The effect of variable frequency stimulation of subthalamic nucleus on freezing gait of patients with Parkinson's disease

Objective To explore the treatment efficacy of variable frequency stimulation (VFS) of subthalamic nucleus (STN) on freezing of gait (FOG) in patients with Parkinson's disease (PD). Methods Seven patients with PD were treated by VFS from May 2016 to July 2017 at Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University. Those patients had failed to improve their FOG with STN stimulation with high frequency stimulation (HFS). All patients were followed up at the outpatient clinic following VFS-STN stimulation. The third part of Unified Parkinson's Disease Rating Scale (UPDRS-Ⅲ) and Freezing of Gait Questionnaire (FOGQ) were employed to explore the treatment efficacy on the patient's motor and gait improvement. Results In the early stage of VFS, the UPDRS-III score was significantly lower than that in baseline (23.3±8.1 vs. 45.3±7.2, P 0.05). The FOGQ score was significantly lower than that in baseline(11.7±6.1 vs. 17.3±5.1, P<0.05). The improvement rate of FOGQ was significantly higher for VHS than that for HFS [(45.6±22.7)% vs. (13.8±10.9)%, P<0.05]. The follow-up time was 3-12 months (mean, 7.3±4.0 months). At this time, the UPDRS-III score was (19.9±7.0) and the improvement rate was (56.2±15.8)%, which was significantly higher than that for HFS (P<0.05) but was not significantly different from that in the early stage. The FOGQ score was (11.0±5.7). The improvement rate of FOGQ was (48.0±19.4)%, which was significantly higher than that in HFS (P<0.05) but was not significantly different from that in the early stage. Conclusion For relief of FOG in patients with PD, the effect of VFS could be more remarkable and stable. Key words: Parkinson's disease; Deep brain stimulation; Subthalamic nucleus; Freezing of gait; Variable frequency stimulation