Focal Vibration Alters Human Digital Sensory Nerve Action Potentials: A Pilot Study

Dong Qing Zhu ,Fang Liu,Duan Lei,Xiang Jin,Robert J Weber ,Linfeng Xu ,Chao Zheng ,Yu Zhu ,Xiang Jun Chen

doi:10.1155/2021/8819169

Abstract

Introduction We studied the impact of vibratory stimulation on the electrophysiological features of digital sensory nerve action potential (SNAP). Methods The antidromic digit 3 SNAP was recorded in 19 healthy adults before, during, and after applying a vibration to either 3rd or 5th metacarpal phalangeal joint (MCPJ) at 60 Hz and amplitude of 2 mm. 100% supramaximal stimulus intensity was performed in 5 subjects (randomly selected from the 19 subjects) where the SNAP sizes were recorded. Results The amplitude of digit 3 SNAP declined to 58.9 ± 8.6% when a vibration was applied to MCPJ digit 3. These impacts did not change by increasing the electrical stimulus intensity. The SNAP regained its baseline value immediately after the cessation of vibration stimulation. The magnitude of size reduction of digit 3 SNAP was less when vibration was moved to from MCPJ of digit 3 to MCPJ of digit 5. Discussion. The marked drop of the SNAP size during vibratory stimulation reflects the decreased responsiveness of Aβ afferents to electrical stimulation, which deserve further investigation in the study of focal vibration in neurorehabilitation.

Highlights

We studied the impact of vibratory stimulation on the electrophysiological features of digital sensory nerve action potential (SNAP)
We found that the mechanical vibration applied to the palm remarkably reduces the size of the digital SNAP
The SNAP amplitude returned to the baseline level immediately after the cessation of the vibration

Summary

Introduction

We studied the impact of vibratory stimulation on the electrophysiological features of digital sensory nerve action potential (SNAP). The amplitude of digit 3 SNAP declined to 58:9 ± 8:6% when a vibration was applied to MCPJ digit 3 These impacts did not change by increasing the electrical stimulus intensity. When applied to the human hands, vibration activates the cutaneous mechanoreceptors, including Merkel disk for low frequencies (5– 15 Hz), Meissner’s corpuscles for midrange (20-50 Hz) in the superficial layers of the skin, and Pacinian corpuscles for high frequencies (60-400 Hz) in deeper layers of the skin and periosteum [4,5,6] These receptors are innervated by Aβtype myelinated fibers. The size of SNAP is proportional to the number of nerve axons depolarized by the testing electrical stimulation Both the function of skin mechanoreceptors and Aβ fibers during vibration could affect the measures of digital 3 SNAP. Our study was designed to examine the electrophysiological features of digital SNAP during acute and transient exposure to vibratory stimulation

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Results

Conclusion