The Relationship Between Dementia and Sleep

Dementia causes many challenges for the people who have it, as well as for their families, loved ones, and caretakers. Among numerous other difficulties, people with dementia frequently have trouble with sleep. They may sleep too much or too little, or they may find it hard to get to sleep, stay asleep, or get enough good quality sleep.

The relationship between sleep and dementia goes in both directions. While dementia can disrupt sleep in many ways, poor sleep can also increase the risk of developing dementia. In addition, research shows that poor sleep can make other dementia symptoms worse.

Learning more about the relationship between dementia and sleep can help caregivers improve the well-being and quality of life for people with this condition.

What Is Dementia?

Dementia is the severe impairment of a person’s ability to think and remember. Dementia was previously labeled “senility” and was accepted as a natural part of the aging process. It is not a disease in itself. Rather, it results from brain damage caused by an underlying disorder.

Approximately 47 million people worldwide have dementia. In the U.S., dementia affects more than 5 million adults aged 65 and older. That number is expected to increase in the coming decades.

The most common cause of dementia is Alzheimer’s disease, a degenerative brain disorder. Alzheimer’s disease damages and kills brain cells, interferes with connections in the brain, and causes areas of the brain to shrink. The brain damage caused by Alzheimer’s disease cannot be cured or reversed.

What Are the Signs of Dementia?

The symptoms of dementia can be different among affected people, but they typically involve changes in memory, personality, thought, and language. These symptoms tend to develop over several years, but the rate can depend on the underlying cause as well as the individual.

Common dementia symptoms include:

  • Trouble remembering recent events
  • Struggles with daily tasks like putting on clothing and shoes
  • Difficulty with communication and expressing needs
  • Becoming lost in a familiar setting
  • Losing or misplacing everyday objects
  • Extreme personality shifts and sudden mood swings
  • Losing interest in day-to-day activities
  • Irritability, anger, fear, and suspicion

What Factors Contribute to Dementia?

The most significant risk factor for dementia is age. Most people who develop dementia are at least 65 years old. But having a close relative with dementia increases the risk as well. Smoking tobacco, drinking too much alcohol, and having uncontrolled diabetes or high blood pressure also contribute to the risk of dementia.

While dementia can be caused by many conditions, Alzheimer’s disease is responsible for approximately 70% of all cases. Dementia caused by Alzheimer’s disease is often called Alzheimer’s dementia.

Besides Alzheimer’s dementia, several other types of dementia are common.

  • Vascular dementia: This type is usually caused by a stroke or the hardening and narrowing of the arteries in the brain.
  • Lewy body dementia: Also called LBD, this condition is caused by abnormal protein deposits in the brain called Lewy bodies.
  • Frontotemporal dementia: Frontotemporal dementia is caused by a buildup of substances inside the brain’s nerve cells, which damages the frontal and temporal lobes.
  • Parkinson’s disease dementia: Like Lewy body dementia, Parkinson’s disease is caused by protein buildup in the brain. However, it begins as a movement disorder and progresses to dementia in its later stages.
  • Mixed dementia: This describes dementia with more than one cause, such as vascular dementia combined with Alzheimer’s disease.

Less commonly, dementia may be caused by HIV, repeated brain injury, genetic conditions such as Huntington’s disease, and rare brain disorders like Creutzfeldt-Jakob disease.

How Does Dementia Impact Sleep?

People with dementia may not have sleep problems in the condition’s early stages. As the dementia progresses, however, it can interfere with sleep quality, timing, and duration. Sleep problems can also make other dementia symptoms worse.

Dementia-related brain damage can affect a part of the brain called the suprachiasmatic nucleus. This group of brain cells is the body’s internal clock, which plays an important role in regulating the sleep-wake cycle and circadian rhythm.

Also, dementia can keep people from getting the deep sleep they need. Even when they get the right amount of sleep, people with dementia spend less time in the deepest stages of sleep, including rapid eye movement (REM) sleep.

Age also plays a part in sleep changes, independent of dementia. As people get older, they naturally tend to sleep less deeply and for shorter periods of time. They also tend to wake up more frequently during the night.

These and other changes mean that people with dementia can have trouble falling asleep and staying asleep through the night. They may also wake too early in the morning, feel excessively tired during the day, and take naps more frequently.

Dementia-Related Sleep Problems

People with dementia are prone to several recognized sleep disorders. Some sleep disorders are associated with specific types of dementia. People with dementia are also susceptible to other issues that can interfere with their sleep.


Insomnia is a condition in which a person has difficulty falling asleep, staying asleep throughout the night, falling back to sleep after waking up, or waking up too early. Insomnia is a commonly encountered issue in older people. As many as half of older adults are believed to have insomnia, and the amount may be higher in older adults with dementia.

The consequences of insomnia for people with dementia can be serious. Insomnia can worsen cognitive problems and mood disturbances, increase the brain damage of dementia, and increase the chance of injury from falling down. Additionally, having chronic insomnia raises the risk of eventually developing dementia.

REM Sleep Behavior Disorder

In rapid eye movement sleep behavior disorder (RBD), people act out physical and verbal behaviors that occur in their dreams. This happens due to a loss of sleep atonia, a temporary muscle paralysis that normally occurs during the REM stage of sleep. RBD affects many people with Parkinson’s disease and Lewy body dementia.

RBD episodes can range from minor limb movement, to yelling and swearing, to thrashing and flailing of the arms and legs. People with dementia who also have RBD risk injuring themselves, or those who share their beds, in their sleep.

Obstructive Sleep Apnea

Obstructive sleep apnea (OSA) is a potentially serious sleep disorder in which a person’s breathing becomes irregular, strained, or stops completely during sleep. OSA is common in older adults and especially so in those with dementia.

It is estimated that OSA affects up to 70% of people with Alzheimer’s disease and up to 60% of people with Parkinson’s disease. In people with dementia, OSA has been linked to greater problems with thinking, memory, and attention.

Restless Legs Syndrome and Periodic Limb Movement Disorder

Restless legs syndrome, sometimes referred to as Willis-Ekbom disease, is a movement disorder that causes a strong urge to move one’s legs. This urge is usually strongest when a person is resting or lying down at the end of the day. Some drugs that treat dementia symptoms may also cause restless legs syndrome or make it worse.

In periodic limb movement disorder, a person’s legs and arms make repeated jerking or twitching movements while the person is asleep. Though the sleeper may not be aware of these movements, they can still interfere with sleep quality. The jerks and twitches amount to a disorder when they disrupt sleep enough to cause problems in a person’s waking life.


Sundowning, or sundown syndrome, is the tendency for some dementia symptoms to become more severe as night approaches. With sundowning, people who have dementia may become more confused, angry, anxious, and disoriented at dusk or at night. This can make it harder for them to fall asleep or stay asleep.

Sundowning is a common problem for people with dementia. While the full cause remains unknown, sundowning may be related to the brain damage caused by diseases like Alzheimer’s. Some studies have found evidence linking sundowning to a disruption in the circadian rhythms of people with dementia.

Can Sleep Affect the Risk of Dementia?

There is a known link between disrupted sleep and dementia. Not only are sleep problems a consequence of dementia, but they can also increase the risk of developing it. Having sleep disturbances, getting too little or too much sleep, waking up often during the night, and regularly having poor quality sleep all contribute to the risk.

While the exact nature of the link is still being studied, some researchers believe that certain sleep issues and types of dementia originate and are influenced by the same parts of the brain. They have also observed that some sleep disorders are likely to coexist with dementia.

How to Help Someone with Dementia Sleep Better

If a person with dementia is having difficulty sleeping, a caregiver may want to try several measures to assist them.

  • Keep a regular schedule: Sleeping and waking at the same times every day and following a consistent bedtime routine can improve sleep for people with dementia. A regular routine throughout the day may also help with remembering tasks.
  • Use environmental cues: Keep windows open or uncovered to remind the person of the time of day. Keep surroundings dark at night, and position clocks where they can easily be seen. 
  • Limit naps and caffeine: Too much coffee or tea, or naps that are too long, can make it harder to sleep through the night.
  • Encourage daily exercise: An exercise routine can ease stress and agitation and lead to better sleep. Just remember to keep activities calm before bedtime.
  • Try a nightlight: A dim light in the bedroom can make their surroundings less confusing.
  • Talk to their doctor: Discuss strategies for better sleep with their health care team, including relief for any pain or discomfort that might affect their rest.


Before giving any sleep medication to a person with dementia, it’s important to talk to their doctor. Over-the-counter sleep aids can increase confusion and other dementia symptoms. This is also true of many prescription sleep medications, which are not generally recommended for those with dementia.

Many people with dementia take multiple drugs, both for dementia symptoms and for other conditions that can come with older age. Since some drugs have interactions or side effects that could affect sleep, it may be helpful to go over a person’s prescriptions with their doctor if they are having sleep problems.


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