Study finds subtle brain damage in some HIV patients on dr...( t response times were equal could mean ...),Health

To assess where HIV-triggered damage might be occurring in the brain, Chao examined the relationship between the strength of CNV activity during the reaction-time test, with MRIs of study subjects' caudate nuclei, a substructure of the basal ganglia. She found that the weaker the CNV among HIV-positive participants the more reduced the caudate volume. "The basal ganglia is a part of the brain known to carry one of the highest viral burdens," she says. Because there is also evidence that the CNV partially originates in this part of the brain, finding this correlation [between weak CNVs and reduced caudate volume] is a nice tie-in that gives us more confidence in our conclusions about where and how damage is occurring."

MRI measurements also revealed that the volume of the brain structure known as the thalamus was smaller both in viremic and in virally suppressed participants than in controls, an indication of damage in this region. The thalamus serves as a relay station for sensory information.

Results of the behavioral tests were mixed. On several tests, there were no differences between the three groups. And on all tests virally suppressed patients scored as well as the control group. But on three tests, scores of viremic participants were significantly lower than those of virally suppressed participants and the controls. "People with lower scores like these might not be able to do such things as type as fast as before, and they might not have as good attention or mental flexibility as the people who scored higher," Chao says. "But unless they were challenged daily, this is something they probably wouldn't notice, because these are the kinds of things that are more easily compensated for."

Previous studies have already shown that when viral load is reduced by antiret
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Contact: Liese Greensfelder
lgreensfelder@pubaff.ucsf.edu
415-476-2557
University of California - San Francisco
13-Nov-2003