Semantic Memory in HIV-Associated Neurocognitive Disorders: an Evaluation of the "Cortical" versus "Subcortical" Hypothesis
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Abstract
While HIV- associated neurocognitive disorders (HAND) have historically been characterized as a subcortical process, there is some evidence to suggest that the cortical regions that support semantic memory may also be affected. The current study examined the effects of HAND on semantic memory. Participants were (N = 459) separated into three groups based on neurocognitive status defined by the Frascati criteria: HIV+ individuals with HAND (n = 85), HIV+ individuals without HAND (n= 191), and HIV negative individuals (n=183). All participants completed the Boston Naming Test (BNT) and the Famous Faces subtest of the Kauffman Adolescent and Adult Intelligence Test (KAIT). Analyses of errors committed on the BNT were conducted to further characterize the nature of semantic memory differences across groups. Linear regressions revealed a significant adverse effect of HAND on total scores on the BNT and the KAIT (all ps < .01). Analyses of BNT errors showed that individuals with HAND committed increased rates of semantically-related errors as compared to the other two groups (all ps < .05). However, there were no group differences in rates of visually based errors, more commonly observed in subcortical diseases (all ps > .10). Findings regarding the cognitive correlates of semantic memory show that executive (rs = -.24, p = .02), speed of processing (rs = -.31, p = .004), and learning (at trend level) domains were shown to be associated with BNT performance, while only the learning domain (rs = -.28, p = .01) was significantly related to KAIT scores within the HAND+ group. Results suggest that HAND may impose adverse effects on individuals’ object naming and identification abilities and suggest that there are mild semantic deficits in HAND that parallel traditional cortical diseases such as Alzheimer’s Disease.