Electrophysiological Study Of The Effect Of Posture On The Sympathetic Skin Response In Normal Subjects And In Diabetic Patients

Abstract

Thirty nine diabetic patients, of both insulin dependent and noninsulin dependent types, and thirty four age and sex matched control subjects were included in this study in an attempt to clarify the effect of changing posture on the peripheral nerves in both groups and to clarify the effect of diabetes on the peripheral nerve by using electromyography. Peripheral nerve dysfunction was evaluated by clinical examination, and electrophysiological testing of the somatosensory and autonomic peripheral nerves in supine and in standing position.The sympathetic skin responses (SSR) evoked by electrical stimulation of right and left median nerves and right and left common peroneal nerves were also recorded and analyzed. The sympathetic skin response test of diabetic patients show a significant reduction in latency and amplitude of the SSR in both upper and lower limbs with more affection in the lower limbs, and it was absent in 7 patients in upper and lower limbs, and in 13 patients in lower limbs only. Also there is a significant reduction in the amplitude of SSR in both control and diabetic groups on standing from supine position. Lastly, we conclude that the electrophysiological assessment of the peripheral nerve is essential for the diagnosis of the peripheral neuropathy which often accompanied with diabetes mellitus. Also we found that the abnormal SSR indicates the early affection of small unmyelinated c fibers in case of diabetic neuropathy. Also, we found that the sympathetic nerve fibers are significantly affected by changing body posture from supine to standing position.