Sixty-three patients were subjected to clinico-electrophysiological examination for precise definition of the features of pathogenesis of the tonic and clonic forms of generalized torsion dystonia. Stimulation electromyography was conducted by the generally accepted method with determination of the composition of motor neurons involved in the reflex response. Torsion dystonia was found to be a pathogenetically heterogeneous disease. Registration of the motor neurons involved in the reflex response yielded additional information on the pathogenetic features of this disease.