Influence of sleep quality, risk of obstructive sleep apnea and sleep deprivation on cortical oxygenation in elderly individuals

Abstract Background Poor sleep quality, obstructive sleep apnea (OSA) and sleep deprivation are risk factors for cardiovascular diseases and cognitive impairment. Cerebral blood flow and its regulation are affected by pathological condition commonly observed in the elder population, such as dementia, history of stroke, diabetes mellitus and hypertension. The aim of this study was to investigate the influence of sleep quality, OSA risk and total sleep time (TST) of prior night in level of activation of the frontal cortex using functional near‐infrared spectroscopy Method We investigated 204 participants without cognitive impairment between the ages of 60 and 85 years. All patients functional near‐infrared spectroscopy (fNIRS) along with cognitive tasks, including digit span, semantic verbal fluency task, stroop test, to investigate hemodynamic response in the fontal cortex of patients with depression compared to a healthy elderly group. The Pittsburgh Sleep Quality Index (PSQI) for sleep quality, STOP‐BANG questionnaire for risk of OSA, and TST of prior night which reported by participants was assessed. Result In poor sleep quality group (PSQI<5), reduced hemodynamics during the Stroop task compared to control group in all channel average (Mean accΔHbO 2 of 0.11μM in poor sleep quality group versus ‐0.12 μM in control, p<0.05) and right channel average (Mean accΔHbO 2 of 0.01μM and ‐0.03 μM, p<0.05). In sleep deprived group (TST<5), reduced hemodynamics during the verbal fluency test was observed in right channel average (Mean accΔHbO 2 of 0.024 in sleep deprived group versus 0.01 μM in control, p<0.05). There was no significant difference between high risk of OSA group (STOP‐BANG>5) and control group in all cognitive tasks. Conclusion Poor sleep quality and sleep deprivation (<5 hours) may be an important factor that influences cortical oxygenation in the elderly population.