Posts tagged Alzheimer's
Posts tagged Alzheimer's
An article in the New York Times was about recent research into physical symptoms that may reflect or predate cognitive symptoms of Alzheimer’s. They found that many people showed altered gait (walking) before they had really noticed memory decline or other cognitive deficits associated with Alzheimer’s and dementia. Sometimes Alzheimer’s won’t be diagnosed until it is much later because the individual cannot identify it in themselves- and there is some normal memory loss/difficulties with normal aging. Anything that might help medical professionals identify people with these problems earlier would help with treatments.
From the article: One study involved more than 1,100 elderly people in Basel, Switzerland. About a quarter of them were cognitively healthy, while the others had mild cognitive impairment, considered a precursor to dementia, or were in various stages of Alzheimer’s.
The participants walked normally on the electronic walkway, and again while performing a cognitive task: counting backward by two’s from 50, or naming animals.
One 72-year-old woman’s first walking test betrayed no problems. But when she walked while counting backward from 50, her gait worsened dramatically, said Dr. Stephanie Bridenbaugh, head of the Basel Mobility Center.
“She teetered and wobbled on one foot,” Dr. Bridenbaugh said. “She almost tipped to the side.” And “she didn’t notice any of it,” she added. “She was mad that she didn’t remember more numbers.”
Dr. Bridenbaugh referred her to the memory clinic, where cognitive testing showed the woman already had mild cognitive impairment.
PET images of Alzheimer’s brain
PET (positron emission tomography; said like “pet”- the animals you have at home) is a type of imaging that relies on a radioactive ligand (injected into the patient) to give off a signal for a particular type of chemical. For instance, if you want to look at a specific receptor or neurotransmitter, you could put in a competitive radioactive ligand that would bind to that receptor and it would tell you where that receptor is and how much of the neurotransmitter is binding. It’s not completely straightforward (for instance, if the signal decreases, it could mean more neurotransmitter is taking up the receptors OR it could mean there are fewer receptors there in general).
This is a PET image of a healthy control and an early/late-stage AD patient’s brain. This type of PET is glucose-based, so it’s just tracking overall brain metabolism. You can see the early AD brain is already decreased in overall glucose metabolism (how much energy the brain is using), and by the late stage, it is severely decreased. This is likely due to the severe, progressive neurodegeneration that occurs in AD.