Are there plastic changes in the human brain of patients with Parkinson's disease treated with long-term deep brain stimulation of the subthalamic nucleus? A 4-years follow-up study with regional cerebral blood flow SPECT

603 Objectives: The availability of clinical and rCBF data during time have given the challenging opportunity to investigate cerebral reorganization of the human brain after or during a disease. Such a studies have recognized the plastic changes to be the principal process responsible for recovery of neural function, spontaneously or related to treatments. Aim of the present prospective follow-up study was to assess persistent motor and regional cerebral blood flow (rCBF) changes in patients with Parkinson’s disease treated with high frequency deep brain stimulation (DBS) of the subthalamic nucleus (STN). Methods: Ten PD patients with STN-DBS underwent three rCBF SPECT at rest, once preoperatively in the off-drug condition (T0), and the other two post-operatively in the off-drug/off-stimulation conditions at 5±2 (T1) and 42±7 months (T2). Patients were administered with UPDRS, H&Y and S&E scales. SPM was used to investigate baseline rCBF changes from the pre- to the post-operative conditions and the relationship between rCBF and UPDRS scores used as covariate of interest Results: All patients showed a clinical improvement which was significant only at 4 years follow-up. The main effect of treatment from T0 to T1 was to produce baseline rCBF increases in the pre-supplementary motor area (pre-SMA), premotor and somatosensory association cortex. From T1 to T2 a further baseline rCBF increase was detected in the pre-SMA (p Conclusions: our study suggests the presence of baseline persistent plastic changes in the human brain of PD patients treated with long-term STN-DBS. Such a neural plasticity may occur mainly in the pre-SMA and it is likely to play a slightly beneficial role in terms of functional compensation of motor impairment related to PD. Although disease progression occurs at subcortical level, persistent plastic changes may occur in cortical motor areas attempting to repair their function.