title: Motor cortical oscillations are abnormally suppressed during repetitive movement in patients with Parkinson's disease.
abstract: OBJECTIVE
  Impaired repetitive movement in persons with Parkinson's disease (PD) is associated with reduced amplitude, paradoxical hastening and hesitations or arrest at higher movement rates. This study examined the effects of movement rate and medication on movement-related cortical oscillations in persons with PD.
  
  
  METHODS
  Nine participants with PD were studied off and on medication and compared to nine control participants. Participants performed index finger movements cued by tones from 1 to 3 Hz. Movement-related oscillations were derived from electroencephalographic recordings over the region of the contralateral sensorimotor cortex (S1/M1) during rest, listening, or synchronized movement.
  
  
  RESULTS
  At rest, spectral power recorded over the region of the contralateral S1/M1 was increased in the alpha band and decreased in the beta band in participants with PD relative to controls. During movement, the level of alpha and beta band power relative to baseline was significantly reduced in the PD group, off and on medication, compared to controls. Reduced movement amplitude and hastening at movement rates near 2 Hz was associated with abnormally suppressed and persistent desynchronization of oscillations in alpha and beta bands.
  
  
  CONCLUSIONS
  Motor cortical oscillations in the alpha and beta bands are abnormally suppressed in PD, particularly during higher rate movements.
  
  
  CONCLUSIONS
  These findings contribute to the understanding of mechanisms underlying impaired repetitive movement in PD.
authors.affiliation: Department of Physical Therapy and Human Movement Sciences, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA; Department of Kinesiology, Iowa State University, Ames, IA 50011, USA. Electronic address: esteg@iastate.edu.
authors.forename: Elizabeth L
authors.initials: EL
authors.lastname: Stegemöller
authors.affiliation: Department of Physical Therapy and Human Movement Sciences, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA. Electronic address: dp.allen62@gmail.com.
authors.forename: David P
authors.initials: DP
authors.lastname: Allen
authors.affiliation: Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA. Electronic address: t-simuni@northwestern.edu.
authors.forename: Tanya
authors.initials: T
authors.lastname: Simuni
authors.affiliation: Department of Physical Therapy and Human Movement Sciences, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA; Department of Neurology, University of Minnesota, Minneapolis, MN 55455, USA. Electronic address: cmakinn@umn.edu.
authors.forename: Colum D
authors.initials: CD
authors.lastname: MacKinnon
mesh_terms: D000368:Aged; D058256:Brain Waves / Q000502:physiology*; D004569:Electroencephalography / Q000379:methods; D004576:Electromyography / Q000379:methods; D005260:Female; D005385:Fingers / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009044:Motor Cortex / Q000503:physiopathology*; D009068:Movement / Q000502:physiology*; D010300:Parkinson Disease / Q000175:diagnosis / Q000503:physiopathology*; D011597:Psychomotor Performance / Q000502:physiology*
keywords: Alpha band; Beta band; Desynchronization; Hastening; Hypokinesia