Vestibular evoked myogenic potentials and habituation to seasickness

•This prospective study examines the cervical vestibular evoked myogenic potential (cVEMP) test as an objective tool for the prediction of continued susceptibility and habituation to seasickness.•cVEMP thresholds differed significantly between crewmembers who had become habituated to seasickness and those remaining severely susceptible.•The lower cVEMP thresholds observed in the habituation group imply a broader dynamic range, which may facilitate the process of habituation to sea conditions.

ObjectiveSeasickness may impose severe limitations on the performance of ships’ crew. Cervical vestibular evoked myogenic potentials (cVEMP) assess the function of the saccule, the organ responsible for monitoring vertical linear acceleration, which has been found to be the most provocative motion stimulus in the evolution of motion sickness. We used the cVEMP test in a prospective evaluation of susceptibility and habituation to seasickness.MethodsForty-six naval recruits underwent the cVEMP test before exposure to sea conditions. After 6 months’ sailing experience, participants completed a questionnaire evaluating their initial and current seasickness severity. Based on their most recent experience, subjects were divided into three groups: non-vomiting non-habituating (NV-NH), vomiting (V), and non-vomiting habituating (NV-H).ResultsStatistically significant lower thresholds for cVEMP were found in subjects who habituated to sea conditions (NV-H), compared with those remaining severely susceptible (V) (77.0 dB HL vs. 84.9 dB HL; p < 0.01).ConclusionsThe ability to produce the cVEMP at lower thresholds represents a broader dynamic range, in which the reflex can respond to a wider array of stimuli amplitudes.SignificanceThe present study demonstrates the potential of the cVEMP test for predicting future habituation to seasickness.