Effects of deep brain stimulation of the internal globus pallidus on primary dystonia: clinical and neurophysiological aspects involved in disease progression

Abstract

Dystonia is a movement disorder characterized by prolonged or intermittent muscle contractions, causing abnormal movements or postures. Its pathophysiology is not well understood, and some studies have shown a pathological cortical neuronal activity in the basal ganglia. Deep brain stimulation (DBS) of the globus pallidus is an effective treatment in refractory dystonia, and allows to study the pathophysiology of dystonia through the local field potential (LFP) record. Recent studies suggest the presence of a pathological synchronization of electrical activity at low frequencies in the internal globus pallidus, between 4 and 12 Hz, which could be suppressed by the DBS. The studies of LFP and its modulation by the DBS are scarce. A new technique of ECP, adaptive, has been developed to adjust the amount of energy supplied by the ECP to concomitant changes recorded through LFP analyzing. This technique allows optimizing clinical effects of ECP, besides studying the pathophysiological changes in dystonia. The present study proposes to study the electrical activity of the globus pallidus through PCEL and their relationship with the activity of the cerebral cortex, through the EEG. The registration will be done at rest and during the movement, evaluating the electrical changes of the internal globus pallidus and cortical surface during daily activities. Twelve patients with refractory dystonia will participate in the study, and will be evaluated for five days after surgery, with the recording of the electrical activity of the globus pallidus conducted by the adaptive DBS. Their motor changes will be recorded and compared with the standard ECP, not adaptive. The study will improve the understanding of the pathophysiology of dystonia and the DBS mechanisms of action. The results will guide further research on the pathophysiological study of this disease as weel as new therapeutic strategies. (AU)