[Characteristics of sympathetic skin response in patients with multiple system atrophy]

Objective: To provide evidence for early clinical diagnosis of multiple system atrophy(MSA)by studying the characteristics of sympathetic skin responses(SSR) in the patients with MSA. Methods: A total of 47 MSA patients and 32 healthy individuals were enrolled as case group and normal control(NC) group, from in and out patients of Neurology Department of Navy General Hospital from July 2013 to August 2015. SSR was tested by Nicolet electromyography, the latency and abnormal and disappeared rate of SSR were compared. Results: The SSR latency of upper limbs and lower limbs in MSA group had statistical significance compared respectively with the NCgroup (upper limbs: SSR latency was(1 485±187)ms in MSA group, and(1 375±108)ms in NC group, P<0.05; lower limbs: SSR latency was(2 200±386)ms in MSA group, and(1 994±240)ms in NC group, P<0.05). Sex and age had no significant effect on the latency and the abnormal and disappeared rate of SSR in two groups (P>0.05). The upper and lower limb SSR latency in MSA patients with disease duration more than 2 years(SSR latency was (1 592±160)ms in upper limb and (2 268±254)ms in lower limb) were longer than those within 2 years(SSR latency was (1 453±184)ms in upper limb and (2 190±442)ms in lower limb), but only the upper limbs had significantly statistical differences (P<0.05). Both SSR abnormal rate and SSR disappeared rate in MSA patients whose disease duration were more than 2 years(SSR abnormal rate: 85.00%, SSR disappeared rate: 75.00%) were higher than those with shorter disease duration(SSR abnormal rate: 55.56%, SSR disappeared rate: 22.22%), and both were statistically significant (SSR abnormal rate: P<0.05, SSR disappeared rate: P<0.001). The upper and lower limb SSR latency of MSA-C subgroup had no statistical difference compared with MSA-P subgroup(P>0.05). The SSR abnormal rate in MSA-C subgroup(78.13%) was higher than that of MSA-P subgroup(46.76%), and were statistically significant (P<0.05). The SSR disappeared rate in MSA-C subgroup has no statistical difference compared with the MSA-P subgroup(P>0.05). Conclusions: SSR is helpful to diagnose MSA. The latency and the abnormal and disappeared rate of SSR are significantly increased with the extension of MSA duration. The SSR abnormal rate in MSA-C patients is higher than that in MSA-P patients, and symmetrically abnormal SSR is more supporting the diagnosis of MSA.