title: The rest-activity rhythm and physical activity in early-onset dementia.
abstract: BACKGROUND
  A substantial part of elderly persons with dementia show rest-activity rhythm disturbances. The rest-activity rhythm is important to study in people with early-onset dementia (EOD) for rest-activity rhythm disturbances are predictive of institutionalization, and caregivers of young patients suffer from high distress.
  
  
  OBJECTIVE
  The aim of this study was to study (1) whether EOD patients have more rest-activity rhythm disturbances compared with cognitively intact adults; and (2) which factors contribute to a disturbed rhythm.
  
  
  METHODS
  We included 61 patients with EOD [mean age 61.9 (4.9) y, 41 (67%) men] and 68 cognitively intact adults [mean age 61.6 (4.5) y, 28 (41%) men]. Rest-activity rhythm was assessed by actigraphy.
  
  
  RESULTS
  EOD patients tended to have higher intradaily variability [0.46 (0.16) and 0.39 (0.10), P=0.03]. EOD patients also lay for a longer time in bed [time in bed: 08:49 (0:51) h and 08:07 (0:47) h, P<0.001] and needed more time to fall asleep [sleep onset latency: 23 (22) min and 15 (15) min, P=0.02]. Disturbances in the rest-activity rhythm were predicted by a low level of physical activity, use of antidepressants and central nervous system neurological medications, and being male.
  
  
  CONCLUSIONS
  EOD patients showed more variability in the rest-activity rhythm compared with cognitively intact adults. The main predictor for rest-activity rhythm disturbances was a low level of physical activity.
authors.affiliation: *Department of Clinical Neuropsychology, VU University †Alzheimer Center & Department of Neurology, Neuroscience Campus Amsterdam ‡Department of Epidemiology and Biostatistics, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Astrid M
authors.initials: AM
authors.lastname: Hooghiemstra
authors.forename: Laura H P
authors.initials: LH
authors.lastname: Eggermont
authors.forename: Philip
authors.initials: P
authors.lastname: Scheltens
authors.forename: Wiesje M
authors.initials: WM
authors.lastname: van der Flier
authors.forename: Erik J A
authors.initials: EJ
authors.lastname: Scherder
mesh_terms: D000367:Age Factors; D000368:Aged; D021081:Chronobiology Disorders / Q000175:diagnosis* / Q000503:physiopathology / Q000523:psychology; D003430:Cross-Sectional Studies; D003704:Dementia / Q000175:diagnosis* / Q000503:physiopathology / Q000523:psychology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009043:Motor Activity / Q000502:physiology*; D012146:Rest / Q000502:physiology* / Q000523:psychology; D012894:Sleep Stages / Q000502:physiology*