Researchers have developed a brain scan biomarker they call the early-onset Alzheimer's disease signature, and a new study in Neurology, a journal of the American Academy of Neurology, reports that it may predict how quickly a person with mild cognitive impairment goes on to develop dementia. The tool works as a map applied to brain scans, measuring atrophy in the regions that handle memory, language and reasoning - the same regions that shrink more in people with the disease than in people without it.
Early-onset Alzheimer's begins before age 65, striking people who are typically still working, raising children or caring for aging parents. It usually starts with mild cognitive impairment, where thinking and memory problems exceed normal aging but fall short of dementia. Progression to dementia tends to be fast in this group, but the timing differs enormously from one person to the next, which has left clinicians with little to offer patients who want to know what is coming.
That uncertainty is exactly what prompted the work. The study team described the question they hear most often in clinic: when will I lose my independence. Existing methods for predicting the shift from mild cognitive impairment to dementia are limited, and the researchers found that shrinkage measured by their signature functioned as a kind of timer, indicating both when dementia was likely to begin and how rapidly a person moved through that transition.
For patients and families, a reliable estimate of the timeline is not a treatment, but it does shape practical decisions about work, finances, caregiving and legal planning during a window when those choices can still be made. It could also help researchers select participants for trials by identifying those most likely to decline soon. The findings come from a single published study, and further work will be needed to confirm how well the biomarker performs across different patient groups and clinical settings.