Diagnostic and prognostic value of external anal sphincter EMG patterns in Multiple System Atrophy

This database includes the raw data linked with the paper “Diagnostic and prognostic value of external anal sphincter EMG patterns in multiple system atrophy”. We collected clinical data and external anal sphincter (EAS) EMG findings in 72 patients with multiple system atrophy (MSA) and 21 with Parkinson’s disease (PD). We ascertained the survival times of 49 MSA patients who died during follow-up. We aimed to assess the diagnostic and prognostic value and clinical correlations of a novel classification of EAS electromyography patterns in MSA. We identified four EAS electromyography patterns, ranging from normal findings (pattern I) to mild, moderate or severe neurogenic damage (patterns II, III and IV, respectively). Pattern I was frequently observed in PD patients, while it was associated with prolonged survival when identified in a few MSA patients. Patterns II, III and IV were predominant in MSA. Subjects with MSA and EAS abnormalities often showed fecal incontinence and urogenital symptoms, which were frequently present at disease onset in patients with patterns III and IV. Abnormal EAS patterns correlated with MSA diagnosis. In particular, pattern IV was associated with the highest likelihood of MSA diagnosis and with the worst prognosis in the MSA cohort.