Systematic review of the etiology of bilateral sensorineural hearing loss in children.
OBJECTIVE
Identification of the etiology of sensorineural hearing loss (SNHL) in children facilitates management and provides important prognostic information. In recent years, the etiology of bilateral SNHL in children has changed due to advances in genetic testing and treatment of perinatal infections. The objective of this study was to determine the frequency of etiologies of moderate-profound bilateral sensorineural hearing loss (SNHL) in children.


METHODS
The English literature was searched in Medline for articles published between 1966 and 2002. The inclusion criteria were studies involving bilateral SNHL >/=40dB in children less than 18 years of age. The studies were required to account for all patients, and provide a breakdown of etiologic factors. Etiologies investigated included genetic and non-genetic (prenatal, perinatal, postnatal). To compare differences between the frequencies of etiologies a two-sample t-test was performed assuming unequal variance. Studies were stratified according to perceived confounders: start date of study, study design, and degree of hearing loss.


RESULTS
Seven hundred and eighty abstracts were screened for relevancy. Forty-three studies satisfied the inclusion criteria. The common etiologies of bilateral SNHL were unknown (41.5%), genetic non-syndromic (27.2%), prenatal (11.5%), perinatal (9.7%), postnatal (6.6%), and genetic syndromic (3.5%). Unknown and Rubella were significantly less frequent etiologies in the more recent studies, while genetic non-syndromic, asphyxia and prematurity were more common. Genetic non-syndromic hearing loss was more frequent in the prospective studies compared to the population and retrospective studies, but this difference was not significant. Genetic non-syndromic hearing loss was more common among patients with profound hearing loss.


CONCLUSIONS
Accounting for the recent decline in infectious etiologies, the most common causes of bilateral SNHL are unknown (37.7%), genetic non-syndromic (29.2%), prenatal (12%), perinatal (9.6%), postnatal (8.2%), and genetic syndromic (3.2%).
Morzaria
Sanjay
S
Division of Pediatric Otolaryngology, British Columbia Children's Hospital, 4480 Oak Street, Vancouver, BC, Canada.
Westerberg
Brian D
BD
Kozak
Frederick K
FK
D002648:Child; D006312:Hearing Loss, Bilateral / Q000150:complications / Q000209:etiology*; D006319:Hearing Loss, Sensorineural / Q000150:complications / Q000209:etiology*; D006801:Humans; D012720:Severity of Illness Index