title: A comparison of gray matter density in restless legs syndrome patients and matched controls using voxel-based morphometry.
abstract: BACKGROUND
  Restless legs syndrome (RLS) is a common neurological disorder the pathophysiology of which is incompletely understood. Four studies have examined structural differences between the brains of RLS patients and healthy controls, using voxel-based morphometry (VBM). All 4 studies have provided different results.
  
  
  METHODS
  Optimized VBM was used to search for structural differences in gray matter density. Sixteen RLS patients naïve to dopaminergic drugs and 16 age- and sex-matched controls received structural T1-weighted MR scans. Structural data were analyzed using FSL-VBM.
  
  
  RESULTS
  No difference in gray matter density was detected between the two groups (voxel-wise significance: no significant voxels at P= .89 (whole brain Family Wise Error (FWE) corrected); no significant voxels at P < .05 (whole brain False Discovery Rate (FDR) corrected; smallest achievable FDR threshold .99).
  
  
  CONCLUSIONS
  The present study did not replicate (confirm) previous findings of structural brain changes in RLS, but instead supported the findings of a recent study showing a lack of gray matter alteration in an elderly RLS population. More specifically, the results do not support neuronal loss as an underlying disease mechanism in RLS. Potential limitations in the application of VBM are also discussed.
authors.affiliation: GlaxoSmithKline Clinical Imaging Centre, London, UK. robert.comley@roche.com
authors.forename: Robert A
authors.initials: RA
authors.lastname: Comley
authors.forename: Simon
authors.initials: S
authors.lastname: Cervenka
authors.forename: Sven E
authors.initials: SE
authors.lastname: Palhagen
authors.forename: Georgios
authors.initials: G
authors.lastname: Panagiotidis
authors.forename: Julian C
authors.initials: JC
authors.lastname: Matthews
authors.forename: Robert Y
authors.initials: RY
authors.lastname: Lai
authors.forename: Christer
authors.initials: C
authors.lastname: Halldin
authors.forename: Lars
authors.initials: L
authors.lastname: Farde
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Nichols
authors.forename: Brandon J
authors.initials: BJ
authors.lastname: Whitcher
mesh_terms: D001921:Brain / Q000473:pathology*; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009474:Neurons / Q000473:pathology*; D015203:Reproducibility of Results; D012148:Restless Legs Syndrome / Q000473:pathology*; D012680:Sensitivity and Specificity