Sympathetic Skin Response In Diagnosing Diabetic Autoneuropathy

Diabetic Peripheral Neuropathy is the most common complication in its nervous system's complications while automatic nervous system is the main part of nervous system, so diabetic dysautonomia has caught more and more attention in recent years. however, lacking of specific symptoms and effecter organs affected by external or internal environment greatly, no effective examination has been found. Detecting of Sympathetic Skin Response (SSR) and are electrophysical testing to assess the automatic nerve function. As a new noninvasive technique to measure the function of C fiber mainly in anatomical aspect and subconscious activation in the functional aspect. SSR combined with EMG-NCV can give a comprehensive evaluation of peripheral nerve function, and are new electrophysiology techniques of measuring the function of small fibers.OBJECTIVES:1. To analyse the characteristics of sympathetic skin response (SSR) in diabetic patients and their correlation with dysaut0nomia.2. To assess the value of SSR in diagnosing diabetic autonomic neuropathy in its early stage.METHODS:SSR were performed in 50 patients are diabetic mellitus. Diagnosis of diabetic mellitus were made according to the diagnostic guideline of American Diabetes Consensus Conference (2002) during the period of February to December in 2006 in Dalian Friendship Hospital and in 36 age-and gender-matched healthy volunteers at the same time. (1) Latency and amplitude of SSR (in resting state and in deep respiration respectively) were recorded and analyzed in two groups. (2) The parameters of SSR were compared in patients who were divided into two groups: with or without polyneuropathy according to the result of electrophysiological test and have or haven't dysautonomia according to clinical symptoms respectively. (3) The relationship between the parameters of SSR and severity of the patients was studied in our research. Severity of the patients were scored by using Toronto Clinical Scoring System (CSS)Result:1. control group:The height of volunteers was significantly positive correlated with latency of SSR, but was not with amplitude. Age and gender were not correlated with latency and amplitude.2, diabetic group:(1) The latency of SSR in the patient without peripheral neuropathy were prolonged and amplitude decreased. These became more obvious especially in amplitude in the patients who had peripheral neuropathy, (2) The potential were not evoked in 30.3% of the patients with peripheral neuropathy and 11% of the patients without peripheral neuropathy. This was more serious in lower limbs than in upper limb. The latency and amplitude of SSR in lower limb were significantly correlated with CSS and duration of condition. (3) Abnormality of SSR in the patients with autonomic symptom was 65% and 61% in those without autonomic symptom. SSR could reveal the subclinical focus of sympathetic nerve system to some extent. (4) The parameters of SSR were correlated with CSS.CONCLUSIONS:1. The abnormality of SSR could reveal the involvement of small fiber-autonomic nerve fiber in anatomical aspect and subclinical autonomic disease in functional aspect.2. The parameters of SSR could be more abnormally when the myelinated nerve are involved.3. SSR testing was one of the new methods of electrophysiology for detecting autonomic nerve fiber, one of small nerve fibers. Combination use of SSR and RRIV with EMG-NCV could give a comprehensive evaluation of peripheral nerve function.