title: Psychiatric symptoms and subthalamic nucleus stimulation in Parkinson's disease. A retrospective study in our Japanese patients.
abstract: Objectives.  With respect to postoperative activities of daily living (ADL), we retrospectively investigated associated psychiatric symptoms that influenced beneficial effects of subthalamic nucleus (STN) stimulation in our Japanese patients with Parkinson disease (PD). Materials and Methods.  Twenty-five patients underwent bilateral STN stimulation. Pre- and 3 months after the surgery, their parkinsonian symptoms were evaluated with Unified Parkinson Disease Rating Scale (UPDRS) and Schwab-England (S-E) ADL scale. Stepwise multiple analysis was performed to determine the factors affecting postoperative ADL. Results.  Eleven out of 25 patients manifested drug-induced psychosis preoperatively, although their mean dosage of levodopa was small (366.4 ± 152.7 mg). Disease duration positively affected the severity of the patients' psychiatric symptoms. Postoperative S-E score showed a significant improvement compared to the pretreatment baseline in both of "on" and "off" medication states, as all their cardinal motor symptoms were significantly ameliorated. Preoperative scores for thought disorder and axial disability negatively impact on the postoperative S-E score in "on" state (p < 0.01). Preoperative score for intellectual impairment was only a significant predictor of worse postoperative ADL in "off" state. Conclusions.  The markedly lower dose of levodopa may suggest ethnic characteristics of our Japanese patients with respect to tolerance for antiparkinsonian medications. Preoperative manifestation of drug-induced psychosis and cognitive dysfunction were the major factor that strikingly suppressed daily activities after STN stimulation.
authors.affiliation: Department of Neurosurgery, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan;              Departments of Neurological Surgery             Clinical Neuroscience, Graduate School of Medicine, The University of Tokushima, Tokushima, Japan.
authors.forename: Kazumichi
authors.initials: K
authors.lastname: Yamada
authors.forename: Satoshi
authors.initials: S
authors.lastname: Goto
authors.forename: Kazuhito
authors.initials: K
authors.lastname: Matsuzaki
authors.forename: Shinji
authors.initials: S
authors.lastname: Nagahiro
authors.forename: Nagako
authors.initials: N
authors.lastname: Murase
authors.forename: Hideki
authors.initials: H
authors.lastname: Shimazu
authors.forename: Ryuji
authors.initials: R
authors.lastname: Kaji
authors.forename: Jun-Ichi
authors.initials: J
authors.lastname: Kuratsu
authors.forename: Yukitaka
authors.initials: Y
authors.lastname: Ushio