title: Intermuscular coherence in Parkinson's disease: effects of subthalamic nucleus stimulation.
abstract: It remains unclear how high frequency stimulation of the subthalamic nucleus (STN) improves parkinsonism. We hypothesized that stimulation may affect the organization of the cortical drive to voluntarily activated muscle. Normally this is characterized by oscillations at 15-30 Hz, manifest in coherence between muscles in the same frequency band. We therefore investigated the effects of STN stimulation on electromyographic (EMG) activity in co-contracting distal arm muscles in nine subjects with Parkinson's disease off drugs. Without stimulation, coherence between EMG signals was diminished at 15-30 Hz compared with nine controls. STN stimulation increased coherence in the 15-30 Hz band, so that it approached that in healthy subjects. The results suggest that STN stimulation facilitates the normal cortical drive to muscles.
authors.affiliation: MRC Human Movement and Balance Unit, Institute of Neurology, Queen Square, London, WC1N 3BG, UK.
authors.forename: J
authors.initials: J
authors.lastname: Marsden
authors.forename: P
authors.initials: P
authors.lastname: Limousin-Dowsey
authors.forename: V
authors.initials: V
authors.lastname: Fraix
authors.forename: P
authors.initials: P
authors.lastname: Pollak
authors.forename: P
authors.initials: P
authors.lastname: Odin
authors.forename: P
authors.initials: P
authors.lastname: Brown
mesh_terms: D000704:Analysis of Variance; D016001:Confidence Intervals; D004599:Electric Stimulation Therapy / Q000379:methods*; D004576:Electromyography / Q000379:methods; D005260:Female; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000502:physiology*; D010300:Parkinson Disease / Q000503:physiopathology* / Q000628:therapy; D020531:Subthalamic Nucleus / Q000502:physiology* / Q000503:physiopathology; D014953:Wrist / Q000502:physiology