Dystonias

Dystonia is described as a motor syndrome characterized by involuntary prolonged muscle contractions causing sustained twisting movements and abnormal postures of affected body parts. The main characteristics of dystonia in surface EMG investigations are cocontractions of antagonistic muscles and overflow activities in distant muscles. Voluntary ballistic movements of affected body parts are slowed and the three-burst pattern in agonist and antagonist muscles is prolonged. A number of brainstem and spinal cord reflex investigations demonstrated an abnormal decrease of inhibitory interneuronal activity. The decre…