title: Exploring the use of actigraphy to investigate sleep problems in older people with intellectual disability.
abstract: BACKGROUND
  The aim of this study was to explore the use of actigraphy to investigate sleep problems in a convenience sample of clients of Dutch intellectual disability (ID) care providers. Based on data obtained in a large multi-centre study on healthy ageing in people with ID, research questions were: 'To what degree are actigraphic measurements successful in this population?' and 'What is the influence of different sensitivity settings of the Actiwatch Sleep Analysis software on the distribution of sleep variables in this group?'
  
  
  METHODS
  Data were collected in a cross-sectional descriptive study design. We included 563 participants, aged 50 years or older, with borderline to profound ID. Sleep-wake data were measured continuously during 14 days and nights using the Actiwatch AW7. A complete measurement of at least 7 days and nights, including at least one weekend day, was considered successful. Objective variables of sleep were analysed using different sensitivity settings of the Actiwatch AW7 Sleep Analysis software.
  
  
  RESULTS
  In 200 participants (35.5%), a successful measurement was obtained. Unsuccessful measurements were caused primarily by problems with wearing the device and incomplete information on bed time and get up time. Of 382 participants who started wearing the Actiwatch, 354 (92.3%) wore it for at least 7 days. Application of different sensitivity settings of the Sleep Analysis software resulted in clear differences of all sleep parameters.
  
  
  CONCLUSIONS
  Further research is needed into the validity of objective sleep parameters, as measured with the Actiwatch, for screening and epidemiological research in older people with ID. It needs to be investigated which sensitivity setting of the Actiwatch gives most valid results in this specific group, whereas reference data on sleep parameters and cut-off values are to be obtained.
authors.affiliation: Intellectual Disability Medicine, Erasmus Medical Centre Rotterdam, Department of General Practice, Rotterdam, the Netherlands. e.vandijk@erasmusmc.nl
authors.forename: E
authors.initials: E
authors.lastname: van Dijk
authors.forename: T I M
authors.initials: TI
authors.lastname: Hilgenkamp
authors.forename: H M
authors.initials: HM
authors.lastname: Evenhuis
authors.forename: M A
authors.initials: MA
authors.lastname: Echteld
mesh_terms: D056044:Actigraphy; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008607:Intellectual Disability / Q000150:complications*; D008297:Male; D008403:Mass Screening; D008875:Middle Aged; D017286:Polysomnography / Q000295:instrumentation*; D012893:Sleep Wake Disorders / Q000150:complications / Q000175:diagnosis* / Q000503:physiopathology