Dementia And Daytime Sleep: What Caregivers Should Know

It is common for people with dementia to experience changes in their sleep patterns, and this can be distressing for friends and family. People with dementia, especially those in the later stages, may sleep a lot during the day and night. This is often due to the increased exhaustion they feel from performing simple tasks, such as communicating or eating. Additionally, time disorientation, a common symptom of dementia, can cause patients to start their day at unusual times, such as in the middle of the night. While sleeping a lot during the day is not always a cause for concern, caregivers should ensure that the person is comfortable and not in distress. It is also important to monitor the person for other health issues that may arise from spending extended periods in bed.

Excessive daytime sleeping may be a precursor to vascular dementia

While excessive daytime sleepiness may be a precursor to vascular dementia, it is not the only cause. Other factors that may contribute to excessive daytime sleepiness include:

• Sleep disturbances at night, such as insomnia, which can lead to napping during the day.
• Coexisting conditions, such as depression, which can cause persistent fatigue and changes in sleep patterns.
• Medications with side effects that induce drowsiness, including certain antidepressants, antipsychotics, antihistamines, and sleeping pills.
• Low melatonin levels, which play a crucial role in regulating sleep-wake cycles.
• Low sleep pressure due to long periods of low activity or boredom during the day, resulting in reduced tiredness at night.

It is important to note that excessive daytime sleepiness can also be a symptom of current vascular dementia. As the disease progresses and causes more extensive damage to the brain, individuals may find it exhausting to perform simple tasks, leading to increased sleep during the day. Additionally, the quality of sleep tends to deteriorate with age, and individuals with dementia may experience disrupted sleep patterns, further contributing to daytime sleepiness.

If excessive daytime sleepiness is a concern, it is recommended to consult a doctor, especially if it occurs alongside other unusual changes or agitation. While it typically does not require medical intervention, caregivers should ensure that individuals who sleep excessively are regularly checked on to prevent the development of secondary health conditions.

Sleep disturbances are common in people with Lewy body dementia and Parkinson's disease

People with Lewy body dementia are often sleepy during the day but experience very restless and disturbed nights. They can suffer from confusion, nightmares, hallucinations, insomnia, sleep apnoea, and restless legs. They may also unknowingly act out their dreams by shouting and moving around in bed, which can cause injury to themselves and their sleeping partner. This is called rapid eye movement (REM) sleep behaviour disorder, and tends to happen from the earliest stages of the disease onwards.

Excessive daytime sleepiness is now part of the proposed criteria for dementia associated with Parkinson's disease. In a study of 3,078 men, those with excessive daytime sleepiness were three times more likely to develop Parkinson's disease. This sleepiness may precede the disease.

Polysomnography and Multiple Sleep Latency Tests can be used to study sleep. Polysomnography reveals increased sleep fragmentation and a reduction in total sleep time, slow-wave sleep, and lower sleep efficiency in people with Parkinson's disease. The Multiple Sleep Latency Test (MSLT) is a daytime polysomnographic study that records initial sleep latency. The MSLT is considered the 'gold standard' for the objective assessment of daytime sleepiness.

In people with Parkinson's disease, sleep attacks are objectively characterised as intrusions of non-REM stage 1 and 2 sleep, and a subset are represented by microsleep episodes, which last 15-20 seconds. Sleep attacks can be caused by the side effects of medication. Anticholinergic drugs, for example, can trigger delirium or delirium-like features.

Restless legs syndrome (RLS) is also a common sleep disturbance for people with Parkinson's disease and Lewy body dementia. About 80% of people with RLS also have periodic limb movements of sleep (PLMS). Treatments that are beneficial to RLS are also generally efficacious and well tolerated in those with PLMS.

Dementia patients may sleep during the day to make up for their inability to sleep at night

People with dementia, especially those in the later stages, often spend a lot of time sleeping during the day and night. This can be distressing for family and friends, who may worry that something is wrong. However, it is a common feature of later-stage dementia. As the disease progresses, damage to the brain becomes more extensive, and the person gradually becomes weaker and frailer. As a result, they may find simple tasks like communicating or eating exhausting, which can cause them to sleep more during the day as their symptoms worsen.

Additionally, the person's internal 'biological clock', which regulates sleepiness and wakefulness throughout the day, may become damaged. Other parts of the brain that control wakefulness may also stop working properly. This can lead to a complete reversal of their normal sleep pattern, with the person staying up all night and sleeping during the day.

Coexisting conditions, such as depression, and side effects of certain medications, including antipsychotics, antidepressants, antihistamines, and sleeping pills, can also contribute to increased sleepiness in dementia patients.

Excessive sleepiness may occur at any stage of dementia and can be challenging to manage. However, it is important to note that sleeping more during the day is not necessarily a cause for concern as long as the person appears comfortable and not distressed.

Sleep disorders affect up to 80% of dementia patients

It is quite common for a person with dementia, especially in the later stages, to spend a lot of their time sleeping – both during the day and night. As the disease progresses, the damage to a person’s brain becomes more extensive, and they gradually become weaker and frailer over time. As a result, a person with dementia may find it quite exhausting to do relatively simple tasks like communicating, eating or trying to understand what is going on around them. This can make the person sleep more during the day as their symptoms become more severe.

Sleeping disorders unrelated to dementia, such as having breathing that occasionally stops during sleep (known as ‘apnoea’), can also contribute to longer sleeping periods. Moreover, certain medications can also cause sleepiness, including some antipsychotics, antidepressants, antihistamines, and sleeping pills.

Additionally, the quality of a person's sleep gradually deteriorates as they get older. They tend to get less deep or ‘slow-wave’ sleep, which helps to keep the brain healthy and refreshed. Even though a person with dementia may sleep more than a typical person of their age, it is unlikely to be good quality sleep.

Furthermore, the type of dementia a person has can also affect their sleep. For example, people with Parkinson’s disease or dementia with Lewy bodies often experience daytime sleepiness but have very restless and disturbed nights, suffering from confusion, nightmares, and hallucinations. They may also act out their dreams, shouting and moving around in bed, which can result in injury to themselves or their sleeping partner. This is called rapid eye movement (REM) sleep behaviour disorder or RBD.

While sleeping more during the day is not usually a cause for concern, if a person is lying down and asleep for most of the time, they will need to be looked after to prevent the development of physical health problems. This care is typically provided by health or social care professionals in a care home or hospice setting.

Dementia patients may sleep more due to melatonin depletion

Sleep disturbances are common in people with dementia, and the amount of sleep they get can vary depending on the type and stage of the disease. In the later stages of dementia, it is quite common for patients to spend a lot of their time sleeping during the day and night. This increase in sleep is due to several factors, including the progression of the disease, the side effects of medications, and other sleep disorders.

One possible explanation for the increased sleep in dementia patients is the depletion of melatonin, a hormone that plays a crucial role in regulating sleep-wake cycles. Melatonin secretion decreases in Alzheimer's disease, and this reduction has been linked to the circadian disorganization and impaired cognitive function observed in these patients. The decrease in melatonin levels contributes to the frequent symptoms of sleep disruption, nightly restlessness, and "sundowning" seen in Alzheimer's patients. Sundowning refers to agitated behavior and disorganized thinking that typically occur in the late afternoon or early evening.

Several studies have shown that melatonin levels are significantly lower in Alzheimer's patients compared to age-matched control subjects. This reduction in melatonin levels can be one of the early markers of Alzheimer's disease, even before cognitive impairment becomes apparent. The decrease in melatonin may be due to dysfunction of noradrenergic regulation, depletion of the melatonin precursor serotonin, or changes in the pathways of light transmission.

The use of melatonin as a therapeutic agent for Alzheimer's disease and mild cognitive impairment has been explored in clinical trials. Some studies have found that melatonin improved sleep quality and reduced sundowning symptoms in Alzheimer's patients. However, the effectiveness of melatonin may depend on the stage of the disease, as it has shown limited success in more advanced cases.

In summary, while there is evidence to suggest a link between melatonin depletion and increased sleep in dementia patients, particularly those with Alzheimer's disease, more research is needed to fully understand the complex relationship between sleep and dementia.

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