Dementia with Lewy bodies

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Introduction0:00–0:25

Lewy body dementia is a type of dementia, where individuals lose their memory and have difficulty learning new information.
Lewy bodies refers to protein deposits found inside neurons, and they’re named after Frederic Lewy, the neurologist who discovered them.
Lewy body dementia is a neurodegenerative disease, meaning that it worsens over time, and it’s the disease that afflicted comedian and actor Robin Williams.

Physiology0:25–0:49

The brain is made up of billions of neurons that communicate with each other by releasing neurotransmitters. Most neurons in the cerebral cortex are called cholinergic neurons because they produce acetylcholine.
In contrast, neurons in a section of the midbrain called the substantia nigra are in charge of initiating movement and other motor functions.
These neurons are called dopaminergic because they produce dopamine. The underlying cause of Lewy body dementia isn’t well understood.

Pathology0:49–1:26

Normally, neurons contain a protein called alpha synuclein, and in Lewy body dementia, this protein gets misfolded within the neurons.
The misfolded alpha-synuclein aggregates to form Lewy bodies that deposit inside neurons, particularly in the cortex and the substantia nigra.
Under a microscope, Lewy bodies look like dark, eosinophilic inclusions inside the affected neurons. As the disease progresses, more and more neurons accumulate Lewy bodies and die.
The significance of Lewy bodies, however, is unknown, but they’re seen in other diseases like Parkinson’s disease and multiple system atrophy.

Symptoms1:26–1:57

In Lewy body dementia, the early symptoms are typically cognitive ones, like difficulty focusing, poor memory, visual hallucinations, disorganized speech, and depression, similar to Alzheimer's disease.
Later symptoms are typically motor ones, like resting tremors, stiff and slow movements, and reduced facial expressions, similar to Parkinson's disease.
But usually these motor symptoms are a bit milder than what’s seen in Parkinson’s disease. Finally, some people have sleep disorders like sleep walking or talking.

Diagnosis1:57–2:07

A diagnosis of Lewy body dementia is based on the pattern of symptoms, but can only be confirmed with a brain autopsy that shows Lewy bodies in neurons.

Treatment2:07–2:24

Treatment is aimed at alleviating symptoms. Motor symptoms respond to drugs used to treat Parkinson's disease like levodopa, a dopamine analogue, while cognitive symptoms may improve with drugs for Alzheimer's disease like donepezil, which increases acetylcholine availability.
All right, as a quick recap, Lewy body dementia is a neurodegenerative disease caused by aggregation of the misfolded protein alpha-synuclein inside of neurons in the brain cortex and substantia nigra.

Recap2:24–2:43

This leads to the early cognitive symptoms, like in Alzheimer's disease, and later motor symptoms, like in Parkinson's disease.