Study Suggests HIV-Associated Neurocognitive Disorders Can Be Predicted Before Symptoms Appear

The results of a study of “cognitively normal” HIV-infected adults aged 50 and over show that behavioral and neuroimaging tests could enable clinicians to identifying noninvasive diagnostic predictors of HIV-Associated Neurocognitive Disorders (HAND).

The increasing prevalence of HIV among older adults increases the urgency of understanding the mechanisms causing HAND, and the importance of finding predictors before clinical manifestation of HAND symptoms.

The study results were published in the November 17, 2015, online issue of the journal AIDS Care, by researchers at the Georgetown University Medical Center (Washington DC, USA).

The neuroscientists used a task-switching paradigm to observe the behavioral, and neural profile of impaired cognitive control in older HIV+ adults (n = 14, 9 HIV+). The subjects were cued (unpredictably), and asked to perform a face-gender, or word-semantic task on images with a superimposed face and word. While the subjects were performing the task the researchers performed functional Magnetic Resonance Imaging (fMRI) scans, and recorded behavioral data. They found that HIV-infected adults were significantly slower than uninfected control subjects in adapting to change in task demand. The subjects showed comparable performance in standard neuropsychology tests designed to probe executive deficits.

The researchers were able to quantify the behavioral impairments related to a difference in fMRI signal at the dorsal Anterior Cingulate Cortex (ACC) region of the brain. According to the researchers, the study results imply that cognitive impairments in older HIV+ adults could be more widespread than know, that ACC is useful in finding cognitive impairments, and that cognitive neuroscience paradigms could be more useful for finding HIV-associated neurocognitive impairments, than standard neuropsychology tests.

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Georgetown University Medical Center