Late cochlear implant in a prelingually hearing impaired subject: electrophysiological and audiometric improvement over time

Objectives: The aim of this study was to evaluate electrophysiological and audiological findings in a prelingually late implanted patient, in two consecutive follow-ups: 3 months after cochlear implant (CI) activation and 1 year later. Methods: As an electrophysiological evaluation, the event-related potentials (ERPs) N100, N200P300 were used. The P300 wave is an objective measure of the central auditory function. It reflects the cortical activity involved during attention, discrimination, memory, integration and decision-making skills and it is a measure of speech discrimination and linguistic recognition. Pure tone audiometry, speech perception tests and electrophysiological examination were performed at 3 and 15 months post-CI activation. Result and Discussion: The N100 and N200 latencies were very similar in both follow-ups, whereas P300 latency decreased significantly 15 months postactivation, reaching a value close to normality. This finding was related to an increase in audiometric and speech performances. Conclusion: A significant improvment in electrophysiological, audiometric and speech performances was observed during the second follow-up, underlining the great importance of the duration of device use, in spite of a late implant surgery. These simultaneous improvements can be related to a general increase of superior cognitive functions.