A Clinical Paradigm for Listening Effort Assessment in Middle-Aged Listeners.

Listening effort (LE) has been known to characterize speech recognition in noise regardless of hearing sensitivity and age. Whereas the behavioral measure of dual-task paradigm effectively manifests the cognitive cost that listeners exert when processing speech in background noise, there is no consensus as to a clinical procedure that might best express LE. In order to assess the cognitive load underlying speech recognition in noise and promote counselling for coping strategies, a feasible clinical paradigm is warranted. The ecological validity of such a paradigm might best be demonstrated in middle-aged adults, exhibiting intact hearing sensitivity on one hand, however, experiencing difficulties in degraded listening conditions, unaware of the implicated cognitive cost of speech recognition in noise. To this end, we constructed a dual-task paradigm that consists of a primary task of sentences-in-noise recognition and a secondary task of simple visual colored-shape matching. Research objective was to develop a clinical paradigm for the assessment of LE in middle-aged adults. Participants were 17 middle-aged adults (mean age of 52.81 years) and 23 young adults (mean age of 24.90 years). All participants had normal hearing according to age. Speech stimuli consisted of the Hebrew Matrix sentences in noise test. SRTn was obtained for 80% correct identification. Visual stimuli were colored geometric shapes. Outcome measures were obtained initially for each task separately, to establish performance ability, and then obtained simultaneously. Reaction time and accuracy in the secondary task were the defined metrics for LE. Results: LE was indicated for both groups, however, was more pronounced in the middle-aged, manifested in the visual accuracy and reaction time metrics. Both groups maintained the 80% correct recognition-in-noise in the dual-task, however, the middle-aged group necessitated a better SNR of 1.4dB than the normal hearing group. Moreover, the middle-aged group was taxed in a greater prolongation of reaction time, in order to uphold the correct recognition. Conclusion: a dual-task paradigm consisting of sentences-in-noise primary task combined with a simple secondary task successfully showed different manifestations of LE in middle-aged adults compared to young adults, thus approximating the use of such a paradigm in a clinical setting.

Listening to music with personal listening devices: monitoring the noise dose using a smartphone application.

OBJECTIVES: To monitor listening habits to personal listening devices (PLDs) using a smartphone application and to compare actual listening habits to self-report data. DESIGN: Two stages: self-report listening habits questionnaire, and real-time monitoring of listening habits through a smartphone application. STUDY SAMPLE: Overall 117 participants aged 18-34 years (mean 25.5 years) completed the questionnaire, and of them, 40 participants (mean age: 25.2 years) were monitored for listening habits during two weeks. RESULTS: Questionnaire main findings indicated that most of the participants reported listening for 4-7 days a week, for at least 30 min at high listening levels with volume control settings at 75-100%. Monitored data showed that actual listening days per week were 1.5-6.5 d, with mean continuous time of 1.56 h, and mean volume control setting of 7.39 (on a scale of 1-15). Eight participants (22%) were found to exceed the 100% noise dose at least once during the monitoring period. One participant (2.7%) exceeded the weekly 100% daily noise dose. Correlations between actual measurements and self-report data were low to moderate. CONCLUSIONS: Results confirmed the feasibility of monitoring listening habits by a smartphone application, and underscore the need for such a tool to enable safe listening behaviour.

Neural correlates of auditory-cognitive processing in older adult cochlear implant recipients.

With the growing number of older adults receiving cochlear implants (CI), there is general agreement that substantial benefits can be gained. Nonetheless, variability in speech perception performance is high, and the relative contribution and interactions among peripheral, central-auditory, and cognitive factors are not fully understood. The goal of the present study was to compare auditory-cognitive processing in older-adult CI recipients with that of older normal-hearing (NH) listeners by means of behavioral and electrophysiologic manifestations of a high-load cognitive task. Auditory event-related potentials (AERPs) were recorded from 9 older postlingually deafened adults with CI (age at CI >60) and 10 age-matched listeners with NH, while performing an auditory Stroop task. Participants were required to classify the speaker's gender (male/female) that produced the words 'mother' or 'father' while ignoring the irrelevant congruent or incongruent word meaning. Older CI and NH listeners exhibited comparable reaction time, performance accuracy, and initial sensory-perceptual processing (i.e. N1 potential). Nonetheless, older CI recipients showed substantially prolonged and less efficient perceptual processing (i.e. P3 potential). Congruency effects manifested in longer reaction time (i.e. Stroop effect), execution time, and P3 latency to incongruent versus congruent stimuli in both groups in a similar fashion; however, markedly prolonged P3 and shortened execution time were evident in older CI recipients. Collectively, older adults (CI and NH) employed a combined perceptual and postperceptual conflict processing strategy; nonetheless, the relative allotment of perceptual resources was substantially enhanced to maintain adequate performance in CI recipients. In sum, the recording of AERPs together with the simultaneously obtained behavioral measures during a Stroop task exposed a differential time course of auditory-cognitive processing in older CI recipients that was not manifested in the behavioral end products of processing. These data may have implications regarding clinical evaluation and rehabilitation procedures that should be tailored specifically for this unique group of patients.

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.

Improving word recognition in noise among hearing-impaired subjects with a single-channel cochlear noise-reduction algorithm.

A common complaint of the hearing impaired is the inability to understand speech in noisy environments even with their hearing assistive devices. Only a few single-channel algorithms have significantly improved speech intelligibility in noise for hearing-impaired listeners. The current study introduces a cochlear noise reduction algorithm. It is based on a cochlear representation of acoustic signals and real-time derivation of a binary speech mask. The contribution of the algorithm for enhancing word recognition in noise was evaluated on a group of 42 normal-hearing subjects, 35 hearing-aid users, 8 cochlear implant recipients, and 14 participants with bimodal devices. Recognition scores of Hebrew monosyllabic words embedded in Gaussian noise at several signal-to-noise ratios (SNRs) were obtained with processed and unprocessed signals. The algorithm was not effective among the normal-hearing participants. However, it yielded a significant improvement in some of the hearing-impaired subjects under different listening conditions. Its most impressive benefit appeared among cochlear implant recipients. More than 20% improvement in recognition score of noisy words was obtained by 12, 16, and 26 hearing-impaired at SNR of 30, 24, and 18 dB, respectively. The algorithm has a potential to improve speech intelligibility in background noise, yet further research is required to improve its performances.

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.

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.

Preferred listening levels of personal listening devices in young teenagers: self reports and physical measurements.

OBJECTIVE: To assess the potential risk of hearing loss to young listeners, due to the use of personal listening devices (PLDs). DESIGN: The study included two parts: (1) A self-report questionnaire on music listening habits, and (2) Physical measurements of preferred listening levels, in quiet and in everyday background noise. STUDY SAMPLE: Young teenagers aged 13 to 17 years. Part 1 included 289 participants with mean age of 14 years. Part 2 included 11 and 74 participants (2A and 2B) with a mean age of 15 years. Eleven listened to PLDs in quiet conditions (2A) and 74 in everyday background noise (2B). RESULTS: Questionnaire main findings indicated that most of the participants reported high or very high volume settings and demonstrated low awareness towards loud music listening consequences. Physical measurements corrected for diffuse field indicated mean preferred listening levels of: 82 (SD = 9) dBA in quiet, and 89 (SD = 9) dBA in the presence of background noise. The potential risk to hearing of PLDs users was calculated using the 8 hour equivalent level. CONCLUSION: More than 25% of the participants in the noisy condition were found to be at risk according to occupational damage risk criteria NIOSH, 1998.

Auditory conflict processing: behavioral and electrophysiologic manifestations of the stroop effect.

BACKGROUND: One of the most extensively studied phenomena in cognitive neuroscience is the Stroop effect. In an enormous corpus of literature, the Stroop task has been used to study conflict processing in the visual modality; however, scarce data exist in the auditory modality. PURPOSE: The main goal of the present study was to investigate auditory conflict processing by means of behavioral and electrophysiologic measures elicited during standard and reversed Stroop tasks. A secondary goal was to examine practice-related effects. RESEARCH DESIGN: Event-related potentials (ERPs) were recorded from 16 adults during tasks requiring classification of word meaning or speaker's gender while ignoring the irrelevant (congruent or incongruent) speaker's gender or word meaning, respectively. The behavioral measures, reaction time and performance accuracy, were simultaneously obtained. RESULTS: Results indicated (1) a significant behavioral Stroop effect manifested by prolonged reaction time and reduced performance accuracy. In contrast, ERP latencies were unaffected by the processing of incongruent versus congruent stimuli, supporting postperceptual conflict processing associated with response selection and execution; (2) reduced N1 amplitude while processing incongruent versus congruent stimuli; (3) similar behavioral Stroop effects in both tasks together with nonsignificant task by stimulus type (incongruent, congruent) interactions for N1 and N4; (4) significantly prolonged N4 and reaction time together with reduced N1 amplitude in the speaker's gender task (to both congruent and incongruent stimuli) compared to those found in the word meaning task; and (5) practice-related improvement in processing efficacy based on enhanced N1 amplitude, as well as shorter N4 and reaction time. CONCLUSIONS: Auditory conflict processing was predominantly postperceptual and was located at the response selection and execution stages. Alterations in the N1 component, however, provided support for an auditory conflict-processing "signature" at the initial stages of the arrival of information to the auditory cortex. The current data indicate that speaker's gender and word meaning intruded on one another in a similar fashion, supporting symmetry between standard and reversed auditory Stroop effects. Nonetheless, improved processing efficacy was evident while classifying word meaning. Utilization of the present methodology may prove advantageous for studying clinical populations exhibiting auditory and/or linguistic processing deficits.

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.

Identification of syllables in noise: electrophysiological and behavioral correlates.

This study was designed to characterize the effect of background noise on the identification of syllables using behavioral and electrophysiological measures. Twenty normal-hearing adults (18-30 years) performed an identification task in a two-alternative forced-choice paradigm. Stimuli consisted of naturally produced syllables [da] and [ga] embedded in white noise. The noise was initiated 1000 ms before the onset of the speech stimuli in order to separate the auditory event related potentials (AERP) response to noise onset from that to the speech. Syllables were presented in quiet and in five SNRs: +15, +3, 0, -3, and -6 dB. Results show that (1) performance accuracy, d', and reaction time were affected by the noise, more so for reaction time; (2) both N1 and P3 latency were prolonged as noise levels increased, more so for P3; (3) [ga] was better identified than [da], in all noise conditions; and (4) P3 latency was longer for [da] than for [ga] for SNR 0 through -6 dB, while N1 latency was longer for [ga] than for [da] in most listening conditions. In conclusion, the unique stimuli structure utilized in this study demonstrated the effects of noise on speech recognition at both the physical and the perceptual processing levels.

Connexin-associated deafness and speech perception outcome of cochlear implantation.

OBJECTIVE: To compare performance after cochlear implantation in children with mutations in connexin (Cx) 26 (GJB2) or Cx30 (GJB6) and children with deafness of unknown etiology. DESIGN: Genetic analysis and speech perception evaluation was performed in the children with and without Cx mutations who had undergone cochlear implantation. Speech perception performance was retrospectively analyzed 6, 12, 24, 36, and 48 months after implantation. Test material was selected according to the child's age and cognitive and language abilities. SETTING: The study took place at speech and hearing and genetic centers of a hospital in the central part of Israel and the genetics departments of 3 additional centrally located hospitals. PATIENTS: A total of 30 children who had undergone cochlear implantation were selected for the study, with control patients matched according to age at implantation, duration of implant use, and mode of communication. There was no evidence for additional disabilities or handicaps in either group. MAIN OUTCOME MEASURES: Speech perception measurements included a questionnaire, as well as closed and open-set tests. RESULTS: Overall, the 2 groups showed significant improvement in speech perception results after implantation. Four years after implantation, both groups achieved mean open-set speech perception scores of approximately 60%, 75%, and 90% for monosyllabic, 2 syllables, and words in sentences tests, respectively. CONCLUSIONS: There were no apparent differences in speech perception performance after implantation between the children with Cx mutations and children with deafness of unknown etiology. These data have important implications as a prognostic indicator when counseling candidates for cochlear implantation.

A longitudinal study of electrical stimulation levels and electrode impedance in children using the Clarion cochlear implant.

CONCLUSIONS: Electrical stimulation levels and electrode impedance values (EIVs) in children using the Clarion cochlear implant (CI) programmed with CIS strategy stabilized after 3 months of implant use. The data presented here may be useful as a general guideline for the programming of infants and young children and may further be of help for the identification of patients who fall outside the "average" range. OBJECTIVES: The purpose of the present study was to evaluate changes in electrical stimulation levels, i.e. threshold (T) levels, comfortable (M) levels, dynamic range (DR), and EIVs during the first 18 months of implant use, in children using the Clarion CI. MATERIALS AND METHODS: The maps of 18 pre-lingual children (mean age at implantation 4.2 years; range 1-8), using the Enhanced Bipolar 1.2 or Bipolar standard electrode with the S-Series speech processor programmed with CIS strategy, were examined at five time points: connection, and 3, 6, 12, and 18 months post-initial stimulation. T levels, M levels, DR and EIVs were analyzed according to four cochlear segments: apical, apical-medial, medial-basal, and basal. RESULTS: During the first 3 months of implant use T levels increased to some extent, whereas M levels and DR increased significantly. From 3 months and through the entire follow-up, T and M levels as well as DR were stable. EIVs of current carrying electrodes decreased significantly from connection to the 3-month visit; thereafter a stabilization of values was evident. Electrical stimulation levels and EIVs did not differ among the cochlear segments during the entire follow-up.

Surgical and medical complications in paediatric cochlear implantation: a review of 300 cases.

The aim of the study was to investigate an incidence of surgical and medical complications in different age groups of cochlear implant children. A retrospective study design was used. Patients' medical records were reviewed for age at the time of implantation, cause of deafness and complications. The incidence of complications was compared between the young (aged up to 2 years, n = 61) and older children (aged 216 years, n = 239). Some 300 paediatric cochlear implantations were performed in our department between January 1993 and March 2005. Major complications, such as facial nerve paralysis, electrode misplacement, foreign body reaction, flap breakdown, protrusion of the positioner and cholesteatoma were rare (3%). Disequilibrium was found to be the most common complication, followed by wound problems and mastoiditis without significant differences between the two groups. However, magnet or receiver-stimulator displacement were more common in the young children (p = 0.028). Most surgical and medical complications could be treated successfully, and only 2% required explantation of the device. Generally, operating on a child aged under 2 years was not particularly different from operating on an older child.

Electrical stimulation levels and electrode impedance values in children using the Med-El Combi 40+ cochlear implant: a one year follow-up.

The present study was designed to follow changes in electrical stimulation levels and electrode impedance values (EIV) in children using the Med-El Combi 40+ cochlear implant (CI) during the first 12 months of implant use. The maps of 24 prelingually deaf children implanted at a mean age of 5.9 years (range 1-15.9 years) using the TEMPO+ speech processor programmed with CIS+ strategy were examined at five time points: initial stimulation, and 1, 3, 6, and 12 months post-initial stimulation. Most comfortable levels (M) and electrode impedance values (EIV) were analyzed according to three cochlear segments: apical, medial, and basal. Results indicated a significant increase in M levels until the 3-month time point, thereafter stabilization was evident. Furthermore, M levels in the apical segment were lower than those in the medial and basal segments. EIV decreased from initial stimulation to the 3-month time point and was then stable through the study follow up. Interestingly, the finding of higher EIV in the apical segment may be attributed to the physical characteristics of the Med-El electrode. In conclusion, the pattern of stabilization of M levels found in the present study is similar to that reported for children using other devices. The data presented here may be useful as a guideline for programming M levels and monitoring EIV in infants and young children. They may further help clinicians to identify those children that fall outside the 'typical' range.

Cochlear implantation in Waardenburg's syndrome.

CONCLUSIONS: Children with Waardenburg's syndrome (WS) derive significant benefit from cochlear implantation (CI) and do so to an extent that is comparable to that of the general population of implanted children. Although we report on a relatively small cohort, our data are useful for counseling the parents of children with WS considering CI. OBJECTIVE: To present our experience with CI in patients with WS. MATERIAL AND METHODS: A retrospective record review was conducted for five children who underwent CI in our department between 1993 and 2004. RESULTS: Children with WS comprised 1.9% of our entire pediatric CI population: four girls had a familial history of WS and the phenotype of WS Type I, and one boy met the criteria for WS Type II. They were all diagnosed as having bilateral profound sensorineural hearing loss 4-24 weeks after birth. Rehabilitation was initiated immediately and included bilateral fitting of hearing aids and intensive speech and language therapy. Otoscopic and temporal bone high-resolution CT findings were normal in all patients. At surgery, all children were found to have a patent cochlea, and the electrodes were implanted into the scala tympani without difficulty. After 1.3-10.2 years of implant use all children achieved open-set recognition of 2-syllable words, with an average score of 81%. Four of the 5 children achieved open-set recognition of monosyllabic words (average score 40%) and 3 achieved open-set recognition of words in sentences (average score 81%).

Speech perception of children using Nucleus, Clarion or Med-El cochlear implants.

OBJECTIVE: The purpose of this study was to present speech perception achievements of implanted children using commercially available cochlear implant devices: Nucleus, Clarion or Med-El. STUDY DESIGN: A retrospective analysis. METHODS: Speech perception data of 96 hearing-impaired children: 27 with Clarion, 49 with Nucleus and 20 with Med-El were collected. Speech tests included the Hebrew Infant Toddlers Meaningful Auditory Integration Scale (HIT-MAIS) for the infants, the Hebrew Early Speech Perception (HESP) closed-set word-identification test and Hebrew Arthur Boothroyd (HAB) open-set one-syllable word recognition test were used for the older children. RESULTS: I HIT-MAIS: (1) Infants showed similar rate of progress, regardless of device. (2) Children implanted under two years of age reached performance within normal development on this test. II HAB: (1) Most children achieved open set results with mean HAB between 40 and 50%, within 1-1.5 years post implantation. (2) Linear regression analyses revealed no statistical differences between the Clarion the Nucleus and the Med-El devices on the mean final measurement of this test. (3) Age of implantation and mode of communication were significant covariate variables: (a) the younger the child is implanted the better the results and (b) oral communication prior to implantation results in better performance than sign language. CONCLUSIONS: There are no apparent differences in speech perception performance between implant devices when considering background variables. The data have important implications on the rehabilitation process of hearing impaired children with cochlear implants in relation to device selection, age at implantation and mode of communication prior to implantation.

NRT-based versus behavioral-based MAP: a comparison of parameters and speech perception in young children.

The present study was designed to evaluate the effect of neural response telemetry (NRT)-based cochlear implant (CI) programming versus behavioral-based programming on electrical stimulation parameters (MAP) threshold (T) and comfortable (C) levels and speech perception abilities in young children, during the first year of implant use. Ten congenitally deaf children at the age of 12-39 months (mean age: 25.2 months) implanted with the Nucleus 24R(CS) CI participated in the study. The group was randomly divided into two: (1) NRT-based MAP group (n = 5) consisted of children who were programmed using intra-operative NRT measurements; (2) behavioral-based MAP group (n = 5) consisted of children who were programmed using the behavioral responses of the patients. MAP parameters as well as sound-field aided thresholds and speech perception abilities were compared between the two groups at consecutive programming sessions: 1, 3, 6, and 12 months post initial stimulation. Results indicated no significant differences among NRT-based MAPs and behavioral-based MAPs. Although MAP profiles at initial stimulation differed in the apical region, these differences decreased with time. In addition, a gradual increase of T and C levels of NRT-based MAPs as well as those of behavioral-based MAPs was evident until the 1-month time point, thereafter stabilization occurred. Sound-field aided thresholds improved with time for both groups; however, they were found to be significantly better for the NRT-based MAP group. Despite these differences, speech perception abilities were comparable among groups at 12 months post initial stimulation. NRT-based programming was found to be significantly shorter than behavioral-based programming. In conclusion, for this small group of children, our findings support the use of NRT for programming of young children during the initial period after implantation.

Reduced auditory efferent activity in childhood selective mutism.

BACKGROUND: Selective mutism is a psychiatric disorder of childhood characterized by consistent inability to speak in specific situations despite the ability to speak normally in others. The objective of this study was to test whether reduced auditory efferent activity, which may have direct bearings on speaking behavior, is compromised in selectively mute children. METHODS: Participants were 16 children with selective mutism and 16 normally developing control children matched for age and gender. All children were tested for pure-tone audiometry, speech reception thresholds, speech discrimination, middle-ear acoustic reflex thresholds and decay function, transient evoked otoacoustic emission, suppression of transient evoked otoacoustic emission, and auditory brainstem response. RESULTS: Compared with control children, selectively mute children displayed specific deficiencies in auditory efferent activity. These aberrations in efferent activity appear along with normal pure-tone and speech audiometry and normal brainstem transmission as indicated by auditory brainstem response latencies. CONCLUSIONS: The diminished auditory efferent activity detected in some children with SM may result in desensitization of their auditory pathways by self-vocalization and in reduced control of masking and distortion of incoming speech sounds. These children may gradually learn to restrict vocalization to the minimal amount possible in contexts that require complex auditory processing.

Reduced medial olivocochlear bundle system function in children with auditory processing disorders.

A common complaint of children with auditory processing disorders (APD) is difficulty in understanding speech in the presence of background noise. Evidence from animal and human studies has suggested that the medial olivocochlear bundle (MOCB) may play a role in hearing in noise. The MOCB function can be evaluated by the suppression effect of the transient evoked otoacoustic emissions (TEOAE) in response to contralateral acoustic stimulation (CAS). The present study was conducted to investigate the suppression effect of TEOAE in APD children. The study groups comprised 15 APD children aged 8-13 years associated with learning disabilities and 15 controls matched for gender and age. The suppression effect of TEOAE was evaluated by comparing the TEOAE levels with and without CAS. A significantly reduced suppression effect of TEOAE was demonstrated in the APD group, when compared to the controls. In addition, higher TEOAE levels were found in the APD group, suggesting inherent reduced MOCB activity on the outer hair cells in APD children. These results imply that some APD children present low activity of the MOCB system, which may indicate a reduced auditory inhibitory function and affect their ability to hear in the presence of background noise.