Analysis on clinical and electrophysiological characteristics of 11 patients with stiff-person syndrome.

Objective To summarize the clinical features and electrophysiological characteristics of stiff-person syndrome (SPS). Methods and Results Clinical data of 11 SPS patients [8 were classic and 3 were stiff-person plus syndrome (SPPS)], who were diagnosed and treated from August 2009 to November 2018, were retrospectively collected. They mainly presented paroxysmal muscle stiffness and pain spasm under stimulation or emotional excitement. The first affected sites were at trunk (4 cases) or limb (7 cases) muscles, and by the time of diagnosis, were mainly at truck muscles (8 cases). Anti - glutamic acid decarboxylase (GAD) antibody testing was positive in 6 cases. Electromyography (EMG) of all the patients showed continuous motor unit activity (CMUA) in the affected muscles at rest state. After treated by benzodiazepines, motor unit potential (MUP) obviously decreased or even disappeared in 6 patients. Conclusions Stiff-person syndrome is a rare autoimmune disease with multiple initial sites, atypical initial symptoms and difficulty in early diagnosis. It should be distinguished from many diseases such as familiar hyperekplexia, tetanus, myotonia congenita and multiple sclerosis (MS). [ABSTRACT FROM AUTHOR]