Sleep-related respiratory disturbance and dementia in elderly females

Sleep-related respiratory disturbance was studied with a microprocessor-based portable monitoring system in female residents of a retirement village aged greater than or equal to 75 years. Comparisons were made between 29 demented subjects Mini-Mental State Examination Score (MMSE) less than 21 and 48 controls (MMSE greater than 25). Respiratory disturbance index (RDI, the number of episodes of apnea and hypopnea/hour of total sleep time) was higher in the demented subjects: mean RDI (+/- SD) 18.5 +/- 18.6 vs 7.3 +/- 10.8, p = .004. The number of minutes per hour of sleep spent with disturbed breathing was greater in demented subjects than in controls (p = .01). These differences between demented subjects and controls persisted after adjustment for age and relevant medical history. Other possible confounders, namely body mass index and use of sedatives, were not significant. We conclude that respiratory disturbance during sleep is more prevalent in elderly demented females than in controls.