Electrical Inhibition of Basal Ganglia Nuclei in Parkinson’s Disease: Long-Term Results

Abstract

Since 1995 a group of 57 patients with familial tremor and Parkinson’s disease have been operated in two main sets: the first, with 11 cases, with predominant tremor, where the ventro-oralis posterior (Vop) thalamic nucleus was stimulated, and the second, with 44 cases, with mainly rigidity and akinesia, where the globus pallidus internus (GPi) was unilaterally (10 cases) or bilaterally (34 cases) stimulated. In 2 cases, a combined thalamic-pallidal stimulation was achieved. In the last cases, an image fusion software with 3D correlation of MR and CT images and volumetric image matching has been used to correct MRI distortion. In all cases, an Itrell II stimulation system (Medtronic) was implanted. Result analysis shows that Vop stimulation is mostly effective for tremor, and GPi stimulation is better for rigidity and akinesia. Transcortical magnetic stimulation tests suggest that GPi pallidal electrical inhibition increases cortical excitability, as opposed to Vop thalamic stimulation, which implies a different mechanism of action.