Cerebrovascular Disease and Patterns of Cerebral Oxygenation During Sleep in Elders

Abstract

Purpose The aim of this descriptive exploratory study was to describe patterns of cerebral oxygen reserves during sleep and their association with cerebrovascular risk factors in elders. Methods Participants--115 elders, age 70+ years--were monitored overnight using standard polysomnography. Measures included arterial oxyhemoglobin (SaO2) and regional measures of percent cerebral oxyhemoglobin saturation (rcSO2) via cerebral oximetry. Subjects were classified based on the magnitude of change in rcSO2 from resting baseline to the end of the first non-rapid-eye-movement (NREM) period. One way ANOVA and Chi-square were used to test group differences in SaO2 and the prevalence of cerebrovascular risk factors. Findings 20 subjects (Group 1) experienced an increase in rcSO2 during sleep along with sleeping rcSO2 levels ≥ 55%; 95 subjects experienced a decline in rcSO2; 72 subjects (Group 2) had sleeping rcSO2 levels ≥ 55%; and 23 subjects had sleeping rcSO2 levels < 55% (Group 3). Although all three groups had equivalent declines in SaO2 levels during sleep, Group 3 had more cardiovascular comorbidity than Groups 1 and 2. Conclusions While SaO2 levels decline in most people during sleep, compensatory vascular responses to these drops in SaO2 are important for preventing rcSO2 from falling during sleep. Those entering sleep with lower baseline rcSO2 levels and those with greater declines in cerebral oxygenation during sleep may have greater cardiovascular burden and be at greater risk for stroke and other forms of disabling cerebrovascular disease.

Use of near-infrared spectroscopy as a measure of cerebrovascular health in aging adults

“…The relationship of oxygenated CBF to diabetes is consistent with Carlson et al (2009), who found that only the concurrent presence of both diabetes and hypertension, not hypertension per se, was related to low baseline oxygenated CBF in their older adult sample. The lack of relationship of other cardiovascular risk factors with either oxygenated CBF or neuropsychological outcome may reflect both the small sample size of the present study and the use of self-report to assess health measures.…”

“…Carlson, Neelon, Carlson, Hartman, and Dogra (2009) used NIRS to examine CBF changes in sleep in 115 adults over the age of 70 with no major sleep, respiratory, or neurological disorders. They divided their sample into three groups: those who showed an increase in oxygenated CBF during the first stage of sleep, those who showed a decline, and those who had low oxygenated CBF at baseline, who also showed a decline during the first stage of sleep.…”

Correlation between Sleep Duration and Risk of Stroke

“…Thus, elderly persons with lower baseline rcSO2 levels and greater declines in cerebral oxygenation during sleep may have greater cardiovascular burden and are at greater risk for stroke or other forms of disabling cerebrovascular disease. 27 Hypertension Hypertension is a major risk factor for stroke as high blood pressure puts stress on the blood vessel walls and causes blood clots or hemorrhage. Various ambulatory blood pressure studies have indicated that even small increases in blood pressure, particularly night-time blood pressure levels, are associated with significant increases in cardiovascular morbidity and mortality.…”