Evaluating Fixed Single-Point Parameters When Applied to Vestibular Evoked Myogenic Potentials: The Effect of Single Point and Signal Window

Abstract

Objectives: Several studies have applied a common objective detection algorithm (fixed single point [F sp]) for detection of the vestibular evoked myogenic potential (VEMP). However, fundamental parameters of F sp, such as establishing the location and duration of a signal window, have not been examined. In addition, F sp criterion values used for response detection have not been established for cervical VEMPs (cVEMPs) or ocular VEMPs (oVEMPs). The purpose of this article was to investigate the effect of various single points and signal windows on F sp, as well as determining F sp criteria to determine response presence for cVEMP and oVEMP in a group of young healthy participants. Design: Twenty young healthy adults under the age of 30 and with no history of hearing or balance concerns were enrolled in the study protocol. Air-conducted cVEMPs and oVEMPs were evoked using 500 Hz tone bursts at 123 dB pSPL recorded at a fixed electromyography activation of 50 µV for cVEMPs and 35° gaze angle for oVEMPs. Responses were analyzed off-line using visual and objective detection. F sp was applied to cVEMPs and oVEMPs using a range of single points and signal windows. Results: Noise variance was lowest for cVEMPs at the latency of P1, and for oVEMPs noise variance was not significantly different across the single-point latencies. On average, extending the length of the signal window lowered the F sp value in cVEMPs and oVEMPs. An F sp value of 2.0 was chosen as the criterion cutoff associated with the 95th percentile during no-response conditions using group data for cVEMPs and oVEMPs, respectively. F sp values for cVEMPs and oVEMPs were not significantly different from each other. Discussion: This study established single-point latency and time-window parameters for VEMP-related applications of the F sp detection algorithm. F sp criteria values were established for cVEMP and oVEMP. Using these parameters, responses were detected in all participants.