Alzheimer’s disease (and other forms of dementia) is often called the ‘cruelest disease,’ because of its systematic attack on the brain’s functions and theft of the essence of what gives each individual their uniqueness. It robs memories, clouds the recognition of loved ones and scrambles all sense of time and space as it progresses. And, as if that is not enough it also affects sleep patterns and the quality of sleep.
How Dementia Affects Sleep
It’s not uncommon for a person with dementia, especially in the later stages of the disease to spend a lot of time sleeping – both during the day and at night. As the disease progresses, the damage to the brain becomes more extensive and the person gradually becomes weaker and frailer over time. As a result, a person suffering from dementia can become quite exhausted, making it more difficult for them to do simple tasks like talking, eating or trying to understand what is going on around them. This can make them want to sleep more, including during the day. At the same time, the changes in the brain brought on by the dementia can mean that the sleep a person is getting results in less deep-sleep (or REM sleep) time.
Nobody completely understands why dementia affects sleeping patterns. For some people, it may be that their internal ‘biological clock’, which judges what time it is, becomes damaged so they start to feel sleepy at the wrong time of day. There are also other parts of the brain, which control whether or not we stay awake, and these may not work properly as brain function deteriorates. In some cases a person with dementia might completely reverse their normal sleep pattern, staying up all night and then sleeping all day.
Changes in sleep patterns often affect a person’s health in other ways beyond failing to get a good night’s sleep and the ramifications that produces. Sleeping too much during the day can keep a person from getting enough to eat. It can also mean less time for social interaction and less physical activity leading to greater isolation and loss of mobility, respectively.
When to See a Doctor
When a person is in the later stages of dementia and they have gradually started sleeping more and more, it is likely to be due to the dementia progressing. However, if the excessive sleeping has started more suddenly, or the person doesn’t seem well in other ways, it may have another cause. If this is the case, the primary care physician should be consulted to rule out other issues that could be having an impact. Physical ailments, such as urinary tract infections or incontinence problems, restless leg syndrome or sleep apnea can cause or worsen sleep problems. It may also be worth asking for a medication review or consulting with a pharmacist as medication can cause a range of sleep-related side effects.
Sources: Cognitive Vitality, a program of Alzheimer’s Drug Discover Foundation; and The Alzheimer’s Association.
We all know what a bad night’s sleep can do to our ability to think clearly the following day, but research suggests that repeatedly getting too little sleep (less than six hours a night) may increase your risk of developing Alzheimer’s disease and dementia.
Alzheimer’s disease is characterized by the presence of amyloid plaques and tau tangles in the brain. Previous studies suggested that lack of sleep and poor sleep quality was associated with the presence of amyloid plaques in cognitively healthy individuals, and that even one night of sleep deprivation can increase the levels of amyloid in the cerebral spinal fluid (CSF). Two recent studies published in Science Translational Medicine and Science suggest that poor sleep may also be associated with increased brain levels of tau.
Not all individuals with amyloid plaques will go on to develop dementia. In fact, studies show that tau accumulation may be a better predictor of cognitive decline than amyloid. However, many questions remain. It is still unknown whether poor sleep directly causes Alzheimer’s. Amyloid plaques begin to emerge about 10-15 years before any cognitive symptoms are present.
While the science is still developing, the connections between lack of adequate sleep and Alzheimer’s disease and other dementias should serve as a wakeup call. (No pun intended.) Failing to get the quality and quantity of sleep our brains and bodies need to properly function is no joke. Too little sleep can also lead to other diseases such as cardiovascular disease, diabetes, and depression – themselves risk factors for Alzheimer’s.
Source: Alzheimer’s Society