Sympathetic Skin Response In Peripheral Neuropathy

Objective:Sympathetic skin response (SSR) is one of several methods to detect sympathesis post-ganglion C type small fiber nerve, and it is convenient, woundless and reliable compared to others. This research determines the value of SSR to evaluate the function of sympathesis post-ganglion C type small fiber nerve in order to reflex the dysfunction of small fiber nerve. We try to make up to the following objectives. 1. To explore the values of SSR when used in peripheral neuropathy and the characteristic of SSR values. 2. Do peripheral neuropathy patients have sympathesis post-ganglion C type small fiber nerve dysfunction? 3. Do some patients which have normal EMG+NCV results but typical symptoms of small fiber nerve dysfunction have evidence of small fiber nerve contamination?Methods:26 healthy subjects and 86 peripheral neuropathy patients, which composed of 18 CTS patients, 25 DM patients, 20 patients with normal NCV results but definite numbness and pain symptoms and 23 immunity-related patients are selected in the research. There age ranges for 20 to 60 years old. Collect there general information, history, clinical signs and EMG+NCV results. The model of the equipment is Keypoint (Medtronic Ltd. Software version 3.62) electromyogram and evoked potential detector. Surface electrodes are used with record electrode positioned at the center of the right palm and plantar, reference electrode positioned at the second dorsal interossei of right hand and the first dorsal interossei of the right foot, ground electrode positioned at right palm transverse striation. Put the negative stimulation electrode at 3cm proximal from the palm transverse striation and stimulate the right median nerve with 20mA single pulse, 0.2s duration, and then record 10s waveform. Repeat the stimulation again on random side of hand with more than 90s interval and 30mA current. Repeat again if the waveform is not satisfactory. The stimulation times is less than 5 and the total test must finish in 15 minutes. Select the wave with highest amplitude and best stability as the final value. Determine the latency manually and record wave form type, latency, amplitude and area under curve of the right palm and plantar. Patient groups receive EMG+NCV examination following. Additionally, DM patients receive plantar tactile and pain sensation examination by a filament used to screen DM foot on 5 points of each plantar.Results: 1. There is no significance different between male and female healthy subjects. There is no significance different between subjects under 35 years old and above 35 years old. This means SSR has no relationship to gender and age. 2. There is significance difference between DM group and control group, which supports the view that DM patients have sympathesis post-ganglion C type small fiber nerve dysfunction. But no linear correlation is found between SSR and chosen possible factors. 3. There is significance difference between CTS group and control group, but no significance difference between mild side and severe side and between healthy side and affect side. There is no significance difference between healthy side and healthy control, but the P value is approximate to 0. 05(0. 06).These results revealed CTS patients have sympathesis post-ganglion C type small fiber nerve dsfunction, and the dysfunction may appeal in the earlier period. So SSR may be an earlier diagnose of SSR. 4. There is no significance difference between NCV normal group and control group of the palm SSR, but the plantar latency and AUC have significance difference, while the P value of plantar amplitude is approximate to 0. 05. It is concluded that the distal nerve of these patients may suffer from sympathesis post-ganglion C type small fiber nerve dysfunction in early stage. 5. There is significance difference between immuno-related peripheral neuropathy group and control group, which means these patients also have sympathesis post-ganglion C type small fiber nerve dysfunction, whether axon or myelin damage .But no difference is found between axon damage, myelin damage and mixing damage, which implies the fragility of small fibers. 6. There is no significance difference among all groups about SSR disappearance rate. But the disappearance occurred in every group except control group. The research is concluded into these items: 1. SSR is an objective electrophysiological method to evaluate small fiber nerves.2.Most peripheral neuropathy patients suffers small fiber dysfuntion. 3. Some patients with limbs numbness and pain may not neurosis but small fiber neuropathy. 4. Sympathesis post-ganglion C type small fiber has the characteristic of fragility.