Test-retest reliability of cortical auditory evoked potential indices of central auditory nervous system inhibition in people with and without tinnitus.

The purpose of this study was to determine the test-retest reliability of cortical auditory evoked potentials (CAEPs) called onset-offset and sensory gating CAEPs. Further, this study compared test-retest reliability across people with and without tinnitus, across different stimulus frequencies (broadband noise, 0.25 kHz, 2 kHz, 8 kHz), and across different CAEP quantification approaches. The results of this study indicated that both sensory gating and onset-offset CAEPs were reliable, however reliability was maximized under certain experimental conditions. Specifically, people with tinnitus did exhibit differences in reliability for the sensory gating CAEP, although this did depend on the bandpass filter that was used to analyze the sensory gating response. Further, reliability was the strongest when the stimulus was a broadband noise as opposed to frequency-specific tones. Regarding CAEP quantification approach, reliability was the strongest for CAEP types that were larger in amplitude and robust CAEP measurements including peak-to-peak amplitude and total response area. Overall, these findings do indicate that both the sensory gating and onset-offset CAEP are reliable for people with and without tinnitus. However, certain experimental methods can be applied to maximize reliability such as using a broadband noise stimulus and/or measuring peak-to-peak amplitude and total response area.