Cortical Processing of Frequency Changes Reflected by the Acoustic Change Complex in Adult Cochlear Implant Users

Abstract

The purpose of this study was to examine neural substrates of frequency change detection in cochlear implant (CI) recipients using the acoustic change complex (ACC), a type of cortical auditory evoked potential elicited by acoustic changes in an ongoing stimulus. A psychoacoustic test and electroencephalographic recording were administered in 12 postlingually deafened adult CI users. The stimuli were pure tones containing different magnitudes of upward frequency changes. Results showed that the frequency change detection threshold (FCDT) was 3.79% in the CI users, with a large variability. The ACC N1’ latency was significantly correlated with the FCDT and the clinically collected speech perception score. The results suggested that the ACC evoked by frequency changes can serve as a useful objective tool in assessing frequency change detection capability and predicting speech perception performance in CI users.

A Preliminary Study of the Effects of Attentive Music Listening on Cochlear Implant Users’ Speech Perception, Quality of Life, and Behavioral and Objective Measures of Frequency Change Detection

“…Numerous studies involving normal-hearing listeners have reported positive effects of music training on pitch perception. For instance, our group and other researchers have reported that musicians, who undergo years of music training, exhibit superior performance of pitch perception and better neurophysiological responses relative to non-musicians (Besson et al, 2007;Kraus et al, 2009;Itoh et al, 2012;Fuller et al, 2014;Brown et al, 2017;Liang et al, 2018). Such long-term music training may be expanded to the speech domain and positively affect speech perception in noise (Parbery-Clark et al, 2009;Baskent and Gaudrain, 2016).…”

“…The advantage of averaging responses from multiple electrodes was that the variability in CI data could be reduced, as the final EEG waveforms include more trials (Roman et al, 2005). The wave peaks of the onset CAEP (N1 and P2 peaks) and ACC response (N1 and P2 peaks) were identified within their own latency ranges (approximately in 100-300 ms after tone onset for the onset CAEP and 600-800 ms after the tone onset for the ACC, respectively, see Liang et al, 2016Liang et al, , 2018.…”

“…Cortical auditory evoked potentials can be evoked by the stimulus onset (onset CAEP) and a change within a stimulus (acoustic change complex or ACC, Friesen and Tremblay, 2006;Martin, 2007;Mathew et al, 2017;Liang et al, 2018). Unlike the onset CAEP that reflects cortical detection of stimulus onset, the ACC reflects a listener's cortical processing of acoustic changes and it is corresponding to auditory discrimination ability (He et al, 2012;Kim, 2015;Brown et al, 2017).…”

Electrophysiological assessment of temporal envelope processing in cochlear implant users

“…Artifact removal effectiveness was assessed based on the phase characteristics of the measured response. We measured in addition to the 40-Hz eASSR, eASSRs to three additional frequencies (34,37, and 43 Hz) and with the same stimulation parameters as the 100% MD stimulus, i.e. stimulated at a maximum perceptual modulation depth (MD % = 100%) and loudness level.…”

“…Given the cortical origin of the ACC it can potentially function as a final detector of how well the TEMs are encoded in the neural signal. The ACC has been successfully used as an electrophysiological measure of gap detection 33 , frequency change detection 34 , and the eACC for electrode discrimination [35][36][37] in CI users. Furthermore, the eACC N1 amplitude shows a similar pattern as the temporal modulation transfer function of CI users 38 .…”