Table 1.

Participants characteristics

Variables	Cognitively unimpaired elderly subjects (n = 30)	SCD/MCI patients (n = 36)∗	Group comparison†
Demographics
Age (years ± SD)	73.3 ± 7	71.5 ± 8.2	NS
Gender (% women)	56.7%	38.9%	NS
Education (years ± SD)	12.1 ± 3.5	11.8 ± 3.2	NS
Body mass index (mean ± SD)	24.5 ± 3	24.6 ± 4.5	NS
Florbetapir SUVr (% positive)‡	1 ± 0.2 (30.8 %)	1.2 ± 0.3 (50 %)	P = .011
MADRS (mean ± SD)	1 ± 1.9	3.4 ± 3.7	P = .002
STAI-B (mean ± SD) Participants on sleep medication (number, (%))§	37.4 ± 10 1 (3.3%)	38.8 ± 8.2 3 (8.3%)	NS NS
Cognition
MMSE (mean ± SD)	28.6 ± 1.2	27.6 ± 2.4	P = .046
Mattis total score (mean ± SD)	140.2 ± 3.3	136.2 ± 6.9	P = .005
Episodic memory composite score (mean ± SD)	0.0 ± 0.7	−0.8 ± 1.3	P = .005
Executive functioning composite score (mean ± SD)	0.0 ± 0.7	−0.8 ± 1.7	P = .020
Sleep parameters
SF intensity (mean ± SD)	30.3 ± 14.7	28 ± 11.1	NS
SF variability (mean ± SD)	10.9 ± 4.7	11.5 ± 5.2	NS

Abbreviations: MADRS, Montgomery and Asberg Depression Rating Scale; MCI, mild cognitive impairment; MMSE, Mini-Mental State Examination; NS, nonsignificant; SCD, subjective cognitive decline; SD, standard deviation; SF, sleep fragmentation; STAI-B, State-Trait Anxiety Inventory form B; SUVr, standard uptake value ratio.

^∗Owing to missing data in some patients, n = 30 for episodic memory, n = 33 for the MADRS, n = 34 for executive functioning.

^†Between-groups differences were assessed using Student's t-tests for all variables, except for gender for which chi-square statistics were used. Statistical significance was set to P < .05.

^‡n = 26 healthy elderly and 34 patients with valid florbetapir-PET scan. Amyloid positivity was defined as >0.985, based on mean SUVr + 2 SDs in a group of 41 healthy young individuals (aged <40 years).

^§Use of sleep medication on a regular basis (>1/week), excluding phytotherapy and homeopathy.