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

Introduction  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. Material and Methods  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. Results  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: r  = -0.202, p  = 0.035; REI: r  = -0.307, p  = 0.003; 3%ODI: r  = -0.321, p  = 0.002; and ESS score: r  = -0.287, p  = 0.005). Also, the BMI, REI, and 3%ODI were significantly correlated with the area under the NIRS curve (BMI: r  = -0.306, p  = 0.002; REI: r  = -0.326, p  = 0.002; and 3%ODI: r =-0.322, p  = 0.002), and BMI was a significant factor associated with the area under the NIRS curve. Conclusions  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.