Hernan Hernandez and colleagues have developed a cross-national “speech clock” that can track biological aging and markers of dementia across a large and diverse sample of Latin American populations. The speech clock could offer a low-cost, culturally relevant aging biomarker for people in low-resource settings who may not have access to more expensive brain- and blood-based biomarkers, the researchers suggest. Features of natural speech are impacted by biological aging, including voice affect, timing and pauses, and changes in semantic memory that affect vocabulary. Hernandez et al. decided to see whether these features could be used to estimate speech age gaps (SAGs) that track deviations between a person’s chronological and speech-predicted age. They gathered speech data from 2,928 people across Argentina, Chile, Mexico, Peru, and Colombia, including people with mild cognitive impairment, Alzheimer’s disease, and non-language/language-dominant frontotemporal dementia. They found that composite speech features could capture an aging signal that could predict SAGs. Different cognitive diagnoses could be identified by SAGs, and SAGs were also associated with biological biomarkers such as plasma levels of a tau protein associated with neurodegenerative disease. “Our findings suggest that speech is not merely a surface-level cognitive marker, but rather a functional expression of systemic aging, integrating biological, motor, cognitive, semantic, affective, and social processes across the life span,” the authors write.

University of Missouri researchers discovered that bullfrogs can produce ketone bodies directly in their brains when glucose levels are low, creating a built-in backup fuel source that helps keep critical neural functions running during energy shortages. The finding not only explains how bullfrogs survive the extreme conditions of winter dormancy but could also provide new insights into human neurological disorders such as Alzheimer's disease, ALS and schizophrenia, which are linked to impaired brain energy metabolism.