Electrically evoked auditory middle latency responses versus perception abilities in cochlear implant users.

Electrical auditory middle latency responses (EAMLRs) were recorded in a group of 12 postlingually and 4 congenitally deaf cochlear implant users. The EAMLRs of the postlingually deaf cochlear implant users were compared to behavioral measures of speech perception. All the cochlear implant users showed pronounced EAMLR morphology and amplitude. EAMLRs of congenitally deaf cochlear implant users were remarkably similar to those of postlingually deaf cochlear implant users. The difference in speech perception ability between congenitally deaf and postlingually deaf cochlear implant users did not seem to be caused by integrity differences of the neural generators of the auditory middle latency response. For the postlingually deaf subjects, EAMLR amplitude variation and interlatency variation seemed to be related to specific aspects of speech perception. The poorer performers demonstrated more diversity in the amplitude of the EAMLR component peaks and a more diffuse EAMLR peak latency organization across the electrodes than the better performers.