Inter-trial coherence as a measure of synchrony in cervical vestibular evoked myogenic potentials

• Published in: Journal of neuroscience methods Vol. 377; p. 109628
• Main Authors: Clinard, Christopher G., Piker, Erin G., Romero, Daniel J.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 15-07-2022
• Subjects: CVEMP; Detection algorithm; Inter-trial coherence; Neural synchrony; Otolith; Phase locking; VEMP; Detection algorithm; Inter-trial coherence; Otolith; VEMP; Phase locking; CVEMP; Neural synchrony; inter-trial coherence; neural synchrony; detection algorithm; phase locking; cVEMP; otolith
• ISSN: 0165-0270; 1872-678X
• DOI: 10.1016/j.jneumeth.2022.109628

Cervical vestibular evoked myogenic potentials (cVEMPs) are surface-recorded responses that reflect saccular function. Analysis of cVEMPs has focused, nearly exclusively, on time-domain waveform measurements such as amplitude and latency of response peaks, but synchrony-based measures have not been previously reported.
Time-frequency analyses were used to apply an objective response-detection algorithm and to quantify response synchrony. These methods are new to VEMP literature and have been adapted from previous auditory research. Air-conducted cVEMPs were elicited using a 500 Hz tone burst in twenty young, healthy participants.
Time-frequency characteristics of cVEMPs and time-frequency boundaries for response energy were established. An inter-trial coherence analysis approach revealed highly synchronous responses with representative inter-trial coherence values of approximately 0.7.
Inter-trial coherence measures were highly correlated with conventional amplitude measures in this group of young, healthy adults (R2 = 0.91 – 0.94), although the frequencies at which these measures had their largest magnitude were unrelated (R2 =.02). Conventional measures of peak-to-peak amplitude and latency were consistent with previous literature. Interaural asymmetry ratios were comparable between amplitude- and synchrony-based measures.
Synchrony-based time-frequency analyses were successfully applied to cVEMP data and this type of analysis may be helpful to differentiate synchrony from amplitude in populations with disrupted neural synchrony.
•Cervical vestibular evoked myogenic potentials (cVEMPs) reflect otolith function.•cVEMPs were elicited with transient tonebursts.•intertrial coherence were applied to measure response synchrony.•cVEMPs were revealed to be highly synchronous.•intertrial coherence is a feasible analysis for cVEMPs.