The Link Between Dementia and Sleep

October 17, 2023

Dementia is an umbrella term for a set of symptoms and behaviours brought on by cognitive decline. Scientific research has found a strong association between sleep problems and dementia. In some cases, disturbed sleep patterns can be an early sign of dementia. Studies also suggest that poor-quality sleep in middle age may increase your risk of cognitive decline.

There is a clear correlation between lack of sleep and dementia, but experts aren’t sure if disturbed sleep causes dementia or if dementia leads to bad sleep. Whatever the causal relationship, dementia has been linked to the following sleep disorders:

Insomnia
Obstructed sleep apnea (OSA)
Circadian Rhythms Problems
REM Behaviour Disorder (RBD)

What is the Link Between Sleep Disorders and Dementia?

Sleep disorders that cause poor-quality sleep may increase your risk of developing dementia. However, sleep problems are also common among dementia patients, so it’s unclear how these two factors interact. Researchers aren’t sure whether sleep disorders cause dementia, whether dementia leads to disrupted sleep, or whether the relationship between the two is circular.

What we do know is that there is a clear relationship between disturbed sleep and cognitive decline.

Obstructed Sleep Apnea and Dementia

Obstructed sleep apnea (OSA) is a common sleep-related breathing disorder in which the muscles in the back of the throat relax and block the airways. This temporarily restricts the person’s breathing, causing them to briefly wake up so the airway can be cleared. People with OSA frequently wake up short of breath or with a snorting, gasping sound. Depending on how severe the problem is, people with OSA may wake up 5-30 times every hour, resulting in seriously impaired sleep quality.

OSA has been linked to cognitive decline and dementia and may increase your risk of both. This is because OSA disrupts sleep patterns, reduces the flow of oxygen to the brain and increases oxidative stress in the brain. Research has found that people with Alzheimer’s disease (the most common form of dementia) are five times more likely to have OSA than other people their age. Furthermore, 50% of Alzheimer’s patients were found to have OSA following their diagnosis.

However, it is unknown whether long-term OSA increases a person’s risk of developing dementia, or if OSA makes dementia symptoms worse.

Sundowning and Nighttime Restlessness

Sundowning (or, sundown-syndrome) describes a set of behaviours in dementia patients that appear or worsen around sunset. The behaviours and emotional disturbances associated with sundowning may include:

Pacing
Wandering
Crying
Yellowing
Violence
Shadowing (i.e., following people closely)
Agitation
Anxiety
Sadness
Fear
Restlessness
Irritability
Paranoia
Confusion
Delusions
Hallucinations

The symptoms of sundowning can be exacerbated by sleep disorders such as:

Insomnia
Circadian-rhythm sleep-wake disorders
Sleep-related breathing disorders (like OSA)
Parasomnias (i.e., sleep-walking or sleep-talking)
Sleep-related movement disorders (repetitive, rhythmic movements when a person is drowsy or sleeping)
Central disorders of hypersomnolence (like narcolepsy or excessive daytime sleepiness)

Prevalence of Sleep Disturbances in People with Dementia

Between a quarter and a third of people with Alzheimer’s disease and other forms of dementia experience sleep disturbances. Some studies suggest that changes in the brain associated with dementia may lead to sleep problems such as:

Reversal of day-night sleeping patterns (causing people to feel sleepy during the day and alert at night)
Frequently waking up at night
Daytime sleepiness
Decreases in slow-wave sleep and rapid eye movement (REM) sleep

Disrupted sleep has been found to increase with the severity of dementia symptoms. The exact reason for this is unknown, but poor-quality sleep could be caused by lifestyle changes associated with dementia, the presence of pain, and certain prescribed medications.

Managing Sleep Issues for Seniors with Alzheimer’s

Non-pharmacological approaches

Sleep disturbances are common among people with Alzheimer’s and other types of dementia, possible due to changes in the brain. There are many ways to manage sleep disturbances in seniors with dementia, including medications. However, non-pharmacological strategies should be tried first. Some drug-free methods for reducing sleep disruptions in dementia patients include:

Maintain a regular schedule for meal times, bed time, and wake time
Encourage exposure to sunlight in the morning
Encourage daily exercise (but not within four hours of bedtime)
Manage pain
Avoid alcohol, caffeine, and nicotine
Make sure the bedroom is a comfortable temperature
Avoid giving certain medications (i.e., cholinesterase inhibitors) at bedtime
Provide security objects and nightlights if needed
Discourage watching television when the person is awake; instead, try to engage them in other dementia-friendly activities

Medications for Sleep Disturbances and Their Considerations

If drug-free interventions fail to improve sleep quality in a dementia patient, their doctor may prescribe medications to help them sleep. Drugs that are commonly used to treat sleep disturbances in people with dementia include atypical antipsychotics, benzodiazepines, sedating antidepressants, other GABAergic drugs, melatonin, and antihistamines.

These medications may help dementia patients to sleep at night, but many have the potential for adverse side-effects (like daytime sleepiness, rebound insomnia, confusion, amnesia, and problems with balance). Several medications prescribed for sleep also carry the risk of physical and psychological addiction.

What is the Best Sleeping Position to Prevent Dementia?

Poor-quality sleep could increase your risk of developing dementia, and so could your sleep posture. Research suggests a link between sleep positions and dementia, and sleeping on your side (instead of your back or stomach) reduces your likelihood of cognitive decline. This is because side-sleeping more effectively removes harmful waste products from your brain, the build-up of which may contribute to the development of Alzheimer’s disease and other types of dementia.

Does Quality of Sleep Matter for People with Dementia?

Sleep disorders are common among dementia patients, but good-quality sleep is important for those with cognitive decline. This is because restful sleep is essential for healthy cognitive function.

Research has found that deep sleep may help to mitigate the effects of dementia and alleviate memory decline. You can help someone with dementia get a better night’s sleep by:

Encouraging exercise during the day
Setting a peaceful mood in the evenings (e.g., by keeping lights low, reducing noise levels, and playing soothing music)
Maintaining a regular bedtime routine
Using nightlights
Limiting caffeine intake

Vascular Dementia and Excessive Sleeping

Increased sleep (including daytime sleep) is common for people with dementia, especially as they enter the late-stages of the illness. Excessive sleepiness can be a symptom of all forms of dementia, including vascular dementia.

However, excessive daytime sleepiness in older adults may be a warning sign of vascular dementia (but not for other types of dementia). Research has found that individuals with severe daytime sleepiness were 4.44 times more likely to develop vascular dementia than the general population.

Could Poor Sleep Habits During Middle Age Increase Your Risk of Dementia?

Bad sleep can increase your risk for dementia, especially if you are not sleeping enough in middle age. One study reported that individuals in their 50s and 60s who slept 6 hours or less per night were 30% more likely to develop dementia than those who slept 7 hours per night.

Too much sleep isn’t good for your brain, either. Further research suggests that regularly sleeping more than 8 hours a night can increase dementia risk by 69% compared to 7-8 hours of sleep. These findings suggest that excessive or inadequate sleep in middle age can contribute to cognitive decline later in life.

Should You Let Dementia Patients Sleep as Long as They Want?

Sleeping more (both at night and during the day) is common for people with dementia, especially those with late-stage dementia. If the increase in sleepiness happens gradually it is probably a sign of dementia progression and not a cause for alarm. As long as they are not uncomfortable or distressed, there is no harm in letting them sleep.

However, a sudden change in sleep behaviour may be caused by other medical issues. If a person with dementia is suddenly excessively tired, make an appointment with their doctor for a professional health assessment.

It is important to be aware that spending long hours in bed can lead to physical health issues such as bed sores. In these cases, the patient will require additional health care.

Conclusion

Researchers have found a strong associated between lack of sleep and dementia. People with dementia are more likely to experience sleep disorders than the general population, and individuals with disordered sleep in their middle age are more likely to develop dementia later in life.

Although there is a clear link between disruptive sleep disorders (such as insomnia, OSA, circadian rhythms problems and REM Behaviour Disorder), scientists are not sure what the causal relationship is. It is currently unknown whether poor-quality sleep causes dementia, or whether dementia causes poor-quality sleep. What is clear, however, is that deep and restful sleep is vital for healthy cognitive function, especially in middle age.

References

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