title: Subthalamic oscillatory activity in parkinsonian patients with off-period dystonia.
abstract: OBJECTIVE
  The study was aimed to explore oscillatory activity in the subthalamic nucleus (STN) in Parkinson's disease (PD) with off-period dystonia, a type of levodopa-induced dyskinesias (LID).
  
  
  METHODS
  Eighteen patients with PD who underwent STN DBS were studied. Nine patients had dyskinesia defined as the LID group and nine patients who did not present any sign of dyskinesia were defined as the control group. Microelectrode recordings in the STN together with electromyogram (EMG) were recorded. Spectral and coherence analyses were performed to study the neuronal oscillations in relation to limb muscles.
  
  
  RESULTS
  Two hundred and fifteen neurons were identified. There were 39 neurons with tremor-frequency band (4-7 Hz) oscillation, 57 neurons with β-frequency band (12-30 Hz, β-FB) oscillation and 100 neurons without oscillation, and 19 neurons with very low-frequency band oscillation at a mean peak power of 1.2 ± 0.5 Hz (LFB). These LFB oscillatory neurons (n = 15) were frequently significantly coherent with EMG of off-period dystonia. Notably, 89% (n = 17) neurons with LFB oscillation were found in the patients in the off-dystonia group. The age at onset of PD, duration of PD, and levodopa equivalent dose daily consumption were statistically different between two groups (P < 0.05).
  
  
  CONCLUSIONS
  Subthalamic LFB oscillatory neurons seem to play an important role in the genesis of off-period dystonia in advanced PD. Clinical and demographic analyses confirmed that the earlier age at onset of PD, longer duration of PD, and levodopa exposure are important risk factors in the development of the type of LID.
authors.affiliation: Beijing Institute of Functional Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China.
authors.forename: X
authors.initials: X
authors.lastname: Li
authors.affiliation: Beijing Institute of Functional Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China. zhuangp@vip.sina.com.|Center of Parkinson's Disease, Beijing Institute for Brain Disorders, Beijing, China. zhuangp@vip.sina.com.|Key Laboratory of Neurodegenerative Diseases (Capital Medical University), Ministry of Education, Beijing, China. zhuangp@vip.sina.com.
authors.forename: P
authors.initials: P
authors.lastname: Zhuang
authors.affiliation: Human Motor Control Section, Medical Neurology Branch, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD, USA.
authors.forename: M
authors.initials: M
authors.lastname: Hallett
authors.affiliation: Beijing Institute of Functional Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China.
authors.forename: Y
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Beijing Institute of Functional Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China.
authors.forename: J
authors.initials: J
authors.lastname: Li
authors.affiliation: Beijing Institute of Functional Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China.
authors.forename: Y
authors.initials: Y
authors.lastname: Li
mesh_terms: D000328:Adult; D000368:Aged; D004409:Dyskinesia, Drug-Induced / Q000503:physiopathology*; D004421:Dystonia / Q000503:physiopathology*; D004569:Electroencephalography; D004576:Electromyography; D005260:Female; D006801:Humans; D007980:Levodopa / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000503:physiopathology*; D020531:Subthalamic Nucleus / Q000503:physiopathology*
chemical_list: D007980:Levodopa
keywords: Parkinson's disease; dyskinesia; microelectrode recording; oscillation; subthalamic nucleus