People with dilated enlarged areas of the brain around small blood vessels may be more likely to develop mental health problems and depression over time than people without these enlarged areas, according to a new study published on January 27, 2021, an online journal Neurology®, the medical journal of the American Academy of Neurology.
Perivascular spaces are involved in clearing waste and toxins from the brain and may be associated with the brain changes associated with aging.
The study included 414 individuals with an average age of 80. Participants took mental tests on thinking and memory skills and were assessed for the presence of depression at the beginning of the study and every two years for eight years. Participants had MRI brain scans to examine for enlarged perivascular spaces in two key areas of the brain at the beginning of the study and then every two years for eight years. The top quarter of those with the highest number of enlarged perivascular spaces were classified as hard cases, compared with those with fewer or no enlarged areas.
“Severe perivascular space disease may be an indication for an increased risk of mental retardation and depression,” said study author Matthew Paradise, MB.Ch.B., M.Sc., of the University of New South Wales in Sydney, Australia. “More research is needed to understand how these enlarged areas develop, as they could be an important biomarker that will help detect dementia early.”
The researchers found that people with the highest number of enlarged perivascular spaces in all areas of the brain were nearly three times more likely to develop dementia during the study than those with fewer or no expanded areas.
97 people, or 24%, were diagnosed with depression during the study. Of the 31 people with severe cases in all areas of the brain, 12, or 39%, were diagnosed with depression.
Those with a large expansion of perivascular spaces in all areas of the brain were also more likely to have a greater decline four years later on their overall psychiatric scores than those with a small or absent enlargement of spaces .
The results followed after researchers adjusted for other factors that may affect either test scores or the development of depression, such as age, high blood pressure, and diabetes. The researchers also noted other signs of disease in the small blood vessels in the brain, which may be a sign of dementia risk.
“These findings suggest that there is an independent mechanism for the perivascular spaces as a biomarker of brain weakness and depression as well as a common symptom of disease in the small vessels,” Paradise said. . “For example, expanded perivascular spaces may act as a biomarker of unbalanced waste clearance in the brain.”
Paradise noted that the study does not prove that enlarged perivascular spaces cause these thought and memory problems over time; it only shows an association.
The limitations of the study include that cognitive test data were only available over four years and that imaging data may 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.
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