Interactive effects of HIV/AIDS, body mass, and substance abuse on the frontal brain: a P300 study

Abstract

In view of the rising prevalence of an overweight body mass among patients living with human immunodeficiency virus/acquired immune deficiency syndrome (HIV/AIDS), clinicians must now be mindful of possible adverse outcomes resulting from the co-occurrence. The present study was designed to examine the additive and interactive effects of HIV/AIDS and an excess body mass, as well as the additional contributions of substance abuse or dependence. The dependent variable was brain function estimated by the measurement of P300 electroencephalographic potentials. P300 potentials were recorded during a task designed to elicit subcomponents with frontal (P300a) and both frontal and non-frontal (P300b) generators. Analyses revealed greater frontal P300a latencies among the 102 HIV-1 seropositive versus the 68 seronegative participants. In addition, frontal P300a latency was further increased by a synergistic interaction of HIV-1 serostatus with a body mass index (BMI)≥25 kg/m². A history of substance abuse/dependence did not alter these changes. However, it did combine with HIV/AIDS to produce a smaller P300a amplitude than was seen in participants with neither disorder. The findings suggest that white matter changes accompanying an excess BMI may exacerbate those that attend HIV/AIDS and thereby slow down frontal brain function. Substance abuse, likewise, interacts with HIV/AIDS but may impair frontal brain function via a different mechanism.

Copyright © 2009 Elsevier Ltd. All rights reserved.

Figures

Figure 1

P300a amplitude in microvolts (+1 SEM) at the Fz electrode. Note the underadditive interaction of HIV/AIDS and substance abuse/dependence. The effects of body mass on P300a amplitude were not statistically significant and are therefore not shown.

Figure 2

Event related potentials at Fz and Pz elicited by the rare nontarget stimulus. The waveforms are averaged within groups and sorted by HIV-1 serostatus and substance abuse treatment history. P300a is the prominent positive peak at approximately 400 ms following stimulus onset.

Figure 3

P300a latency in milliseconds (+1 SEM) at the Fz electrode. Note the synergistic interaction of HIV/AIDS and BMI. The effects of substance abuse treatment history were not significant.

Figure 4

Scatterplots illustrating the relationship between BMI and Fz P300a latency separately for the HIV− and HIV+ groups. For this analysis, Fz P300a latency is the standardized residual after the variance association with depression level (BDI-II score); childhood Conduct Disorder symptoms, and alcohol (MAST) and drug abuse (DAST-10) problems; and age was removed. The figure demonstrates a significant increase in Fz P300a latency as a function of BMI in the HIV+ group. This relationship is absent in the seronegative group.