Bilateral versus unilateral hearing aids for bilateral hearing impairment in adults.

Acquired hearing loss is common and its incidence increases markedly with age. In most people, 'age-related' hearing loss is sensorineural (due to the loss of cochlear hair cells) and bilateral, affecting both ears to the same degree. Hearing loss categorised as mild, moderate or severe is primarily managed with hearing aids. People with bilateral hearing loss may be offered one aid, fitted to one specific ear, or two aids fitted to both ears. There is uncertainty about the relative benefits to people with hearing loss of these different strategies.