Variable patterns of neuropsychological performance in HIV-1 infection

Abstract

Based upon prior findings with group means, a "prototypical pattern" of neuropsychological results with HIV infection has emerged: impaired executive functioning, motor skills, speed of information processing, and learning, with intact memory retention, most language skills, and visuospatial functioning. We examined neuropsychological results from 553 HIV+ adults to determine the number of patterns seen among individuals with HIV infection. Factor analysis of a relatively comprehensive neuropsychological battery identified 6 component factors: verbal memory (VeM), visual memory (ViM), processing speed (PS), attention/working memory (A/ WM), executive function (EF), and motor (M). These factor scores were submitted to hierarchical cluster analysis, to determine the appropriate number of clusters or patterns in the cohort. Final cluster membership was then determined by K-means analysis, based on the Lange, Iverson, Senior, and Chelune (2002) method. A 6-cluster solution was found to be most appropriate. The definitions of the clusters were based upon ipsative scoring of factor scores to indicate relative strengths and weaknesses (independent of overall level of performance): Cluster 1: strong EF; Cluster 2: strong M, weak VeM and EF; Cluster 3: strong PS, weak ViM and EF; Cluster 4: strong VeM, weak M; Cluster 5: strong A/WM; Cluster 6: strong VeM, weak EF. Neuropsychologicalimpairment rates differed across clusters, but all 6 clusters contained substantial numbers of impaired and unimpaired individuals. Cluster membership was not explained by demographic variables or psychiatric or neuromedical confounds. Thus, there does not appear to be a single, prototypical pattern of neuropsychological impairment associated with HIV infection for this battery of representative neuropsychological tests.In using neuropsychological tests for diagnostic purposes, clinicians typically evaluate a range of abilities and then compare the pattern of results with expectations for various types of brain disorders. Although these decisions are made for individual patients, most of the research concerning patterns of impairment considered prototypical of disorders involves analysis of group averages rather than examination of individual performance. This invites the possibly unwarranted assumption that patterns of group means on tests apply to most or all of the individuals within the groups.For example, in general, studies of individuals infected with HIV suggest a prototypical pattern involving poor attention and working memory, speed of information processing, learning, executive functions, and motor skills, but with relatively intact language skills, visuospatial skills, memory (delayed retention), and sensory-perceptual skills (Heaton et al., 1995;Reger, Welsh, Razani, Martin, & Boone, 2002;Sahakian et al., 1995). This pattern is consistent with neuropathological and neuroimaging evidence of preferential involvement of fronto-striatal brain areas in individuals infected with HIV (Pomara, Crandall, Choi, Johnson, & Lim, 2001...

Neurocognitive profiles of marginally housed persons with comorbid substance dependence, viral infection, and psychiatric illness

“…For illustrative purposes, Figure 2 provides corresponding corrected T-score profiles based upon the established normative test references. Profiles are described in terms of strengths and weaknesses when a given mean differs from the overall mean score (across the six neurocognitive variables) of its respective profile, by at least 0.5 absolute standard deviations (see Dawes et al, 2008). Cluster 1, the smallest group, is characterized Figure 1.…”

Cortical brain atrophy and intra-individual variability in neuropsychological test performance in HIV disease

“…The pattern of neuropsychological deficits in HIV disease has been described as variable, or “spotty” (Butters et al 1990), with impairment reported across various cognitive domains, including memory, attention and working memory, language (fluency), psychomotor processing, and executive functioning (Woods et al 2006; Dawes et al 2008). Aside from relatively consistent deficits in psychomotor functioning, there does not appear to be a single “prototypical pattern” of neuropsychological impairment associated with HIV infection (Dawes et al, 2008), possibly due to the variable underlying neuropathology (Everall et al 2005).…”

“…Aside from relatively consistent deficits in psychomotor functioning, there does not appear to be a single “prototypical pattern” of neuropsychological impairment associated with HIV infection (Dawes et al, 2008), possibly due to the variable underlying neuropathology (Everall et al 2005). …”

Effects of information processing speed on learning, memory, and executive functioning in people living with HIV/AIDS

“…As complex HIV populations age, diffuse impairments in processing speed, learning, memory, motor ability, and executive functioning are being described (Baldewicz et al, 2004; Heaton et al, 2011; Reger, Welsh, Razani, Martin, & Boone, 2002). Although processing speed is still an important aspect of HAND, CART-era cognitive impairments may lack a distinctive diagnostic pattern (Dawes et al, 2008) and clear pathophysiologic mechanism (Lindl, Marks, Kolson, & Jordan-Sciutto, 2010; McArthur, Steiner, Sacktor, & Nath, 2010). Thus, understanding the genesis of diffuse HIV-associated cognitive abnormalities, and the potential relatedness of components of the cognitive syndromes, is important in advancing our understanding of CART-era impairments, as it may provide insights as to whether one, or multiple neural insults instigate the patterns of deficits observed in HIV populations.…”