Sleep and apnea in the elderly: reliability and validity of 24-hour recordings in the home

Two studies investigated the reliability and validity of measures of sleep and apnea using the home sleep monitoring system (HMS), which requires no instrumentation of the subject. From a pressure-sensitive pad on the subject's bed, signals from respiration and motility are recorded. These are scored for sleep and the occurrence of apneas, and the following measures are obtained: time in bed, total sleep time, number of awakenings from sleep, waking after sleep onset, sleep efficiency, and number of apneas. Overnight recordings of 14 adults were made concurrently with polysomnographic recordings in the New Haven Sleep Disorders Center. Significant agreement was found for each sleep measure and the apnea index. Four weekly 24-h recordings were made of eight elderly women, aged 62 to 90, in the home. There were significant individual differences and measurement reliability for each sleep measure and number of apneas. Some of the elderly showed highly episodic sleep patterns; and three of them showed high and variable apneas over the four weeks. These studies indicate the potential of the HMS for characterizing sleep in the elderly from nonintrusive, naturalistic observations in the home.