title: Longitudinal association of delta activity at sleep onset with cognitive and affective function in community-dwelling older adults.
abstract: This investigation sought to determine whether delta activity at sleep onset (DASO) in the sleep electroencephalography of older adults represents normal variation or is associated with clinical pathology. To this end, we examined its longitudinal associations with cognitive and affective function in older adults without dementia.
  
  
  
  Participants were 153 community-dwelling older adults without dementia. We evaluated polysomnography (PSG), cognitive performance, and affective function at four time points: baseline, 12, 24, and 36 months. All participants completed PSG and measures of global cognition, delayed verbal memory, information processing speed, attention, inhibition, verbal naming, visuospatial ability, and measures of anxiety and depression. DASO was defined as sequences of rhythmic anterior delta activity on PSG in the transition from awake to sleep during the baseline assessment (Figure ).
  
  
  
  At the baseline, 83 women and 70 men, mean age 71.3 ± 0.6 years participated and 19.6% of participants exhibited DASO. Age, years of education, gender, and body mass index did not differ according to DASO status. Linear mixed modeling showed that the presence of DASO was actually associated with lower levels of anxiety and depression. Further, participants with DASO, versus those without DASO, exhibited a trend towards better cognitive performance over time, although none of these associations reached statistical significance.
  
  
  
  Whereas DASO was associated with better affective function, no significant association was found between DASO and cognitive change over time. These longitudinal findings support the view that the presence of DASO in healthy older adults represents normal variation rather than pathological aging. Copyright © 2016 John Wiley & Sons, Ltd.
authors.affiliation: Department of Psychiatry and Behavioral Sciences, Stanford University, School of Medicine, Stanford, CA, USA. mkawai71@stanford.edu.
authors.forename: Makoto
authors.initials: M
authors.lastname: Kawai
authors.affiliation: Department of Psychiatry and Behavioral Sciences, Stanford University, School of Medicine, Stanford, CA, USA.|Sierra Pacific Mental Illness Research Education and Clinical Centers, VA Palo Alto Health Care System, Palo Alto, CA, USA.|School of Psychology, University of Queensland, Brisbane, Australia.
authors.forename: Sherry A
authors.initials: SA
authors.lastname: Beaudreau
authors.affiliation: Department of Psychiatry and Behavioral Sciences, Stanford University, School of Medicine, Stanford, CA, USA.|Geriatric Research Education and Clinical Center, VA Palo Alto Health Care System, Palo Alto, CA, USA.
authors.forename: Christine E
authors.initials: CE
authors.lastname: Gould
authors.affiliation: Department of Psychiatry and Behavioral Sciences, Stanford University, School of Medicine, Stanford, CA, USA.|Sierra Pacific Mental Illness Research Education and Clinical Centers, VA Palo Alto Health Care System, Palo Alto, CA, USA.
authors.forename: Nathan C
authors.identifier: 0000-0002-4261-8330
authors.initials: NC
authors.lastname: Hantke
authors.affiliation: Department of Psychiatry and Behavioral Sciences, Stanford University, School of Medicine, Stanford, CA, USA.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Cotto
authors.affiliation: Department of Psychiatry and Behavioral Sciences, Stanford University, School of Medicine, Stanford, CA, USA.|California School of Professional Psychology at Alliant, International University, San Francisco, CA, USA.
authors.forename: Josh T
authors.initials: JT
authors.lastname: Jordan
authors.affiliation: Palo Alto University, Palo Alto, CA, USA.
authors.forename: Rayna B
authors.initials: RB
authors.lastname: Hirst
authors.affiliation: Department of Psychiatry and Behavioral Sciences, Stanford University, School of Medicine, Stanford, CA, USA.|Sierra Pacific Mental Illness Research Education and Clinical Centers, VA Palo Alto Health Care System, Palo Alto, CA, USA.|School of Psychology, University of Queensland, Brisbane, Australia.
authors.forename: Ruth
authors.initials: R
authors.lastname: O'Hara
mesh_terms: D000339:Affect / Q000502:physiology*; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000523:psychology; D001007:Anxiety / Q000209:etiology; D001288:Attention / Q000502:physiology*; D001921:Brain / Q000502:physiology*; D003071:Cognition / Q000502:physiology*; D003072:Cognition Disorders; D003700:Delta Rhythm / Q000502:physiology*; D003863:Depression / Q000209:etiology; D004569:Electroencephalography; D056344:Executive Function / Q000502:physiology; D005260:Female; D006801:Humans; D007266:Inhibition, Psychological; D008137:Longitudinal Studies; D008297:Male; D008568:Memory / Q000502:physiology; D008875:Middle Aged; D017286:Polysomnography; D012890:Sleep / Q000502:physiology*
keywords: affective function; cognition; delta activity at sleep onset