Stellenbosch University researchers have recently discovered that HIV directly affects the brain in the early stages of the infection.
Previously it was unclear as to whether HIV had a direct effect on the brain, but many people with HIV have been known to experience cognitive symptoms like depression and poor memory.
“Our research shows that HIV does have an impact on the brain and that these low-grade cognitive symptoms are likely not just function loss due to patients feeling sick, tired or depressed,” said Dr Stéfan du Plessis, lead author of a series of articles about the research published in “AIDS” and other international journals.
Du Plessis and his team compared the brain activity of people with HIV to those without, using functional resonance imaging (FMRI) – a scan that shows how blood flows to certain parts of the brain when someone is performing certain tasks or is experiencing certain emotions.
The team discovered that HIV-positive participants had less blood flow in the striatal region of the brain while performing tasks involving higher motor functions. They also noticed that HIV-positive patients had little action and blood flow to the nucleus accumbens – the section of the brain involved with motivation, apathy and enthusiasm – when performing a task involving a monetary reward.
“The FMRI scans show how the HI virus affects important parts of the brain involved with motivation. We theorise that this could happen to such an extent that patients are often simply not motivated enough to take their medication, or even get out of bed,” said Du Plessis, who conducted the research as part of his PhD in psychiatry.
Researchers also studied the structure of the frontal cortex, a brain region that atrophies in HIV patients. They discovered a link between the levels of atrophy and brain functional impairment – the thinner the frontal lobe was, the lower the levels of function.
“The study highlights a previously unknown functional effect that HIV has on the brain. We hope that these results will stimulate further studies to test the effects of anti-retrovirals, or other interventions, that could improve brain function and therefore the lives and well-being of patients with HIV,” said Du Plessis.
From subtle impairment detectable only through sophisticated cognitive tests, to severe psychosis, earlier studies have shown that up to 50% of HIV-positive people may suffer from cognitive impairment.
Many patients suffered from HIV-related dementia before the introduction of anti-retroviral therapy. ART has noticeably improved symptoms of dementia in people who are HIV-positive since.