the effects of bilateral subthalamic nucleus stimulation on cognitive and neuropsychiatric functions in parkinson’s disease: a case-control study

introduction: parkinson’s disease is one of the most disabling diseases which by electrode implantation and stimulation of subthalamic nucleus (stn), much progress has been made in the treatment of drug resistant patient. this new method of neurosurgery may have some neuropsychological side effects on the patients. the main aim of this study is to evaluate the effects of this kind of treatment on the different neuropsychological aspect of patients.methods: the case-control study designed for comparing two groups of patients with parkinson’s disease. thirty patients, who underwent electrode implantation and deep brain stimulation (dbs), compare with 60 patients treated with antiparkinson’s drugs. these two groups matched in age, sex, parkinson’s disease duration and parkinson’s  severity scores. measurements: the updr scale was used to assess the severity of the parkinson’s severity. beck depression inventory questionnaire (bdi) and hamilton anxiety rating scale questionnaire (hars) were used to evaluate the depression and anxiety consequences of dbs.mini mental status examination (mmse) and clock drawing test (cdt) were used to evaluate the cognitive and executive function of the study subjects. results: patients with stn stimulation showed lower level of anxiety and depression, however, the cognitive status were more deteriorated in study subjects than control group. discussion: patient with dbs surgery have to be followed up for neuropsychiatric symptoms particularly for the cognitive deterioration in long term period.