Blink reflexes in Parkinsonism

39 patients with parkinson disease were studied by clinical and electrophysiological methods for their spontaneous and reflex blink movements. The responsiveness of the rhythmic and evoked blink reflexes against L Dopa was investigated by serial examinations. The spontaneous and rhythmic blink movements were significantly reduced in parkinsonian patients. Blink reflexes induced by glabellar tap were brisk and did not show habituation. These clinical features were found to be correlated with the severity and degree of the hypokinesia rigor and of hypomimia in the patients examined. During regular stimulation of the glabellar region with the successive 100 electrical shocks in every second frequency the second component of the blink reflexes recorded from the orbicularis oculi muscle electromyographically, did not show any habituation. The duration of the second component was significantly prolonged. On the whole, these clinical and electrophysiological features were significantly corrected by L Dopa treatment. The neurophysiological significance of the results is discussed. (Journal received: January 18, 1977)