This marker binds to plaques and fibrous tangles in the brain, which are hallmarks of Alzheimer’s disease and other forms of dementia. They then were able to see the tangles and plaque through positron emission tomography (PET)—which all adds up to a new way of diagnosing dementia's early signs.
Previously, the only way to reliably detect these dementia-related markers in the brains of Down syndrome patients was through autopsy. This brain-scan technique offers a new method for detecting the disorder.
"Brain scan technique gives new hope to diagnose dementia in Down syndrome adults."
This brain scan is particularly helpful to detect Alzheimer’s disease and dementia in Down syndrome adults because it’s more difficult to track the symptoms in these adults in other ways, according to the study, whose senior author is Gary Small, professor at the Semel Institute for Neuroscience and Human Behavior at UCLA.
Comparing normal cognitive function with dementia-impaired function in this population is more challenging, the researchers said.
In the study, researchers administered the chemical marker intravenously and performed PET brain scans on 19 adults with Down syndrome without dementia, 10 healthy control subjects and 10 patients with Alzheimer’s disease. The investigators found more brain tangles and deposits in the adults with Down syndrome when compared with healthy control subjects, and more tangles and deposits in the areas of the brain controlling memory, behavior and reasoning in Down syndrome adults compared with Alzheimer’s patients.
Autopsy studies have shown that all Down syndrome adults eventually develop these plaques and tangles, but rather than memory and cognitive decline, aging Down syndrome adults are more likely to develop behavioral problems.
Researchers next plan to study the benefits of different types of brain scans using various chemical markers.
Down syndrome adults (average age 37), compared to adults with Alzheimer’s disease (average age 66) and healthy control subjects (average age 43). Compared with Alzheimer’s disease patients, Down syndrome participants also showed higher levels of the chemical marker in the areas of the brain relating to memory, behavior and reasoning.