Effects of Sleep-Disordered Breathing on Daytime Brain Activity in Community-Dwelling Older Adults.

Sleep-disordered breathing (SDB) is associated with an increased risk of cardiovascular diseases. The present study aimed to examine the influence of SDB on daytime brain activity in the community-dwelling older adults.  Eighty one consecutive volunteers aged 60 years or older (mean age 70.5 ± 4.8 years) participated in the present study. Daytime brain activity was assessed by measuring the peak cortical oxygenated hemoglobin (OxyHb) levels and area under the near-infrared spectroscopy (NIRS) curve. The respiratory event index (REI) and 3% oxygen desaturation index (3%ODI) were evaluated using a home sleep-apnea test.  The peak OxyHb and area under the NIRS curve were significantly lower in the participants with REI ≥ 15/h than those with REI < 15/h. The body mass index (BMI), REI, 3%ODI, and Epworth sleepiness scale (ESS) scores were significantly correlated with peak OxyHb levels (BMI:  = -0.202,  = 0.035; REI:  = -0.307,  = 0.003; 3%ODI:  = -0.321,  = 0.002; and ESS score:  = -0.287,  = 0.005). Also, the BMI, REI, and 3%ODI were significantly correlated with the area under the NIRS curve (BMI:  = -0.306,  = 0.002; REI:  = -0.326,  = 0.002; and 3%ODI: =-0.322,  = 0.002), and BMI was a significant factor associated with the area under the NIRS curve.  Brain activity during wakefulness was associated with severities of SDB and obesity. A simple NIRS may yield unique information for characterizing the decline in daytime brain activity of the community-dwelling older adults.