Neuropsychological changes and bilateral subthalamic deep brain stimulation in Parkinson's disease

Introduction: To investigate neuropsychiatric changes in Parkinson's disease (PD) patients after 12 months of bilateral subthalamic deep brain stimulation (DBS-STN). Subjects: Nine out of 23 patients with PD subjected to DBS-STN were included. The mean follow-up of this cohort was 12 months, mean disease duration 14.2 +/- 5.5 years and mean UPDRS motor score in <<off>> 43.2 +/- 13.7. Methods: Patients were selected on the basis of CAPSIT criteria. They underwent bilateral implant of stimulators in STN under stereotactic conditions. Quality of life scale (PDQ 39), depression scale (Brev-Cet), frontal function test (Stroop, Wisconsin, verbal fluency) and memory evaluation (Barcelona test) were monitored at baseline in <<on>> medication and after 12 months in <<on>> medication/<<on>> stimulation. Results: The patients' motor scores improved on an average of 40.2% (p = 0.0002) in <<off>> medication situation and 58% in quality of life scores. We observed a benefit in depression scores (52%, p = 0.003). Immediate verbal memory improved as well, 25% (p = 0.04) in recall memory and 14% (p = 0.02) in recognition memory. No changes were observed in visual memory, verbal fluency and/or global cognitive tests. Conclusion: DBS-STN in PD patients seems to be an effective tool for improving their quality of life, due to its benefits on motor function, verbal memory and mood. Bilateral DBS-STN did not affect either verbal fluency or executive functions in our patients. Neuropsychological assessment is a good tool for selection and study of the operated patients.