A new study, published on July 10 in the online issue of Neurology, focuses on predicting the speed at which individuals with early Alzheimer’s disease will experience cognitive decline. The study also examines how newly approved drugs for Alzheimer’s might slow this decline.
“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 study author Pieter J. van der Veere, M.D., from Amsterdam University Medical Center, Netherlands.
The researchers created models to predict how quickly individuals’ scores would decline on tests of thinking and memory skills. They compared these models with actual results from people over time.
The study included 961 participants with an average age of 65. Of these, 310 had mild cognitive impairment, and 651 had mild dementia. All participants had amyloid-beta plaques in their brains, an early sign of Alzheimer’s disease targeted by the new drugs.
The cognitive test scores range from zero to 30. Scores of 25 and higher indicate no dementia, scores of 21 to 24 suggest mild dementia, scores of 10 to 20 indicate moderate dementia, and scores below 10 signify severe dementia.
At the beginning of the study, people with mild cognitive impairment had an average score of 26.4, which dropped to 21.0 after five years. Those with mild dementia saw their scores decline from 22.4 to 7.8 over the same period.
The models helped predict the rate of cognitive decline but also showed the uncertainty of these predictions.
For half of the people with mild cognitive impairment, the actual test score differed by less than two points from the predicted score. For those with mild dementia, the scores differed by less than three points for half of the participants.
The researchers predicted that a hypothetical person with mild cognitive impairment, a baseline test score of 28, and a certain level of amyloid plaques would reach moderate dementia (a test score of 20 points) after six years.
If a treatment reduced the rate of decline by 30%, this person would not reach moderate dementia until after 8.6 years.
For a hypothetical person with mild dementia, a baseline score of 21, and a certain level of amyloid, the predicted time to reach a score of 15 points was 2.3 years, or 3.3 years if the decline rate was reduced by 30%.
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 related to 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.”
A limitation of the study was that the cognitive tests were not always administered at the same time of day. People with cognitive decline might score lower later in the day when they are more tired. This variability in testing times could affect the results.
The study highlights the importance of personalized prediction models in understanding the progression of Alzheimer’s disease and how treatments might alter the course of cognitive decline.
It provides a foundation for future research aimed at improving the quality of life for those affected by Alzheimer’s and their loved ones.
If you care about Alzheimer’s disease, please read studies that bad lifestyle habits can cause Alzheimer’s disease, and strawberries can be good defence against Alzheimer’s.
For more information about brain health, please see recent studies that oral cannabis extract may help reduce Alzheimer’s symptoms, and Vitamin E may help prevent Parkinson’s disease.
The research findings can be found in Neurology.
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