title: Napping in older people 'at risk' of dementia: relationships with depression, cognition, medical burden and sleep quality.
abstract: Sleep disturbance is prevalent in older adults, particularly so in those at a greater risk of dementia. However, so far the clinical, medical and neuropsychological correlates of daytime sleep have not been examined. The aims of this study were to investigate the characteristics and effects of napping using actigraphy in older people, particularly in those 'at risk' of dementia. The study used actigraphy and sleep diaries to measure napping habits in 133 older adults 'at risk' of dementia (mean age = 65.5 years, SD = 8.4 years), who also underwent comprehensive medical, psychiatric and neuropsychological assessment. When defined by actigraphy, napping was present in 83.5% (111/133) of participants; however, duration and timing varied significantly among subjects. Nappers had significantly greater medical burden and body mass index, and higher rates of mild cognitive impairment. Longer and more frequent naps were associated with poorer cognitive functioning, as well as higher levels of depressive symptoms, while the timing of naps was associated with poorer nocturnal sleep quality (i.e. sleep latency and wake after sleep onset). This study highlights that in older adults 'at risk' of dementia, napping is associated with underlying neurobiological changes such as depression and cognition. Napping characteristics should be more routinely monitored in older individuals to elucidate their relationship with psychological and cognitive outcomes.
authors.affiliation: Healthy Brain Ageing Program, Brain & Mind Research Institute, The University of Sydney, Camperdown, NSW, Australia.
authors.forename: Nathan
authors.initials: N
authors.lastname: Cross
authors.affiliation: Healthy Brain Ageing Program, Brain & Mind Research Institute, The University of Sydney, Camperdown, NSW, Australia.
authors.forename: Zoe
authors.initials: Z
authors.lastname: Terpening
authors.affiliation: Concord Medical School, Concord Centre for Cardiometabolic Health in Psychosis, The University of Sydney, Sydney, NSW, Australia.
authors.forename: Naomi L
authors.initials: NL
authors.lastname: Rogers
authors.affiliation: Healthy Brain Ageing Program, Brain & Mind Research Institute, The University of Sydney, Camperdown, NSW, Australia.
authors.forename: Shantel L
authors.initials: SL
authors.lastname: Duffy
authors.affiliation: Healthy Brain Ageing Program, Brain & Mind Research Institute, The University of Sydney, Camperdown, NSW, Australia.
authors.forename: Ian B
authors.initials: IB
authors.lastname: Hickie
authors.affiliation: Healthy Brain Ageing Program, Brain & Mind Research Institute, The University of Sydney, Camperdown, NSW, Australia.
authors.forename: Simon J G
authors.initials: SJ
authors.lastname: Lewis
authors.affiliation: Healthy Brain Ageing Program, Brain & Mind Research Institute, The University of Sydney, Camperdown, NSW, Australia.
authors.forename: Sharon L
authors.initials: SL
authors.lastname: Naismith
mesh_terms: D056044:Actigraphy; D000368:Aged; D000369:Aged, 80 and over; D015992:Body Mass Index; D003071:Cognition / Q000502:physiology*; D060825:Cognitive Dysfunction / Q000503:physiopathology; D003704:Dementia / Q000503:physiopathology*; D003863:Depression / Q000503:physiopathology*; D005260:Female; D015577:Geriatric Assessment; D006184:Habits; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D057566:Self Report; D012890:Sleep / Q000502:physiology*; D007319:Sleep Initiation and Maintenance Disorders / Q000503:physiopathology; D013997:Time Factors
keywords: ageing; cognitive decline; mood disorder; morbidity; nap; objective sleep quality