In two Indigenous communities living pre-industrial lifestyles in the Bolivian Amazon, dementia is remarkably uncommon. However, a new longitudinal study reveals why earlier estimates told only part of the story.

Among the Tsimané and Mosetén communities, dementia incidence, or the rate of new cases, didn’t dramatically differ from rates in U.S. and northern European populations, especially for individuals under 80 years old. Shorter survival after dementia develops appears to play a significant role in why dementia prevalence – the total proportion of people living with the disease at a given time – in the Tsimané and Mosetén populations is unusually low.

“The surprising finding was that there weren’t big differences in dementia incidence,” said lead author Margaret Gatz, a professor of psychology and gerontology at USC and a senior scientist at the USC Center for Economic and Social Research. “That challenges us to identify the risk factors for developing dementia in the Tsimané population.”

Salk researchers establish microprotein atlas from human frontal cortex samples with and without Alzheimer’s disease, identifying more than 1,000 new microproteins, including one that may contribute to age-related dysfunction in the brain’s resident immune cells. The publicly available resource will allow scientists to consider microproteins in their studies, lighting the path to new potential targets for neurodegenerative diseases. The study may also be used as a framework for building additional microprotein atlases for other tissues and disease areas.

A new study from Korea investigates whether plasma p-tau217 can help track biological responses to lecanemab in people with early Alzheimer’s disease. By following changes in this blood-based biomarker and cognitive measures during treatment, researchers found that greater p-tau217 reductions were associated with more favorable cognitive trajectories. The findings highlight the potential of repeated blood-based biomarker measurements for monitoring treatment response and supporting more individualized care in Alzheimer’s disease.