Auditory Event-Related Potentials Elicited From Cochlear Implant Recipients and Hearing Subjects

Auditory event-related evoked potentials (ERP) were recorded from 10 cochlear implant recipients and 10 age-matched hearing subjects using an oddball paradigm in which frequently occurring tone bursts of 500 Hz were interspersed within rarely occurring tone bursts of 1000, 2000, or 3000 Hz. Signals were delivered acoustically to both groups of subjects through a loudspeaker. P-300 peak latencies for the implant recipients were significantly longer than those for the hearing subjects for the 500-1000 and 500-2000 Hz frequency contrast conditions, but not for the 500-3000 Hz contrast condition. For the hearing subjects, P3 latency did not change significantly across the three frequency contrast conditions; however, for the implant recipients, P3 latencies were significantly longer for the 500-1000 Hz signal contrasts than for 500-2000 and 500-3000 Hz signal contrasts. These results suggest that although implant recipients had more difficulty than hearing subjects in discriminating the 500-1000 and 500-2000 Hz contrasts, the implant recipients and hearing subjects discriminated the widest 500-3000 Hz frequency contrast equally well. The ERP appears to be a reliable index of signal detection and discrimination in cochlear implant recipients and consequently may be useful for device programming and for monitoring the progress of these individuals.