May 2 (HealthDay News) -- There's a significant difference in sleep disturbances experienced by Alzheimer's disease patients and the sleep woes of their caregivers, new research shows.

A team from the University of Washington, in Seattle, found that poor sleep in either a patient or caregiver aren't always connected.

The researchers studied 44 older adults, aged 63 to 93, with probable or possible Alzheimer's disease and their adult family caregivers, aged 21 to 87. One week of sleep-wake activity for the patients and caregivers was measured using a wrist-movement recorder.

Total minutes of nighttime sleep, percentage of time spent asleep, number of awakenings, duration of time awake at night, total daytime sleep, and circadian rest-activity variables were among the areas analyzed by the researchers. They also evaluated the participants for mood, physical function, medication use, caregiver behavior management style and patient cognitive status.

Among patients, the most stable aspect of sleep was time of night they went to bed, while the least stable aspect was total hours of sleep per night. For caregivers, the greatest stability was total wake time at night, while the least stable aspect was time in bed.

The study also found there was a sizable number (25 percent to 41 percent) of patient-caregiver duos on any given night where one person slept well while the other slept poorly. In some cases, the poor sleeper was the caregiver.

Instances where both the patient and caregiver slept poorly over seven nights were more likely to involve patients who had a lower level of physical function, more severe dementia, and required more sleep medications.

"Factors that we might expect would explain much of the relationship between patient and caregiver sleep, such as sharing a room at night, were not significant predictors of outcome," study author Susan M. McCurry said in a prepared statement. "Understanding the complex inter-relationship of sleep in Alzheimer's disease patients and caregivers is an important first step towards the development of individualized and effective treatment strategies."

The study is published in the May 1 issue of Sleep.

SOURCE: American Academy of Sleep Medicine, news release, May 1, 2008