Disclosures: Fang Liu, MD: No financial relationships or conflicts of interest
Objective: Quantitative examination of the change in SNAP amplitude with isotonic and isometric Tonic Vibration Reflex(TVR).
Design: Digit 3 SNAP following median nerve stimulation was measured in 6 healthy adults (3 male, 3 female, 27 to 33 years old) for a total of 12 hands. A 2 mm displacement and 70 Hz conditioning vibration stimuli was applied to Digit 3 proximal phalanx’s mid-diaphysis. Supramaximal 3 Hz electrical stimulation was applied at the wrist. 50 responses were averaged. SNAP was recorded prior to vibration, at vibration onset, and at 40-60 seconds of vibration in restrained digit for isometric and non-restrained digit for isotonic TVR. Setting : Digit 3 was restrained by the tape while vibrating on the 3rd metacarpal phalangeal joint. Otherwise non-restrained digit 3 for isotonic TVR. Participants : 6 healthy adults (3 male, 3 female, 27 to 33 years old) for a total of 12 hands
Interventions: A 2 mm displacement and 70 Hz conditioning vibration stimuli was applied to Digit 3 proximal phalanx’s mid-diaphysis. Supramaximal 3 Hz electrical stimulation was applied at the wrist.
Main Outcome Measures: Sensory Nerve Action Potential was recorded prior to vibration, at vibration onset, and at 40-60 seconds of vibration in restrained digit for isometric and non-restrained digit for isotonic TVR. 50 responses were averaged.
Results: Digit 3 SNAPs amplitude at 40-60 seconds of vibration decreased by 18.7% in the restrained (isometric TVR position) and 57.9% in the unrestrained (isotonic TVR position). This difference was statistically significant. Conclusions: The motion produced in the late period by the isotonic TVR significantly enhances the digital SNAP reduction, while isometric TVR does not. This finding could provide a strategy to decrease nerve damage in Hand Arm Vibration Syndrome by keeping a fixed muscle length when vibration is applied.
Level of Evidence: Level V
To cite this abstract in AMA style:
Liu F, Colasante CA, Zhu Py. Isotonic but Not Isometric Tonic Vibration Reflex Enhances the Reduction of Digital Sensory Nerve Action Potential Caused by Vibration [abstract]. PM R. 2020; 12(S1)(suppl 1). https://pmrjabstracts.org/abstract/isotonic-but-not-isometric-tonic-vibration-reflex-enhances-the-reduction-of-digital-sensory-nerve-action-potential-caused-by-vibration/. Accessed May 16, 2025.« Back to AAPM&R Annual Assembly 2020
PM&R Meeting Abstracts - https://pmrjabstracts.org/abstract/isotonic-but-not-isometric-tonic-vibration-reflex-enhances-the-reduction-of-digital-sensory-nerve-action-potential-caused-by-vibration/