Sympathetic skin response: correlation with autonomic and somatic involvement in multiple sclerosis

Area of Science:

• Neurology
• Autonomic Nervous System Function
• Clinical Neurophysiology

Background:

• Multiple sclerosis (MS) is a chronic neurological disease affecting the central nervous system.
• Autonomic dysfunction is a common complication in MS, impacting various bodily functions.
• The sympathetic skin response (SSR) is a measure of sympathetic sudomotor function.

Purpose of the Study:

• To investigate the utility of SSR testing in evaluating patients with multiple sclerosis.
• To assess the correlation between SSR abnormalities and clinical disability in MS.
• To determine the diagnostic value of SSR for autonomic dysfunction in MS.

Main Methods:

• SSR was recorded from palms and soles in 63 MS patients (54 definite, 9 probable) using electric stimuli.
• Patients were assessed using the Kurtzke Expanded Disability Status Scale (EDSS).
• Comparisons were made with other evoked potentials (VEP, BAEP, SEP) and signs of autonomic dysfunction (bladder impairment).

Main Results:

• Abnormal SSR (absent or delayed) was found in 41% of MS patients.
• Abnormal SSR correlated positively with higher EDSS scores and increased latencies.
• Bladder impairment was the most frequent autonomic dysfunction associated with altered SSR.
• Visual evoked potentials showed a positive correlation with SSR abnormalities.

Conclusions:

• SSR is a simple test for dynamic evaluation in MS, correlating with disability and detecting subclinical sympathetic lesions.
• SSR has limited localizing value and low sensitivity for bladder-related autonomic impairment.
• SSR is not a primary diagnostic tool for MS but can aid in monitoring disease progression.