Epidemiology of permanent childhood hearing loss in Glasgow, 1985-1994

This retrospective study was undertaken to document the epidemiology of permanent childhood hearing impairment (PCHI) in Glasgow and to make some assessment of the current practice to identify these children before universal neonatal hearing screening (UNHS) is implemented. Subjects were those with bilateral permanent hearing impairments of at least 40 dB in the better hearing ear, born between 1985 and 1994, in Greater Glasgow. The subjects were identified and data extracted from the Educational Audiology database. The case records at the Royal Hospital for Sick Children were also reviewed to identify possible aetiology groups. The prevalence rate of all permanent hearing impairments was 1.23 per thousand live births. Eleven percent of all hearing impairments were acquired or progressive. There was no significant effect of sex on aetiology (X2 = 6.509, df = 6, p, = 1), age at identification of hearing impairment and hearing aid provision (Kruskal Wallis, p = 0.484 and 0.782 respectively). For those identified as congenitally hearing impaired, the median ages at diagnosis of hearing impairment and hearing aid provision were 18 months and 31 months respectively. Age at diagnosis of hearing impairment and hearing aid provision were unaffected by aetiology of hearing impairment (Kruskal Wallis, p = 0.782 and p = 0.484 respectively). The prevalence rate of PCHI and the ages at identification and intervention in Glasgow are typical of the rest of the UK. Audiological surveillance measures are falling well below the standard of care expected today and the introduction of UNHS is likely to improve outcomes as long as the additional health and educational resources are in place to deal with the earlier identification of these children.