Sleep onset/maintenance difficulties and cognitive function in nondemented older adults: the role of cognitive reserve.
This study examined the relationship between cognitive function and sleep onset/maintenance difficulties (SO/MD) in nondemented older adults. We hypothesized that SO/MD negatively impacts cognition and that older adults with lower education would be especially vulnerable to its effects. The sample comprised 549 older adults from the Einstein Aging Study (EAS), a community-based cohort. Participants completed neuropsychological assessment and a sleep questionnaire. Univariate ANCOVAs were performed with cognitive performance as a dependent variable, SO/MD (present or absent) and education (lower: ≤ 12 years; higher: >12 years) as between-subjects factors, and age, ethnicity, gender, depression, and cardiovascular comorbidies as covariates. Participants were an average age of 79.7 ± 5.0 years (range = 71-97 years). Fifty-seven percent (n = 314) of the sample met criteria for SO/MD. Among participants with SO/MD, those with lower education performed more poorly on a test of category fluency than participants with higher education (means: 35.2 vs. 41.0; p < .001); among older adults without SO/MD, educational attainment had no measurable effect on cognition (SO/MD × education interaction (F(1,536) = 14.5; p = .00)). Consistent with the cognitive reserve hypothesis, older adults with lower education appear selectively vulnerable to the negative effects of sleep onset/maintenance difficulties on tests of verbal fluency.
Department of Neurology, Albert Einstein College of Medicine, Bronx, New York 10461, USA. molly.zimmerman@einstein.yu.edu
Molly E
ME
Zimmerman
Marcelo E
ME
Bigal
Mindy J
MJ
Katz
Adam M
AM
Brickman
Richard B
RB
Lipton
D000368:Aged; D000369:Aged, 80 and over; D000375:Aging; D001288:Attention; D003072:Cognition Disorders / Q000503:physiopathology*; D058245:Cognitive Reserve / Q000502:physiology*; D004522:Educational Status; D056344:Executive Function; D005260:Female; D006801:Humans; D008297:Male; D008568:Memory; D009483:Neuropsychological Tests; D007319:Sleep Initiation and Maintenance Disorders / Q000503:physiopathology*; D018709:Statistics, Nonparametric; D011795:Surveys and Questionnaires; D014706:Verbal Learning