Dementia And Sleep Disorders: A Bad Combination

Obstructive sleep apnea and REM sleep behavior disorder are common in dementia.

Posted Jun 06, 2020

Sleep disturbances in dementia are common. In our last blog we discussed sleep disruption caused by sleep cycle and sleep hygiene issues; in this blog we will consider sleep disorders. If your loved one is having trouble falling asleep, waking up in the middle of the night and wandering around, or sleeping in the middle of the day, they could be suffering from a sleep disorder.

Sleep disturbances may be due to a medical disorder

Sleep can be disrupted by many medical disorders as well as side effects of medications. If your loved one is not sleeping well, is sleeping too much, or is excessively tired, you should speak with their doctor, as some sleep disorders are very serious if untreated. Here we discuss some of the common sleep disorders that affect either breathing or movement.

If your loved one snores loudly, wakes up at night gasping for air, or just doesn’t sleep well, they may have obstructive sleep apnea, which affects more than 20 million Americans. This condition reduces oxygen to the brain leading to strokes and a smaller hippocampus—the part of the brain that forms new memories. Obstructive sleep apnea can be detected on a sleep study, and there are a number of effective treatments. So, if you are worried that your loved one may have trouble breathing at night, make sure you discuss this issue with their doctor.

Sleep disorders may cause abnormal movements

Does your loved one move around excessively while they are sleeping or falling asleep? There are three common sleep disorders that cause abnormal movements in individuals with dementia, and some patients have all of them. There are treatments for each, so if you suspect them in your loved one, make sure you discuss them with their doctor.

In restless leg syndrome, one experiences unpleasant sensations in the feet or legs, such as crawling, creeping, pulling, throbbing, aching, itching, or electricity. The sensations occur mainly at night when individuals are awake but are in the process of falling asleep. They may also begin after lying or sitting during other times of the day. Movement of the legs may temporarily relieve the uncomfortable feeling.

Periodic limb movement disorder occurs when individuals are asleep. Typically, there are repetitive movements of the legs, such as bending of the big toe, ankle, knee, and hip. Sometimes the arms are involved as well. They usually occur every 5 to 90 seconds during light, non-dream sleep. They may be exacerbated by medications, including some antidepressants, antihistamines, and antipsychotics. Because these movements occur during sleep, bed partners are usually the ones to report this problem. Individuals themselves may experience disrupted sleep causing daytime drowsiness and fatigue.

One of the most interesting sleep disorders is when one acts out their dreams while sleeping. Usually only our eyes can move while we dream—for this reason dream sleep is often referred to as rapid eye movement or REM sleep. In REM sleep behavior disorder, the entire body moves during dreams. Individuals who dream they are swimming may begin doing the breaststroke in bed. If they dream they are fighting they may kick, punch, wrestle, or try to throttle their bed partner. They may also get out of bed while dreaming (with their eyes closed), trip over something, fall to the floor, and seriously injure themselves. This sleep disorder is very common in dementia with Lewy bodies but can be seen in other dementias as well.

Key Questions:

  • My wife is waking up at 2 AM every night and then keeps me up for three hours before we finally get back to sleep. What should I do about?
  • Start by trying to sort out what the cause is. Is she spending too much time in bed doing activities other than sleeping? Did she fall into a bad sleep cycle? Is she trying to sleep too many hours a day? Is she napping too much in the afternoon? Is she snoring loudly? Is she moving in her sleep? Answering these questions will help you sort out the cause, which is the first step toward a solution.

© Andrew E. Budson, MD, 2020, all rights reserved.


Budson AE, O’Connor MK. Seven Steps to Managing Your Memory: What’s Normal, What’s Not, and What to Do About It, New York: Oxford University Press, 2017.