Objective The purpose of the present study was to determine whether electroencephalographic (EEC) and cardiac arousal, i.e. heart rate elevation at the termination of apnea/hypopnea are related to aging.
Methods The subjects were 13 middle-aged (40-60 years of age, 47.8±5.35 years) and 10 elderly (>60 years of age, 69.8±5.31 years) male patients with obstructive sleep apnea syndrome. We evaluated the number of apneas per an hour of sleep (apnea index: AI), the number of hypopneas per an hour of sleep (hypopnea index: HI), the summation of HI and AI (apnea/hypopnea index: AHI), sleep stage, the amount of time during which nocturnal oxygen saturation was decreased below 90% (oxygen desaturation time: ODT), and EEG and cardiac arousal at the termination of apnea/hypopnea using polysomnography with pulse oximetry.
Results There was no significant difference in AHI, duration of apnea/hypopnea, and sleep stage distribution between the two groups. However, the ratio of apnea/hypopnea with EEG and cardiac arousal was significantly higher in middle-aged than in elderly patients. The ratio of HI to AHI was significantly lower in middle-aged than in elderly patients. In middle-aged patients, EEG and cardiac arousal were significantly correlated with AI, AHI, and ODT, whereas, in elderly patients, these parameters were not similarly correlated.
Conclusion Our findings suggest that the differences in EEG and cardiac arousal, and the pattern of sleep-disordered breathing (SDB) between middle-aged and elderly patients with SDB might be a physiological phenomenon of aging.
(Internal Medicine 39: 375-380, 2000)
The Japanese Society of Internal Medicine