in a prospective study of sleep-disordered breathing among healthy elderly controls ( n = 23 ) , major depressives ( n = 17 ) , and demented patients with probable alzheimer 's disease ( n = 21 ) , sleep apnea ( defined as an apnea index of 5 or more ) was found in 42.9 % of demented patients , 17.6 % of depressives , and 4.3 % of controls ( chi 2 = 9.90 , p less than .01 ) .
C0037315
sleep apnea
C0003578
apnea