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ORCID
https://orcid.org/0009-0001-9804-8461
Date of Graduation
5-15-2025
Semester of Graduation
Spring
Degree Name
Doctor of Audiology (AuD)
Department
Department of Communication Sciences and Disorders
First Advisor
Christopher Clinard
Second Advisor
Erin Piker
Third Advisor
Yingjiu Nie
Fourth Advisor
Ayasakanta Rout
Abstract
Ocular vestibular evoked myogenic potentials (oVEMPs) are produced by highly synchronous bursts of extraocular muscle activity in response to bone or air-conducted stimuli. Surface electromyography (EMG) electrodes can be used to record these responses which reflect utricular function. The traditional analysis of oVEMPs has been limited to time-domain waveform measurements, such as amplitude and latency of response peaks.
Recently, a method grounded in synchrony-based time-frequency analysis was successfully applied to cervical vestibular evoked myogenic potentials (cVEMPs) by Clinard et al. (2022). This approach to VEMP analysis can be used as a means to differentiate synchrony from amplitude, quantifying how phase locked a response is. Despite its use in evoked potentials elicited from auditory, somatosensory, visual, and olfactory stimulation, time-frequency analysis has not yet been applied to oVEMP responses.
This study used methods new to VEMP literature put forth by Clinard et al. (2022). Time-frequency analysis, known as inter-trial coherence (ITC), was used to apply an objective response-detection algorithm and to quantify response synchrony. Air-conducted oVEMPs were elicited using a 500 Hz tone burst in 21 young, healthy participants at a neutral (0o) and upward (+30 o) gaze angle. oVEMP responses were analyzed using an ITC approach to establish synchrony-based measures.
Individual data were analyzed for time and frequency points that had statistically-detected response energy. Time-frequency response boundaries were established using the median of each parameter. Peak latency and amplitude were not significantly different between the left and right ears.
Results indicate ITC was successfully applied to the analysis of oVEMPs and may be used to quantify neural synchrony. Latencies and magnitudes of ITC and waveform morphology were consistent with one another. Future implications of ITC in regard to oVEMP analysis may include objective detection algorithms and possible automated screening tools. It also may be applied clinically to differentiate synchrony from response amplitude in older individuals and those believed to have asynchronous neural activity.
