{
  "abstract": "Introduction Habitual poor sleep is linked to dementia risk. Impairments in neurovascular coupling (NVC) may precede dementia symptoms, however, the impact of habitual sleep on cerebral perfusion and NVC remains poorly understood.Methods Total sleep time (TST), time in deep sleep (N3) and sleep efficiency were quantified during three home sleep assessments using an electroencephalography-based device (Somfit, Compumedics) in 96 participants (60 female, age 10.5-76.8 years). Cerebral blood velocity (CBv) through the middle (MCAv) and posterior (PCAv) cerebral arteries was measured using transcranial Doppler ultrasound. Percent change in PCAv from eyes closed to peak PCAv during a visual search task was taken to represent NVC. Hierarchical multiple regressions were used to explore the associations between CBv, NVC, age, and sleep.Preliminary results: TST ranged from 3.9-10.0 hours, time in N3 from 3-200 minutes, N3 sleep percentage from 0-39%, and sleep efficiency from 56-97%. Resting MCAv and PCAv ranged from 35–107 cm/s, and 24–75 cm/s respectively. NVC responses ranged from 6.8–53.8%.Older age was associated with lower TST (R2=0.223), N3 sleep (time: R2=0.262; percentage: R2=0.162) (figure 1), and sleep efficiency (R2=0.123; all P<0.001). Age was not associated with resting PCAv or NVC, and adding TST, N3 sleep (time or percentage) or sleep efficiency to these models did not change the relationship (all R2<0.100, P>0.05). However, age was associated with decreased resting MCAv (R2=0.163, P<0.001) (figure 2). Both TST and time in N3 independently showed trends toward positive associations with MCAv (both R2>0.022, P<0.100), but neither explained additional variance beyond age in the model with MCAv (R2 change<0.01).Conclusions Preliminary analyses suggest that resting MCAv decreases with age, while NVC does not. TST, N3 sleep, nor sleep efficiency mediated these relationships. Further data collection is underway to capture a wider range of sleep and ages.Abstract O27 Figure 1The relationships between total sleep time and age (open circles), and time in N3 sleep and age (closed triangles)Abstract O27 Figure 2The relationships between resting blood velocity through the posterior (closed triangles) and middle (open circles) cerebral arteries and total sleep time",
  "authors": [
    {
      "affiliations": [
        "University of Exeter, Exeter, United Kingdom",
        "University of Queensland, Brisbane, Australia"
      ],
      "name": "Alice Lester"
    },
    {
      "affiliations": [
        "University of Exeter, Exeter, United Kingdom"
      ],
      "name": "Bert Bond"
    },
    {
      "affiliations": [
        "University of Exeter, Exeter, United Kingdom"
      ],
      "name": "Jon Fulford"
    },
    {
      "affiliations": [
        "University of Queensland, Brisbane, Australia"
      ],
      "name": "Dwayne Mann"
    },
    {
      "affiliations": [
        "University of Queensland, Brisbane, Australia"
      ],
      "name": "Simon Smith"
    },
    {
      "affiliations": [
        "University of Queensland, Brisbane, Australia"
      ],
      "name": "Jenna Taylor"
    }
  ],
  "title": "O27 Rest assured? Habitual sleep likely does not further explain age-related changes in cerebral blood velocity outcomes (preliminary findings)",
  "uid": "8492b742-8336-5b6e-a564-0512481e8cbc"
}