An evaluation of ABR audiometry for the screening and detection of hearing loss in ex-SCBU infants

The study aimed to use auditory brainstem response (ABR) audiometry to test ex-SCBU infants born during 1986 in West Berkshire. Two hundred and forty-three babies were tested as out-patients, thus achieving a coverage rate of 86% of the target population. Mean post-conceptional age at test was 48 weeks. Whenever possible, full ABR threshold determination was performed on both ears and the mean ABR threshold was found to be 14 dB nHL. Of those babies attending, 85% showed ABRs at ≤ 30 dB nHL bilaterally and the remaining 15% were referred for further assessment. Approximately two-thirds of these were recalled successfully for repeat testing. The estimated prevalence rate for bilateral sensorineural hearing impairment was 1.4% with four confirmed cases. Two additional permanent unilateral hearing losses were also detected. On the basis of recorded ABR data, sensitivity, specificity and positive predictive values were estimated for click intensities which could be used for single-intensity ABR screens. It is concluded that delaying screening until the post-neonatal stage is a viable alternative to screening neonates prior to discharge from the SCBU.