The Gerontological Society of America has published "Understanding Breakthroughs in Brain Health: Top 10 Articles of 2025," the newest entry in its Insights & Implications in Gerontology series. Rather than a single study, the report is a curated selection of the year's most consequential research on cognitive decline, dementia detection, and brain health across the lifespan, assembled with primary care clinicians as the intended audience.
The numbers behind that focus are hard to ignore. Alzheimer's disease affects roughly 7.2 million Americans aged 65 and older, about 11 percent of that age group, and the figure is climbing as the population ages. Health and long-term care costs reached an estimated $384 billion in 2025, on top of $413 billion worth of unpaid care provided by some 12 million family members and friends. Yet the disease is still substantially underdiagnosed, especially at the early stages when intervention has the most to offer.
One finding cited in the report captures the gap: on average, 3.5 years pass between the first symptoms and a formal dementia diagnosis. That delay can close the window on disease-modifying therapies and push back the practical work of care planning. Only 8 to 11 percent of mild cognitive impairment cases are identified early, and the report notes that underdiagnosis falls hardest on Black and Hispanic patients.
Soo Borson, MD, co-lead of the BOLD Public Health Center of Excellence on Early Detection of Dementia and a professor at USC's Keck School of Medicine, who served on the report's expert advisory panel, pointed out that primary care is where most people with dementia are first diagnosed and where most of their care happens. The report's argument is that clinicians in those settings already have enough evidence to act sooner and more confidently, and that the bottleneck is systematic change in how primary care practices approach cognitive screening.