title: Investigation of white matter pathology in ALS and PLS using tract-based spatial statistics.
abstract: OBJECTIVE
  We aimed to investigate differences in fractional anisotropy (FA) between primary lateral sclerosis (PLS) and amyotrophic lateral sclerosis (ALS) and the relationship between FA and disease progression using tract-based spatial statistics (TBSS).
  
  
  METHODS
  Two scanners at two different sites were used. Differences in FA between ALS patients and controls scanned in London were investigated. From the results of this analysis, brain regions were selected to test for (i) differences in FA between controls, patients with ALS and patients with PLS scanned in Oxford and (ii) the relationship between FA and disease progression rate in the Oxford patient groups.
  
  
  RESULTS
  London ALS patients showed a lower FA than controls in several brain regions. Oxford patients with PLS showed a lower FA than ALS patients and than controls in the body of the corpus callosum and in the white matter adjacent to the right primary motor cortex (PMC), while ALS patients showed reduced FA compared with PLS patients in the white matter adjacent to the superior frontal gyrus. Significant correlations were found between disease progression rate and (i) FA in the white matter adjacent to the PMC in PLS, and (ii) FA along the cortico-spinal tract and in the body of the corpus callosum in ALS.
  
  
  CONCLUSIONS
  We described significant FA changes between PLS and ALS, suggesting that these two presentations of motor neuron disease show different features. The significant correlation between FA and disease progression rate in PLS suggests the tissue damage reflected in FA changes contributes to the disease progression rate.
authors.affiliation: Department of Brain Repair and Rehabilitation, Institute of Neurology, University College London, Queen Square, London. o.ciccarelli@ion.ucl.ac.uk
authors.forename: Olga
authors.initials: O
authors.lastname: Ciccarelli
authors.forename: Timothy E
authors.initials: TE
authors.lastname: Behrens
authors.forename: Heidi
authors.initials: H
authors.lastname: Johansen-Berg
authors.forename: Kevin
authors.initials: K
authors.lastname: Talbot
authors.forename: Richard W
authors.initials: RW
authors.lastname: Orrell
authors.forename: Robin S
authors.initials: RS
authors.lastname: Howard
authors.forename: Rita G
authors.initials: RG
authors.lastname: Nunes
authors.forename: David H
authors.initials: DH
authors.lastname: Miller
authors.forename: Paul M
authors.initials: PM
authors.lastname: Matthews
authors.forename: Alan J
authors.initials: AJ
authors.lastname: Thompson
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Smith
mesh_terms: D000328:Adult; D000368:Aged; D000690:Amyotrophic Lateral Sclerosis / Q000473:pathology* / Q000503:physiopathology; D001921:Brain / Q000473:pathology* / Q000503:physiopathology; D001931:Brain Mapping / Q000379:methods; D015331:Cohort Studies; D003337:Corpus Callosum / Q000473:pathology / Q000503:physiopathology; D003627:Data Interpretation, Statistical; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D018450:Disease Progression; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008297:Male; D008875:Middle Aged; D009044:Motor Cortex / Q000473:pathology / Q000503:physiopathology; D016472:Motor Neuron Disease / Q000473:pathology* / Q000503:physiopathology; D009413:Nerve Fibers, Myelinated / Q000473:pathology*; D015588:Observer Variation; D011237:Predictive Value of Tests; D011712:Pyramidal Tracts / Q000473:pathology / Q000503:physiopathology