Sympathetic skin response in diabetic neuropathy

Area of Science:

• Neurology
• Diabetology
• Autonomic Neuroscience

Background:

• Diabetic neuropathy commonly involves peripheral nerves.
• Autonomic dysfunction is a frequent complication of diabetes mellitus.
• Assessing autonomic function in diabetic patients is clinically important.

Purpose of the Study:

• To investigate the utility of the sympathetic skin response (SSR) in evaluating autonomic dysfunction in diabetic neuropathy.
• To correlate SSR abnormalities with clinical and electrophysiological findings in diabetic patients.

Main Methods:

• Studied SSR in 47 diabetic patients with peripheral neuropathy and 24 healthy controls.
• Assessed presence/absence of SSR at hand and foot.
• Correlated SSR findings with nerve conduction studies, electromyography, and autonomic function tests (cardiac variability, pupil cycle time).

Main Results:

• SSR was absent in 66% of diabetic patients at the foot and 27.7% at the hand, versus 0% in controls.
• Absence of SSR did not correlate with routine electrophysiological parameters.
• Absent SSR was more common in patients with autonomic dysfunction symptoms (P<0.05) and abnormal cardiac variability and pupil cycle time.
• A strong correlation was found between SSR amplitude and the expiratory:inspiratory (E:I) ratio (r=0.81, P<0.001).

Conclusions:

• Sympathetic skin response (SSR) is frequently absent in diabetic neuropathy patients, especially affecting the feet.
• SSR may serve as a valuable tool for assessing autonomic involvement in diabetic neuropathy.
• Further research is needed to determine the sensitivity of SSR for diagnosing autonomic dysfunction in diabetes.