title: Corpus callosum atrophy is strongly associated with cognitive impairment in multiple sclerosis: Results of a 17-year longitudinal study.
abstract: BACKGROUND
  Cognitive impairment is common in multiple sclerosis (MS) and may be subtle. The corpus callosum is essential for connectivity-demanding cognitive tasks and is significantly affected in MS, therefore it may serve as a marker for cognitive function.
  
  
  OBJECTIVE
  The objective of this paper is to longitudinally study the normalized corpus callosum area (nCCA) as a marker of cognitive function and disability in MS.
  
  
  METHODS
  Thirty-seven MS patients were followed from 1996 with follow-ups in 2004 and 2013. A healthy matched control group was recruited. The Expanded Disability Status Scale (EDSS) and Symbol Digit Modalities Test (SDMT) were assessed. The nCCA was measured on T2-weighted images. Volumetry was performed with FreeSurfer.
  
  
  RESULTS
  Disease duration spanned five decades (1.6-46 years). Annual corpus callosal atrophy rate decreased with disease duration. nCCA was strongly correlated with SDMT (r = 0.793, p < 0.001) and moderately correlated with EDSS (r = -0.545, p < 0.001) after adjusting for disease duration, age and sex. The correlations of brain parenchymal fraction, white matter fraction, gray matter fraction and normalized lesion volume were less strong.
  
  
  CONCLUSIONS
  The nCCA correlates well with physical and cognitive disability in time perspectives close to two decades, outperforming volumetric measurements. The nCCA is fast and could be feasible for clinical implementation where it may help identify patients in need of neuropsychological evaluation.
authors.affiliation: Department of Clinical Science, Intervention and Technology, Karolinska Institutet, Stockholm, Sweden/Department of Radiology, Karolinska University Hospital, Stockholm, Sweden tobias.granberg@ki.se.
authors.forename: Tobias
authors.initials: T
authors.lastname: Granberg
authors.affiliation: Department of Clinical Science, Intervention and Technology, Karolinska Institutet, Stockholm, Sweden/Department of Radiology, Karolinska University Hospital, Stockholm, Sweden.
authors.forename: Juha
authors.initials: J
authors.lastname: Martola
authors.affiliation: Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden/Department of Neurology, Karolinska University Hospital, Stockholm, Sweden.
authors.forename: Gösta
authors.initials: G
authors.lastname: Bergendal
authors.affiliation: Department of Clinical Science, Intervention and Technology, Karolinska Institutet, Stockholm, Sweden/Department of Radiology, Karolinska University Hospital, Stockholm, Sweden.
authors.forename: Sara
authors.initials: S
authors.lastname: Shams
authors.affiliation: Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Soheil
authors.initials: S
authors.lastname: Damangir
authors.affiliation: Department of Clinical Science, Intervention and Technology, Karolinska Institutet, Stockholm, Sweden/Department of Radiology, Karolinska University Hospital, Stockholm, Sweden.
authors.forename: Peter
authors.initials: P
authors.lastname: Aspelin
authors.affiliation: Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden/Department of Neurology, Karolinska University Hospital, Stockholm, Sweden.
authors.forename: Sten
authors.initials: S
authors.lastname: Fredrikson
authors.affiliation: Department of Clinical Science, Intervention and Technology, Karolinska Institutet, Stockholm, Sweden/Department of Radiology, Karolinska University Hospital, Stockholm, Sweden.
authors.forename: Maria
authors.initials: M
authors.lastname: Kristoffersen-Wiberg
mesh_terms: D000328:Adult; D001284:Atrophy; D003072:Cognition Disorders / Q000209:etiology / Q000473:pathology*; D003337:Corpus Callosum / Q000473:pathology*; D004185:Disability Evaluation; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000150:complications / Q000473:pathology*; D009483:Neuropsychological Tests
keywords: Corpus callosum; MRI; atrophy; cognitive impairment; multiple sclerosis