Cerebral “Dirty-Appearing” White Matter and Its Link to Cognitive Decline and Dementia Risk

Background

Cerebral white matter changes are common in older adults and are often seen on brain MRI as areas of signal abnormality. Two patterns are especially relevant in aging and cerebrovascular disease: white matter hyperintensities, which are usually more clearly defined, and diffusely abnormal white matter, often described as “dirty-appearing” white matter. Diffusely abnormal white matter, or DAWM, is a subtler MRI finding that may reflect early or mild tissue injury in the brain’s white matter.

White matter contains the nerve fibers that help different parts of the brain communicate. When this tissue is affected by chronic small vessel disease, it can become less efficient, and over time this may contribute to slower thinking, problems with memory, and eventually dementia. However, not every white matter abnormality has the same clinical meaning. The study summarized here asked an important question: in community-dwelling older adults who had relatively limited baseline small vessel disease, is DAWM linked to present-day cognition, future cognitive decline, or later dementia risk?