title: Gray matter atrophy and freezing of gait in Parkinson's disease: Is the evidence black-on-white?
abstract: OBJECTIVE
  The pathophysiology underlying freezing of gait (FOG) in Parkinson's disease (PD) is poorly understood. We tested whether gray matter (GM) atrophy contributes to FOG in PD.
  
  
  METHODS
  Voxel-based morphometry quantified GM atrophy in 106 patients who were classified as freezers (n = 30) or nonfreezers (n = 76). Well-matched smaller subgroups were also studied. Balance, gait, and cognitive function were assessed, and we evaluated the relationship between GM, FOG severity, and symptoms associated with FOG.
  
  
  RESULTS
  GM was significantly reduced in the inferior parietal lobe and angular gyrus in the matched freezers (n = 22), compared to nonfreezers (n = 22; P < 0.015, cluster-level corrected). In the entire cohort, FOG severity was related to bilateral caudate volumes.
  
  
  CONCLUSIONS
  GM atrophy in cortical (i.e., parietal lobe and angular gyrus) and subcortical areas (i.e., caudate) are related to FOG. Disparities among the existing findings suggest that inferences regarding specific brain regions should be made with caution.
authors.affiliation: Movement Disorders Unit, Department of Neurology, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel; The Dr. Miriam and Sheldon G. Adelson Graduate School of Medicine, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Talia
authors.initials: T
authors.lastname: Herman
authors.forename: Keren
authors.initials: K
authors.lastname: Rosenberg-Katz
authors.forename: Yael
authors.initials: Y
authors.lastname: Jacob
authors.forename: Nir
authors.initials: N
authors.lastname: Giladi
authors.forename: Jeffrey M
authors.initials: JM
authors.lastname: Hausdorff
mesh_terms: D000368:Aged; D001921:Brain / Q000473:pathology* / Q000503:physiopathology; D003071:Cognition / Q000502:physiology; D005260:Female; D005684:Gait / Q000502:physiology*; D020233:Gait Disorders, Neurologic / Q000473:pathology* / Q000503:physiopathology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D036421:Nerve Fibers, Unmyelinated / Q000473:pathology*; D009483:Neuropsychological Tests; D010300:Parkinson Disease / Q000473:pathology* / Q000503:physiopathology
keywords: Parkinson's disease; freezing of gait; gray matter; volumetric MRI