Overview

Lewy body dementia is a disease caused by an accumulation of a protein called alpha-synuclein. This in turn causes damage to neurons which are important for communication within the brain and the rest of the body. This damage causes symptoms such as problems with thinking, movement, behaviour and mood. Diagnosis of Lewy body dementia is difficult because there are many overlapping symptoms with other brain diseases or psychiatric disorders.

Causes of Lewy body dementia

It is known that damage in Lewy body dementia is caused by deposits of protein causing damage to neurons. This can result in the loss of neurons that are essential as they produce chemicals that act as messengers between cells such as acetylcholine which is vital for memory and learning. It can also lead to a of dopamine which is essential for cognition, behaviour, movement, motivation, sleep, and mood.  However, why these deposits occur is unknown. It is believed that there is a mix of environmental and genetic factors, however, more research is required to determine the exact causes.¹

Symptoms of Lewy body dementia

Symptoms of Lewy body dementia are progressive meaning that the symptoms are initially mild and then progress into more severe symptoms. Damage caused by the protein deposits can be different from patient to patient. Due to the individual differences, there is a wide range of symptoms that a patient with Lewy body dementia may present with:²

• Hallucinations and hearing voices (e. g. seeing, hearing or smelling things that are not there)
• Problems with understanding, thinking, memory and judgment (similar to Alzheimer’s disease however commonly memory is less affected in patients with Lewy body dementia compared to patients with Alzheimer’s disease)
• Confusion
• Sleepiness
• Slow movement, stiff limbs and/or uncontrolled shaking
• Disturbed sleep (usually in conjunction with violent movements and shouting)
• Fainting, unsteadiness and falls
• Depression
• Anxiety

Diagnosing Lewy body dementia

There is not an exact test for Lewy body dementia. Based on the symptoms doctors may be able to perform several examinations and tests to determine whether a patient has Lewy body dementia. Some of these include:³

• Neurological and physical examinations (e. g. testing of reflexes, strength, ability to walk, muscle tone, eye movements, balance, and sense of touch)
• Assessment of mental abilities (determines patient’s thinking skills, and ability to remember information)
• Blood tests (looking for lack of thyroid activity or deficiency of b-12 vitamin, which may affect brain functioning)
• Brain scans (Magnetic resonance imaging or computed tomography to look for a stroke or tumour. Alternatively, fluorodeoxyglucose positron emission tomography or photon emission computerized tomography can provide further details about the brain, such as dopamine transporter uptake in the brain, characteristic of Lewy body dementia)
• Sleep evaluation (polysomnogram test used to check for REM sleep behaviour can help determine whether there are problems with blood pressure instability or heart rate associated with Lewy body dementia)
• Heart test (myocardial scintigraphy can be ordered to check how blood flows to the heart, changes in blood flow can indicate Lewy body dementia)

Treatment for Lewy body dementia

Because symptoms of Lewy body dementia vary and are individual there is no specific treatment for Lewy body dementia. Therefore the symptoms and patient health history will be taken into account when discussing treatment options. No currently available treatment will cure Lewy body dementia but can potentially alleviate its symptoms. Common treatment methods include:⁴

• Acetylcholinesterase inhibitors (Donepezil, Exelon, Reminyl)

Increase the amount of time that acetylcholine (neurotransmitter decreased in Lewy body dementia) is present in the brain. This can help decrease the symptoms of hallucinations, confusion and sleepiness in some patients.

• Memantine

This medication blocks the effects of glutamate (neurotransmitter), which in large amounts can cause neurotoxicity and therefore more damage to the brain. Memantine is likely to be suggested if for some reason a patient cannot take acetylcholinesterase inhibitors.

• Clonazepam

Likely to be given to patients with sleep behaviour disorders specifically in REM sleep.

• Levodopa

May help patients who have issues with movement however, it may cause more severe symptoms of Lewy body dementia which must be taken into account.

• Antipsychotics

May help with behavioural problems that are putting the patient or others at risk. However, can also cause serious side effects and must be discussed with a healthcare professional.⁴

Summary

In conclusion, Lewy body dementia is a subtype of dementia that has lots of overlap with other disorders. There are some distinct symptoms however, it is difficult to diagnose and currently, there is no specific treatment. There are some options to help alleviate symptoms of the disorder.