Laterality of vestibular evoked myogenic potentials

Area of Science:

• Neuroscience
• Otolaryngology
• Physiology

Background:

• Vestibulocollic reflexes with short latency, known as vestibular evoked myogenic potentials (VEMPs), are crucial for head stability.
• Understanding the laterality of VEMPs is essential for their clinical interpretation and understanding their neurophysiological basis.

Purpose of the Study:

• To investigate the laterality of acoustically evoked VEMPs recorded from bilateral sternocleidomastoid muscles (SCMs).
• To determine if VEMPs exhibit ipsilateral or contralateral dominance in response to unilateral acoustic stimulation.

Main Methods:

• Twenty-one healthy volunteers participated in the study.
• Surface electrodes were placed on the SCM muscles for recording VEMP responses.
• Unilateral acoustic stimulation was delivered using clicks and 500-Hz tone-bursts at 95 dB nHL.

Main Results:

• All subjects demonstrated ipsilateral VEMP responses on the SCM muscles to both click and tone-burst stimuli.
• Click stimulation rarely evoked contralateral SCM responses (1 of 42 ears).
• Tone-burst stimulation showed minimal or no contralateral SCM responses in most ears (4 of 42 ears showed small responses).

Conclusions:

• Vestibular evoked myogenic potentials (VEMPs) are predominantly ipsilateral responses.
• The ipsilateral dominance of VEMPs supports the hypothesis of their saccular origin.
• These findings enhance the understanding of VEMP neurophysiology and clinical applications.