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Aetiological investigations of hearing loss in childhood: a review.

Advances in genetics, improvements in neonatal intensive care and the introduction of universal immunisation programmes have resulted in major changes in the epidemiology of hearing loss in children. Perinatal factors now account for 27% of the child population with hearing loss, compared to 2% about 25 years ago. 1 In the UK, the prevalence of hearing impairment in children with a history of treatment in the neonatal intensive care unit has increased fourfold over a period of 15 years, 2 and is higher than in other European countries. 3 A combination of neonatal intensive care unit status, family history of hearing loss and craniofacial abnormality noticeable at birth may account for up to 64% of all types of hearing loss. 2 The overall prevalence of bilateral hearing loss in children is estimated to be between 0.5/1000 live births 4 to 1.2/1000 2 and up to 2.1/1000 5 in different studies, depending on factors such as methods of hearing loss ascertainment, degree of hearing loss targeted, geographical area and time period of the study. 
 
 
 
Investigation of the hearing impaired child aims to identify the cause of the hearing loss and to provide information relevant to hearing loss management, coexisting medical problems and prognosis for the child and the family. In addition, these investigations may also help to clarify phenotypes in genetic hearing loss and to provide a more accurate picture of epidemiology, which is necessary for planning effective hearing loss prevention and surveillance programmes. 
 
 
 
The objective of this paper is to review the current literature on this topic and to assist the clinician in devising an investigative plan for this population.