Causes of sleep disturbance in dementia

Jun 22, 2020

Causes of sleep disturbance in dementia

Causes of sleep disturbance in dementia

Posted in : Living with dementia on by : Pooja Jain

As we age, we might start to sleep a little less than we used to when we were younger. However, we still need the same quality of well-rested and deep sleep so our bodies and minds can recover and re energise for the next day. 

While the hours spent sleeping vary amongst people with dementia, their frequency and severity of sleep disturbances are significantly higher than older adults without dementia. For more information on identifying sleep problems, have a look at the article Understanding sleeping problems in dementia.  

In this article, we look at the possible reasons WHY a person with dementia may struggle to get a good night’s sleep. If you can understand why someone is struggling to sleep, then you can make changes to try and help them sleep better.

Changes in the brain 

Dementia causes changes to the brain that can affect the sleep-wake cycle, disturbing normal sleeping patterns. The sleep-wake cycle is a 24-hour cycle that our body goes through every day. It makes sure that we are awake and active during the day and feel sleepy at night. When this cycle is changed, it results in many unusual and disruptive sleeping patterns. This includes being awake at night, problems falling asleep and maintaining sleep, day-time drowsiness and frequently napping during the day. These sorts of changes are seen in many types of dementia. 

Poor sleep hygiene 

The sleeping environment (i.e. the bedroom) might not be suitable for the person with dementia. 

  • Lighting: 
    • Limited exposure to bright light or natural sunlight during the day 
    • Reduced lighting in the room can create shadows that can be confusing and cause someone with dementia to be afraid
  • Sound: Loud noises in and around the house 
  • Temperature: Sensitivity to heat or the cold
  • Hidden sleep stealer: Access to alcohol and caffeine just before bedtime
  • The bed: Uncomfortable mattress, blanket or pillows  

Activity levels   

There is a link between physical activity and sleep. If the person with dementia is not active, and taking frequent naps during the day, this negatively impacts their sleep-wake cycle and therefore the quality and duration of sleep. Their body is also probably not tired enough, and so it’ll take them longer to fall asleep. 

Comorbidities & Untreated pain  

Most people with dementia are older adults and are probably at risk for various age-related comorbid conditions. These can further worsen sleep issues and increase the risk for development for sleep problems. These comorbidities can also cause pain and discomfort that will interfere with sleep. This disturbed sleep, in turn, reduces pain threshold causing a vicious cycle. Some examples include:

  • Arthritis can cause pain at night
  • Heart failure can cause early morning pains with shortness of breath and nocturia
  • Depression can make it difficult to maintain sleep and feel excessively sleepy 
  • Delirium can cause fragmented sleep-wake cycle
  • Obesity can lead to snoring and sleep apnea (a sleeping disorder described later in the article)
  • Incontinence issues 

Medication side effects

  • Medications that are used to control chronic pain can cause excessive daytime sleepiness
  • Many medications prescribed to alleviate the symptoms of Parkinson’s contribute to daytime sleepiness and nighttime awakenings
  • Medications used for reducing behavioural challenges in Alzheimer’s are often associated with feeling active and awake during the night and sometimes negatively impact dreaming 
  • Antidepressants and anti-anxiety medications can make the person feel sluggish and disrupt the quality of nighttime sleep
  • Beta-blockers used for high blood pressure and some cholesterol-lowering drugs may cause nightmares and waking during the night 

Sleeping disorders 

  • Rapid eye movement sleep behaviour disorder causes people to act out their dreams through moving or talking in their sleep and is usually common with Lewy Body dementia and Parkinson’s.
  • Sleep apnea is a condition where the person has difficulty breathing when they are asleep. 
  • Restless legs syndrome also known as Willis-Ekbom disease, is a common condition of the nervous system that causes an overwhelming urge to move your legs, usually faced by people with Parkinson’s. 
  • Insomnia is present in almost 50% of people with dementia, where they struggle to fall asleep and maintain the sleeping state.   


Dehydration often interferes with physical and mental functioning, worsening dementia symptoms. It can lead to the person to become constipated which causes them discomfort and will in turn disturb their sleep quality. A person who is dehydrated can also experience cramping in the limps, headaches or just generally feel unwell. As a result they may become irritable and have difficulty falling asleep. 


Many people who experience sundowning will struggle to sleep at night. Sundowning can be identified by increased confusion, wandering and agitation that tends to happen later afternoon into early evening and usually occurs in Alzheimer’s during the moderate to late stages of the condition. You can find out more about sundowning by reading Understanding sundowning in dementia. One of the causes of sundowning is thought to be related to changes in the sleep-wake cycle and secretion of melatonin (a hormone that promotes sleep). 

It might be helpful to start a journal or use an app to document the patterns and disturbances that the person you are caring for is facing to identify and relate to the above list of reasons. Once you think you know the reason(s) for the sleeping problems, head over to the article Sleeping better with dementia for potential solutions. 

Make sure that when you start to observe sleeping difficulties, you share this information with your doctor as they can help identify and come up with a treatment plan for better quality sleep. 


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