title: Decision-making under explicit risk is impaired in multiple sclerosis: relationships with ventricular width and disease disability.
abstract: BACKGROUND
  Decision-making is an essential function of everyday life. Decision-making under explicit risk requires developing advantageous decision strategies based on fixed outcomes (e.g., probabilities of winning or losing a bet). Decision-making and its neural substrates have been rarely studied in MS. We expected performance in decision-making under risk to be lowered in MS patients, and negatively correlated with disease-related disability, cognition, and ventricular width.
  
  
  METHODS
  Three groups were included: 32 MS patients and 20 healthy controls were examined with conventional neuropsychological tests and the Game-of-Dice Task (GDT) assessing decision-making under explicit risk. Linear 2-D ventricular width was assessed on MS patients' clinical MRIs and compared to a third group, 20 non-MS neurological control patients.
  
  
  RESULTS
  Compared to healthy controls, MS patients showed impaired GDT and neuropsychological performance, depending on the MS-subtype (relapsing-remitting (RR), n = 22; secondary progressive, n = 10) and disability severity among RR-MS patients. In MS patients, GDT performance correlated with processing speed, intercaudate ratio, and third ventricle ratio (p's < 0.05). Mediation analysis showed that the link between GDT performance and processing speed was fully explained by ventricular size.
  
  
  CONCLUSIONS
  Decision-making under explicit risk was reduced in MS patients, but only those with more pronounced disability. Independent of processing speed, decision-making under explicit risk correlates inversely with central atrophy in MS.
authors.affiliation: Department of Psychiatry, University of Alberta, 1E1.01 WCM Health Sciences Centre, Edmonton, Alberta, T6G 2R7, Canada. adr2@ualberta.ca.
authors.forename: Ashley D
authors.initials: AD
authors.lastname: Radomski
authors.affiliation: Department of Psychiatry, University of Alberta, 1E1.01 WCM Health Sciences Centre, Edmonton, Alberta, T6G 2R7, Canada. chris.power@ualberta.ca.|Department of Medicine (Neurology), University of Alberta, Edmonton, Canada. chris.power@ualberta.ca.
authors.forename: Christopher
authors.initials: C
authors.lastname: Power
authors.affiliation: Department of Psychiatry, University of Alberta, 1E1.01 WCM Health Sciences Centre, Edmonton, Alberta, T6G 2R7, Canada. scot.purdon@albertahealthservices.ca.|Neuropsychology Service, Alberta Hospital Edmonton, Edmonton, Canada. scot.purdon@albertahealthservices.ca.
authors.forename: Scot E
authors.initials: SE
authors.lastname: Purdon
authors.affiliation: Department of Radiology and Diagnostic Imaging, University of Alberta, Edmonton, Canada. demery@ualberta.ca.
authors.forename: Derek J
authors.initials: DJ
authors.lastname: Emery
authors.affiliation: Department of Medicine (Neurology), University of Alberta, Edmonton, Canada. gregg.blevins@ualberta.ca.
authors.forename: Gregg
authors.initials: G
authors.lastname: Blevins
authors.affiliation: Department of Medicine (Neurology), University of Alberta, Edmonton, Canada. swarren@ualberta.ca.
authors.forename: Kenneth G
authors.initials: KG
authors.lastname: Warren
authors.affiliation: Department of Psychiatry, University of Alberta, 1E1.01 WCM Health Sciences Centre, Edmonton, Alberta, T6G 2R7, Canada. efujiwara@ualberta.ca.
authors.forename: Esther
authors.initials: E
authors.lastname: Fujiwara
mesh_terms: D000328:Adult; D002552:Cerebral Ventricles / Q000473:pathology*; D003657:Decision Making / Q000502:physiology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000473:pathology* / Q000503:physiopathology*; D012309:Risk-Taking; D012720:Severity of Illness Index; D013647:Task Performance and Analysis