S77. Non-invasive closed-circuit brain stimulation for gait rehabilitation of patients with Parkinsonian syndrome

Introduction Gait disturbance of Parkinsonian syndrome is characterized by dysrhythmic gait cycle including freezing, small steps and slowness. These symptoms are often not sufficiently responsive to dopaminergic therapy. Recently, we developed new rehabilitation system using non-invasive closed–circuit brain stimulation targeting on dysrhythmic gait dysfunction. Methods The objective of this study is to investigate whether the oscillatory closed-circuit brain stimulation mimicking the appropriate gait cycle can modulate the gait speed and cycle in patients with parkinsonian syndrome. Six patients with Parkinsonian syndrome participated in this study. Three were diagnosed as Parkinson’s disease, two as corticobasal syndrome and one as vascular parkinsonism. Before gait rehabilitation, we decided optimal brain stimulation frequency to each subject as 1/averaged gait cycle when they were best on condition. All participants performed gait rehabilitation for total ten days which contained 4 sessions (4 min. walk and 3 min. rest) per each day. During gait rehabilitation, slow oscillatory DC stimulation (current intensity 0–2 mA) was applied over ipsilateral cerebellum as symptom dominant side, which was triggered by their flat foot switch attached to the ipsilateral heels. Closed-circuit system enabled the implementation of the oscillatory brain stimulation with a fixed pre-set phase lag with respect to the intrinsic gait cycle. Ten m gait speed, cadence, laterality of gait cycle and frozen of gait questionnaire (FOGQ) were evaluated before and after gait rehabilitation. Results Gait speed and cadence were significantly increased after gait rehabilitation (speed: 98 ± 39 cm/s before and 116 ± 38 cm/s after, cadence: 114 ± 18 steps/min before and 124 ± 20 steps/min after). Laterality of gait cycle and FOGQ were significantly decreased after the rehabilitation (laterality: 0.07 ± 0.05 before and 0.0021 ± 0.004 after, FOGQ: 10 ± 7 before and 7 ± 5 after). Conclusion Closed-circuit brain stimulation during walking is useful method to parkinsonian gait disturbance possibly by normalizing dysrhythmic and lateralized gait control system in patients with Parkinsonian syndrome. This new system may provide the personalized rehabilitation in patients with Parkinson related disorders.