Brain shrinkage and its link to different types of dementia

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Dementia is a scary word for many of us. It refers to a group of symptoms that affect memory, thinking, and social abilities.

Alzheimer’s disease is perhaps the most well-known type of dementia, but there are others too, like dementia with Lewy bodies.

What are Lewy Bodies?

Lewy bodies are tiny clumps of protein that can form in the brain. Their presence is linked with a type of dementia called ‘dementia with Lewy bodies’.

This disease can cause hallucinations, mental decline, rigid muscles, slow movement, and tremors. Because its symptoms are similar to both Alzheimer’s and Parkinson’s diseases, it can be tough to diagnose accurately.

The Role of the Hippocampus

The hippocampus is a small part of the brain that plays a big role in memory and thinking. In Alzheimer’s disease, the hippocampus starts to shrink early on. This shrinkage, or ‘atrophy’, is often a tell-tale sign of the disease.

But what happens in the hippocampus when a person has dementia with Lewy bodies? A group of scientists from Mayo Clinic decided to investigate this question.

The Mayo Clinic Study

The researchers studied 160 people who had mild cognitive impairment, a condition marked by slight but noticeable changes in memory and thinking abilities.

These people had brain MRI scans to measure the size of their hippocampus. They also took yearly tests for an average of two years.

During the study, 61 of these people (38%) developed Alzheimer’s disease. Another 20 people (13%) progressed to probable dementia with Lewy bodies.

We say ‘probable’ because we can only diagnose Lewy body disease for sure after a person has passed away and their brain is examined.

The team discovered something interesting: those who showed no shrinkage in the hippocampus were 5.8 times more likely to develop probable dementia with Lewy bodies than Alzheimer’s.

In fact, 85% of those who developed dementia with Lewy bodies had a normal hippocampus volume. On the other hand, 61% of people who developed Alzheimer’s disease showed shrinkage in the hippocampus.

This link between hippocampus volume and disease was even stronger among people who didn’t have memory issues.

This is notable because dementia with Lewy bodies often affects thinking skills, like attention, problem-solving, and visual interpretation, rather than memory.

The Importance of Early Diagnosis

These findings could help doctors identify people at risk of developing dementia with Lewy bodies earlier. This is crucial because an early diagnosis can inform the right treatments.

For instance, around 50% of people with Lewy body disease have severe reactions to antipsychotic drugs. Knowing this in advance can guide doctors to avoid such medications.

This study was published in the journal Neurology, led by researcher Kejal Kantarci. The team’s findings underline the complexity of dementia and the need for ongoing research in the field.

They remind us that understanding and managing dementia requires attention to the specific types of this condition.

If you care about brain health, please read studies about how the Mediterranean diet could protect your brain health, and a quick, easy scan can reveal your dementia risk.

For more information about brain health, please see recent studies about antioxidants that could help reduce dementia risk, and higher magnesium intake could help benefit brain health.

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