title: Fatigability disrupts cognitive processes' regulation of inflammatory reactivity in old age.
abstract: OBJECTIVE
  High fatigability, a dysfunctional adaption to fatigue, may lead to difficulties performing otherwise regularly encountered cognitive activities and may be related to pro-inflammatory reactivity. The purpose of the study was to investigate the effect of fatigability on cognitive processes and inflammatory response after an acute cognitive stress task in older adults.
  
  
  METHODS
  In an observational stress reactivity study conducted in a light- and temperature-controlled laboratory, we measured IL-6, self-reported acute fatigue, and frontally oriented cognitive processes in 55 community-dwelling individuals aged 75 years or older as part of a demanding set of cognitive tasks intended to induce stress.
  
  
  RESULTS
  Subjects were classified into groups of low and high fatigability based on cluster analysis of their self-report acute fatigue before and after the cognitive tasks. The two clusters were comparable on levels of baseline IL-6 and cognitive processes; however, the high fatigability cluster had significantly higher levels of IL-6 response than the low fatigability cluster. After controlling for multiple covariates, fatigability moderated the relationship between speed of processing and IL-6 reactivity. Further exploratory analyses indicated significant adverse associations between speed of processing and attention and IL-6 reactivity in the group with low but not high fatigability.
  
  
  CONCLUSIONS
  Although observational, these data are consistent with the notion that pro-inflammatory states in older adults might be reduced by improvements in cognitive processes. Because fatigability was associated with increased acute inflammatory response and disrupted the normal stress regulation provided by the cognitive processes, future randomized studies might examine whether fatigability alleviation reduces IL-6.
authors.affiliation: School of Nursing, University of Rochester, Rochester, NY; Department of Psychiatry, School of Medicine and Dentistry, University of Rochester, Rochester, NY. Electronic address: vankee_lin@urmc.rochester.edu.
authors.forename: Feng
authors.initials: F
authors.lastname: Lin
authors.affiliation: William S. Middleton Memorial Veterans Hospital, Madison, WI.
authors.forename: Rachel
authors.initials: R
authors.lastname: Roiland
authors.affiliation: School of Nursing, University of Rochester, Rochester, NY; Department of Microbiology and Immunology, School of Medicine and Dentistry, University of Rochester, Rochester, NY.
authors.forename: Oksana
authors.initials: O
authors.lastname: Polesskaya
authors.affiliation: Department of Psychiatry, School of Medicine and Dentistry, University of Rochester, Rochester, NY.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Chapman
authors.affiliation: School of Nursing, University of Rochester, Rochester, NY.
authors.forename: Melissa
authors.initials: M
authors.lastname: Johnson
authors.affiliation: School of Nursing, University of Rochester, Rochester, NY.
authors.forename: Judith
authors.initials: J
authors.lastname: Brasch
authors.affiliation: School of Nursing, University of Rochester, Rochester, NY; Department of Biostatistics and Computational Biology, School of Medicine and Dentistry, University of Rochester, Rochester, NY.
authors.forename: Ding-Geng
authors.initials: DG
authors.lastname: Chen
authors.affiliation: Department of Neurology, School of Medicine and Dentistry, University of Rochester, Rochester, NY.
authors.forename: Mark
authors.initials: M
authors.lastname: Mapstone
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000097:blood / Q000502:physiology*; D056344:Executive Function / Q000502:physiology*; D005221:Fatigue / Q000097:blood / Q000503:physiopathology*; D005260:Female; D006801:Humans; D007249:Inflammation / Q000097:blood / Q000503:physiopathology; D015850:Interleukin-6 / Q000097:blood*; D008297:Male; D011597:Psychomotor Performance / Q000502:physiology*; D013315:Stress, Psychological / Q000097:blood / Q000503:physiopathology*
chemical_list: D015850:Interleukin-6
keywords: Fatigability; aging; attention; executive function; interleukin-6 reactivity; speed of processing