title: Apathy/depression, but not subjective fatigue, is related with cognitive dysfunction in patients with multiple sclerosis.
abstract: BACKGROUND
  Cognitive impairment could affect quality of life for patients with multiple sclerosis (MS), and cognitive function may be correlated with several factors such as depression and fatigue. This study aimed to evaluate cognitive function in Japanese patients with MS and the association between cognitive function and apathy, fatigue, and depression.
  
  
  METHODS
  The Brief Repeatable Battery of Neuropsychological tests (BRB-N) was performed in 184 Japanese patients with MS and 163 healthy controls matched for age, gender, and education. The Apathy Scale (AS), Fatigue Questionnaire (FQ), and Beck Depression Inventory Second Edition (BDI-II) were used to evaluate apathy, fatigue, and depression, respectively. Student's t-test was used to compare MS patients and healthy controls. Correlations between two factors were assessed using the Pearson correlation test, and multiple regression analysis was used to evaluate how much each factor affected the BRB-N score.
  
  
  RESULTS
  In all BRB-N tests, patients with MS scored significantly lower than controls, and the effect size of symbol digit modalities test was the highest among the 9 tests of the BRB-N. Patients with MS had higher AS (p < 0.001), FQ (p < 0.0001), and BDI-II (p < 0.0001) scores than controls. In patients with MS, scores on most of the BRB-N tests correlated with scores on the AS and BDI-II; however, there was little correlation between scores on the BRB-N tests and those on the FQ.
  
  
  CONCLUSIONS
  Cognitive function was impaired, particularly information-processing speed, and decreased cognitive function was correlated with apathy and depression in Japanese patients with MS. Despite the association between cognitive variables and depression/apathy, cognitive function was impaired beyond the effect of depression and apathy. However, subjective fatigue is not related with cognitive impairment. Taken together, this suggests that different therapeutic approaches are needed to improve subjective fatigue and cognition, and thereby quality of life, in patients with MS.
authors.affiliation: Department of Clinical Research, Hokkaido Medical Center, Yamanote 5jo 7chome, Nishi-ku, Sapporo 063-0005, Japan. niino@hok-mc.hosp.go.jp.
authors.forename: Masaaki
authors.initials: M
authors.lastname: Niino
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Mifune
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Kohriyama
authors.forename: Masahiro
authors.initials: M
authors.lastname: Mori
authors.forename: Takashi
authors.initials: T
authors.lastname: Ohashi
authors.forename: Izumi
authors.initials: I
authors.lastname: Kawachi
authors.forename: Yuko
authors.initials: Y
authors.lastname: Shimizu
authors.forename: Hikoaki
authors.initials: H
authors.lastname: Fukaura
authors.forename: Ichiro
authors.initials: I
authors.lastname: Nakashima
authors.forename: Susumu
authors.initials: S
authors.lastname: Kusunoki
authors.forename: Katsuichi
authors.initials: K
authors.lastname: Miyamoto
authors.forename: Kazuto
authors.initials: K
authors.lastname: Yoshida
authors.forename: Takashi
authors.initials: T
authors.lastname: Kanda
authors.forename: Kyoichi
authors.initials: K
authors.lastname: Nomura
authors.forename: Takashi
authors.initials: T
authors.lastname: Yamamura
authors.forename: Fumihito
authors.initials: F
authors.lastname: Yoshii
authors.forename: Jun-ichi
authors.initials: J
authors.lastname: Kira
authors.forename: Shunya
authors.initials: S
authors.lastname: Nakane
authors.forename: Kazumasa
authors.initials: K
authors.lastname: Yokoyama
authors.forename: Makoto
authors.initials: M
authors.lastname: Matsui
authors.forename: Yusei
authors.initials: Y
authors.lastname: Miyazaki
authors.forename: Seiji
authors.initials: S
authors.lastname: Kikuchi
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D057565:Apathy; D003072:Cognition Disorders / Q000175:diagnosis / Q000453:epidemiology / Q000523:psychology*; D003863:Depression / Q000175:diagnosis / Q000453:epidemiology / Q000523:psychology*; D005221:Fatigue / Q000175:diagnosis / Q000453:epidemiology / Q000523:psychology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000175:diagnosis / Q000453:epidemiology / Q000523:psychology*; D009483:Neuropsychological Tests; D055815:Young Adult