NCT04621747

Trial Investigating the Characteristics of Knismesis - a Lever to Explore Allodynia in Neuropathic Pain

• Status: Unknown
• Phase: N/A
• Study type: Interventional
• Enrollment: 24 (estimated)
• Sponsor: University Hospital, Clermont-Ferrand · Academic / Other
• Sex: All
• Age: 18 Years – 50 Years
• Healthy volunteers: Accepted

Summary

Also known as a "moving itch", knismesis is a mildly annoying sensation caused by a light movement on the skin, such as from a crawling insect. Its underlying mechanism rely on spatial summation, i.e. amplification of the signal due to summation of stimulated fields, like it is for dynamic allodynia in neuropathic pain. This physiological study aims at determining the physical factors of the cutaneous stimulation inducing knismesis as well as the effect of confounding factors. The main area of exploration will be the back, because of its size and the possibility to blind the participant. The information collected, along with animal data in surrogate models, would help to better understand neuropathic pain in the future.

Detailed description

This is a physiological proof-of-concept, also aiming to validate a functional exploration model in healthy volunteers. Each participant will undergo a battery if psychometric then psychophysics tests, presented sequentially. However, most of the main study tests (knismesis) will be admistered in a random order (crossover). The primary endpoint is to characterise, in the healthy human, the physical determinants of the cutaneous stimulation inducing knismesis: length of the pathway, speed, direction, intensity, continuity break of the contact, hairiness, body site, or distraction by other cutaneous stimuli. The secondary endpoint is to study the relationship between the individual sensitivity to spatial summation (knismesis) and other individual sensitivities or profiles.

Conditions

• Healthy

Interventions

Type	Name	Description
OTHER	Battery of neurophysiological explorations	Visit 1: Biometry collection: gender, age, weight, height, eye colour. * Questionnaires : the State and Trait Anxiety Inventory and the Pain Sensitivity * Threshold of unpleasant light brightness, mechanical sensitivity threshold (von Frey hair). * Training to estimate unpleasantness Under nociceptive and tickling stimuli, to use the handgrip. * Mechanical pain threshold (electronic von Frey), heat pain threshold (Medoc Pathway). * 48 stimulations applied to the back skin, following a predetermined plan with 12 different pathways, imbricated with 4 different speeds of movement. Visit 2 (1 to 8 days later) : * 42 stimulations applied to the back skin, to test the effect of stimulation intensity, the side of application, continuity break of the contact, and distraction by other cutaneous stimuli. The stimuli will follow the best paradigm as identified at the previous visit. * 12 stimulations applied to forearm, cheeks, lower limbs, also testing the effect of hairiness.

Timeline

• Start date: 2021-11-23
• Primary completion: 2022-12-01
• Completion: 2022-12-01
• First posted: 2020-11-09
• Last updated: 2021-12-02

Locations

1 site across 1 country: France