Brain Structural And Functional Changes After Action Observation Therapy In Parkinson’s Disease Patients With Freezing Of Gait (S21.003)

OBJECTIVE: To assess brain functional and structural changes following action observation therapy (AOT) in patients with PD and freezing of gait (PD-FoG). BACKGROUND: FoG is a disabling impairment for PD patients and may not respond to medications. AOT may enhance physical therapy in PD-FoG. DESIGN/METHODS: 20 PD-FoG patients underwent a 4-week (W4) rehabilitation training. Subjects were randomized into 2 groups: in AOT-group, therapy consisted of AO combined with practicing the observed actions; control-group performed the same training combined with landscape-videos observation. At baseline (T0) and W4, patients underwent: clinical and motor functional evaluations, and 3D-T1-weighted and functional MRI. FMRI tasks consisted of: foot simple-movement; observation of videos showing a man in circumstances precipitating FoG; motor imagery in the same circumstances as observation task. Clinical and motor functional assessments were repeated at week 8 (W8). RESULTS: At W4, both groups showed reduced FOG severity and walking speed improvement. AOT-group showed additional UPDRS III, balance, and quality of life (QoL) improvements. At W8, functional motor improvements were confirmed in both groups, while positive effects on UPDRS III and QoL were observed in AOT-group only. At W4, AOT was associated with an increased grey matter (GM) volume of cerebellar and parietal regions bilaterally; in control-group an increased primary motor cortex volume was observed bilaterally. FMRI showed that AOT was associated with increased recruitment of primary sensorimotor/premotor cortices, mirror neuron system (MNS) and caudate nucleus bilaterally during simple-motor and motor imagery tasks. At W4, control-group showed reduced recruitment of the primary sensorimotor areas during all tasks. In both groups, structural and functional brain changes were associated with clinical improvements at W4 and predicted clinical evolution at W8. CONCLUSIONS: AOT has a positive additional effect on walking ability recovery of PD-FoG patients. In PD, AOT promotes brain structural and functional plasticity of both the primary sensorimotor and MN systems. Study Supported by: A grant from Jacques und Gloria Gossweiler Foundation.