title: Intermuscular coherence in Parkinson's disease: relationship to bradykinesia.
abstract: We hypothesised that bradykinesia may be partly due to the failure of the corticomuscular system to engage in high frequency oscillatory activity in Parkinson's disease (PD). In healthy subjects such oscillations are evident in coherence between active muscles at 15--30 Hz. We therefore investigated the effects of therapeutic stimulation of the basal ganglia on this coherence and related it to changes in bradykinesia in the contralateral arm. Increases in coherence at 15--30 Hz and improvements in bradykinesia upon stimulation were correlated (r = 0.564, p < 0.001). This suggests that the basal ganglia modulate oscillatory activity in the corticomuscular system and that impairment of the motor system's ability to engage in synchronised oscillations at high frequency may contribute to bradykinesia in PD.
authors.affiliation: Sobell Department of Neurophysiology, Institute of Neurology, Queen Square, London, WCIN 3BG, UK.
authors.forename: P
authors.initials: P
authors.lastname: Brown
authors.forename: J
authors.initials: J
authors.lastname: Marsden
authors.forename: L
authors.initials: L
authors.lastname: Defebvre
authors.forename: F
authors.initials: F
authors.lastname: Cassim
authors.forename: P
authors.initials: P
authors.lastname: Mazzone
authors.forename: A
authors.initials: A
authors.lastname: Oliviero
authors.forename: M G
authors.initials: MG
authors.lastname: Altibrandi
authors.forename: V
authors.initials: V
authors.lastname: Di Lazzaro
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: Odin
authors.forename: P
authors.initials: P
authors.lastname: Pollak
mesh_terms: D004599:Electric Stimulation Therapy; D004576:Electromyography; D005260:Female; D005917:Globus Pallidus / Q000503:physiopathology*; D006801:Humans; D018476:Hypokinesia / Q000503:physiopathology* / Q000628:therapy; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000294:innervation / Q000502:physiology; D010300:Parkinson Disease / Q000503:physiopathology* / Q000628:therapy; D010507:Periodicity; D020531:Subthalamic Nucleus / Q000503:physiopathology*