Research Study Abstract

Associations between sleep duration and cognitive impairment in mild cognitive impairment

  • Published on April 21, 2019

Summary: The prevalence of mild cognitive impairment (MCI) increases among elderly people and is associated with a high risk of dementia. Identifying factors that may contribute to the progress of MCI to dementia is critical. The objective of this study was to examine the association of objective sleep with cognitive performance in MCI patients. A subsample of 271 participants with a diagnosis of probable Alzheimer’s disease (AD; N = 50) or mild cognitive impairment (MCI; N = 121) and 100 persons who were not cognitively impaired (NI) were recruited from a large population‐based cohort in the island of Crete, Greece (3140 older adults aged >60 years). All participants underwent extensive neuropsychiatric/neuropsychological evaluation and a 3‐day 24‐hr actigraphy. Objective sleep variables and their association with neuropsychological performance were examined across the three groups, controlling for demographics, body mass index, depression, sleep apnea symptoms and psychotropic medications. Patients with AD had significantly longer 24‐hr total sleep time (TST) compared to the MCI and NI groups. Long 24‐hr TST was associated with reduced performance on tasks that placed significant demands on attention and processing speed in the MCI group and the AD group. Elderly patients with MCI have similar objective sleep duration to normal controls, whereas AD patients sleep longer. Long sleep duration in patients with multidomain subtypes of MCI is associated with critical non‐memory cognitive domains. It appears that within the MCI group those that sleep longer have more severe cognitive impairment.


  • Maria Basta 1
  • Panagiotis Simos 1,2
  • Alexandros Vgontzas 1
  • Eirini Koutentaki 1
  • Sophia Tziraki 1
  • Ioannis Zaganas 3
  • Symeon Panagiotakis 4
  • Stefania Kapetanaki 3
  • Nikolaos Fountoulakis 4
  • Christos Lionis 5


  • 1

    Department of Psychiatry, University of Crete, University Hospital of Heraklion, Heraklion, Crete, Greece

  • 2

    Institute of Computer Science, Foundation of Research and Technology, Heraklion, Crete, Greece

  • 3

    Department of Neurology, University of Crete, University Hospital of Heraklion, Heraklion, Crete, Greece

  • 4

    Department of Medicine, University of Crete, University Hospital of Heraklion, Heraklion, Crete, Greece

  • 5

    Clinic of Social and Family Medicine, School of Medicine, University of Crete, Heraklion, Crete, Greece


Journal of Sleep Research


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