title: Sleep-wake cycle disturbances in elderly acute general medical inpatients: Longitudinal relationship to delirium and dementia.
abstract: BACKGROUND
  Sleep disturbances in elderly medical inpatients are common, but their relationship to delirium and dementia has not been studied.
  
  
  METHODS
  Sleep and delirium status were assessed daily for a week in 145 consecutive newly admitted elderly acute general hospital patients using the Delirium Rating Scale-Revised-98 (DRS-R98), Diagnostic and Statistical Manual 5, and Richards-Campbell Sleep Quality Scale measures. The longitudinal relationship between DRS-R98 and Richards-Campbell Sleep Quality Scale sleep scores and delirium, also with dementia as a covariate, was evaluated using generalized estimating equation logistic regression.
  
  
  RESULTS
  The cohort was divided into delirium only, dementia only, comorbid delirium-dementia, and no-delirium/no-dementia subgroups. Mean age of total group was 80 ± 6.3, 48% were female, and 31 (21%) had dementia, 29 had delirium at admission (20%), and 27 (18.5%) experienced incident delirium. Mild sleep disturbance (DRS-R98 sleep item score ≥1) occurred for at least 1 day in all groups, whereas moderate sleep disturbance (score ≥2) occurred in significantly more of the prevalent delirium-only (81%;n= 17) cases than incident delirium-only (46%;n= 13) cases (P< .001). There were more cases with DRS-R98 sleep item scores ≥2 (P< .001) in the delirium-only group compared with the other subgroups. Severity of sleep-wake cycle disturbance over time was significantly associated with Diagnostic and Statistical Manual 5 delirium status but not with age, sex, or dementia (P< .001).
  
  
  CONCLUSIONS
  Observer-rated more severe sleep-wake cycle disturbances are highly associated with delirium irrespective of dementia status, consistent with being a core feature of delirium. Monitoring for altered sleep-wake cycle patterns may be a simple way to improve delirium detection.
authors.affiliation: University of Limerick Graduate Entry Medical School, Limerick, Ireland; Cognitive Impairment Research Group, Centre for Interventions in Infection, Inflammation & Immunity (4i), Graduate Entry Medical School, University of Limerick, Limerick, Ireland.
authors.forename: James M
authors.initials: JM
authors.lastname: FitzGerald
authors.affiliation: Centre for Gerontology and Rehabilitation, School of Medicine, University College Cork, Cork, Ireland.
authors.forename: Niamh
authors.initials: N
authors.lastname: O'Regan
authors.affiliation: Cognitive Impairment Research Group, Centre for Interventions in Infection, Inflammation & Immunity (4i), Graduate Entry Medical School, University of Limerick, Limerick, Ireland; Research and Academic Institute of Athens, Athens, Greece; Sligo-Leitrim Mental Health Services, Sligo, Ireland.
authors.forename: Dimitrios
authors.initials: D
authors.lastname: Adamis
authors.affiliation: Centre for Gerontology and Rehabilitation, School of Medicine, University College Cork, Cork, Ireland.
authors.forename: Suzanne
authors.initials: S
authors.lastname: Timmons
authors.affiliation: University of Limerick Graduate Entry Medical School, Limerick, Ireland; Cognitive Impairment Research Group, Centre for Interventions in Infection, Inflammation & Immunity (4i), Graduate Entry Medical School, University of Limerick, Limerick, Ireland.
authors.forename: Colum P
authors.initials: CP
authors.lastname: Dunne
authors.affiliation: Indiana University School of Medicine, IN, USA; Tufts University School of Medicine, MA, USA.
authors.forename: Paula T
authors.initials: PT
authors.lastname: Trzepacz
authors.affiliation: University of Limerick Graduate Entry Medical School, Limerick, Ireland; Cognitive Impairment Research Group, Centre for Interventions in Infection, Inflammation & Immunity (4i), Graduate Entry Medical School, University of Limerick, Limerick, Ireland; Department of Psychiatry, University Hospital Limerick, Limerick, Ireland.
authors.forename: David J
authors.initials: DJ
authors.lastname: Meagher
keywords: Delirium; Dementia; Elder care medicine; Sleep disturbance detection