The following is a summary of “Investigation of directional discrimination in the nociceptive system using temperature-controlled laser stimuli,” published in the March 2024 issue of Pain by Rujoie et al.
Researchers started a retrospective study to assess how a temperature-controlled laser system refines the evaluation of directional discernment within the nociceptive system.
They involved 20 healthy volunteers. A diode laser was used to deliver thermal stimuli, adjusting the laser beam across the skin in four directions (distal, proximal, lateral, and medial) and two displacement lengths (3 for lateral-medial and 5 for distal-proximal). Two temperature control modes, open-loop and closed-loop control, were employed. Participants rated perceived stimulus direction, certainty, and intensity on a 0-10 scale (3 denoting pain threshold).
The results showed that stimulus orientation was significantly more accurately discriminated under closed-loop control than open-loop control. The directional discrimination threshold was 31.9 mm for distal-proximal and 26.1 mm for lateral-medial directed stimuli during closed-loop control. The numerical rating scale was significantly higher for lateral/medial directions. Furthermore, the closed-loop control system reduced variability in the discrimination threshold.
Investigators concluded that the closed-loop system discriminated better in lateral-medial directions, highlighting its potential for exploring nociceptive system dynamics.
Source: onlinelibrary.wiley.com/doi/full/10.1002/ejp.2259
