Gait initiation evaluation after deep brain stimulation for Parkinson's disease: A 7-year follow-up

This study evaluated the long-term effects of deep brain stimulation of the subthalamic nucleus (DBS-STN) on gait initiation. Six Parkinson's disease (PD) patients who had undergone DBS-STN and 31 control subjects were evaluated. PD subjects were assessed at two different time periods: 11.3 ± 10.3 (P1) and 78.9 ± 10.6 (P2) months after surgery. Subjects under stimulation were tested in two conditions: without medication and with medication. Principal components (PC) analysis was separately applied on vertical, anterior-posterior and medial-lateral ground reaction force (GRF) from gait initiation, during the anticipatory postural adjustment (APA) phase. Three PC scores were chosen by the scree test for each GRF component. The higher loading factors pointed to major differences between controls and PD patients on maximum APA amplitude for vertical and anterior-posterior GRF. Friedman test showed a significant difference in standard distance among conditions (P = 0.006), with the post-hoc test recognizing differences only between P1 and P2 in the medication-on condition. All distances increased in the follow-up evaluation (P2), when considering the same medication condition, indicating a worsening in gait initiation after 7 years of follow-up.