Korean J Otorhinolaryngol-Head Neck Surg.  2018 Jan;61(1):15-23. 10.3342/kjorl-hns.2017.00703.

Behavioral Perception and Neural Correlates of Categorical Perception in Cochlear Implant Users

• Park JH
• Han JH

• KMID: 2436420
• DOI: http://doi.org/10.3342/kjorl-hns.2017.00703

Abstract

BACKGROUND AND OBJECTIVES
Although many cochlear implant (CI) recipients receive significant benefits from using the implants, speech perception ability is still known to vary among CI users, and the variability is closely related to the ability of users to process temporal information. As one of the important temporal cues for speech perception in CI users, voice onset time (VOT) can be used to examine behavioral perception and neural correlates of temporal processing. In this study, we measured categorical perception and N1-P2 cortical auditory evoked potentials (CAEPs) using a /ba/-/pa/ VOT continuum in CI users as well as in normal-hearing (NH) listeners.
SUBJECTS AND METHOD
Ten CI subjects and 11 NH controls participated in syllable identification tasks and in electroencephalography recording. CI subjects were divided into two groups, which were "˜good' and "˜poor' performers based on their speech perception scores. The stimuli used in both experiments were a synthetic /ba/-/pa/ VOT continuum. The identification boundary and N1-P2 peak-to-peak amplitude were measured for each subject group.
RESULTS
Behavioral results revealed that poor CI performers had a delayed identification boundary compared to NH listeners and good CI performers. However, N1-P2 peak-to-peak amplitudes in both good and poor CI performers were significantly smaller than those in NH group.
CONCLUSION
N1-P2 amplitudes reflected decreased auditory cortical activity of temporal cues in CI users. The categorical perception of good CI performers was similar to that of NH listeners, whereas their cortical responses were decreased to the level similar to that of poor CI performers. This finding indicates that CAEPs would be more sensitive to altered temporal processing of CI users than to behavioral measures.

Keyword

Categorical perception; Cochlear implant; N1-P2 cortical auditory evoked potentials; Temporal processing; Voice onset time

MeSH Terms

Cochlear Implants*
Cues
Electroencephalography
Evoked Potentials, Auditory
Methods
Speech Perception
Voice