Large Perivascular Spaces may predict dementia risk

A total of 97 people, or 24%, were diagnosed with dementia during the study. Of the 31 people with severe cases in both areas of the brain, 12 people, or 39%, were diagnosed with dementia.

The people with severe enlargement of perivascular spaces in both areas of the brain were also more likely to have greater decline four years later on their overall scores of cognition than the people with mild or absent enlargement of spaces.

The results persisted after researchers adjusted for other factors that could affect either scores on tests or the development of dementia, such as age, high blood pressure and diabetes. The researchers also took into account other signs of disease in the small blood vessels in the brain, which can also be a sign of risk of dementia.

"These results suggest that there is an independent mechanism for the perivascular spaces as a biomarker of cognitive impairment and dementia apart from being a general marker of disease in the small vessels," Paradise said. "For example, enlarged perivascular spaces may be a biomarker of impaired waste clearance in the brain."

Paradise noted that the study does not prove that enlarged perivascular spaces cause these thinking and memory problems over time; it only shows an association.

Limitations of the study include that cognitive test data was only available over four years and that imaging data could have missed some enlarged perivascular spaces in the brain.

The study was supported by the Australian National Health and Medical Research Council and the Josh Woolfson Memorial Scholarship.