The epidemiology of childhood hearing impairment: factor relevant to planning of services.
In the Nottingham District Health Authority we found that one in 943 babies born between 1983-1986 have a sensorineural or mixed hearing impairment (at 50 dB HL or greater in the better ear averaged over the frequencies 0.5, 1, 2, 4 kHz) that is either congenital or progressive in nature. If this figure is broken down between non-neonatal intensive care unit babies and neonatal intensive care unit (NICU) graduates, we find that one in 174 NICU graduates have a hearing impairment compared with one in 1278 non-NICU babies. Excluding from the non-NICU baby population those with a known family history of hearing impairment, and those with a known relevant syndrome at birth, there is a 10.2 to 1 odds ratio for babies in NICU to have such hearing impairments compared to this restricted 'normal' baby population. In addition NICU babies with a hearing impairment were considerably more likely to have another disability (odds ratio 8.7 to 1). Acquired sensorineural or mixed impairments comprised about 9% of the children with impairments by 3 years of age. Twenty per cent of the patients seen at the Children's Hearing Assessment Centre (CHAC) with better-ear impairment of 95 dB HL or greater had acquired hearing impairments. The mean age of referral for congenital hearing impairments was found to be a function of severity and NICU status. For children with better-ear hearing impairments of 80 dB HL or greater, the mean and median ages of referral were both 8 months (s.d. 4 months).
Davis
A
A
MRC Institute of Hearing Research, University Park, Nottingham, UK.
Wood
S
S
D001301:Audiometry, Pure-Tone; D002648:Child; D002675:Child, Preschool; D004739:England / Q000453:epidemiology; D005260:Female; D006285:Health Planning / Q000458:organization & administration* / Q000592:standards; D006309:Hearing / Q000502:physiology*; D006310:Hearing Aids; D006311:Hearing Disorders / Q000151:congenital* / Q000453:epidemiology; D006319:Hearing Loss, Sensorineural / Q000151:congenital* / Q000453:epidemiology / Q000503:physiopathology; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D015931:Intensive Care, Neonatal; D008297:Male; D015997:Neonatal Screening; D015995:Prevalence; D012307:Risk Factors; D012720:Severity of Illness Index