title: Pallidotomy effect on the cortical excitability in patients with severe Parkinson's disease.
abstract: Surgical lesions in the medial pallidum have been shown to ameliorate motor deficits in patients with Parkinson's disease (PD). It is believed that interruption of the pallidothalamocortical projections to the motor cortex is required for the satisfactory results. In this report, we adopt cortico-cortical inhibition as the tool to assess the pallidotomy effect on cortical excitability in PD. Interstimulus interval between 1 and 15 msec were investigated. The average peak-to-peak amplitude was measured and calculated at each delay. A total of 8 patients (M:F = 4:4) 54.9 years of age (SD = 9.6) and 10 controls were recruited for the study. In the controls, the inhibitory phenomenon was observed from the 1-msec to the 4-msec delay points and the maximal inhibition was at the 3-msec delay point (33.69% +/- 6.50% of the control response). Mild facilitation was noticed since the 5-msec delay point and thereafter. In patients before operation, a similar trend of inhibition was also observed in the initial 4 msec with the maximal inhibition also at the 3-msec delay point (64.66 +/- 6.77% of the control response). In the postoperative group, the short interstimulus interval inhibition can no longer be observed and the conditioned response was 95.06 +/- 23.68% of the control at the 3-msec delay point. The suppression was gone at and after the 7-msec delay point. Results of repeated-measures analysis of variance show a significant difference among the controls and PD patients before and 3 months after pallidotomy (F = 3.40, P = 0.05). Post hoc examination revealed a significant difference between the controls and PD patients 3 months after pallidotomy at the 3-msec delay point (P = 0.004). However, no correlation was observed between the 3-msec inhibition and the Unified Parkinson's Disease Rating Scale Motor score or the dyskinesia score. The results suggest that pallidotomy can modulate the cortical inhibitory circuitry in patients with PD.
authors.affiliation: Neuroscience Laboratory, Department of Neurology, China Medical University Hospital, Taichung, Taiwan, Republic of China.|Institute of Medical Science, China Medical University, Taichung, Taiwan, Republic of China.
authors.forename: Chon-Haw
authors.initials: CH
authors.lastname: Tsai
authors.affiliation: Neuroscience Laboratory, Department of Neurology, China Medical University Hospital, Taichung, Taiwan, Republic of China.
authors.forename: Fang-Chia
authors.initials: FC
authors.lastname: Chang
authors.affiliation: Movement Disorders Unit, Department of Neurology, Chang Gung Memorial Hospital, Taipei, Taiwan, Republic of China.
authors.forename: Chin-Song
authors.initials: CS
authors.lastname: Lu
authors.affiliation: Department of Neurosurgery, Chang Gung Memorial Hospital, Taipei, Taiwan, Republic of China.
authors.forename: Shih-Tseng
authors.initials: ST
authors.lastname: Lee
authors.affiliation: Movement Disorders Unit, Department of Neurology, Chang Gung Memorial Hospital, Taipei, Taiwan, Republic of China.
authors.forename: Yu-Ting
authors.initials: YT
authors.lastname: Huang
authors.affiliation: Neuroscience Laboratory, Department of Neurology, China Medical University Hospital, Taichung, Taiwan, Republic of China.
authors.forename: Ming-Kuei
authors.initials: MK
authors.lastname: Lu
authors.affiliation: Movement Disorders Unit, Department of Neurology, Chang Gung Memorial Hospital, Taipei, Taiwan, Republic of China.
authors.forename: Rou-Shayn
authors.initials: RS
authors.lastname: Chen
authors.affiliation: Movement Disorders Unit, Department of Neurology, Chang Gung Memorial Hospital, Taipei, Taiwan, Republic of China.
authors.forename: Tony
authors.initials: T
authors.lastname: Wu
authors.affiliation: Department of Electrical Engineering, Chang Gung Memorial Hospital, Taipei, Taiwan, Republic of China.
authors.forename: Jiann-Der
authors.initials: JD
authors.lastname: Lee
authors.affiliation: Movement Disorders Unit, Department of Neurology, Chang Gung Memorial Hospital, Taipei, Taiwan, Republic of China.
authors.forename: Yi-Hsin
authors.initials: YH
authors.lastname: Weng
authors.affiliation: Movement Disorders Unit, Department of Neurology, Chang Gung Memorial Hospital, Taipei, Taiwan, Republic of China.
authors.forename: Hsiu-Chen
authors.initials: HC
authors.lastname: Chang
mesh_terms: D000328:Adult; D000368:Aged; D004576:Electromyography / Q000295:instrumentation; D005260:Female; D005917:Globus Pallidus / Q000503:physiopathology* / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009044:Motor Cortex / Q000503:physiopathology*; D009415:Nerve Net / Q000503:physiopathology*; D009433:Neural Inhibition / Q000502:physiology; D019635:Neurosurgical Procedures / Q000379:methods*; D010300:Parkinson Disease / Q000503:physiopathology* / Q000601:surgery*; D011300:Preoperative Care; D013788:Thalamus / Q000503:physiopathology*