title: Does subjective sleep affect cognitive function in healthy elderly subjects? The Proof cohort.
abstract: OBJECTIVE
  Some epidemiological data are available on the association between sleep duration and sleep quality, sleep complaints, and the aging related cognitive impairment in the elderly. In this study we examined a large sample of healthy elderly subjects to assess the relationship between sleep quality, subjective cognitive complaints, and neuropsychological performance.
  
  
  METHODS
  A total of 272 elderly subjects (mean age 74.8 ± 1.1 years) were recruited from a population-based cross-sectional study on aging and cardiovascular morbidity. All subjects filled in self-assessment questionnaires evaluating cognitive function, anxiety, depression, sleep-related parameters, and the Pittsburgh Sleep Quality Index (PSQI). Ambulatory polygraphy and extensive neuropsychological tests were also performed. Based on the total PSQI score, subjects were classified as good sleepers (GS, PSQI<5, n=116) and poor sleepers (PS, PSQI≥5, n=156).
  
  
  RESULTS
  Poor sleep did not affect the subjective cognitive function score, subjective cognitive impairment being mainly related to anxiety, depression, and sleep medication intake. No significant differences were seen between GS and PS in any of the objective cognitive function tests except for the Trail Making Test A (TMA-A), processing speed being longer in the PS group (p<0.001). Neither the presence of sleep-related breathing disorders nor gender affected cognitive performance.
  
  
  CONCLUSIONS
  Our results suggest that in healthy elderly subjects, subjective sleep quality and duration did not significantly affect subjective and objective cognitive performances, except the attention level, for that the interference of sleep medication should be considered.
authors.affiliation: Department of Clinical Physiology and Exercise, Pole NOL, CHU and Faculty of Medicine of Saint-Etienne, UJM and PRES University of Lyon, France. magali.stmartin@orange.fr
authors.forename: Magali
authors.initials: M
authors.lastname: Saint Martin
authors.forename: Emilia
authors.initials: E
authors.lastname: Sforza
authors.forename: Jean Claude
authors.initials: JC
authors.lastname: Barthélémy
authors.forename: Catherine
authors.initials: C
authors.lastname: Thomas-Anterion
authors.forename: Frédéric
authors.initials: F
authors.lastname: Roche
mesh_terms: D000368:Aged; D001007:Anxiety / Q000209:etiology; D003071:Cognition / Q000502:physiology; D003072:Cognition Disorders / Q000209:etiology*; D003430:Cross-Sectional Studies; D003863:Depression / Q000209:etiology; D005260:Female; D006801:Humans; D008297:Male; D009483:Neuropsychological Tests; D017286:Polysomnography; D012737:Sex Factors; D012890:Sleep / Q000502:physiology; D012893:Sleep Wake Disorders / Q000150:complications*; D011795:Surveys and Questionnaires