title: Effects of cognitive task demands on subsequent symptoms and activity in adults with symptomatic osteoarthritis.
abstract: OBJECTIVE
  Adults with osteoarthritis (OA) experience fatigue in daily life that is negatively related to physical activity; however, it is unclear how task demands affect fatigue and occupational performance. We examined effects of a cognitive task on subsequent symptoms and activity.
  
  
  METHODS
  Adults with knee or hip OA completed a standardized cognitive task during a lab visit. Objective physical activity and symptoms were tracked during two home-monitoring periods (i.e., 4-day period before and 5-day period after the lab visit). Multilevel modeling was used to compare pretask with posttask fatigue, pain, and activity levels.
  
  
  RESULTS
  Fatigue increased and pain decreased for 2 days after performing the lab task. The authors found no pretask to posttask changes in activity levels. At posttask, daily fatigue and activity patterns changed relative to baseline.
  
  
  CONCLUSIONS
  For adults with symptomatic OA, cognitive task demands may be an important contributor to fatigue and pain.
authors.affiliation: Anna L. Kratz, PhD, is Assistant Professor, Department of Physical Medicine and Rehabilitation, University of Michigan, Ann Arbor.
authors.forename: Anna L
authors.initials: AL
authors.lastname: Kratz
authors.forename: Stacey L
authors.initials: SL
authors.lastname: Schepens
authors.forename: Susan L
authors.initials: SL
authors.lastname: Murphy
mesh_terms: D061725:Accelerometry; D000203:Activities of Daily Living; D000368:Aged; D003071:Cognition; D015897:Comorbidity; D005260:Female; D006801:Humans; D008297:Male; D005222:Mental Fatigue / Q000453:epidemiology*; D009043:Motor Activity; D015207:Osteoarthritis, Hip / Q000453:epidemiology* / Q000503:physiopathology; D020370:Osteoarthritis, Knee / Q000453:epidemiology* / Q000503:physiopathology; D010146:Pain / Q000453:epidemiology* / Q000503:physiopathology; D013647:Task Performance and Analysis