Postural stability under globus pallidus internus stimulation for dystonia

Abstract

ObjectiveDeep brain stimulation of the globus pallidus internus (GPi-DBS) is an efficient and safe treatment for medically refractory dystonia. However, recent studies reported gait problems, falls and bradykinesia in patients after the DBS procedure. The aim of this study was to quantify the effect of GPi-DBS on postural performance in patients with cranio-cervical dystonia. MethodsThirteen patients with focal/segmental dystonia and GPi-DBS participated in the study. We performed two postural tests (pull test and push and release test) in on- and off-stimulation conditions and recorded the movements of the patients with inertial sensors. ResultsUnder stimulation patients exhibited a higher number of steps (p=0.015), reduced first step length (p=0.011) and lower stepping velocity (p=0.001), compared to off stimulation. We observed a higher number of steps in the push and release test compared to the pull test (p=0.038). The interaction between stimulation condition and test type was significant (p=0.027). ConclusionsThe velocity and amplitude of postural reactions are compromised by GPi-DBS in patients with cranio-cervical dystonia. SignificanceThis information corresponds to patient’s reports of falls and postural instability after GPi-DBS. Pre-operatively, patients should be informed about the possibility of the occurrence of such phenomena.