Children benefit the most as do many adults

Multichannel cochlear implant systems were approved by the Food and Drug Administration for adults in 1985 and for children in 1990. NHS funding became available in the early 1990s. About 4000 patients have received implants in the United Kingdom (50 000 worldwide). Children now outnumber adults by 2:1. Cochlear implants are reliable, and cochlear implant surgery is safe despite recent concerns regarding a risk of meningitis. The numbers of suitable candidates is rising as selectioncriteria change, and it is timely to consider the benefits and risks of the technique.

A cochlear implant takes the place of the damaged organ of Corti and stimulates the spiral ganglion cells directly. Acquired causes of hair cell loss include infection such as rubella, cytomegalovirus infection, mumps, measles, meningitis, and middle ear infection, drug toxicity, trauma, and autoimmune disease, as well as Menière's disease and cochlear otosclerosis. Congenital hair cellloss may be due to recessive inheritance or may be the result of failure of normal intrauterine development of the inner ear due to causes of which some are known, some as yet unidentified.