Auditory system plasticity in children after long periods of complete deafness.

Deaf children fitted with a cochlear implant provide a unique opportunity to examine the effects of auditory deprivation on the maturation of the human auditory system. We compared cortical evoked potentials recorded in implanted and normal-hearing children and found that age-dependent latency changes for the P1 component, fitted to a decaying exponential curve, showed the same rate of maturation. For implanted children, however, maturational delays for P1 latency approximated the period of auditory deprivation prior to implantation. This indicates the auditory system does not mature without stimulation. Nonetheless, the auditory system retains its plasticity during the period of deafness since the re-introduction of stimulation by the cochlear implant resumes the normal maturational sequence.