title: Subliminal gait initiation deficits in rapid eye movement sleep behavior disorder: A harbinger of freezing of gait?
abstract: Muscle activity during rapid eye movement sleep is markedly increased in people with rapid eye movement sleep behavior disorder and people with Parkinson's disease (PD) who have freezing of gait. This study examined whether individuals with rapid eye movement sleep behavior disorder who do not have a diagnosis of PD show abnormalities in gait initiation that resemble the impairments observed in PD and whether there is a relationship between these deficits and the level of rapid eye movement sleep without atonia.
  
  
  
  Gait initiation and polysomnography studies were conducted in 4 groups of 10 participants: rapid eye movement sleep behavior disorder, PD with and without freezing of gait, and controls.
  
  
  
  Significant reductions were seen in the posterior shift of the center of pressure during the propulsive phase of gait initiation in the groups with rapid eye movement sleep behavior disorder and PD with freezing of gait when compared with controls and PD nonfreezers. These reductions negatively correlated with the amount of rapid eye movement sleep without atonia. The duration of the initial dorsiflexor muscle burst during gait initiation was significantly reduced in both PD groups and the rapid eye movement sleep behavior disorder cohort.
  
  
  
  These results provide evidence that people with rapid eye movement sleep behavior disorder, prior to a diagnosis of a degenerative neurologic disorder, show alterations in the coupling of posture and gait similar to those seen in PD. The correlation between increased rapid eye movement sleep without atonia and deficits in forward propulsion during the push-off phase of gait initiation suggests that abnormities in the regulation of muscle tone during rapid eye movement sleep may be related to the pathogenesis of freezing of gait. © 2016 International Parkinson and Movement Disorder Society.
authors.affiliation: Department of Physical Therapy, Rosalind Franklin University of Medicine and Science, North Chicago, Illinois, USA.|Department of Neuroscience, Rosalind Franklin University of Medicine and Science, North Chicago, Illinois, USA.
authors.forename: Laila
authors.initials: L
authors.lastname: Alibiglou
authors.affiliation: Neurological Clinical Research Institute, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Aleksandar
authors.initials: A
authors.lastname: Videnovic
authors.affiliation: Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida, USA.
authors.forename: Peggy J
authors.initials: PJ
authors.lastname: Planetta
authors.affiliation: Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida, USA.|Department of Biomedical Engineering, University of Florida, Gainesville, Florida, USA.
authors.forename: David E
authors.initials: DE
authors.lastname: Vaillancourt
authors.affiliation: Department of Neurology, University of Minnesota, Minneapolis, Minnesota, USA.|Department of Physical Therapy and Human Movement Sciences, Northwestern University, Chicago, Illinois, USA.
authors.forename: Colum D
authors.initials: CD
authors.lastname: MacKinnon
mesh_terms: D000368:Aged; D001696:Biomechanical Phenomena; D005260:Female; D020233:Gait Disorders, Neurologic / Q000209:etiology / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000150:complications / Q000503:physiopathology*; D017286:Polysomnography; D020187:REM Sleep Behavior Disorder / Q000150:complications / Q000503:physiopathology*
keywords: PD; RBD; freezing; gait; sleep