Difference of disability between electrophysiologic subgroups of essentialtremor

Objective: The aim of the study was to test the validity of the controversi al subdivision of essential tremor (ET) patients into electrophysiological subgroups. Methods: We evaluated a hundred patients with ET using surface e lectromyogaphic (EMG) recordings of antagonist forearm muscles and distingu ished three groups: the first group showed synchronous activity of antagoni stic muscles, the second showed alternating activity of antagonist muscles; and the third, group consisted of patients whose EMG recordings were not c ompatible with the other two groups, We compared patients with synchronous and alternating activity in terms of sex, age at onset, duration of illness , family history of tremor, symmetry and frequency of tremor, and the score s of a disability scale, Results: The only significant difference between t he patients with synchronous and alternating activity was that the patients with synchronous activity were more disabled. Conclusion: This result adds to the evidence for distinct electrophysiological subgroups of ET with dis tinct clinical properties.