recommended for young children with UHL because these devices can introduce noise to normal hearing ear and young children are not able to competently monitor their listening environment and to make judgments about when these devices may be appropriate. Conventional hearing aid (HA) has the potential of providing binaural hearing for UHL children with amplifiable hearing and the studies realized the binaural hearing when UHL children wore HA. However adherence to HA is poor because of some reasons including parents' reluctance to fit a HA in the presence of a normal-hearing ear and stigma effect. Long term follow up data of these interventions for UHL children are lacking. So fully informed consent is required during decision making process for UHL children until the concrete guideline of intervention for UHL children is established.

Changes in the Hearing Thresholds of Infants Who Failed the Newborn Hearing Screening Test and in Infants Treated in the Neonatal Intensive Care Unit

OBJECTIVES: The aim of this study was to investigate changes in the hearing thresholds during the first year of life in infants who failed the newborn hearing screening (NHS) test and of infants treated in the neonatal intensive care unit (NICU). METHODS: From March 2007 to November 2010, 193 healthy infants who failed the NHS test and 51 infants who were treated in the NICU were referred for evaluation of hearing acuity. Their hearing was evaluated using impedance audiometry, auditory brainstem response (ABR), and otoacoustic emission before 6 months of age, and follow-up hearing tests were administered before 12 months of age. Changes in their hearing thresholds were then analyzed. RESULTS: Of the 193 healthy infants who failed the NHS test, 60 infants (31%) had normal hearing acuity, 126 infants (65%) had sensorineural hearing loss (SNHL, ABR threshold > or =40 dB) and 7 infants (4%) had auditory neuropathy (AN). On the follow-up hearing tests, which were conducted in 65 infants, 6 infants showed a hearing threshold deterioration of more than 20 dB, and 19 infants showed a hearing threshold improvement of more than 20 dB. Of the 51 infants who were treated in the NICU, 38 infants (75%) had normal hearing acuity, 12 infants (24%) had SNHL, and one infant (2%) had AN. In the follow-up hearing tests, which were performed in 13 infants, one infant with normal hearing progressed to severe hearing loss. Five infants who had SNHL showed a hearing threshold improvement of more than 20 dB, and 4 infants recovered to normal hearing. CONCLUSION: The hearing thresholds of infants with congenital SNHL can change during the first year of life; therefore, the importance of administration of follow-up hearing tests is emphasized. Irreversible intervention such as cochlear implantation should be considered with great caution within the first year after birth.

Hearing Threshold Prediction Using Auditory Brainstem Response and Auditory Steady-State Response in Infants and Young Children / 대한이비인후과학회지

Between one and three of every 1,000 neonates have sensorineural hearing loss (SNHL). It is of utmost importance to minimize the duration of auditory deprivation between the onset of bilateral deafness and intervention using hearing devices such as hearing aids and cochlear implants for achieving the best speech percpetion ability. To fit amplification accurately for children with SNHL, hearing thresholds for frequencies in the range of human communication should be evaluated. However, infants and young children are difficult to test using conventional behavioral tests, and hearing thresholds of them can be predicted using auditory brainstem response (ABR) and auditory steady-state response (ASSR). ABR is best evoked by applying a click stimulus, which allows an estimate over a broad range of high frequencies. ABR elicited by tone burst stimulus provides frequency-specific audiometric information. However, it can be difficult to record and observe at near-threshold levels, especially at lower frequencies. ABR thresholds for click and tone burst stimuli are highly correlated with behavioral thresholds, and often give an idea of the shape of an audiogram. ASSR is an auditory evoked potential, elicited with modulated tones. It provides frequency-specific hearing thresholds across the audiometric frequencies, which are well correlated with behavioral thresholds. However, the accuracy of threshold prediction decreases directly with the decrease of degree of hearing loss, and hearing thresholds cannot be predicted for auditory neuropathy. ASSR is most useful for estimating auditory thresholds for patients with no evidence of auditory neuropathy by the click ABR and OAEs, and who have an ABR only at high intensities or no ABR at a maximum stimulus level. Even if hearing thresholds are predicted through ABR and ASSR, behavioral testing including behavioral observation audiometry, visual reinforcement audiometry, or play audiometry should be employed repeatedly to verify the predicted thresholds, becasue the thresholds of ABR and ASSR are not true measure of hearing acuity but just responses generated at the brainstem.

The Relationship between Thresholds of Electrically Evoked Compound Action Potential and Speech Perception in Children with Cochlear Implants / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Neuropathology around the cochlea could create variation from site to site in physiological thresholds of cochlear implant users. This variability would be detrimental to speech recognition with a cochlear implant for a variety of reasons, including distortion of the place code and variation in the number of neurons. The purpose of this study is to examine the relationship between thresholds of electrically evoked compound action potential (ECAP) and speech perception in children implanted with the Nucleus Freedom devices. SUBJECTS AND METHOD: Fifty-seven children implanted with the Nucleus Freedom device participated in this study. ECAP thresholds were recorded using the automated neural response telemetry test protocol. We then calculated mean threshold and three metrics to assess across-site variation within subjects: 1) the variance of T levels for all tested sites, 2) the range of T levels (highest minus lowest) across all tested sites and 3) site-to-site variation. For each subject, these measures were compared with performance on tests of word recognition. RESULTS: There was considerable across-site (within-subject) and across-subject variability in thresholds. However, we found no significant correlation between speech recognition and across-site variation of thresholds as well as mean threshold levels. CONCLUSION: These data suggest that the ECAP measures of thresholds may not be an accurate predictor of speech perception ability.

The Effect of Transcranial Direct Current Stimulation on Cortical Excitability and Motor Function in a Stroke Patient: A case report

In this case study, we investigated the change of cortical excitability and motor function recovery after transcranial direct current stimulation (tDCS). A patient with chronic right middle cerebal artery territory infarction received tDCS. We performed anodal tDCS on her ipsilesional primary motor cortex which was found by motor evoked potential and conventional occupational therapy for 2 weeks. We evaluated upper extremity function with Fugl-Meyer Assessment (FMA) before and after, one and three months after tDCS. In addition, functional magnetic resonance imaging (FMR) was carried out to evaluate the change of cortical excitability. FMA score was improved after tDCS and the improvement was prominent at one and three months later compared to pre-treatment score. And cortical excitability of ipsilesional primary motor cortex was increased after tDCS. As these results show tDCS seems to be useful tool in promoting motor recovery through increasing cortical excitability in stroke patients.

Effect of Virtual Reality on Cognition in Stroke Patients

OBJECTIVE: To investigate the effect of virtual reality on the recovery of cognitive impairment in stroke patients. METHOD: Twenty-eight patients (11 males and 17 females, mean age 64.2) with cognitive impairment following stroke were recruited for this study. All patients were randomly assigned to one of two groups, the virtual reality (VR) group (n=15) or the control group (n=13). The VR group received both virtual reality training and computer-based cognitive rehabilitation, whereas the control group received only computer-based cognitive rehabilitation. To measure, activity of daily living cognitive and motor functions, the following assessment tools were used: computerized neuropsychological test and the Tower of London (TOL) test for cognitive function assessment, Korean-Modified Barthel index (K-MBI) for functional status evaluation, and the motricity index (MI) for motor function assessment. All recruited patients underwent these evaluations before rehabilitation and four weeks after rehabilitation. RESULTS: The VR group showed significant improvement in the K-MMSE, visual and auditory continuous performance tests (CPT), forward digit span test (DST), forward and backward visual span tests (VST), visual and verbal learning tests, TOL, K-MBI, and MI scores, while the control group showed significant improvement in the K-MMSE, forward DST, visual and verbal learning tests, trail-making test-type A, TOL, K-MBI, and MI scores after rehabilitation. The changes in the visual CPT and backward VST in the VR group after rehabilitation were significantly higher than those in the control group. CONCLUSION: Our findings suggest that virtual reality training combined with computer-based cognitive rehabilitation may be of additional benefit for treating cognitive impairment in stroke patients.

Cochlear Implant Failure due to Cochlear Nerve Deficiency in a Child with Normal Internal Auditory Canal / 대한이비인후과학회지

The cochlear nerve, which propagates electrical signals to the auditory cortex, must function well for successful cochlear implantation. A narrow internal auditory canal (IAC) increases the risk of hypoplasia or aplasia of cochlear nerve, which may result in the failure of cochlear implantation. Therefore, a functioning cochlear nerve must be verified before deciding to do cochlear implantation by means of behavioral audiometry, electrophysiologic tests, or imaging studies in cases with narrow IAC. On the other hand, a candidate with a normal IAC can be overlooked in investigating the presence of functioning cochlear nerve. Because normal IAC does not always guarantee the presence of normal cochlear nerve, the functioning cochlear nerve should be proved prior to cochlear implantation in those cases. We report on a child, who had normal IAC and cochlea but failed auditory stimulation after cochlear implantation, and who was diagnosed as having cochlear nerve deficiency through retrospective review.

A Survey of Speech Perception Tests for Children with Hearing Loss Used in Cochlear Implant Centers in Korea / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Various speech perception tests have been developed for children with hearing loss (HL) in Korea, although they are not standardized yet. This study aims to examine the actual condition of speech perception tests for children with HL in Korea. SUBJECTS AND METHOD: Survey questionnaires and speech perception tests for children with HL were collected from 24 cochlear implant (CI) centers between March and July 2009. The speech perception tests were classified according to target ages, speech stimulus levels, and response formats. We interviewed speech therapists who had developed monosyllabic word (MW) tests, and gathered source materials, considerations, and limitations of the MW tests. We also analyzed vocabulary familiarity and phonetic balancing of words in the most commonly used MW tests. RESULTS: Thirty-eight kinds of speech perception tests for children with HL were collected from 24 CI centers. Among these tests, open-set MW tests and sentence tests were used in all centers. Speech therapists responsible for developing MW tests had selected words from textbooks, storybooks, and spontaneous speech data to secure vocabulary familiarity and phonetic balancing within each list. Four commonly used MW tests revealed that vocabulary familiarity was compatible with commonly used MW in preschoolers and demonstrated a similar trend in phoneme frequencies. CONCLUSION: The results of this study showed that current speech perception tests for children with HL should be verified, revised, and standardized in an experimental setting.

A Case of Cochlear Implantation in a Patient with Mutation in the Coagulation Factor C Homology Gene(W117R) / 대한이비인후과학회지

The autosomal dominant deafness disorder at the DFNA9 locus has been described and the clinical aspects extensively characterized, showing adult-onset, progressive sensorineural hearing loss and vestibular dysfunction. DFNA9 is caused by mutations of the human Coagulation factor C homology (COCH)gene. COCH encodes cochlin, a highly abundant secreted protein of unknown function in the inner ear. Several mutations have been identified so far: P51S, V66G, G87W, G88E, V104del, I109T, I109N, W117R, A119T, M512T, C542F, C542T. We hereby report a case of cochlear implantation in a 55-year-old man with bilateral sensorineural hearing loss, which is caused by a mutation in COCH gene (W117R).

Open-Set Monosyllabic Speech Perception Test for Preschool Children / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: An open-set monosyllabic speech perception test is necessary, not only to devise habilitation programs but to select candidates and estimate performance in pediatric cochlear implant program. The purpose of this study is to develop a validated open-set monosyllabic speech perception test for preschool children. SUBJECTS AND METHOD: Qualitative test development was based on vocabulary familiarity, syllabic and phonemic frequency, and phonetic balancing between the lists. The devised test lists were applied to 138 normal hearing children and 46 children with cochlear implant to examine the validity and reliability. RESULTS: The final two test lists were made up of 100 items with 260 phonemics. The consequential validity of this devised test was proven by the applied results that the speech perception score of children with implanted devices was significantly lower than that of normal children, when controlling for the length of auditory experience. CONCLUSION: The developed monosyllabic speech perception test is the validated instrument for preschool children. It is sensitive to perceptual characteristics of articulatory function in cochlear implanted children. The validity of this test needs to be enhanced by clinical application and further item analysis.

Open-Set Speech Perception Performance and Its Contributing Factors for Children Received Cochlear Implantation at Older Age / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: This study aims to investigate the development of open-set speech perception abilities in children who received cochlear implantation at older age and to examine the preoperative variables contributing to the postoperative speech perception outcomes. SUBJECTS AND METHOD: Open-set speech perception abilities were assessed with the Monosyllabic Word and Common Phrases Tests for 37 prelingually deafened children who received implantation between the ages of 7 and 17 years. Their performance was compared to that of 60 children who received implantation before 7 years of age. To identify the factors contributing to the postoperative open-set speech perception abilities, we analyzed age at hearing aid fitting, age at implantation, duration of implant use, preoperative language and speech perception abilities, and pure tone thresholds in the better ear. RESULTS: The children who received implantation after 7 years of age significantly improved during the first year of implant use, but reached a plateau by 1.5 to 2 years after implantation, reaching scores between 60% and 70%. Children who received implantation after age 7 showed higher speech perception scores than the younger children over the first year of implant use, but showed lower scores than the younger children after 2-3 years of implant use. The variables associated with the postoperative open-set speech perception abilities were speech perception ability, language ability, and hearing levels before implantation. CONCLUSION: Prelingually deafened children who received implantation at older age can obtain substantial open-set speech perception understanding, but tended to reach a plateau between 1.5-2 years after implantation. Speech perception, language abilities, and hearing level before implantation contribute to the outcome.

A Study of Electrical Middle Latency Response in a Cat: Effect of Stimulation Rate and Pulse Duration / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Electrically evoked middle latency response (EMLR) has several advantages over electrically evoked auditory brainstem response (EABR). The major component peaks of EMLR lie outside the region of stimulus artifacts and it reflects the activation of a more significant portion of the auditory pathway than EABR. It is known that several conditions alter the general morphology, amplitude, and latency of the waveforms of EMLR. The purpose of this study was to record and evaluate the effects of stimulation rate and pulse duration on detectability, latency and amplitude of EMLR in the cat. MATERIALS AND METHOD: EMLR was recorded in response to 9 experimental conditions-3 conditions of pulse duration (150, 200, 250 micron sec biphasic) at each of 3 conditions of stimulation rate (2, 6 and 10/sec)-after electrical stimulation at the round window in 7 cats. RESULTS: PA was identified in all conditions. PB was obtained from 17 of the 63 waves. The latency of PA was significantly shorter and the amplitude of PA was significantly larger for the stimulation rate of 10/sec and the pulse duraion of 250 micron sec compared with other conditions. CONCLUSION: We found that based on the present data, the optimal stimultion condition for EMLR in our laboratory was the stimulation rate of 10/sec and the pulse duration of 250 micron sec. This data can provide a basis for the appropriate stimulation condition of EMLR in human.

Bilateral Cochlear Implantation in Four Children / 대한이비인후과학회지

The benefits of bilateral cochlear implants (CIs) include better understanding of speech in noise and localization of sound sources. Following the improvement observed in adults, children were also included in the bilateral CIs program. The aim of this study was to investigate the impact of bilateral CIs use on speech perception in quiet and in noise. Four children underwent testing from 9 to 18 months after activation of bilateral hearing. Speech perception tests in quiet and in noise (signal to noise ratio of +10 dB) were performed in all children with the first CI alone and bilaterally. Subjects showed varying degrees of improved performance on speech perception tests in quiet and in noise according to bilateral auditory experience. Bilateral CIs can offer a substantial benefit in speech perception in quiet and in noise. The extent of the advantage, however, may require a more prolonged period of adjustment and learning.