How HIV Can Affect the Brain

Very little understand of how HIV can affect the brain. However, today researchers are trying to understand how HIV damages the brain.

People with HIV sometimes have declines in memory and other cognitive abilities, but information about how the virus actually damages the brain has been scarce. A new technique to measure the thickness of the cortex, the outer surface of the brain that contains most of the brain cells, is providing some insight into how HIV affects the brain.

A recent study carried out at UCLA by Paul Thompson and colleagues used MRI scans to image the brain. Using these images they found cortical thinning of up to 20% in visual, motor and frontal regions of the brain in people with HIV, compared to non-infected individuals. Of particular interest is that the degree of cortical thinning in the parietal and frontal lobes is associated with impairments in cognitive function, and with T-cell counts (an index of immune function) in those with HIV.

These striking findings are the first to demonstrate the 3-dimensional nature of brain changes due to HIV infection, and to show the relation between damage in specific brain areas and immune system deterioration. Use of MRI-based maps such as these may provide biological markers of disease progression, and a novel way to gauge the impact of new anti-viral drugs in clinical trials.