Memory, language, problem-solving, as well as other cognitive skills, are all affected by dementia, which is a permanent loss of brain function1. There are several kinds of dementia, that are more common in older people. Dementia is characterised by brain cells that do not function properly and die off at a faster rate than those who do not have dementia. Although there is no known cure, there are therapies that can help to halt its course.

Sleep disturbances are prevalent in dementia patients, and sleep deprivation can increase or contribute to the severity of many other dementia symptoms. One of the most unpleasant dementia symptoms, according to caregivers, is interrupted sleep2. Detecting and treating sleep problems is an important element of dementia treatment since it reduces stress for both patients and carers.

What Effects Does Dementia Have on Sleep Patterns?

Circadian rhythm is a set of physically and psychologically processes4 that regulate our sleep-wake cycle in response to environmental cues. People with dementia have fundamental disruptions in their circadian rhythm, which makes it difficult to acquire decent sleep on a consistent schedule.

The suprachiasmatic nucleus (SCN) is a region of the brain that acts as an internal clock, responding to stimuli like light to tell us when we should be awake and when we should be sleeping. Cells eventually in the SCN5 and reduced cellular activity in this area of the brain are prevalent in people with Alzheimer's disease, the most common form of dementia.

As a result of this malfunction, patients are frequently unable to maintain a 24-hour sleep-wake cycle, sleeping excessively during the day and sleeping very little at night.

Differences in sleep structure have also been linked to dementia. Our bodies go through a variety of sleep stages when we sleep, from light sleep (stages 1 and 2) through deep sleep (stage 3 or slow-wave sleep), and finally dream sleep (stage 4). (also called rapid eye movement or REM sleep). Slow-wave sleep, as well as REM sleep, are important aspects of how sleep helps the body and mind heal. Dementia patients spend less time in slow-wave and REM sleep and greater time in the early phases of sleep. The loss of deep sleep and REM sleep is a result of this decline.

Common Sleep Disorders in Dementia Patients

Sleep disturbances are common among people with dementia. The following sleep disturbances are most common in older persons, but they are considerably more common in dementia patients.

RLS (restless legs syndrome) is characterized by a strong need to move one's legs, particularly during the night. RLS is frequent in persons who have Lewy body dementia, a kind of dementia.

PLMD (periodic limb movement disorder) is a disorder in which the arms and/or legs twitch uncontrollably during the night. RLS affects a large number of people with PLMD.

Obstructive sleep apnea (OSA) is a disorder in which the airway collapses during sleep, resulting in short pauses in breathing. OSA is particularly frequent in Alzheimer's disease patients, accounting for 40% of cases.

REM sleep behaviour disorder: Individuals with REM sleep behaviour disorder play out their dreams, sometimes even in harmful ways. It's particularly common in people with Lewy body dementia, and it's frequently the very first symptom8 that comes with the disease.

Depression is related to sleeplessness and other sleep difficulties, even though it is a mood illness. Depression is widespread in patients with dementia, and it appears to be becoming worse9 as the disease develops.

Other Sleep Problems with Dementia Patients

Individuals with dementia who suffer more agitation10 later in the day because in the evening are said to be 'sundowning.' Confusion, anxiety, roaming, and screaming are all signs of sundowning. When sundowning practices persist throughout the night, they can lead to insomnia as well as other sleep issues. Sundowning might be caused by alterations in the circadian rhythm that happen in dementia, as well as exhaustion, despair, and pain.

If a person with dementia is unable to sleep, they may talk, shout, or cry out. Some dementia sufferers have a proclivity for wandering11 away from the home, which may be perilous at night. Shouting, grasping, leaping, and other activities are linked to dream enactment during sleep in dementia patients with REM sleep behaviour disorder12.

What Role Does Sleep Play in Dementia Risk?

Sleep and dementia might have had a bidirectional association, according to experts13. This suggests that, while sleep may influence dementia risk and symptoms, sleep quality is also affected by the existence or absence of dementia. The buildup of a molecule called amyloid-beta, which eventually forms masses called amyloid plaques, is one of the early Alzheimer's disease signs in the brain. Sleep deprivation increases amyloid-beta levels in the brain, according to animal research and a small human study14. Alzheimer's patients with amyloid plaques, on the other hand, have been proven to have poorer sleep quality than Alzheimer's patients without amyloid plaques.

Sleep is also recognised to be important for our brain performance and memory development. Sleep problems have been linked to cognitive decline15 including dementia in observational studies. These studies, however, do not establish a cause-and-effect link. Although more study is required to better understand the relationship between sleep and dementia risk, there are several tried-and-true ways to enhance your sleep.