Speech-perception-in-noise and bilateral spatial abilities in adults with delayed sequential cochlear implant.

OBJECTIVE: To determine speech-perception-in-noise (with speech and noise spatially distinct and coincident) and bilateral spatial benefits of head-shadow effect, summation, squelch and spatial release of masking in adults with delayed sequential cochlear implants. STUDY DESIGN: A cross-sectional one group post-test-only exploratory design was employed. Eleven adults (mean age 47 years; range 21-69 years) of the Pretoria Cochlear Implant Programme (PCIP) in South Africa with a bilateral severe-to-profound sensorineural hearing loss were recruited. Prerecorded Everyday Speech Sentences of The Central Institute for the Deaf (CID) were used to evaluate participants' speech-in-noise perception at sentence level. An adaptive procedure was used to determine the signal-to-noise ratio (SNR, in dB) at which the participant's speech reception threshold (SRT) was achieved. Specific calculations were used to estimate bilateral spatial benefit effects. RESULTS: A minimal bilateral benefit for speech-in-noise perception was observed with noise directed to the first implant (CI 1) (1.69 dB) and in the speech and noise spatial listening condition (0.78 dB), but was not statistically significant. The head-shadow effect at 180 degrees was the most robust bilateral spatial benefit. An improvement in speech perception in spatially distinct speech and noise indicates the contribution of the second implant (CI 2) is greater than that of the first implant (CI 1) for bilateral spatial benefit. CONCLUSION: Bilateral benefit for delayed sequentially implanted adults is less than previously reported for simultaneous and sequentially implanted adults. Delayed sequential implantation benefit seems to relate to the availability of the ear with the most favourable SNR.

The influence of non-linear frequency compression on the perception of music by adults with a moderate to sever hearing loss: subjective impressions.

OBJECTIVE: To date, the main direction in frequency-lowering hearing aid studies has been in relation to speech perception abilities. With improvements in hearing aid technology, interest in musical perception as a dimension that could improve hearing aid users' quality of life has grown. The purpose of this study was to determine the influence of non-linear frequency compression (NFC) on hearing aid users' subjective impressions of listening to music. DESIGN & SAMPLE: A survey research design was implemented to elicit participants' (N=40) subjective impressions of musical stimuli with and without NFC. RESULTS: The use of NFC significantly improved hearing aid users' perception of the musical qualities of overall fidelity, tinniness and reverberance. Although participants preferred to listen to the loudness, fullness, crispness, naturalness and pleasantness of music with the use of NFC, these benefits were not significant. CONCLUSION: The use of NFC can increase hearing aid users' enjoyment and appreciation of music. Given that a relatively large percentage of hearing aid users express a loss of enjoyment of music, audiologists should not ignore the possible benefits of NFC, especially if one takes into account that previous research indicates speech perception benefits with this technology.

Development of a music perception test for adult hearing-aid users.

The purpose of this research was twofold: firstly, to develop a music perception test (MPT) for hearing-aid users, and secondly, to evaluate the influence of non-linear frequency compression (NFC) on music perception with the use of the self-compiled test. This article focuses on the description of the development and validation of the MPT. To date, the main direction in frequency-lowering hearing-aid studies has been in relation to speech perception abilities. As hearing-aid technology has improved, interest has grown in musical perception as a dimension that could improve hearing-aid users' quality of life. The MPT was designed to evaluate different aspects of rhythm, timbre, pitch and melody. The development of the MPT could be described as design-based. Phase 1 of the study included test development and recording, while phase 2 entailed presentation of stimuli to normal hearing listeners (n = 15) and hearing-aid users (n = 4). Based on the findings of phase 2, item analysis was performed to eliminate or change stimuli that resulted in high error rates. During phase 3 the adapted version of the test was performed on a smaller group of normal hearing listeners (n = 4) and 20 hearing-aid users. Results proved that adults with normal hearing as well as adults using hearing aids were able to complete all the sub-tests of the MPT, although hearing-aid users scored lower on the various sub-tests than normal hearing listeners. For the rhythm section of the MPT normal hearing listeners scored on average 93.8% versus 75.5% of hearing-aid users; for the timbre section the scores were 83% versus 62.3% respectively. Normal hearing listeners obtained an average score of 86.3% for the pitch section and 88.2% for the melody section, compared with the 70.8% and 61.9% respectively obtained by hearing-aid users. This implies that the MPT can be used successfully for assessment of music perception in hearing-aid users within the South African context and may therefore result in more effective hearing-aid fittings taking place. The test can be used as a counselling tool to assist audiologists and patients in understanding the problems they experience regarding music perception, and might be used for future musical training in areas where participants experience problems in customising individual fittings.

Hearing instrument fittings of pre-school children: do we meet the prescription goals?

Verifying the match to prescribed electro-acoustic performance is essential in a scientific approach to pediatric hearing instrument fittings. This study aimed to compare hearing instrument output values, at 65 and 90 dB sound-pressure level (SPL) input signals, of instruments fitted to pre-school children in South Africa to the targets prescribed by the DSLm [i/o] (version 5.0) across the frequency range. Outputs of 31 BTE hearing instruments (20 children, 3-6 years) were verified using coupler-based SPL measurements and measured real-ear-to-coupler differences (RECDs). Results revealed that most of the hearing instrument fittings (regardless of the degree of hearing loss) did not match the prescribed targets. Only 25% of the fittings matched three or more output targets at 65 dB SPL input signal. Output values at 90 dB SPL input signal were far below the prescribed targets. It can be concluded that the lack of a systematic evidence-based approach might lead to inconsistent hearing instrument fittings. Findings may be used to educate clinicians to ensure optimal pediatric hearing instrument fittings.

Continuous versus pulsed pure-tone audiometry in a group of school-aged children.

Pure-tone testing is the primary audiological test procedure for the differential diagnosis of hearing loss and hearing disorders in school-aged children. No research is currently available internationally for children's responses to continuous versus pulsed pure-tones. The aim of this exploratory investigation was to compare the performance of a group of school-aged children on continuous versus pulsed pure-tone audiometry. The aims were to determine whether a threshold difference existed between continuous versus pulsed pure-tones and to record whether a listener preference existed between continuous versus pulsed tones for the frequency range of 125 to 8000 Hz. Eighteen children (36 ears) aged between 8-12 years, participated in a hearing evaluation as well as in a brief three-question interview. Descriptive statistics viz. average threshold, mean difference and standard deviation of thresholds were used to analyse data. Listeners' perceived preferences were calculated in percentages and reasons for preferring one signal over another was analysed qualitatively. Although the automatically pulsed tone threshold (averaged across the frequencies tested) was lower than for the continuous tone, the difference was only 0.2 dB in the left ear and 0.5dB in the right ear. This small difference is not important in clinical applications for which 5 dB increments are used in pure-tone audiometry. Where a listener preference was indicated, however, the continuous tones were preferred over pulsed tones by 56% percent of subjects. These findings differ from similar studies involving adults. This revealed that children may yield different preferences during pure-tone testing than adults and that these preferences should be taken into consideration during testing.

[Auditory functioning with cochlear implants of bimodal amplification]. / Die ervarings van jong volwassenes met Kogleêre inplantings aangaande bimodale versterking.

The main function of a cochlear implant is to optimise the auditory and communicative abilities of individuals with hearing loss. The use of a hearing aid in the non-implanted ear further optimises binaural hearing, which leads to improved sound localization, speech discrimination in noise and quiet surroundings, and refined sound quality. The goal of the study was to determine the experiences of young adults with cochlear implants regarding bimodal amplification. Considering that all age groups are implanted with cochlear implants and that binaural amplification is beneficial to all age groups, it is important that information on young adults also be included. This study addressed bimodal amplification in terms of auditory, communicative, and cosmetic aspects, and handling and care of apparatus. A qualitative, descriptive research design was employed, and questionnaires were completed by five clients who are part of the Pretoria Cochlear Implant Program. Three of the participants took part in the focus group discussion in support of the results taken from the completed questionnaires. The results of the study indicate that the participants experience bimodal amplification positively, especially in terms of auditory and everyday communicative functioning. The participants largely perceived cosmetic aspects, handling and care of apparatus negatively. The outcomes of the study can be used by audiologists in order to adequately inform and counsel candidates regarding bimodal amplification. Potential barriers can also be addressed appropriately.

The needs of teachers of children with hearing loss within the inclusive education system.

In South Africa, the current movement towards the inclusion of children with disabilities, including children with hearing loss, is likely to have far-reaching consequences for both teachers and learners. Undoubtedly, needs will arise from teachers during the transition, especially in the areas pertaining to the audiological and educational management of children with hearing loss. Therefore, a descriptive research design was developed comprising of a questionnaire survey followed by focus group interviews to determine teachers' needs. The questionnaire survey explored the needs of 664 teachers while focus group interviews were conducted with 19 teachers of children with hearing loss. Teachers were mostly from special schools as only a very small number of children are educated outside these establishments. Findings revealed that, although participants realised the importance of various aspects of development of the child with hearing loss, they generally did not realise the importance of receiving support from an educational audiologist.