As people age, changes in the tiniest blood vessels in the brain, a condition called cerebral small vessel disease, can lead to thinking and memory problems and stroke. These changes can also affect the blood-brain barrier, a layer of cells that protect the brain from toxins circulating in the blood. Now a new study has found that people with cerebral small vessel disease who have blood-brain barrier leakage had more brain tissue damage over two years than people with less blood-brain barrier leakage. The study is published in the March 24, 2021, online issue of Neurology.