EFFECT OF ACTIVITIES AND EXERCISE ON SLEEP IN DEMENTIA

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This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. While investigators have examined the effects of increasing social or physical activities or both on sleep in elders in nursing homes and assisted living facilities, one study lacked a control group or tests of significance, another was conducted in an assisted living facility as opposed to a nursing home and included only cognitively-intact participants who are much easier to engage in social activities and exercise, and the other studied only incontinent residents. In the only study that did not find an improvement in the sleep of residents after an exercise program, the exercise may have been of insufficient duration (both minutes per day and length of the intervention period) and intensity. Prolonged bedrest, fear of falling, and dependency in activities of daily living result in declining muscle strength in residents. As we have demonstrated, this declining muscle strength leads to further physical inactivity and sleep disturbance. We have shown that high intensity PRT is safe, feasible, and markedly increased muscle strength and physical activity in residents with CI. The literature supports our hypothesis that increased daytime physical activity will directly improve nighttime sleep and indirectly improve nighttime sleep by decreasing daytime napping. Future outcome studies require more precise measures of sleep. Other investigators have used actigraphy 31,32 or observations by nursing home staff. The only study that measured sleep using polysomnography occurred in an assisted living facility with cognitively intact elders. Polysomnography, the gold standard for sleep measurement, precisely measures nocturnal total sleep time and sleep stages. Investigators have conducted descriptive studies of sleep in CI elders using polysomnography, but no one to our knowledge has measured the efficacy of an intervention using it. Although actigraphy and observation are better tolerated in CI elders than polysomnography, only polysomnography can provide information on the effects of the intervention on important variables that affect sleep quality such as sleep stages. For example, consistent effects of exercise on stages 2, 3 and 4 NREM sleep in young adults would have remained undetected if researchers had only used actigraphy or observation to measure sleep. The literature supports our hypothesis that the proposed ISA and PRT will each increase nocturnal total sleep time and sleep-wake rhythm amplitude. Further, combining ISA and PRT will result in the greatest improvement in nighttime total sleep time and sleep-wake rhythm amplitude because they will each increase the homeostatic sleep drive, and they will each increase circadian pacemaker entrainment. No other team has investigated the effect of high intensity PRT on sleep in elders with CI. Further, no other research team has targeted residents with disturbed sleep. This is extremely important because conducting an intervention for every resident, or even every incontinent resident, is too costly and unlikely for nursing home staffs to implement. We have shown that ISA reduces excessive daytime sleep and may improve nighttime sleep in residents with CI, but our findings were inconclusive. Further testing with more sensitive instrumentation is indicated. We propose to use polysomnography to more precisely reflect total sleep time.