Neuropsychological function and cerebral metabolites in HIV-infected youth

The effects of HIV on brain metabolites and cognitive function are not well understood. Sixteen HIV+youths (15 vertical, 1 transfusion transmissions) receiving combination antiretroviral therapy and 14 age-matched HIV- youths (13-25 years of age) were evaluated with brain two-dimensional (2D) magnetic resonance spectroscopy (MRS) at 3 Tesla (T) and a neuropsychological battery that assessed three cognitive domains (attention/processing speed, psychomotor ability, and executive function). The relationship between brain metabolite ratios and cognitive performance was explored. Compared to HIV- controls, HIV+ subjects had higher sycllo-inositol (Scy)/total creatine (tCr) (+32%, p = 0.016) and higher Scy/total choline (tCho) (+31%, p = 0.018) on 2D-MRS in the right frontal lobe. HIV+ subjects also had higher glutamate (Glu)/tCr (+13%, p = 0.022) and higher Glu/tCho (+15%, p = 0.048) than controls. HIV+ subjects demonstrated poorer attention/processing speed (p = 0.011, d = 1.03) but similar psychomotor and executive function compared to HIV- controls. The attention/processing score also correlated negatively with the ratio of N-acetylaspartate (NAA) to tCr on 2D-MRS (r = -0.75, p = 0.0019) in the HIV- controls, but not in the HIV+ subjects (Fisher's r-z transformation, p < 0.05). Our results suggest that attention/processing speed is impacted by early HIV infection and is associated with right hemisphere NAA/tCr. Scy and Glu ratios are also potential markers of brain health in chronic, lifelong HIV infection in perinatally infected youths receiving antiretroviral therapy.