Revision History

A 25-year study of 290 adults over 80 with the memory of 50-year-olds has identified striking biological differences — from doubled neurogenesis rates to resistance against tau protein tangles — but the field faces hard questions about small sample sizes, lack of diversity, and whether these findings can translate into treatments for the 7.2 million Americans living with Alzheimer's. Critics argue the focus on biological outliers risks diverting attention from the social determinants — poverty, chronic stress, educational access — that shape dementia risk for the broader population.