Feasibility in Recording Vestibular Evoked Myogenic Potentials from the Gastrocnemius Muscles Using Acoustic...

Area of Science:

• Neuroscience
• Physiology
• Biomechanics

Background:

• Vestibulo-spinal reflexes (VSR) are crucial for postural control, extending from the neck to lower limbs.
• Cervical vestibular evoked myogenic potentials (cVEMPs) assess upper VSR but no clinical tools evaluate the full VSR.
• Previous studies on lower-limb VEMPs have yielded inconsistent results.

Purpose of the Study:

• To investigate the feasibility of recording VEMPs from the gastrocnemius muscle via acoustic stimulation.
• To determine if acoustic stimulation can reliably elicit VEMPs in the lower extremities.

Main Methods:

• A feasibility study with a single-group, cross-sectional design.
• Thirteen healthy participants (aged 20-26) with existing cVEMP responses.
• Gastrocnemius VEMP recordings using acoustic (air and bone conduction) and 500-Hz tone burst stimuli at high intensity (132 dB peak SPL).

Main Results:

• Replicable gastrocnemius VEMPs were observed in only two out of thirteen participants.
• Responses in the two positive cases showed N1P1 and N2P2 peaks between 55-105 ms.
• Stimuli were perceived as loud and uncomfortable, with participant fatigue reported.

Conclusions:

• Acoustic stimulation at 132 dB peak SPL is largely ineffective for eliciting gastrocnemius VEMPs in young, healthy individuals.
• Current methods for recording lower limb VEMPs via acoustic stimulation appear clinically unfeasible.
• Alternative methods, like galvanic stimulation, warrant exploration for assessing lower extremity VSR.