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Publication Abstract Display
Type: Poster
Title: Assessing callosal fiber tracts in methamphetamine dependence and HIV infection.
Authors: Bolden K, Brown GG, Woods SP and Grant I
Date: 02-06-2013
Abstract:Background: There is a higher prevalence of METH dependence (METH+) in individuals diagnosed with HIV (HIV+). Both disorders have degenerative effects on overlapping brain systems, but the synergetic effects of comorbid diagnosis are not well understood. Investigations of neurological integrity in both HIV+ and METH+ have shown white matter injury in the corpus callosum (CC) for both disorders. Methods: 20 HIV+ participants, 19 METH+ participants, 10 HIV+/METH+ comorbid, and 20 HIV-/METH- participants underwent MRI scanning (including diffusion tensor imaging, DTI). We used a tractography method to generate the fibers going through the 3 sections of the CC (splenium, genu, and body). We analyzed Fractional Anisotropy (FA) for all 4 groups in the aforementioned regions. Results: We performed a 2X2 repeated measures ANOVA examining the effects of group and region on FA. We did not find an interaction of diagnosis and the 3 regions of the CC. We did find a statistically significant effect of HIV on FA with a medium to large effect size (p<.05, η2=.122) across subregions of the CC, though there was a numerically larger effect in the body of the CC. We did not find a main effect of METH on FA, nor did we see a significant interaction between HIV and METH (p>.05, η2< .001). However, a post-hoc range test revealed the FA of the HIV+/METH+ group fell in between the HIV+ and METH+ groups, with METH+ having slightly higher FA than HIV-/METH- and HIV+ having significantly lower FA than HIV-/METH- and METH+. Conclusion: We found significantly lower FA in the HIV+ group compared to HIV-/METH-, whereas METH+ had slightly higher FA than HIV-/METH-. Moreover, we did not find an interaction between HIV and METH abuse, which may indicate opposing, but nevertheless additive and detrimental effects of comorbid diagnosis on FA in the CC. These findings may suggest differences in the types white matter injury associated with HIV infection and METH abuse and further research on the neural mechanisms of the possible opposing effects of HIV and METH should be undertaken.

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