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Lewy Body Dementia

Lewy Body Dementia

Although Lewy body dementia (LBD) is the second most common form of dementia, it can present in different ways which means that it can be difficult to diagnose. It is a progressive condition that can affect thinking and memory, and also cause visual hallucinations (seeing things that are not there), as well as sleep disturbances and movement changes similar to Parkinson’s disease. LBD is sometimes called dementia with Lewy bodies (DLB), which is a different name to describe the same condition.

LBD is an umbrella term that includes two subtypes: dementia with Lewy bodies and Parkinson’s disease dementia. In dementia with Lewy bodies, changes in thinking, memory and sleep usually precede movement difficulties (also known as parkinsonism) while in Parkinson’s disease dementia, movement difficulties precede cognitive changes, usually by about a year or more. As the condition progresses, symptoms will become similar in both people with dementia with Lewy bodies and Parkinson’s disease dementia. It is important to note that whilst the risk of developing dementia is increased in someone who develops Parkinson’s disease, not everyone with Parkinson’s will develop dementia.

About 10-15% of all people living with dementia have LBD. It affects both men and women, although more commonly men. It usually affects people over the age of 65, although about 10% of younger people with dementia have dementia with Lewy bodies. LBD affects different people in different ways. The symptoms that people with LBD will experience depend on which part of the brain is affected. Although day to day memory can also be affected, it is usually less severe than in people living with typical Alzheimer’s disease.

The common symptoms of LBD include:

Cognitive symptoms (thinking): attention, alertness and visual processing may be affected in the following ways:

  • becoming slower to respond
  • problems with concentrating and staying alert
  • visual problems such as difficulty reading clocks
  • difficulty with judging distances
  • struggling with planning and organising
  • difficulty with day-to-day memory
  • fluctuations in thinking and memory abilities – with difficulties varying from day to day or even hour to hour

Motor symptoms (movement): movement can be affected in similar ways to those in Parkinson’s disease:

  • movements may become slower, or more stiff
  • facial expressions can be blank
  • limbs may shake (tremors)
  • more prone to falls


Some individuals may have visual hallucinations (seeing things that are not real). These hallucinations, often of animals or people, may seem real to the person living with LBD and can sometimes be distressing. Hallucinations can improve with adjustments to medications. However, it is advised that people discuss this with a specialist in case the treatments they are taking are triggering or making their hallucinations worse. For many though, these are not generally troublesome and would only need treatment if they became distressing.

People with LBD can also experience auditory hallucinations (hearing things that are not real). However, this is less common. They can also sometimes experience delusions, which means that they believe ideas which are not true.

Sleep symptoms:

People with LBD may also have problems with sleep. This can happen years before other problems develop. The most common sleep problem is people having vivid dreams and acting out their dreams, which can result in injuries. This is called REM sleep behaviour disorder. People with LBD may also experience severe daytime sleepiness, insomnia, difficulty waking associated with temporary loss of consciousness and restless leg syndrome. If this is causing disturbances for other members of the family, there are treatments that can be tried to calm these symptoms.

Other symptoms:

People living with LBD can also experience problems with bladder or bowel function such as constipation or urinary incontinence. These symptoms are called autonomic symptoms, because they involve dysregulation of the autonomic nervous system which controls many involuntary functions such as breathing and temperature regulation. Other autonomic symptoms include sexual dysfunction (hypersexuality or impotence); problems with temperature regulation, with blood pressure control, which can cause dizziness or fainting and cardiac symptoms such as atrial fibrillation or loss of sense of smell. Some people may also experience mood problems such as depression or anxiety.

Not everyone will develop all these symptoms. LBD affects different people in different ways. The symptoms that people with LBD will experience depend on which part of the brain is affected. It is also a progressive condition and symptoms generally become worse over time, though the rate at which symptoms become worse vary from person to person. These symptoms can also be unpredictable, fluctuating from day to day, even hour to hour. Some symptoms can also be challenging to manage, for example movement symptoms because medications to manage them can worsen thinking and memory symptoms. This can be distressing for both the person living with dementia as well as their family and friends.

LBD is caused by a build-up of proteins called ‘Lewy bodies’ in the brain. These same proteins can also be found in people with Parkinson’s disease. Scientists still don’t know exactly how they cause dementia, but they may lead to a loss of connections between brain cells. The symptoms that people with LBD will experience depend on where the Lewy bodies are found. When they are mostly found in the deeper parts of the brain, they lead to problems with movements and Parkinson’s disease. When they are found in the outer parts of the brain they tend to lead to LBD. In the early stages it can be difficult to diagnose LBD and people can initially be diagnosed as having Alzheimer’s disease or Parkinson’s disease. Other things that can cause similar symptoms, including infections or the side effects of medication, also need to be ruled out.

Getting the right diagnosis is particularly important if LBD is suspected. This is mainly because people with LBD can benefit from some medications, but also react very badly to others. To diagnose LBD, the doctor will talk to the person, and someone who knows them well. They will ask about the person’s medical history, when the symptoms started, and how these are affecting their life now. A neurological examination (looking at reflexes or stiffness and balance, for example) will also be done. If the person shows signs of LBD, brain scans can also be used to help clarify the diagnosis. Computed tomography (CT) or magnetic resonance imaging (MRI) scans may be done to rule out brain conditions (such as a brain tumour or bleed) which can sometimes cause similar symptoms. If there is still doubt, a more specialised brain scan might be carried out. This can confirm a diagnosis of LBD if it shows loss of function of a particular type of cells (dopamine nerve cells) at the base of the brain. Treatment for LBD also usually requires a multidisciplinary team of healthcare professionals, including physicians and occupational therapists to better manage the different symptoms.

Another Presence is a film that explores the experiences of people living with LBD.

If you are wondering if you should contact your primary health care provider regarding a diagnosis, visit:

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