Sympathetic skin responses in hemiplegic patients with and without complex regional pain syndrome

Background and Aims: To investigate whether there were changes in the sympathetic skin responses (SSR) in the limbs with complex regional pain syndrome (CRPS) type I in hemiplegic patients.
Setting: A physical medicine and rehabilitation center in Turkey
Materials and Methods: Sympathetic skin responses were evaluated in 69 stroke patients (41 with CRPS and 28 without CRPS) and 20 healthy volunteers. SSR were recorded on the paretic and healthy hands after stimulation of the ipsilateral median nerve. Patients′ ages ranged from 33 to 77 years, with a mean of 60.0 ± 12.9 years.
Results: The SSR were obtained in all patients with CRPS, whereas SSR was absent in 9 of 28 patients with hemiplegia who did not have CRPS after stimulation of the plegic side and the difference was statistically significant ( P =0.023). SSR amplitudes were increased at the hemiplegic limbs in patients affected by CRPS compared to individuals unaffected; this group difference was statistically significant ( P =0.014). The mean amplitude of the SSR in the advanced stage of CRPS was greater than lower stage and the difference was statistically significant ( P =0.035).
Conclusion: Our results suggest that SSR can be obtained in stroke patients with CRPS even in the early stages of CRPS. SSR acquirability and amplitude increase as the stage of the disease advances. As an electrophysiologic technique, SSR may be used in the evaluation of the sympathetic function in hemiplegic patients and also in the diagnosis of CRPS and in monitoring of its treatment.

Keywords
Autonomic dysfunction, complex regional pain syndrome, hemiplegia, stroke, sympathetic skin responses