When people’s loved ones are diagnosed with the disease, they ask questions about what to expect. We examine new research that looks into cognitive decline and how the new drugs approved for Alzheimer’s could help.
In July 2023, the U.S Food and Drug Administration (FDA) granted full approval for lecanema to treat Alzheimer’s in people who received an early diagnosis. The drug was hailed as ‘groundbreaking’ and since this period it seems research into the disease has only strengthened. Yesterday, 10th June 2024, a new study was published in the online issue of Neurology, the medical journal of the American Academy of Neurology, which looks into the question: Can we predict how fast cognitive decline will occur with early Alzheimer’s?
‘The rate of cognitive decline varies greatly from person to person, and people are very interested in what to expect from the disease in themselves or their loved ones, so better prediction models are urgently needed,’ said Pieter J. van der Veere, M.D of Amsterdam University Medical Centre, Netherland.
To conduct the research, experts developed models to predict how quickly people’s scores would decline on a test of thinking and memory skills. They compared these results with data gathered from real individuals over time. Overall, the team studied 961 people with an average age of 65 and from the group, 310 had mild cognitive impairment and 651 had mild dementia. Every person taking part had the amyloid-beta plaques in their brains which is an indicator of early-onset Alzheimer’s and are targeted by the new drugs.
On the tests scores ranged from zero to 30, with scores of 25 or higher indicating no dementia, and scores lower than 10 indicating severe dementia. The test scores of the people with mild cognitive impairment declined from 26.4 at the beginning of the study to 21.0 five years later. The scores of people with mild dementia declined from 22.4 to 7.8 five years later.
The models created not only helped to predict the rate of cognitive decline, but they also displayed the uncertainty of said predictions. Van der Veere remarked that for half of the people with mild cognitive impairment, the actual test score differed by less than two points from the predicted score. For the people with mild dementia, the scores differed by less than three points for half of the people.
In addition, researchers determined that a hypothetical person with mild cognitive impairment, a baseline test score of 28 and a certain level of amyloid plaques would reach a ‘moderate’ stage of dementia after six years. When a treatment with drugs would reduce the rate of decline by 30%, this person would not reach the stage of moderate dementia until after 8.6 years.
Van der Veere said: ‘We understand that people with cognitive problems and their care partners are most interested in answers to questions like ‘How long can I drive a car?’ or ‘How long can I keep doing my hobby?’ In the future, we hope that models will help make predictions about these questions about quality of life and daily functioning. But until then, we hope these models will help physicians translate these predicted scores into answers for people’s questions.’
He also noted that research is still ongoing into this topic and a limitation of the study was that cognitive tests weren’t always given at the same time of day meaning people could have scored lower if they were tired.
Image: Josh Riemer
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