The Link Between Alzheimer’s and Sleep

Table of Contents

Alzheimer’s disease (AD) is a common form of dementia that causes problems with memory, thinking, and speech. AD gets worse over time, sometimes progressing until people with AD cannot recognize loved ones or take care of themselves. 

Alzheimer’s disease is linked to a number of sleep changes. Alzheimer’s disease and sleep problems are sometimes called “bidirectional.” This means that while the disease can cause poor sleep, poor sleep can worsen or increase the risk of developing the disease. 

Sleep disorders can also have a negative impact on the quality of life of caregivers who help people with AD. The presence of sleep disorders makes it more likely that a person with AD will need to live in a care facility. Addressing sleep problems can help lessen symptoms and improve the quality of life of people with AD and their loved ones.

People with Alzheimer’s disease commonly experience sleep problems. For example, many people with AD experience disrupted sleep and spend more awake time in bed than other people their age without the disease. 

Also, the sleep disorder obstructive sleep apnea (OSA) occurs in 40% to 70% of people with AD. Circadian rhythm problems, which involve one’s sleep schedule becoming misaligned with the daylight cycle, are also common. 

Recent research has shown that sleep changes often occur before AD is diagnosed. For instance, people who experience fragmented sleep, meaning they awaken frequently during the night, are more likely to develop AD. 

Changes in sleep patterns, such as spending less time in deep sleep, along with sleep deprivation, may also cause changes in brain chemistry that could lead to the development of AD. Some research suggests that insomnia and obstructive sleep apnea may increase the likelihood of a person developing Alzheimer’s.

Also, normal aging itself causes changes in sleep. Taking longer to fall asleep, waking up more during the night, snoring more, and wanting more daytime naps are common. These sleep changes often occur in older adults without Alzheimer’s. However, the frequency of sleep problems and their impact on quality of life may be greater in people with Alzheimer’s.

Alzheimer’s Disease and the Brain

The way Alzheimer’s disease affects the brain may help explain why sleep troubles can precede the onset of the disorder. 

AD causes problems with neurons, special cells that transmit information in the brain. In people with AD, abnormally high levels of a natural protein called beta-amyloid forms clumps. These clumps, also called plaques, form around neurons and interfere with cell function. This toxic protein builds up faster when people don’t sleep well. 

Malfunctioning or damaged neurons lead to problems with memory, speech, and behavior. Alzheimer’s disease usually starts by damaging neurons that are involved in forming memories. With time, AD leads to damage that causes impairments in social interaction, speech, and logic.

Other brain changes observed in people with Alzheimer’s disease include tangled threads of protein called tau and the buildup of a type of cells called glial cells, which may cause chronic inflammation. 

Scientific research has found that during sleep, beta-amyloid, the toxic protein found in excess in people with Alzheimer’s, is removed from the brain. This clean-up process appears to work even more efficiently during deep sleep. Consequently, levels of beta-amyloid in the brain decrease during sleep.

Sleep deprivation causes an increase in beta-amyloid and tau, two proteins found in abnormally high levels in the brains of people with Alzheimer’s. More research is needed to see if improving sleep quality can reduce the chances of developing AD.

Sleep disturbances are common in people with Alzheimer’s disease. They frequently appear early in the course of disease, and may be detectable before a diagnosis has been made. Typically, sleep problems get worse as Alzheimer’s disease progresses. Multiple types of sleep issues occur more commonly in people with AD.

Circadian Rhythm Disruption

Changes in a person’s circadian rhythms, which are daily physical cycles that include sleep-wake times, often occur in people with AD. These changes may be detected in the early stages of AD or seen before a diagnosis is made. They worsen as the disease progresses. Although seen in normal aging, sleep-wake cycle problems are worse in people with AD. 

Circadian disturbances can cause changes in body temperature, hormone secretion, and physical movements. The most noticeable change, however, is in the sleep-wake cycle. Alterations in the normal sleep-wake cycle can cause difficulty falling asleep and staying asleep, resulting in excessive daytime sleepiness.

People with Alzheimer’s often have weaker circadian rhythms, which can lead to them being more active at night than during the day. In turn, they may sleep a lot during the day. People with AD are also more likely to experience irregular sleep-wake rhythms, such as sleeping for shorter periods, multiple times per day rather than in one longer period. 

Experts believe these changes in Alzheimer’s disease may be due to degeneration of a critical brain structure, the suprachiasmatic nucleus (SCN), which controls daily body rhythms. People with AD have also been seen to have lower levels of melatonin, a hormone that induces sleepiness and is normally made in response to darkness. 

Circadian rhythm is affected by external cues, such as eating, exercise, and, most importantly, sunlight. The impact of these cues may be weakened in older adults and people with Alzheimer’s. Living in a nursing home or residential facility, as well as having visual problems associated with aging, like cataracts, that affect light perception can weaken circadian rhythm.

Changes in Sleep Patterns

People with Alzheimer’s disease spend less time in deep sleep and rapid eye movement (REM) sleep stages. Less deep sleep means less time spent clearing the brain of harmful proteins. Loss of REM sleep may affect memory and prompt brain degeneration. 

Additionally, sleep tends to be more fragmented in people with AD, meaning they awaken more often. Research into the relationship between sleep fragmentation and the abnormal brain chemistry of AD is ongoing. While less sleep causes symptoms, it’s also possible that elevated beta-amyloid levels cause sleep fragmentation and other sleep troubles.

Insomnia

As well as being implicated in the development of Alzheimer’s disease, insomnia is more common in people with AD. Insomnia involves difficulty falling asleep, staying asleep, or awakening too early in the morning. The prevalence of insomnia increases with age, particularly in people with dementia. 

Researchers estimate that at least 25% of people with dementia experience insomnia. Alzheimer’s itself along with medications and related mood issues may contribute to sleep difficulties like insomnia.

Obstructive Sleep Apnea

Obstructive sleep apnea is more common in older adults generally, and even more common in people with AD. In fact, people with AD are five times more likely to have OSA. Research shows that between 40% and 70% of people with AD meet the criteria for an OSA diagnosis, and severity of dementia may be linked to the severity of the breathing problems.

OSA can worsen daytime symptoms often associated with AD, like attention and memory problems. Although it can be challenging to get people with Alzheimer’s disease to use continuous positive airway pressure (CPAP) therapy, the most common treatment for OSA, research has shown that it may slow the development of cognitive symptoms and improve mood.

Having OSA is also a risk factor for developing dementia, which means that people who have OSA first are more likely to develop Alzheimer’s or other forms of dementia.

Periodic Limb Movement Disorder and Restless Legs Syndrome

Some research has shown that periodic limb movements are more common in people with Alzheimer’s disease. Periodic limb movement disorder (PLMD) involves repeated movements of the arms or legs during sleep, which the sleeper is unaware of. PLMD can cause sleep disturbances that worsen mental and social impairment in people with dementia.

Research shows that periodic limb movements during sleep and restless leg syndrome (RLS) often occur together. RLS is a disorder in which people have a powerful urge to move their legs, particularly at night. The symptoms of RLS can interfere with falling asleep. 

Researchers don’t know if RLS occurs more commonly in people with AD. Some research indicates that people with dementia have RLS at about the same rate as other people their age without dementia. 

RLS may occur with the use of certain drugs, including antidepressants, antihistamines, anti-nausea drugs, and antipsychotics. These drugs are not used to treat Alzheimer’s disease itself, but some of them may be used to treat symptoms of Alzheimer’s.

REM Sleep Behavior Disorder

Usually, people’s muscles do not move during rapid eye movement (REM) sleep, a sleep stage known for dreaming, so they don’t act out their dreams. In REM sleep behavior disorder, people speak and move around, sometimes violently, during REM sleep. These episodes are associated with vivid dreaming. 

REM sleep behavior disorder is more strongly linked to other degenerative diseases of the nervous system, such as Parkinson’s or Lewy body dementia than to Alzheimer’s disease. In fact, sometimes health care providers ask people who may be developing dementia if they act out their dreams as a way of ruling out Alzheimer’s. 

There is no conclusive evidence suggesting REM sleep behavior disorder is more common among people with Alzheimer’s disease. However, some drugs that are given for Alzheimer’s disease, classified as cholinergic treatments, may be associated with REM sleep behavior disorder. 

People with dementia, including Alzheimer’s disease, frequently experience a phenomenon called “sundowning, ” or “sundown syndrome.” Sundowning is characterized by an increase in restlessness, confusion, and irritability in the evening, as the sun goes down. Coping with sundowning can be a significant source of stress for caregivers. 

Sundowning may be more likely to develop in people with dementia who have a disrupted sleep-wake cycle. Researchers believe that sundowning may be caused by damage to the same part of the brain that controls circadian rhythm and the sleep-wake cycle: the suprachiasmatic nucleus.

If a person shows signs of a sleep disorder, like obstructive sleep apnea, diagnosing the disorder is important. OSA may be noticed by a caregiver or bed partner, as it can cause a person to stop breathing while they sleep or to snore loudly. Other symptoms include daytime sleepiness, morning headaches, and frequent nighttime awakenings.

Once someone has been diagnosed with Alzheimer’s, determining if they have a sleep disorder can be challenging. One complicating factor is that normal aging causes many of the same sleep issues as Alzheimer’s disease. Alzheimer’s is more common in older adults, a group of people who often experience sleep changes even when dementia is not present. 

Diagnosing sleep disorders also requires talking to people about what they’re experiencing. Questioning people with Alzheimer’s about their symptoms may be difficult because of the confusion and memory impairment caused by AD. While sleep studies provide more reliable information, some people with AD have trouble cooperating with this sort of test. 

Because of the challenges involved with performing a sleep study in a lab, other types of sleep tests may be used for people with Alzheimer’s. Actigraphy, which measures sleep and activity using a wristband device, may be a useful diagnostic tool for sleep disorders in some people with AD.

Helping people with Alzheimer’s disease get better sleep is important, since it may make their condition more manageable. 

In people with AD who have insomnia or trouble sleeping, but not another diagnosed sleep disorder, many experts prefer to try strategies for improving sleep that do not involve drugs. Caregivers play an important role in improving sleep, and may help assess whether sleep is improving by keeping sleep diaries for the person with dementia.

Non-Drug Strategies

A number of steps can be taken to help a person with Alzheimer’s disease improve their sleep.

• Improve the sleep environment: It is important to keep the sleeping area dark at night and brightly lit in the daytime. Light is the most important environmental cue for keeping people’s daily sleep-wake cycles on track. 
• Eliminate noise and disruptions: Keep the sleeping space quiet. Try to avoid or limit waking up a person with AD during the night for medical reasons, such as to give medications or take vitals. 
• Practice good sleep hygiene: People with Alzheimer’s and their caregivers should be mindful of good sleep hygiene practices. These habits include sticking to a regular bedtime and wake time, limiting caffeine, exercising during the day, and avoiding large meals at night. 
• Limit naps: The caregiver can help improve a person with AD’S nighttime sleep by limiting their naps during the day, especially after 3 p.m. Although excessive daytime sleepiness is common in people with Alzheimer’s, too much napping late in the day can interfere with getting to sleep at night.

Medication

Experts recommend against using medication to treat insomnia in people with Alzheimer’s or other forms of dementia. The drugs that may help people sleep can also make dementia symptoms worse. 

It’s also important to make sure medications taken for other health issues are not worsening sleep problems. Older adults, including people with Alzheimer’s, often take multiple medications. Many drugs, including decongestants, stimulants, antipsychotic medications, and blood pressure medications, may be linked to sleep problems. 

Talking to a doctor about medications and how certain drugs may impact sleep is an important step. Medical providers can determine whether it may be helpful for a person with AD and sleep problems to discontinue certain drugs or take them earlier in the day.

Caregivers Need Rest Too

Caring for someone with dementia can cause high levels of emotional and physical stress. Sleep disturbances in people with AD can be particularly difficult for their caregivers. 

When caregivers don’t get enough sleep because of nighttime disturbances, they may experience fatigue, worse mood, weakened immunity, and other symptoms of sleep deprivation. Caregivers who have trouble getting enough sleep might want to take steps that may help them get more rest.

• Talk to the doctor: The doctor of a person with AD may be able to suggest treatments or changes to care that will improve sleep. The doctor cannot help unless they know there is a problem, and input from caregivers is very important in diagnosing sleep problems in people with dementia. 
• Investigate community resources: Many caregivers use services, like home care, respite care, hospice, or adult day care, to give themselves time off to rest and take care of themselves. 
• Find a support group: Meeting with an Alzheimer’s caregivers group or a general caregivers support group can help. Not only is it comforting to talk to people who know what you’re going through, you may also pick up tips from people who have had similar experiences. 
• Take a class: Some hospitals and support organizations offer classes that may help you learn the best ways to care for a loved one with Alzheimer’s disease. Ask the doctor, social worker, the Area Agency on Aging, or an Alzheimer’s organization about educational programs for caregivers of people with dementia.

About The Author

Dr. Michael Breus

Clinical Psychologist, Sleep Medicine Expert

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Michael Breus, Ph.D is a Diplomate of the American Board of Sleep Medicine and a Fellow of The American Academy of Sleep Medicine and one of only 168 psychologists to pass the Sleep Medical Specialty Board without going to medical school. He holds a BA in Psychology from Skidmore College, and PhD in Clinical Psychology from The University of Georgia. Dr. Breus has been in private practice as a sleep doctor for nearly 25 years. Dr. Breus is a sought after lecturer and his knowledge is shared daily in major national media worldwide including Today, Dr. Oz, Oprah, and for fourteen years as the sleep expert on WebMD. Dr. Breus is also the bestselling author of The Power of When, The Sleep Doctor’s Diet Plan, Good Night!, and Energize!

• POSITION: Combination Sleeper
• TEMPERATURE: Hot Sleeper
• CHRONOTYPE: Wolf

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