Table 1. Cohort descriptors.

	Healthy subjects (n = 120)
Age	74.8±5.7 (62–88)
Gender (% women)	55.7%
Years of education	17.4±2.1 (12–20)
MMSE	29±1.1 (26–30)
ISI total score	4.9±4.2 (0–16)
ISI score categories (%)
No clinically significant insomnia (0–7)	71
Subthreshold insomnia (8–14)	26
Clinical insomnia (moderate severity) (15–21)	3
Clinical insomnia (severe) (22–28)	0
GDS score	2.5±2.9 (0–15)
BA score (% low risk)	80.2

Data are presented as means ± standard deviation (range). MMSE, Mini Mental State Examination; ISI, Insomnia Severity Index; GDS, Geriatric Depression Scale; BA, Berlin Apnea index.