11-Clinical benefit of pallidal stimulation in dystonia is related to improved intracortical inhibition and local grey matter hypertrophy

Abstract

Background Treatment efficacy of pallidal stimulation (GPi DBS) in dystonia varies and the benefit increases slowly, suggesting induction of slow plastic processes in regions involved with motor control. Methods We examined 19 patients (mean age 48 ± (SD)18 years) with cervical (N = 7) or generalized dystonia (N = 12) of various origin by chronic GPi DBS for 57 ± 28 months. Voxel-based morphometry of postoperative T1-weighted images was calculated for gray matter (GM) density in every patient and compared with 20 matched controls. Paired TMS was applied to the motor cortex to elicit short-latency intracortical inhibition (SICI) of the motor evoked potential. The clinical effect of GPi DBS was expressed as a change in the dystonic score (BFMDS or TWSTRS) between actual GPi DBS ON condition and the preoperative state. Results Dystonia patients showed increased GM density in the SMA and middle cingulate in comparison with healthy controls (p Conclusions Brain changes of chronically GPi DBS treated patients possibly reflect “hardwire” rebuilding of motor regions associated with functional improvement. Supported by the grant GACR 16-13323S.