British journal of audiology最新文献

The Health Visitor Distraction Test (HVDT) screen for hearing was replaced in West Berkshire in 1989 with a vigilance programme incorporating a questionnaire. The detection of permanent congenital deafness (bilateral > 50 dB HL) for all children born since 1984 has been audited to compare the two regimes. Sixty-two cases met the criteria, giving an ascertainment of 1.0 per 1000. Performance was similar under the two systems for severe/profound losses (> 70 dB HL), but there was a longer tail of late-detected moderate losses (50-70 dB HL) under the vigilance regime. The sensitivity of the Health Visitor questionnaire in referring those with permanent hearing loss was very similar to that of the HVDT (39% compared with 42%). Coverage for the questionnaire was approximately 87%, but only 78% for the known cases. Referral rate was lower under the vigilance programme, at approximately 3%. The results suggest that a vigilance programme is likely to perform as well as the HVDT but no better. Despite subsequent modifications to the vigilance programme, the poor pickup of moderate losses probably indicates the limitations of parental and professional observation in detecting partial hearing problems. The evidence adds support to the recent recommendations for universal neonatal screening.

A model for predicting loudness for people with cochlear hearing loss was applied to the problem of the initial fitting of a multi-channel compression hearing aid. The fitting was based on two constraints: (1) The specific loudness pattern evoked by speech of a moderate level (65 dB SPL) should be reasonably flat (equal loudness per critical band), and the overall loudness should be similar to that evoked in a normal listener by 65-dB speech (about 23 sones for binaural listening); (2) Speech with an overall level of 45 dB SPL should just be audible in all frequency bands from 500 Hz up to about 4 kHz, provided that this does not require compression ratios exceeding about 3. These two constraints were used to determine initial values for the gain, compression ratio and compression threshold in each channel of a multi-channel compression system. This initial fitting was based entirely on audiometric thresholds; it does not require suprathreshold loudness measures. The fitting method was evaluated using an experimental fast-acting four-channel compression system. The initial fitting was followed by an adaptive procedure to 'fine tune' the fitting, and the aids were then used in everyday life. Performance was evaluated by use of questionnaires and by measures of speech intelligibility. Although the fine tuning resulted in modest changes in the fitting parameters for some subjects, on average the frequency response shapes and compression ratios were similar before and after the fine tuning. The fittings led to satisfactory loudness impressions in everyday life and to high speech intelligibility over a wide range of levels. It was concluded that the initial fitting method gives reasonable starting values for the fine tuning.

A collaborative nine-centre study was designed to follow the routes to identification of all children up to the age of seven years newly diagnosed with permanent hearing impairment (> or = 50 dB HL) during the period 1993-1994. Ages of identification were compared with the standards set by the National Deaf Children's Society (NDCS), ascertaining whether these targets could be achieved with current service provision. Of the 126 children identified, 104 had congenital sensorineural hearing loss: 19% were identified by the age of six months and 39% by their first year. These results fall short of the NDCS targets of 40% and 80%, respectively, and point to the need for modifications of current practice, such as the introduction of universal neonatal screening.

Many classrooms are noisy and this interferes with listening and teaching. FM soundfield (FM) amplification systems have been developed which provide a uniform soundfield throughout the classroom and increase the speech-signal:noise ratio. The effect on comprehension of such a system was investigated. Forty-nine pupils (comprising the two top classes of a mainstream primary school) participated in this study, with a mean age of 9.92 years (range 8.58-11.42 years). The Neale Analysis of Reading Ability (Neale, 1988a, b) was modified and administered as a spoken comprehension test. Tests of nonverbal intelligence, auditory memory and a questionnaire were given. The passages spoken though the FM amplification system were understood better than the comparable unamplified passages. Auditory memory, sex and non-verbal intelligence had no effect on improved comprehension. FM amplification significantly improved comprehension and could be considered for use in other schools.

The accuracy of the analyses of vestibular test results obtained from a computerized electronystagmography (ENG) system depends on the accuracy with which the system has been calibrated to record the patient's eye movements. The variability of the calibration sensitivity was investigated by analysing the records of 50 consecutive patients who attended for vestibular testing and a study was carried out using 16 volunteer subjects to examine the contributions that time, changes in lighting and subject movement made to this variability. The effect of calibration frequency on the results obtained from caloric testing was also examined by analysing 16 patient records. The mean percentage change in sensitivity between the first two calibrations carried out on patients was found to be -17%, with a standard deviation of 18%. However, there seems to be little baseline drift over time under constant lighting conditions. Changes in lighting have a marked effect, and the adjustment to lighting changes is slow. Gentle movement has little effect. Repeated calibration does not seem to be an effective method to control the calibration-related errors in caloric test results. Careful control of room illumination and the use of adequate adaptation periods to allow patients to adjust to the lighting should help to improve accuracy but, even in the absence of satisfactory calibration, the use of a computerized ENG system can provide valuable diagnostic information.

The aim of this study was to establish whether and to what degree certain types of communication strategies (hearing tactics) used by hearing-impaired adults could be shown to co-occur, and to find out which strategies were more likely to be used in which type of communicative situations. A consecutive series of 100 patients attending an audiological rehabilitation clinic was given a questionnaire asking how often they used each of five different hearing tactics in 11 different situations. 'Avoidance' and 'request for repetition' were the tactics used most commonly. 'Pretending to hear/understand' and 'positioning self to improve hearing' were used less frequently, with 'interruption' the least commonly used. There was some association between tactics and situations but no clear picture emerged. In a reassessment of our methodology and results, we suggest that the future research of communication strategies would benefit from a sociolinguistic approach based on the qualitative analysis of naturally occurring discourse (conversation) of hard-of-hearing people, focusing on the use of different strategies in relation to communicators' goals in interaction.