Profound deafness in early childhood has major consequences for the child, its family, and society. Critical periods exist for speech and language development during which the developing nervous system is particularly responsive to auditory stimulation. Inadequate sensory input during these periods leads to lifelong linguistic and communicative deficits.1 Fortunately, if identified early enough, most hearing losses can be satisfactorily managed by hearing aids and rehabilitation. Until the advent of cochlear implantation, however, the outlook for children who were too deaf to hear speech through a hearing aid was less promising and they often failed to develop intelligible spoken language.

Conrad found that the median reading age of profoundly deaf 16year olds was that of normal hearing 9year olds and that no fewer than half these children could not read.2 As a consequence, their educational and employment opportunities were restricted. In the United Kingdom about 220children are born each year with hearing losses in excess of 95dB and a further 80lose their hearing, mainly through bacterial meningitis.3

In profoundly deaf patients auditory nerve …