Health

Damaged areas of the brain can explain the confusion of people with dementia

The cause of the confusion that people with dementia experience when something unexpected happens can be a specific network in the brain. New research will help us better understand these neural connections and better manage the potentially upset situation of the patient and her loved ones.

A new study by doctors and researchers at the University of Cambridge and Oxford brings together 10 years of data to reveal brain changes in people with dementia, including those with Alzheimer’s disease. Affect their reaction to new scenarios..

To do this, they used a technique called magnetoencephalography. It can scan the brain 1,000 times per second. This allowed us to see exactly how the human brain responds to unexpected events and compare it to the brains of people with dementia.

“This is called a mismatch negative test and you can put a person in a scanner to play the same stimulus. Here we use the beep as an auditory stimulus, but we change it from time to time.” Dr. Thomas E. Corp.One of the authors of the MRC Cognitive and Brain Science Unit and Department of Clinical Neuroscience, University of Cambridge.

“Then, when you change it, the brain responds to that change.”

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In the test, the change may simply be a different pitch, or a new rhythm. However, how the brain reacts to this works just like a real surprise, with topics changing in the middle of a conversation, room furniture moving around, and so on.

In a healthy brain, the reaction is in two stages. The first correlates with the “sound-aware” auditory system, but subsequent activity is a different area of the brain that recognizes differences, Corp said. “The brain reacts when it learns that the sounds are different. [The brain tells you to] Pay attention to it, think about it, and see what you need to do with it. “

However, in patients with dementia, Corp and the team found a decline in the second stage. Their brain didn’t tell them that there was a change, and it didn’t tell them what to do about it.

This may be the reason why many people with dementia are struggling when an unexpected event occurs.

“It’s really okay if people with Alzheimer’s disease are in their home environment and surrounded by familiar things. They can be confused together. But one day, if something small changes. For example, if the kettle breaks, they have to react differently, but they can’t. They can’t figure out what to do. “

The team combined a magnetoencephalogram with a more familiar MRI scan to show that this second phase is in a specific area of the brain. These areas make up what is called a multi-demand network.

“These are all parts of the brain that we are much larger than animals like dogs and mice,” says Corp. “Our visual and auditory cortex are similar to those of dogs, but the intelligence network, which is the” thinking bit “of our brain, is much larger in us. “