Brain thinning detected before dementia in people under 65

An observational study examined 292 people under 65 with brain scans and spinal-fluid tests. Researchers tested for amyloid-beta and a modified form of tau, proteins used as Alzheimer’s markers. They defined a thinning pattern in the brain’s outer layer by comparing people with test-confirmed Alzheimer’s dementia against a reference group with subjective cognitive decline—self-reported worsening of thinking—who tested negative for both markers.

In mild cognitive impairment, which involves problems with memory or thinking, thinning was more extensive when both markers were positive than when only amyloid was positive. In subjective cognitive decline, localised thinning was detected with both markers positive, but no structural changes were detected with only amyloid positive. Thinning was associated with memory for events and spatial information in mild cognitive impairment. No links between brain structure and thinking performance were found in subjective cognitive decline.