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. Neuropsychological-impairment 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.

The research described was supported by the following grants from the National Institutes of Health: MH59745, MH62512, and DA12065. The San Diego HIV Neurobehavioral Research Center (HNRC) group is affiliated with the University of California, San Diego, the Naval Hospital, San Diego, and the Veterans Affairs San Diego Healthcare System and includes: Director: Igor Grant; Codirectors: J. Hampton Atkinson, Ronald J. Ellis, and J. Allen McCutchan; Center Manager: Thomas D. Marcotte; Naval Hospital San Diego: Braden R. Hale; Neuromedical Component: Ronald J. Ellis, J. Allen McCutchan, Scott Letendre, Edmund Capparelli, Rachel Schrier; Neurobehavioral Component: Robert K. Heaton, Mariana Cherner, Steven Paul Woods, Sharron Dawes; Neuroimaging Component: Terry Jernigan, Christine Fennema-Notestine, Sarah L. Archibald, John Hesselink, Jacopo Annese, Michael J. Taylor, Brian Schweinsburg; Neurobiology Component: Eliezer Masliah, Ian Everall, T. Dianne Langford; Neurovirology Component: Douglas Richman, David M. Smith; International Component: J. Allen McCutchan; Developmental Component: Ian Everall, Stuart Lipton; Clinical Trials Component: J. Allen McCutchan, J. Hampton Atkinson, Ronald J. Ellis, Scott Letendre; Participant Accrual and Retention Unit: J. Hampton Atkinson, Rodney von Jaeger; Data Management Unit: Anthony C. Gamst, Clint Cushman (Data Systems Manager), Michelle Frybarger, Daniel R. Masys, (Senior Consultant); Statistics Unit: Ian Abramson, Christopher Ake, Deborah Lazzaretto. The views expressed in this article are those of the authors and do not reflect the official policy or position of the Department of the Navy, Department of Defense, or the United States Government.

Notes

¹Correlation match (p < .05): H2 = K3, H4 = K4, H5 = K1, H6 = K6; correlation match (p > .05): H1 = K2, H3 = K5.