title: Strong association of the rest-activity rhythm with well-being in demented elderly women.
abstract: OBJECTIVE
  The objective of this study is to investigate the association between actigraphic estimates of the sleep-wake rhythm and a range of functional domains that contribute to well-being in demented elderly patients.
  
  
  METHODS
  Eighty-seven women aged 85.5 +/- 5.9 years (mean +/- standard deviation) wore an actigraph for two weeks. Activity profiles were analyzed using nonparametric variables, including dichotomy indices, interdaily stability (IS), intradaily variability (IV), and relative amplitude (RA). The associations between these variables and cognitive, functional, behavioral, and emotional states (obtained from standardized neuropsychologic assessments and questionnaires administered to caregivers) were investigated by partial correlations and stepwise regressions.
  
  
  RESULTS
  Cognitive, functional, behavioral, and emotional states showed medium to strong correlations with multiple rhythm variables. Partial correlations indicated that this could not be attributed to a uniform worsening with advancing cognitive decline. Stepwise regressions indicated three most distinctive rhythm variables: 1) the interdaily stability of the 24-hour rhythm was most strongly, negatively, related to cognitive decline and depression; 2) the median level of daytime activity was most strongly, negatively, related to impairments of function, of activities of daily living, and of social interaction; and 3) nocturnal restlessness was secondarily, positively, related to impairments of function and social interaction.
  
  
  CONCLUSIONS
  Especially the interdaily stability and median daytime activity level, and secondarily nocturnal restlessness, showed a strong relationship with the functional status and well-being of demented elderly. This raises the possibility that treatments that enhance daytime activity and the stability of the rest-activity rhythm may improve well-being.
authors.affiliation: Netherlands Institute for Neuroscience, Amsterdam, The Netherlands.
authors.forename: S Sandra
authors.initials: SS
authors.lastname: Carvalho-Bos
authors.forename: Rixt F
authors.initials: RF
authors.lastname: Riemersma-van der Lek
authors.forename: Jim
authors.initials: J
authors.lastname: Waterhouse
authors.forename: Thomas
authors.initials: T
authors.lastname: Reilly
authors.forename: Eus J W
authors.initials: EJ
authors.lastname: Van Someren
mesh_terms: D000203:Activities of Daily Living / Q000523:psychology; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000175:diagnosis / Q000523:psychology*; D040561:Assisted Living Facilities; D002940:Circadian Rhythm; D003866:Depressive Disorder / Q000175:diagnosis / Q000523:psychology; D018450:Disease Progression; D004644:Emotions; D005260:Female; D015577:Geriatric Assessment; D006707:Homes for the Aged; D006801:Humans; D009043:Motor Activity; D009426:Netherlands; D009483:Neuropsychological Tests; D011595:Psychomotor Agitation / Q000175:diagnosis / Q000523:psychology; D011788:Quality of Life / Q000523:psychology*; D012890:Sleep; D013223:Statistics as Topic; D011795:Surveys and Questionnaires; D014851:Wakefulness