We have used a comprehensive register of hearing-impaired children born in the former Oxford Health Region to study risk factors for sensorineural hearing loss. The occurrence of a wide variety of risk factors was documented from the case notes of 145 children; these were all the cases known at the time of the study with all degrees of hearing loss born between 1984 and 1988. Comparison with the normal Regional population showed that maternal age over 35 years and Asian ethnic origin were significant risk factors for congenital (non-acquired) hearing loss (odds ratio 1.7 and 2.5 respectively). Black/Asian children were also significantly more likely to have acquired losses. Low birthweight (below 2500 g) also gave a significantly increased risk, with an odds ratio of 4.5, rising to 9.6 for birthweight less than 1500 g. We also found that significantly more hearing-impaired cases were in lower social classes compared with the general population. A high proportion of cases (24%) had cranio-facial abnormalities (CFA), including many non-aural abnormalities and dysmorphic features, which therefore should be counted as high risk. Hearing losses acquired due to perinatal causes were almost all mild or moderate. Four factors-admission to special care baby unit for more than 72 hours, CFA, family history, and meningitis-accounted for 69% of all cases in this study. Targeted neonatal screening based on the first three factors, plus obligatory testing following meningitis, therefore, should be highly efficient at detecting deafness early.

Otoacoustic emission (OAE) screening and oto-admittance testing (678 Hz probe tone) were performed on both ears of 84 special care neonates, as part of a larger study of middle-ear effusion in neonates and infants. OAE results, tympanometry, and acoustic reflex results are all strongly and significantly associated. No evidence was found of any maturational effects in the results. Based on the findings, a tentative classification scheme for neonatal tympanograms is suggested. We conclude that 678 Hz tympanometry is a useful indicator of middle-ear status in very young babies, and that middle-ear effusion does strongly affect OAEs in neonates. OAEs are also strongly affected by negative middle-ear pressure (MEP), and mean MEP in ears failing OAE screens was significantly more negative than in those passing. The prevalence of abnormal tympanometry, which may indicate middle-ear effusion or dysfunction, was 20% of ears (29% of babies) in this group. It appears that middle-ear effusion could account for about half of the ears failing an OAE screen on the special care baby unit. We also find that length of stay on the special care baby unit is an important risk factor for development of middle-ear effusion: those on the unit for over 30 days have about four times the risk of bilateral abnormal tympanometry.

Nonorganic hearing loss or pseudohypacusis is a condition in which there is an apparent hearing loss without any evidence of an organic cause. In a 2-year period, 43 children were seen in our department with this diagnosis. Thirty-three of them were female and 10 were male. Their hearing loss varied from 30 dB HL to 100 dB HL. The diagnosis made on clinical impression was confirmed using the ascending and the descending mode pure tone audiometry, tympanometry, stapedial reflexes and speech audiometry. Explanation, encouragement and reassurance were the only treatment required in these patients. All the 43 patients showed normal pure tone thresholds within a period of 1 year.

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 less than or equal to 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.