title: Gray matter atrophy distinguishes between Parkinson disease motor subtypes.
abstract: OBJECTIVE
  To assess differences in gray matter (GM) atrophy between 2 Parkinson disease (PD) subtypes: the tremor dominant (TD) subtype and the postural instability gait difficulty (PIGD) subtype.
  
  
  METHODS
  Patients were classified as belonging to the predominately PIGD (n = 30) or predominately TD (n = 29) subtype. Voxel-based morphometry was used to compare GM in these 2 subtypes and to evaluate correlations between predefined regions of interest and the degree of symptoms. In the regions where GM atrophy was associated with symptoms, the relationship between GM volumes and functional connectivity was examined.
  
  
  RESULTS
  GM was reduced in the predominately PIGD group, compared with the predominately TD group, in areas that involve motor, cognitive, limbic, and associative functions (p < 0.05, false discovery rate corrected). Lower GM volumes in the pre-supplementary motor area (SMA) and in the primary motor area were associated with increased severity of PIGD symptoms (r = -0.42, p < 0.001; r = -0.38, p < 0.003, respectively). Higher GM volumes within the pre-SMA were associated with stronger functional connectivity between the pre-SMA and the putamen (r = 0.415, p < 0.025) in the patients with predominately PIGD.
  
  
  CONCLUSIONS
  In patients with PD, PIGD symptoms are apparently associated with GM atrophy in motor-related regions and decreased functional connectivity. GM degeneration and a related decrease in spontaneous coactivation between cortical and subcortical motor-planning areas may partially account for the unique clinical characteristics of a subset of patients with PD.
authors.affiliation: Movement Disorders Unit, Department of Neurology, Tel-Aviv Sourasky Medical Center, Tel Aviv, Israel.
authors.forename: Keren
authors.initials: K
authors.lastname: Rosenberg-Katz
authors.forename: Talia
authors.initials: T
authors.lastname: Herman
authors.forename: Yael
authors.initials: Y
authors.lastname: Jacob
authors.forename: Nir
authors.initials: N
authors.lastname: Giladi
authors.forename: Talma
authors.initials: T
authors.lastname: Hendler
authors.forename: Jeffrey M
authors.initials: JM
authors.lastname: Hausdorff
mesh_terms: D000368:Aged; D000978:Antiparkinson Agents / Q000008:administration & dosage / Q000627:therapeutic use; D001284:Atrophy; D001921:Brain / Q000473:pathology*; D003071:Cognition / Q000502:physiology; D003627:Data Interpretation, Statistical; D005260:Female; D020233:Gait Disorders, Neurologic / Q000473:pathology; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007980:Levodopa / Q000008:administration & dosage / Q000627:therapeutic use; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009069:Movement Disorders / Q000209:etiology / Q000503:physiopathology; D009415:Nerve Net / Q000473:pathology; D009434:Neural Pathways / Q000473:pathology; D009483:Neuropsychological Tests; D010300:Parkinson Disease / Q000145:classification / Q000175:diagnosis* / Q000473:pathology*; D011597:Psychomotor Performance / Q000502:physiology; D012307:Risk Factors
chemical_list: D000978:Antiparkinson Agents; D007980:Levodopa