DAVID GREENE, HOST:
Sleepwalking is not the only form of disrupted sleep. As we age, our sleep patterns change and many people have problems falling and staying asleep. Now researchers have found a link between disrupted sleep and dementia, as NPR's Patti Neighmond reports.
PATTI NEIGHMOND, BYLINE: Psychiatrist Kristine Yaffe runs a clinic for people at risk of developing dementia. She's at the University of California, San Francisco. She says many of her older patients say they just don't sleep well.
DR. KRISTINE YAFFE: Either have difficulty falling asleep, waking up on and off throughout the night, feeling tired in the day or, you know, having to nap a lot in the day. Those kind of things are very common.
NEIGHMOND: In fact, Yaffe says as many as 40 percent of older adults have sleep problems, including sleep apnea. She recently conducted a series of studies that showed that older adults who had trouble sleeping were also more likely in some cases, twice as likely to suffer cognitive problems.
YAFFE: We've been very interested in trying to tease out what's chicken and egg. Is it the sleep disorders that seem to predict getting clinically cognitive problems or is it the clinical cognitive problems that then lead to sleep disorders?
NEIGHMOND: Research hasn't produced an answer yet, but Yaffe suggests that sleep problems may be a hint of later cognitive decline.
But there is something of a silver lining. Psychologist Sonia Ancoli-Israel studies sleep and aging at the University of California, San Diego. She says people can actually re-learn how to go to sleep.
SONIA ANCOLI-ISRAEL: You know, they look at the bed and they go, oh my God, I know I'm not going to be able to sleep - and we sort of turn that around so that when they look at the bed and they go, ah, sleep.
NEIGHMOND: First step, control outside stimulation.
ANCOLI-ISRAEL: And what this therapy says is you're not allowed to do anything in bed but sleep. Sleep and sex, but nothing else. You can't pay your bills in bed, you don't take your computer or your iPhone or your iPad to bed with you, you don't watch television in bed, you don't read in bed.
NEIGHMOND: And if you don't fall asleep in about 20 minutes, get out of bed. Watch or read something relaxing, and after 20 minutes, try again. And the clock, get rid of it.
ANCOLI-ISRAEL: You know, the first thing you do when you wake up at night is you look at the clock. In order to look at the clock, you have to open your eyes, maybe lift your head, but what's worse is you have to take yourself from transitional sleep to full awakening to comprehend that it's 1:10 in the morning and you want to be asleep.
NEIGHMOND: If you need the alarm, cover the clock or put it under the bed. You'll still hear it go off.
Now, there's another sleep difficulty faced by older adults. Natural body rhythms change.
ANCOLI-ISRAEL: Sleep is controlled in part by our core body temperature. Body drops at night - that's when we get sleepy, it rises in the morning hours, and that's when we wake up.
NEIGHMOND: And that changes at different times of our lives. Teenagers' body temperature drops late in the evening, so they don't get tired till around midnight and don't naturally wake up till late morning.
ANCOLI-ISRAEL: For older adults, it's the opposite. Their body temperature drops really early in the evening, around 8 o'clock and rises really early in the morning, about four. So, if your lifestyle allows it, go to bed early and when you wake up, get up.
NEIGHMOND: For those who don't want to do that, Ancoli-Israel suggests get lots of light.
ANCOLI-ISRAEL: Light is the strongest cue that our body has to know when to go to sleep and when to get up. And lots of light exposure during the day helps us have a strong biological clock.
NEIGHMOND: And the best source of light? The sun. A late afternoon or early evening walk, when the sun is still out, is the best. That delays the circadian rhythm and helps people stay alert later on in the evening and sleep longer in the morning.
Patti Neighmond, NPR News.
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