Objective: To investigate the effect of deep brain stimulation (DBS) or coagulation of the internal globus pallidus (GPi) for choreic movements of various disorders and clarify the physiological mechanisms underlying choreic movements.

Background: Overall efficacy of pallidal surgery on choreic movements of various etiologies has not been fully assessed. Little is known about the physiological mechanisms underlying choreic movements.

Method: Five patients with choreic movements (striatal lacunar infarction, dentatorubral-pallidoluysian atrophy, diabetic hemichorea-hemiballism, Huntington’s disease, tardive dyskinesia) were treated with pallidotomy or GPi DBS. During intra-operative mapping we recorded spontaneous neuronal activity from single neurons in the GPi and the external globus pallidus (GPe). Neuronal discharge rates and patterns were analyzed and compared to those collected from patients with Parkinson’s disease (PD).

Results: Choreic movements were abolished after pallidal surgery in all patients and have not returned over the follow-up period up to 2 years. We analyzed 49 GPi and 44 GPe neurons from the chorea patients and 183 GPi and 176 GPe neurons from 28 patients with PD. The discharge frequencies of the GPi (mean±SD, 50.0±31.7Hz) and GPe (32.6±21.4Hz) in choreic disorders were significantly lower (p<0.005) than those of the GPi (86.6±31.7Hz) and GPe (60.3±26.3Hz) in PD, and discharge patterns of the GPi were more irregular in choreic disorders. Oscillatory activity was different between these two groups.

Conclusion: Pallidal surgery was highly effective for the treatment of choreic movements regardless of their etiology, suggesting they may share a common neural mechanism. Compared to PD, neuronal discharge rates and patterns of activity in the GPi were different in choreic movements resembling those reported previously in dystonia. The lower mean discharge rates in the GPe and GPi would suggest the direct pathway plays a predominant role in determining the discharge rates of GPi neurons in chorea and are consistent with overactivity in the direct pathway. We hypothesize that chorea develops as a result of the altered patterns of neuronal activity in the GPi disrupting information processing in the thalamocortical and cortical-cortical circuits that is restored though either removing or modulating this aberrant output from the GPi.

« Back to 2019 International Congress

MDS Abstracts - https://www.mdsabstracts.org/abstract/pallidal-surgery-and-physiological-mechanism-in-choreic-movements/