Afferent thermosensory function in relapsing-remitting multiple sclerosis following exercise-induced increases in...

Area of Science:

• Neurology
• Sensory Physiology

Background:

• Multiple sclerosis (MS) commonly causes heat sensitivity, leading to symptom exacerbation with increased body temperature.
• While efferent neurological functions in MS are studied concerning heat, the impact on afferent sensory pathways remains unclear.

Purpose of the Study:

• To investigate alterations in afferent thermosensory function in MS patients following exercise-induced body temperature increases.
• To quantify the effects of mild heat stress on thermal perception in individuals with MS.

Main Methods:

• A cohort of eight MS patients and eight age-matched controls underwent a quantitative sensory test.
• Participants rated cold and warm stimuli on their hands before and after 30 minutes of cycling in a heated environment (30°C).
• Body temperature changes were monitored, and thermosensitivity was assessed for various thermal stimuli.

Main Results:

• A modest body temperature increase (∼0.4°C) significantly reduced cold, but not warm, skin thermosensitivity in MS patients.
• These reductions in cold sensitivity were more pronounced and occurred over a wider temperature range in MS patients compared to controls.
• Control subjects showed reduced sensitivity only to colder stimuli, unlike MS patients.

Conclusions:

• Exercise-induced heat stress impairs afferent cold thermosensitivity in MS patients, impacting neural pathways.
• The findings suggest that even minor body temperature elevations can alter sensory function in MS.
• The developed quantitative sensory testing method shows promise for evaluating afferent sensory function in MS under heat stress conditions.