Silent gap CAEPs in tinnitus and control subjects (Morse & Vander Werff, 2019)

Purpose: Previous research suggests the existence of gap detection impairments because of tinnitus. The current study aimed to determine whether there was objective evidence of gap impairment in individuals with tinnitus by recording silent gap in white noise cortical auditory evoked potentials (CAEPs) in a chronic tinnitus group and a no-tinnitus group. The results were compared to previous gap-evoked potential and behavioral gap detection studies.Method: Chronic tinnitus and no-tinnitus groups were formed by matching pairs of subjects (n = 26) based on age, gender, and hearing thresholds. Behaviorally determined gap detection thresholds were used to define the electrophysiological gap duration conditions of subthreshold, threshold, and suprathreshold gaps in white noise. Amplitude, latency, and area of the CAEP were analyzed by group and condition using mixed-model analyses of variance.Results: Across all participants, as the duration of the gap increased, amplitude and area of the CAEP increased. There were no significant differences by tinnitus status between groups for any outcome measures, except for a significant interaction between group and gap duration for P1 latency.Conclusions: Silent gap-evoked CAEPs can be recorded in adults with and without tinnitus. Amplitude and area were sensitive to gap duration across groups; latency was not. Contrary to hypotheses, there was little evidence supporting differences in gap-evoked CAEPs between the tinnitus and control groups. Stimulus and other factors that may have contributed to the lack of a group difference in the current study are discussed, as well as implications for future studies of objective measures of tinnitus perception.Supplemental Material S1. Spearman’s rank order correlations (Spearman’s ρ) between behavioral tinnitus variables (THI score, tinnitus pitch, tinnitus loudness) and BGDT with measures of silent gap evoked P1-N1-P2 responses for the ChT group.Morse, K., & Vander Werff, K. (2019). Comparison of silent gap in noise cortical auditory evoked potentials in matched tinnitus and no-tinnitus control subjects. American Journal of Audiology, 28, 260–273. https://doi.org/10.1044/2018_AJA-18-0074