Is there a contribution of low-threshold mechanoreceptors to mechanical sensitivity in the area of secondary hyperalgesia induced by high frequency electrical stimulation?

Details

Supervisors

Mouraux, André ; Lenoir, Cédric ; van den Broeke, Emanuel

Faculty

Faculté des sciences de la motricité

Degree label

Master [60] en kinésithérapie et réadaptation

Abstract

High frequency electrical stimulation (HFS) of the skin induces an increase in mechanical pinprick sensitivity. Mechanical pinprick stimuli activate high- and low-threshold mechanoreceptors (HTMs and LTMs). This study aims to determine the involvement of LTMs in secondary hyperalgesia by comparing the perceived intensity elicited by tactile stimuli, activating LTMs to that elicited by pinprick stimuli, activating LTMs and HTMs. In 21 healthy right-handed volunteers, we delivered to the dominant or non-dominant volar forearm pinprick and tactile stimuli at different times: before HFS, 20 minutes and 35 minutes after HFS. Each modality has four different intensities (32 mN, 64 mN, 128 mN and 256 mN). Intensity and quality of perception of the stimuli as well as pain were collected during stimulations. Compared to baseline, there was a significant increase in perceived intensity for pinprick stimuli 20 minutes after HFS which was not maintained 35 minutes after HFS compared to baseline. For tactile stimuli, a significant decrease was observed between baseline and 35 minutes after HFS. We observed an increase in the use of the pricking descriptor for both modalities after HFS. The results also showed by matching the pressure of the pinprick and the tactile stimulator that pressure is not a main parameter in secondary hyperalgesia. In conclusion, LTMs do not convey increase in mechanical pinprick sensitivity in the area of secondary hyperalgesia induced by HFS.