Sleep apnoea and daytime function in the elderly--what is the impact of arousal frequency?

Arousals from sleep result in hyperventilation and hypocapnia that can lead to sleep apnoea. We have investigated whether sleep apnoea in the elderly is associated with more arousals compared with younger people. Additionally, the impact of arousals on daytime symptoms was noted. Four groups (n = 11) of elderly (> 65 years) and young (< 39 years) apnoeic (EA and YA), and age-matched non-apnoeics (EN and YN) were studied. The arousal index (AI) and apnoea/hypopnoea index were determined from polysomnography. Sleepiness (Epworth Sleepiness Scale) and Quality of life (QoL, SF-36) were assessed. The mean (SD) AI was: EN 23.1 (7.6), EA 46.5 (8.8), YN 13.2 (6.6), YA 38.5 (12.1) events/h. AI was higher in the elderly (P = 0.002) and in apnoeics (P = 0.001); however, the increase in AI associated with sleep apnoea was not age dependent (P = 0.73). The influence of sleep apnoea on sleepiness was similar in both age groups. YA but not EA reported reduced physical functioning (P = 0.04), vitality (P = 0.007) and general health (P = 0.04) compared to non-apnoeics. We conclude that (1) the effect of sleep apnoea on arousal is no greater in the elderly compared to the young (2) despite similar levels of sleepiness, elderly apneoics perceive a reduced loss of QoL compared to younger patients.