Neuropsychological and psychiatric assessments following bilateral deep brain stimulation of the sub-thalamic nucleus in Japanese patients with Parkinson’s disease 日本人パーキンソン病患者における両側視床下核深部脳刺激後の神経心理学的および精神医学的評価 Mental changes in PD with STN-DBS

The physical benefits of subthalamic nucleus deep brain stimulation (STN-DBS) in Parkinson’s disease(PD) patients are well documented, but the mental benefits are uncertain, particularly in Japanese patients. This study evaluated the clinical and neuropsychological characteristics before and after STN-DBS surgery in Japanese PD patients. PD patients (n=13, age 67.0 ± 7.8 years) were evaluated pre-surgery (baseline) and at one and six months post-surgery by two trained psychiatrists. The motor symptoms were assessed by the Unified Parkinson’s Disease Rating Scale (UPDRS) motor score. The neuropsychological and psychiatric tests performed were the Mini-Mental State Examination, the Wisconsin Card Sorting Test (WCST), the verbal fluency test (VFT), the Hamilton Depression Rating Scale and the Hamilton Anxiety Rating Scale (HAM-A). The UPDRS motor score (p<0.001) and HAM-A score (p=0.004) showed significant improvement at one month post-surgery, but a significant decline was observed in the WCST total error (p=0.005) and the semantic VFT score (p<0.001). The phonetic VFT also showed a substantial decline (p=0.015) at one month post-surgery. At six months post-surgery, the improvement in the UPDRS motor score was maintained, and the scores on the neuropsychological and psychiatric tests had returned to baseline. Although bilateral STN-DBS did not appear to have long-term effects on neuropsychological and psychiatric outcomes, the microlesion effects associated with STN-DBS appear to increase the risk of transient cognitive and psychiatric complications. These complications should be monitored by careful observation of neurological and psychiatric symptoms.