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Paraspinal muscle response to electrical vestibular stimulation
F N Ardic1, L D Latt, M S Redfern
1Department of Otolaryngology, University of Pamukkale, School of Medicine, Denizli, Turkey.
Acta Oto-Laryngologica
|April 25, 2000
Summary
Galvanic vestibular stimulation (GVS) activates paraspinal and lower leg muscles to control posture. Paraspinal muscles show an early response to GVS, suggesting a key role in maintaining balance during standing.
Area of Science:
- Neuroscience
- Biomechanics
- Human Physiology
Background:
- Vestibular system plays a crucial role in postural control.
- Galvanic vestibular stimulation (GVS) is a tool to investigate vestibular function.
- Previous research has primarily focused on lower limb responses to GVS.
Purpose of the Study:
- To determine the timing and pattern of paraspinal muscle activation in response to GVS.
- To compare paraspinal muscle responses with those of lower leg muscles (gastrocnemius).
- To elucidate the role of paraspinal muscles in the human postural response to vestibular input.
Main Methods:
- Binaural-bipolar GVS applied to mastoid processes in 10 subjects standing with eyes closed.
- Center of Pressure (COP) measured using a force plate.
- Surface electromyography (EMG) recorded from bilateral paraspinal and gastrocnemius muscles.
- Differential EMG (dEMG) calculated to isolate GVS-evoked responses.
Main Results:
- Both paraspinal and gastrocnemius muscles activated in response to GVS, consistent with COP changes.
- A primary response in both muscle groups moved the body towards the anode, starting earlier in paraspinal (74 ms) than gastrocnemius (118 ms) muscles.
- A secondary, opposing response initiated later (around 232-262 ms) decelerated the body and stabilized posture.
Conclusions:
- Paraspinal muscles exhibit a rapid and significant activation pattern following GVS.
- The timing of paraspinal muscle activation suggests a primary role in the immediate frontal plane postural control response to vestibular stimulation.
- Findings highlight the importance of paraspinal muscles in integrating vestibular information for maintaining upright stance.