APOE and obstructive sleep apnea syndrome: We found that the effect of APOE4 on REM-sleep percentage was (1) significant in the older group (F = 8.47, p = .005, ηp2 = 0.08), and a trend in the younger group (F = 3.45, p = .066, ηp2 = 0.036), (2) significant in women (F = 7.1, p = .01, ηp2 = 0.085), and a trend in men (F = 11.7, p = .056, ηp2 = 0.032), (3) significant in cognitively unimpaired (F = 11.7, p < .001, ηp2 = 0.10) but not in aMCI participants, and (4) significant in both participants with (F = 4.1, p = .046, ηp2 = 0.049) and without (F = 8.1, p = .005, ηp2 = 0.07) OSA.