Recordings of Cortical Auditory Evoked Potentials in Cochlear Implant Listeners: A Preliminary Study

Lee, Jee Yeon; Yang, Chan Joo; Lee, Hwan Seo; Lim, Won Sub; Moon, Hyun; Nam, Soo Jung; Park, Hong Ju

Abstract

BACKGROUND AND OBJECTIVES
There is a need for fast and reliable objective measures of cochlear implant (CI) performance, especially in young children. The aim of the study was to investigate the detection and characterization of cortical auditory evoked potentials (CAEP) of different types of sound stimulation in CI listeners using a commercially available system, HEARLabâ„¢.
SUBJECTS AND METHOD
Sound field CAEPs were obtained from 10 CI listeners, using three natural speech sounds (/m/, /g/, and /t/) presented at 55, 65, and 75 dB SPL. Detection rates, the latencies and amplitudes of CAEP waves were analyzed and compared with those of the normal hearing (NH) group.
RESULTS
It was possible to detect CAEP responses in all CI listeners. Of the three stimuli (/m/, /g/, /t/), /g/ was the most robust waveform, although this was not statistically significant. Latencies for the /m/ stimulus were relatively longer than those for /t/ and especially for /g/, suggesting that CI listeners hear high-frequency sounds better than low-frequency sounds. When compared to the NH group, CAEP of CI listeners tended to show smaller amplitudes of various waves and longer latencies especially at P1 wave.
CONCLUSION
CAEP responses could be obtained in all CI listeners and normal adults successfully, indicating that CAEP can be applied clinically as an objective assessment tool of hearing. Further studies are needed for CI listeners especially in infants and toddlers using this protocol to assess its clinical usefulness.