title: The impact of subjective cognitive fatigue and depression on cognitive function in patients with multiple sclerosis.
abstract: The association between subjective cognitive fatigue and objective cognitive dysfunction in patients with multiple sclerosis (PwMS) has been studied, with conflicting results.
  
  
  
  To explore the impact of fatigue on cognitive function, while controlling for the influence of depression, disability, comorbidities, and psychotropic medications.
  
  
  
  PwMS completed a computerized cognitive testing battery with age- and education-adjusted cognitive domain scores. Disability (Expanded Disability Status Scale (EDSS)), cognitive fatigue, and depression were concurrently evaluated.
  
  
  
  In all, 699 PwMS were included. Both cognitive fatigue and depression were significantly and negatively correlated with the same cognitive domains: information processing speed, executive function, attention, motor function, and memory (-0.15 ⩽ r ⩽ -0.14 for cognitive fatigue; -0.24 ⩽ r ⩽ -0.19 for depression). Multivariate analysis revealed significant but small independent correlations only between depression and neuropsychological test results, while cognitive fatigue had no independent correlation with objective cognitive function except for a trend toward impaired motor function in highly fatigued PwMS. Depression and cognitive fatigue accounted for no more than 6% of the variance in objective cognitive domain scores.
  
  
  
  Cognitive fatigue is not independently related to objective cognitive impairment. Depression may influence cognitive function of PwMS primarily when it is severe. Cognitive impairment in PwMS should not be ascribed to fatigue or mild depression.
authors.affiliation: Department of Neurology, Lady Davis Carmel Medical Center, Haifa, Israel/The Ruth and Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel.
authors.forename: Daniel
authors.initials: D
authors.lastname: Golan
authors.affiliation: Department of Clinical Research, NeuroTrax Corporation, Modiin, Israel/The Joseph Sagol Neuroscience Center, Sheba Medical Center, Ramat Gan, Israel/Center of Advanced Technologies in Rehabilitation, Sheba Medical Center, Ramat Gan, Israel.
authors.forename: Glen M
authors.initials: GM
authors.lastname: Doniger
authors.affiliation: South Shore Neurologic Associates, Patchogue, NY, USA.
authors.forename: Karl
authors.initials: K
authors.lastname: Wissemann
authors.affiliation: South Shore Neurologic Associates, Patchogue, NY, USA.
authors.forename: Myassar
authors.initials: M
authors.lastname: Zarif
authors.affiliation: South Shore Neurologic Associates, Patchogue, NY, USA.
authors.forename: Barbara
authors.initials: B
authors.lastname: Bumstead
authors.affiliation: South Shore Neurologic Associates, Patchogue, NY, USA/Stony Brook University, Stony Brook, New York USA.
authors.forename: Marijean
authors.initials: M
authors.lastname: Buhse
authors.affiliation: South Shore Neurologic Associates, Patchogue, NY, USA.
authors.forename: Lori
authors.initials: L
authors.lastname: Fafard
authors.affiliation: Department of Community Medicine and Epidemiology, Lady Davis Carmel Medical Center, Haifa, Israel.
authors.forename: Idit
authors.initials: I
authors.lastname: Lavi
authors.affiliation: Washington Neuropsychology Research Group, Fairfax, VA, USA/Department of Neurology, Georgetown University, Washington, DC, USA.
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Wilken
authors.affiliation: South Shore Neurologic Associates, Patchogue, NY, USA.
authors.forename: Mark
authors.initials: M
authors.lastname: Gudesblatt
mesh_terms: D000328:Adult; D060825:Cognitive Dysfunction / Q000503:physiopathology*; D003863:Depression / Q000503:physiopathology*; D003936:Diagnosis, Computer-Assisted; D059026:Diagnostic Self Evaluation; D005260:Female; D006801:Humans; D008297:Male; D005222:Mental Fatigue / Q000503:physiopathology*; D008875:Middle Aged; D012189:Retrospective Studies
keywords: Cognitive function; computerized cognitive assessment; depression; fatigue; multiple sclerosis