E. J. Barker

Speech perception in children with auditory neuropathy/dyssynchrony managed with either hearing AIDS or cochlear implants.

Objective: To evaluate speech perception skills in children with auditory neuropathy (AN)/auditory dyssynchrony (AD)-type hearing loss managed with either hearing aids or cochlear implants. Study Design: Prospective data collection in 3 subject groups: AN/AD children fitted with bilateral amplification, AN/AD children fitted with cochlear implant (in 1 or both ears), and a matched control group of implanted children with sensorineural hearing loss. Main Outcome Measure: Open-set monosyllabic words (consonant-nucleus-consonant). Results: Of the 10 implanted AN/AD children, 9 demonstrated significant speech discrimination (consonant-nucleus-consonant phoneme score ≥55%). Similar results were obtained for the aided AN/AD group. Findings for both AN/AD subject groups were poorer than those of the implanted sensorineural cohort. Conclusion: Cochlear implantation can offer useful hearing in subjects with AN/AD-type hearing loss. However, expectations for this group may need to be lower than for patients with peripheral (cochlear) loss.

A clinical report on receptive vocabulary skills in cochlear implant users

Objective The aim was to measure the rate of vocabulary acquisition for cochlear implant users and compare the pre- and postoperative rates with published data for other groups with normal or impaired hearing. The hypothesis was that the postoperative rate would be greater than the preoperative rate. Design The Peabody Picture Vocabulary Test (PPVT) was administered to 32 children, adolescents, and prelinguistically deafened adults implanted with the 22-electrode cochlear implant. Age at implantation ranged from 2 yr 6 mo to 20 yr and implant use ranged from 6 mo to 7 yr 8 mo. Results The group mean postoperative performance at various postoperative intervals was significantly higher than mean preoperative performance. Single-subject data indicated statistically significant gains over time on this test for 13 of the subjects. The mean postoperative rate of vocabulary acquisition of 1.06 times the rate for normally hearing children was significantly greater than the mean preoperative rate of 0.43. Conclusions These rates of improvement were in accord with previous reports on smaller numbers of implant users, but could not be attributed unambiguously to use of the implant because no control group was used for this clinical work. Variables such as age at implantation, duration of profound deafness, communication mode, and speech perception skill failed to significantly predict rate of improvement on the PPVT.

Speech perception ability in individuals with Friedreich ataxia.

The aim of this study was to investigate auditory pathway function and speech perception ability in individuals with Friedreich ataxia (FRDA). Ten subjects confirmed by genetic testing as being homozygous for a GAA expansion in intron 1 of the FXN gene were included. While each of the subjects demonstrated normal, or near normal sound detection, 3 of the 10 showed electrophysiological evidence of auditory pathway disorder [presenting with the auditory neuropathy/dyssynchrony (AN/AD) result pattern], and 9 of the 10 showed abnormal speech understanding when tested with levels of background noise typical of everyday listening conditions. Information transmission analyses of the speech perception findings for the three FRDA subjects with AN/AD type hearing loss when compared with those of a cohort of individuals with peripheral [sensorineural (SN)] hearing loss, showed a distinct pattern of perceptual disruption. Where the listeners with SN loss confused sounds on the basis of frequency (pitch) differences, the FRDA subjects with AN/AD made errors that reflected an inability to perceive temporal (timing) cues in the speech sounds.

Speech perception in children using cochlear implants: prediction of long-term outcomes

Abstract A group of 102 children using the Nucleus multichannel cochlear implant were assessed for open-set speech perception abilities at six-monthly intervals following implant surgery. The group included a wide range of ages, types of hearing loss, ages at onset of hearing loss, experience with implant use and communication modes. Multivariate analysis indicated that a shorter duration of profound hearing loss, later onset of profound hearing loss, exclusively oral/aural communication and greater experience with the implant were associated with better open-set speech perception. Developmental delay was associated with poorer speech perception and the SPEAK signal coding scheme was shown to provide better speech perception performance than previous signal processors. Results indicated that postoperative speech perception outcomes could be predicted with an accuracy that is clinically useful.

Speech perception in noise for children with auditory neuropathy/dys-synchrony type hearing loss.

Objective: To evaluate the effect of background noise on speech perception in children with auditory neuropathy/dys-synchrony (AN/AD) type hearing loss. Design: Open and closed-set speech perception abilities were assessed in 12 school-age children who had been diagnosed with AN/AD in infancy. Data were also obtained from a cohort of subjects with sensorineural (SN) hearing loss and from a group of normal-hearing children. Results: Closed-set speech understanding was more affected by the presence of a competing signal in the hearing impaired than in the normal-hearing subjects. The mean S/N ratio required to identify a spondee in noise was –11.5 ± 2.0 dB for the normal group, whereas the ratio required for the SN group was –5.4 ± 5.1 dB and for the AN/AD group was –2.5 ± 4.7 dB. Closed-set perception in noise was not significantly different for the AN/AD children and their SN counterparts although there was a trend toward poorer performance in the AN/AD group. The effect of background noise on open-set speech perception was also similar across hearing-impaired subjects although again, the AN/AD cohort tended to show greater difficulties in noise than their SN peers. Conclusions: Listening in background noise was more difficult for our group of children with AN/AD-type hearing loss than for their normal-hearing peers. However, the noise effects were not consistent across subjects and some children demonstrated reasonable perceptual ability at low signal-to-noise ratios. The ways in which speech understanding is affected by competing signals may be different for different types of hearing deficit, but the results of this investigation indicate that significant perceptual disruption occurs both in children with auditory neuropathy/dys-synchrony and sensorineural type hearing loss.

A clinical report on speech production of cochlear implant users

Objective The aim was to assess articulation and speech intelligibility over time in a group of cochlear implant users implanted at 8 yr or over. The hypothesis was that the postoperative speech production performance would be greater than the preoperative performance. Design A test of intelligibility using sentences and an articulation test measuring non-imitative elicited speech were administered to 11 and 10 subjects, respectively, who were implanted with the 22-elec-trode cochlear implant. Nine subjects received both tests. Age at implantation ranged from 8 yr to 20 yr and implant use ranged from 1 yr to 4 yr 5 mo. Results For both the intelligibility and articulation tests roughly half of the subjects showed significant improvements over time and group mean postoperative performance significantly exceeded preoperative performance. Improvements occurred for front, middle, and back consonants; for stops, fricatives, and glides and for voiceless and voiced consonants. Conclusions Despite being deprived of acoustic speech information for many childhood years, roughly half of the patients assessed showed significant gains in speech intelligibility and articulation postimplantation. The lack of a control group of non-implanted patients means that we cannot separate out the influence of the implant on speech production from other influences such as training and tactile-kinaesthetic feedback.

Speech and language outcomes in children with auditory neuropathy/dys-synchrony managed with either cochlear implants or hearing aids

The aim of this study was to assess the receptive language and speech production abilities of a group of school-aged children with auditory neuropathy/dys-synchrony-type hearing loss. Ten children who had received a cochlear implant in one or both ears participated. Findings for this group were compared with those for a matched cohort of implanted children with other forms of sensorineural hearing loss and with those for a group of auditory neuropathy/dys-synchrony children who were long-term hearing aid users. Results for 9 of the ten implanted children with auditory neuropathy/dys-synchrony were similar to those of the general population of paediatric implant recipients. (One child, who gained little perceptual benefit from his device, showed severely delayed spoken language development). Results for the group of aided auditory neuropathy/dys-synchrony subjects were comparable to those for their implanted counterparts suggesting that affected children should not automatically be considered cochlear implant candidates.

Speech perception outcomes in older children who use multichannel cochlear implants: Older is not always poorer

Speech perception outcomes for early-deafened children who undergo implantation as teenagers or young adults are generally reported to be poorer than results for young children. It is important to provide appropriate expectations when counseling adolescents and their families to help them make an informed choice regarding cochlear implant surgery. The considerable variation of results in this group makes this process more difficult. This study considered a number of factors in a group of 25 children who underwent implantation in Melbourne between the ages of 8 and 18 years. Each subject completed open-set speech perception testing with Bamford-Kowal-Bench sentences before and after implantation and preoperative language testing with the Peabody Picture Vocabulary Test. Data were collected regarding the type of hearing loss, age at implantation, age at hearing aid fitting, audiometric details, and preoperative and postoperative communication mode. Results were submitted to a stepwise multiple linear regression analysis with postoperative open-set sentence scores as the dependent variables. The analysis suggested that 3 factors have a significant predictive value for speech perception after implantation: preoperative open-set sentence score, duration of profound hearing loss, and equivalent language age. These 3 factors accounted for 66% of the variance in this group. The results of this study suggest that children who have useful speech perception before implantation, and higher age-equivalent scores on language measures, would be expected to do well with a cochlear implant. Consistent with other studies, a shorter duration of profound hearing loss is also advantageous. The mean sentence score for this group, 47%, was not significantly different from the mean result across all children in the Melbourne program.

Receptive language and speech production in children with auditory neuropathy/dyssynchrony type hearing loss

Objective: The purpose of this study was to characterize the receptive language and speech production abilities of school-aged children with auditory neuropathy/dyssynchrony (AN/AD) and to compare those abilities to children with sensorineural (SN) hearing loss of similar age and degree of hearing loss. Design: Standardized speech and language tests were carried out on 12 AN/AD children, aged between 57 and 167 mo. Each of these subjects was a full-time hearing aid user or had been just before testing. Receptive language skills were assessed using the Peabody Picture Vocabulary Test (PPVT) and speech production ability was measured using the Diagnostic Evaluation of Articulation and Phonology (DEAP) and a Speech Intelligibility Rating Scale. Data from a matched cohort of children with sensorineural hearing loss were also obtained. Results: Receptive vocabulary and speech production were delayed (to varying degrees) in each of the AN/AD subjects (relative to normally hearing children). The group PPVT Language Quotient score was 0.65 ± 0.19 and the average number of pronunciation errors was 11 ± 8.4% higher than expected for age. Results for the AN/AD group were however similar to those obtained for a matched group of children with sensorineural hearing loss on both language and speech production measures. Conclusions: The findings of this study indicate that while AN/AD type hearing loss can pose a significant developmental risk, at least some children fit with conventional amplification can develop reasonable speech and language abilities.

Auditory perception in individuals with Friedreich's ataxia.

Introduction: Friedreich’s ataxia (FRDA) is an inherited ataxia with a range of progressive features including axonal degeneration of sensory nerves. The aim of this study was to investigate auditory perception in affected individuals. Methods: Fourteen subjects with genetically defined FRDA participated. Two control groups, one consisting of healthy, normally hearing individuals and another comprised of subjects with sensorineural hearing loss, were also assessed. Auditory processing was evaluated using structured tasks designed to reveal the listeners’ ability to perceive temporal and spectral cues. Findings were then correlated with open-set speech understanding. Results: Nine of 14 individuals with FRDA showed evidence of auditory processing disorder. Gap and amplitude modulation detection levels in these subjects were significantly elevated, indicating impaired encoding of rapid signal changes. Electrophysiologic findings (auditory brainstem response, ABR) also reflected disrupted neural activity. Speech understanding was significantly affected in these listeners and the degree of disruption was related to temporal processing ability. Speech analyses indicated that timing cues (notably consonant voice onset time and vowel duration) were most affected. Conclusion: The results suggest that auditory pathway abnormality is a relatively common consequence of FRDA. Regular auditory evaluation should therefore be part of the management regime for all affected individuals. This assessment should include both ABR testing, which can provide insights into the degree to which auditory neural activity is disrupted, and some functional measure of hearing capacity such as speech perception assessment, which can quantify the disorder and provide a basis for intervention.