Evidence for a Right-Ear Advantage in Newborn Hearing Screening Results.

The aim of the present study was to investigate the effect of ear asymmetry, order of testing, and gender on transient-evoked otoacoustic emission (TEOAE) pass rates and response levels in newborn hearing screening. The screening results of 879 newborns, of whom 387 (study group) passed screening successfully in only one ear in the first TEOAE screening, but passed screening successfully in both ears thereafter, and 492 (control group) who passed screening successfully in both ears in the first TEOAE, were retrospectively examined for pass rates and TEOAE characteristics. Results indicated a right-ear advantage, as manifested by significantly higher pass rates in the right ear (61% and 39% for right and left ears, respectively) in the study group, and in 1.75 dB greater TEOAE response amplitudes in the control group. The right-ear advantage was enhanced when the first tested ear was the right ear (76%). When the left ear was tested first, pass rates were comparable in both ears. The right-ear advantage in pass rates was similar in females versus males, but manifested in 1.5 dB higher response amplitudes in females compared with males, regardless of the tested ear and order of testing in both study and control groups. The study provides further evidence for the functional lateralization of the auditory system at the cochlear level already apparent soon after birth in both males and females. While order of testing plays a significant role in the asymmetry in pass rates, the innate right-ear advantage seems to be a more dominant contributor.

Asymmetric interaural generalization of learning gains in a speech-in-noise identification task.

The pattern of generalization of learning gains to untrained conditions in adult human perceptual skill learning has been used as an effective behavioral probe for studying the functional organization of the learning system. Learning gains were previously reported to generalize symmetrically between the ears for tonal stimuli. However, given the open question concerning the specialization of the hemispheres in the processing of speech sounds, it is not clear whether symmetrical interaural generalization will follow training on such stimuli. Here the effect of monaural single-session training on the identification of consonant-vowel stimuli in noise was examined. Participants showed similar robust gains in performance at 24 h post-training in both trained ears. There was, however, an asymmetrical generalization of the learning gains from the trained to the untrained ear, with more transfer from the right-trained to the left-untrained ear than vice versa. Training and transfer gains were retained for both ears over an interval of several months, although for the untrained ear a brief exposure was necessary to relearn the task. These results provide first-time evidence for an asymmetry in interaural generalization for speech sounds following training and provide further support to the lateralization of speech sounds along the auditory system.

Delay in auditory behaviour and preverbal vocalization in infants with unilateral hearing loss.

AIM: To evaluate the impact of unilateral hearing loss (UHL) on early aural/oral communication skills of infants by comparing performance to infants with bilateral normal hearing (BNH). METHOD: Thirty-four infants with UHL (median age 9.4mo, 25th-75th centile 7.34-12.15) and 331 control infants with BNH (median age 9mo, 6.0-13.38) were divided into two subgroups based on risk factors known to cause developmental delay: low risk and high risk. Early auditory skills and preverbal vocalizations were assessed using two parent questionnaires: the Infant-Toddler Meaningful Auditory Integration Scale and the Production of Infants Scale Evaluation. RESULTS: Of the infants with UHL, 21% showed delays in auditory behaviour and 41% delays in preverbal vocalizations, compared to their peers with BNH (p<0.01). After adjusting for risk level, delayed auditory behaviour and preverbal vocalizations were approximately four and nine times more common in infants with UHL compared to BNH respectively (p<0.01). INTERPRETATION: This is the first study to show that infants with UHL are at higher risk of delay in early aural/oral communication abilities compared to infants with BNH even in the absence of other known risk factors for developmental delay. This has important implications for early intervention and habilitation of infants with UHL, in order to reduce some of the negative long-term consequences of what was once considered 'minor' hearing loss.

Hearing with Two Ears: Evidence for Cortical Binaural Interaction during Auditory Processing.

BACKGROUND: Integration of information presented to the two ears has been shown to manifest in binaural interaction components (BICs) that occur along the ascending auditory pathways. In humans, BICs have been studied predominantly at the brainstem and thalamocortical levels; however, understanding of higher cortically driven mechanisms of binaural hearing is limited. PURPOSE: To explore whether BICs are evident in auditory event-related potentials (AERPs) during the advanced perceptual and postperceptual stages of cortical processing. RESEARCH DESIGN: The AERPs N1, P3, and a late negative component (LNC) were recorded from multiple site electrodes while participants performed an oddball discrimination task that consisted of natural speech syllables (/ka/ vs. /ta/) that differed by place-of-articulation. Participants were instructed to respond to the target stimulus (/ta/) while performing the task in three listening conditions: monaural right, monaural left, and binaural. STUDY SAMPLE: Fifteen (21-32 yr) young adults (6 females) with normal hearing sensitivity. DATA COLLECTION AND ANALYSIS: By subtracting the response to target stimuli elicited in the binaural condition from the sum of responses elicited in the monaural right and left conditions, the BIC waveform was derived and the latencies and amplitudes of the components were measured. The maximal interaction was calculated by dividing BIC amplitude by the summed right and left response amplitudes. In addition, the latencies and amplitudes of the AERPs to target stimuli elicited in the monaural right, monaural left, and binaural listening conditions were measured and subjected to analysis of variance with repeated measures testing the effect of listening condition and laterality. RESULTS: Three consecutive BICs were identified at a mean latency of 129, 406, and 554 msec, and were labeled N1-BIC, P3-BIC, and LNC-BIC, respectively. Maximal interaction increased significantly with progression of auditory processing from perceptual to postperceptual stages and amounted to 51%, 55%, and 75% of the sum of monaural responses for N1-BIC, P3-BIC, and LNC-BIC, respectively. Binaural interaction manifested in a decrease of the binaural response compared to the sum of monaural responses. Furthermore, listening condition affected P3 latency only, whereas laterality effects manifested in enhanced N1 amplitudes at the left (T3) vs. right (T4) scalp electrode and in a greater left-right amplitude difference in the right compared to left listening condition. CONCLUSIONS: The current AERP data provides evidence for the occurrence of cortical BICs during perceptual and postperceptual stages, presumably reflecting ongoing integration of information presented to the two ears at the final stages of auditory processing. Increasing binaural interaction with the progression of the auditory processing sequence (N1 to LNC) may support the notion that cortical BICs reflect inherited interactions from preceding stages of upstream processing together with discrete cortical neural activity involved in binaural processing. Clinically, an objective measure of cortical binaural processing has the potential of becoming an appealing neural correlate of binaural behavioral performance.

Pain in cochlear implant recipients: an uncommon, yet serious, consequence of cochlear implantation.

OBJECTIVES/HYPOTHESIS: We describe pain around the receiver/stimulator [RS] presenting months to years after implantation. STUDY DESIGN: A retrospective chart review. METHODS: We performed a retrospective review of all cochlear implant recipients complaining of pain around their RS through the years 2009 through 2013, with a follow-up of at least 6 months. Excluded from the study were patients with an identifiable cause for their pain such as trauma, local infection, or skin breakdown. The therapy regimen and outcomes were reviewed. RESULTS: Thirty patients complained of delayed pain over their RS, representing 2.8% of 1,044 implantations performed at the Sheba Medical Center, Tel Hashomer, Israel, as of 2013. The time from implantation to the presentation of pain ranged from 3 months to 12 years. The pain was perceptible even when the external magnet and processor were not used, and was usually most obvious in specific points around the RS. Seventy-seven percent of our patients responded well to conservative therapy. Fifteen (50%) responded to prolonged antibiotic treatment. Five patients (17%) responded to antiinflammatories alone. One patient (3%) responded to deactivation of two electrodes. Six patients (20%) required reimplantation, after which the pain resolved in all. At explantation, no signs of infection, foreign body reaction, or obvious device damage were found. CONCLUSION: Delayed pain around the RS that is unrelated to use is a serious consequence of cochlear implantation, and in some cases, those necessitating reimplantation, should be considered a major complication. LEVEL OF EVIDENCE: 4.

Universal neonatal cytomegalovirus screening using saliva - report of clinical experience.

OBJECTIVES: To analyze the results of a neonatal universal screen for congenital cytomegalovirus (CMV) using saliva real-time polymerase chain reaction (rt-PCR). STUDY DESIGN: During one year (15/5/2011-15/5/2012), saliva was collected from 9845 infants (97% of 10,137 newborns). Viral DNA was extracted by Magna-Pure LC (Roche) and was tested for the presence of CMV IE and gB genes. Urine culture was collected from positive infants for confirmation. For all infants with congenital CMV maternal data were collected and head ultrasound, blood count, liver enzymes, retinal examination and auditory brainstem response testing were performed. Parents were notified in advance and had the option to avoid screening. The ethical committee approved retrospective analysis of the data. RESULTS: Fifty six infants (0.57%) had a positive saliva assay. Of these, 47 were confirmed by urine rt-PCR and culture, in another one maternal sero-conversion was documented during pregnancy (48 infants). Twenty-eight mothers (28/47, 60%) had primary infection during pregnancy, 14 (30%) had non-primary infection, and no serological data were obtained from five (10%). Four infants (8.5%), two with prenatal diagnosis of CMV and normal fetal brain imaging and two born to mothers sero-positive before pregnancy, exhibited symptoms related to CMV and were offered antivirals. Hearing impairment was diagnosed in two infants (late onset HI in one case). CONCLUSIONS: Saliva rt-PCR assay is a feasible and effective means of universal neonatal CMV screening that can detect affected infants who might benefit from treatment and follow-up. The long-term clinical significance of screening and its cost effectiveness are yet to be determined.

Evidence for a right cochlear implant advantage in simultaneous bilateral cochlear implantation.

OBJECTIVES/HYPOTHESIS: To compare speech perception performance with right versus left cochlear implants (CIs) in children with bilateral CIs implanted simultaneously. STUDY DESIGN: Prospective case series of patients undergoing simultaneous bilateral cochlear implantation. METHODS: Speech perception performance was tested in 10, right-handed children who received bilateral CIs simultaneously between 11 and 36 months (mean, 21 months), had at least 18 months of bilateral CI use, and were 5.3 years of age during testing. All children exhibited bilateral symmetrical severe-to-profound hearing loss prior to implantation and did not benefit from hearing aids. Speech perception performance was evaluated with the right CI and the left CI by means of an open-set monosyllabic word test in quiet presented at 45 dB HL in a sound field. RESULTS: All children exhibited higher performance with the right CI compared to the left CI. Group mean performance with the right CI was 66.5% compared to 52% with the left CI (P = .002), yielding a 14.5% difference. With increasing duration of bilateral CI use and age at evaluation, the right-left difference increased (r = 0.72, P = .019 and r = 0.74, P = .014, respectively). CONCLUSIONS: Current preliminary data indicate that children with bilateral CIs implanted simultaneously exhibit a significant right ear advantage for speech. Similarly to reports on normal-hearing children, right ear preference for speech increased with increasing age and auditory-linguistic experience. Thus, simultaneous bilateral cochlear implantation may lead to normal development of auditory pathways and may be an important contributor to the superior auditory, language, and communication skills reported in children with bilateral versus unilateral CIs.

Abnormalities in auditory efferent activities in children with selective mutism.

Two efferent feedback pathways to the auditory periphery may play a role in monitoring self-vocalization: the middle-ear acoustic reflex (MEAR) and the medial olivocochlear bundle (MOCB) reflex. Since most studies regarding the role of auditory efferent activity during self-vocalization were conducted in animals, human data are scarce. The working premise of the current study was that selective mutism (SM), a rare psychiatric disorder characterized by consistent failure to speak in specific social situations despite the ability to speak normally in other situations, may serve as a human model for studying the potential involvement of auditory efferent activity during self-vocalization. For this purpose, auditory efferent function was assessed in a group of 31 children with SM and compared to that of a group of 31 normally developing control children (mean age 8.9 and 8.8 years, respectively). All children exhibited normal hearing thresholds and type A tympanograms. MEAR and MOCB functions were evaluated by means of acoustic reflex thresholds and decay functions and the suppression of transient-evoked otoacoustic emissions, respectively. Auditory afferent function was tested by means of auditory brainstem responses (ABR). Results indicated a significantly higher proportion of children with abnormal MEAR and MOCB function in the SM group (58.6 and 38%, respectively) compared to controls (9.7 and 8%, respectively). The prevalence of abnormal MEAR and/or MOCB function was significantly higher in the SM group (71%) compared to controls (16%). Intact afferent function manifested in normal absolute and interpeak latencies of ABR components in all children. The finding of aberrant efferent auditory function in a large proportion of children with SM provides further support for the notion that MEAR and MOCB may play a significant role in the process of self-vocalization.

Hearing aid satisfaction and use in the advanced digital era.

OBJECTIVES/HYPOTHESIS: To evaluate satisfaction ratings and use patterns of advanced digital hearing aids (HAs) in a group of hearing-impaired adults by means of self-report questionnaires. STUDY DESIGN: A self report questionnaire study. METHODS: One hundred seventy-seven hearing-impaired adults who were fitted with advanced digital HAs at the Speech and Hearing Center at Sheba Medical Center were asked to participate in a structured telephone interview regarding HA satisfaction and use by means of the Satisfaction With Amplification in Daily Life (SADL) questionnaire. Patients who were not using their HAs completed a nonuse questionnaire. RESULTS: One hundred thirty-one patients participated in the survey, yielding a response rate of 74%. Eighty-three percent used their HAs regularly, whereas 17% were nonusers. Of the users, 92% were satisfied to some degree with their HAs. The global SADL score was 5.12 on a scale of 1 to 7. Background variables that were significantly associated with satisfaction ratings were hours of HA use per day, fitting mode (binaural vs. monaural), age, and degree of hearing loss. Although nonuse was not significantly associated with background variables, the main reasons for nonuse were excessive amplification in background noise and minimal functional benefit. CONCLUSIONS: High satisfaction and use rates were characteristic of adults fitted with advanced digital HAs. Patients should be advised that longer use of HAs per day may lead to higher satisfaction and that binaural amplification is advantageous, especially while communicating in noise. Finally, expectation from HA functionality in challenging listening situations should be realistic, as additional research and technology development is still needed.

Multicentre investigation on electrically evoked compound action potential and stapedius reflex: how do these objective measures relate to implant programming parameters?

OBJECTIVES: The aims of this study were to collect data on electrically evoked compound action potential (eCAP) and electrically evoked stapedius reflex thresholds (eSRT) in HiResolution(TM) cochlear implant (CI) users, and to explore the relationships between these objective measures and behavioural measures of comfort levels (M-levels). METHODS: A prospective study on newly implanted subjects was designed. The eCAP was measured intra-operatively and at first fitting through neural response imaging (NRI), using the SoundWave(TM) fitting software. The eSRT was measured intra-operatively by visual monitoring of the stapes, using both single-electrode stimulation and speech bursts (four electrodes stimulated at the same time). Measures of M-levels were performed according to standard clinical practice and collected at first fitting, 3 and 6 months of CI use. RESULTS: One hundred seventeen subjects from 14 centres, all implanted unilaterally with a HiResolution CII Bionic Ear(®) or HiRes 90K(®), were included in the study. Speech burst stimulation elicited a significantly higher eSRT success rate than single-electrode stimulation, 84 vs. 64% respectively. The NRI success rate was 81% intra-operatively, significantly increasing to 96% after 6 months. Fitting guidelines were defined on the basis of a single NRI measurement. Correlations, analysis of variance, and multiple regression analysis were applied to generate a predictive model for the M-levels. DISCUSSION: Useful insights were produced into the behaviour of objective measures according to time, electrode location, and fitting parameters. They may usefully assist in programming the CI when no reliable feedback is obtained through standard behavioural procedures.

Evidence for atypical auditory brainstem responses in young children with suspected autism spectrum disorders.

AIM: The aim of this study was to characterize the auditory brainstem responses (ABRs) of young children with suspected autism spectrum disorders (ASDs) and compare them with the ABRs of children with language delay and with clinical norms. METHOD: The ABRs of 26 children with suspected ASDs (21 males, five females; mean age 32.5 mo) and an age- and sex-matched group of 26 children with language delay (22 males, four females) were analysed. All children had normal hearing. The absolute latencies of waves I, III, and V, and interpeak latencies (IPLs) I to III, I to V, and III to V of the group with ASDs and the group with language delay were compared. Data from both groups were further compared with clinical norms. RESULTS: All absolute latencies and IPLs were significantly prolonged in the group with suspected ASDs compared with the group with language delay, excluding IPL III-V (all p-values <0.05) and with clinical norms (all p-values <0.001; IPL III-V, p<0.05). Significant prolongation of absolute and IPLs was also evident in the group with language delay compared with clinical norms, excluding IPL III to V (all p-values <0.001). The prevalence of abnormal findings in two or more absolute latencies was found to be significantly higher in the group with ASDs (50%) than in the group with language delay (8%; p=0.002). INTERPRETATION: The results provide first-time evidence for a neurodevelopmental brainstem abnormality that is already apparent in young children with suspected ASD and language delay. The overlap in ABR findings supports the assertion that an auditory processing deficit may be at the core of these two disorders.

Binaural masking level difference in skilled reading children and children with dyslexia.

BACKGROUND: Combining stimuli arriving at both ears makes it possible to locate sounds in the environment and to better detect signals or understand speech in noise when the sound sources are separated spatially. The sensitivity of the binaural system to interaural differences in time and amplitude can be investigated by means of the binaural masking level difference (BMLD). The age at which the BMLD reaches adult levels appears to depend partly upon masker bandwidth. Less is known about the effect of masker's level on the development of BMLD in children. In the present study we assessed the effect of masker level on the BMLD of 3rd and 5th grade skilled reading children. In view of possible binaural hearing effects in dyslexia, the BMLD of a group of 5th grade children with reading difficulties was measured. METHODS: Detection thresholds of 500 Hz pure tone were measured at noise levels of 40 dBHL, 50 dBHL and 60 dBHL. RESULTS: All subjects presented increased MLD values with the rise of noise intensity between 40 dBHL and 60 dBHL. Among the skilled readers the results showed that younger children had smaller BMLDs than older children at all masker levels. However, a significant group-by-intensity interaction indicated that although the reading disabled group had reduced BMLD values than older skilled readers at noise levels of 50 dBHL and 60 dBHL, no difference was found between their BMLD values and those of the young skilled readers at noise levels of 50 dBHL and 60 dBHL. Moreover, their BMLD values at noise level of 40 dBHL were higher than those of the 3rd grade typically reading students while no difference was found between them and 5th grade efficient readers. CONCLUSIONS: These results support the existence of both quantitative and qualitative differences in binaural hearing of children with developmental dyslexia.

[Bilateral cochlear implantation].

Cochlear implant surgery became the standard of care in hearing rehabilitation of patients with severe to profound sensorineural hearing loss. This procedure may alter the lives of children and adults enabling them to integrate with the hearing population. In the past, implantation was performed only in one ear, despite the fact that binaural hearing is superior to unilateral, especially in noisy conditions. Cochlear implantation may be performed sequentially or simultaneously. The "sensitive period" of time between hearing loss and implantation and between the two implantations, when performed sequentially, significantly influences the results. Shorter time spans between implantations improve the hearing results after implantation. Hearing success after implantation is highly dependent on the rehabilitation process which includes mapping, implant adjustments and hearing training. Bilateral cochlear implantation in children is recommended as the proposed procedure in spite of the additional financial burden.

Listening preference for the native language compared to an unfamiliar language in hearing and hearing-impaired infants after cochlear implantation.

OBJECTIVE: The goal of this study was to investigate the preference for the native language compared with an unfamiliar language in normally hearing (NH) and hearing-impaired infants with cochlear implants (CIs). BACKGROUND: Preference for the native language is an important step in the process of language acquisition because it helps infants to attend to the important signals of their environment. This preference has been shown very early in the infants' life. In the case of infants with CI, it is of interest to determine whether they show similar perceptual biases as NH infants despite their impaired auditory system and impoverished input provided by the CI device. METHODS: Nine hearing-impaired infants with CI (most with 1-2 mo of CI use) and 19 NH infants were tested on their preference for their native language (Hebrew child-directed speech) compared with a nonnative language (English child-directed speech). The central fixation preference procedure was used in which listening times were measured via orientation responses of the infant to visual stimuli. RESULTS: 1) Normal hearing and infants with CI had perceptual bias for their native language (Hebrew) when compared with a nonnative language (English). 2) Infants with CI have shorter attention to speech stimuli compared with NH. CONCLUSION: The findings of the present study are the first to show that hearing-impaired infants with CI bring the same perceptual biases to the task of language learning as NH infants. These have important implications on understanding the process by which infants with CI acquire language via the CI device.

Cochlear implant recipients' hearing sensation as manifested by their maps during pregnancy and postpartum.

OBJECTIVE: To investigate possible changes in hearing sensation as manifested in the maps' psychoacoustic parameters, threshold (T), and most comfortable (C/M) levels among cochlear implant (CI) female recipients during pregnancy and after delivery. SETTING: University-affiliated tertiary referral center. DESIGN: : Retrospective study. METHOD: Two MedEl device and 3 Nucleus device users' medical records were reviewed for age at the time of implantation, cause of deafness, type of anesthesia used during delivery, and maps' parameters (T and C/M levels) during pregnancy and after childbirth. RESULTS: Two CI recipients underwent uncomplicated cesarean deliveries under spinal anesthesia, and 3 others had natural delivery without anesthesia. There were no changes in map values during pregnancy, delivery, and the postpartum period in 4 of 5 CI recipients. Only 1 CI recipient showed significant increase in T levels that was resolved after she completed breastfeeding 3 months postdelivery. CONCLUSION: The elevation in T levels might indicate that pregnancy and delivery can result in some temporary reversible changes in hearing sensation manifested by map levels of CI users.

Cochlear implantation in elderly patients: surgical and audiological outcome.

BACKGROUND: Deteriorated hearing affects speech perception and speech production, and negatively impacts on social interaction, employment, income, and, as a result, the quality of life of the elderly population. Lack of satisfaction with conventional hearing aids motivated part of them to turn to more sophisticated cochlear device systems. OBJECTIVE: To investigate the outcome of cochlear implantation (CI) among elderly cochlear implant recipients. METHODS: The medical records of 20 postlingual patients aged >65 years at the time of CI, who were followed up for a period of at least 12 months were retrospectively reviewed for age at the time of CI, the cause and duration of deafness, hearing aid experience, comorbidities, complications of the procedure and audiological outcome. Pre- and post-CI speech perception performance was tested using a battery of speech perception tests. RESULTS: In addition to bilateral severe to profound hearing loss, all 20 patients had some comorbidities and 13 had more than 2 pathologies that are associated with hearing impairment. Major complications such as facial nerve paralysis and foreign body reaction were rare (n = 2). Minor complications such as disequilibrium (n = 5) and wound problems (n = 5) resolved spontaneously or were successfully managed conservatively. There were no complications associated with general anesthesia used during the CI procedure. Statistical analysis using the Wilcoxon Signed Rank Test showed significant differences (p < 0.01) between the pre- and postspeech perception categories. No significant correlations were found between the background data: unaided thresholds, aided thresholds, duration of profound deafness, duration of hearing aid use prior to CI, speech perception before CI and speech perception performance after CI using Pearson correlations. CONCLUSION: CI was found to be associated with significant hearing benefit in elderly candidates. However, every CI candidate must be informed about possible complications associated with the procedure, especially related to the vestibular system. At the same time, it should be made clear that life-threatening conditions are rare and that the surgery is usually safe.

Factors affecting choice of device by cochlear implant candidates.

OBJECTIVE: To investigate the ways the various cochlear devices are chosen by candidates/surrogates and analyze the factors that influenced their decisions. SETTING: University-affiliated tertiary referral center. METHOD: : A questionnaire that included general items and questions on device's aesthetics, technical considerations, and quality was sent to 429 patients who underwent cochlear implantation between June 1997 and December 2006 in our department. RESULTS: One hundred eighty-four questionnaires were returned, yielding a response rate of 42.9%. Some patients did not receive the questionnaires because of the postal address changes. In addition, recently implanted patients/their surrogates were more ready to answer on the questionnaire on decision-making process compared with those who received their devices before 2001. The Nucleus users were more influenced by the questions pertaining to the quality/reliability of the device than the aesthetic and technical aspects. The ABC users were more influenced by the aesthetic aspects, and the MED-EL users were generally influenced by all the groups of questions equally. Females used the Internet as the source of information on the devices significantly more than males, and their decisions were more influenced by their families than those of the males. In addition, the females were more influenced by the quality of a device's function compared with males. Pediatric candidates (aged 1-16 yr) were significantly more influenced by the experience of other implant users, the medical staff, and religious considerations than adults. Adults arrived at decisions more easily than children or their surrogates. The adults and older children were more influenced by the ease of the device's functioning compared with the young children. CONCLUSION: Choosing the type of cochlear implant device is a highly individualized process that depends on various personal, social and cultural factors, and factors linked directly to the device itself.

Cortical neural activity underlying speech perception in postlingual adult cochlear implant recipients.

Auditory event-related potentials (AERPs) and the simultaneously obtained behavioral measures (performance accuracy and reaction time) were used to study speech perception in postlingual adult cochlear implant (CI) recipients and in normal-hearing (NH) controls. AERPs were recorded while subjects were performing oddball discrimination tasks with increasing acoustic-phonetic demand. The tasks consisted of pairs of natural syllables that differed by one of the following phonetic contrasts: vowel place, voicing, vowel height, and place of articulation. Results indicated that the P3 potential was comparable in CI recipients and NH controls when the acoustic cues to the perception of the phonetic contrast were accessible. With the reduction in accessibility to the essential temporal and/or spectral cues, CI recipients exhibited delayed (prolonged P3 latency) and less synchronous (reduced amplitude) central speech-sound processing compared to NH controls. Among the phonetic contrasts used in the present study the place of articulation contrast yielded (1) the most prominent differences between CI recipients and NH controls across all measures, and (2) significant correlations between the neurophysiologic manifestation of speech discrimination (i.e. P3 latency), and conscious integration of perceptual information (i.e. performance accuracy and reaction time). Thus, P3 exposed the difficulties imposed on the impaired auditory system of CI recipients especially when elicited by speech contrasts that required processing of brief temporal-spectral cues. These findings support the P3 potential as a sensitive neural index of cortical processing that may provide information regarding accessibility and neural encoding of distinct acoustic-phonetic cues in CI recipients.

Effects of speech in noise and dichotic listening intervention programs on central auditory processing disorders.

Twenty children with central auditory processing disorders [(C)APD] were subjected to a structured intervention program of listening skills in quiet and in noise. Their performance was compared to that of a control group of 10 children with (C)APD with no special treatment. Pretests were conducted in quiet and in degraded listening conditions (speech noise and competing speech). The (C)APD management approach was integrative and included top-down and bottom-up strategies. It focused on environmental modifications, remediation techniques, and compensatory strategies. Training was conducted with monosyllabic and polysyllabic words, sentences and phrases in quiet and in noise. Comparisons of pre- and post-management measures indicated increase in speech recognition performance in background noise and competing speech for the treatment group. This improvement was exhibited for both ears. A significant difference between ears was found with the left ear showing improvement in both the short and the long versions of competing sentence tests and the right ear performing better in the long competing sentences only following intervention. No changes were documented for the control group. These findings add to a growing body of literature suggesting that interactive auditory training can improve listening skills.