Verbal Fluency Component Analysis in Adults with HIV/AIDS

ABSTRACT

The present study examined the impact of HIV disease severity, depressed mood, and highly-active antiretroviral therapy (HAART) on verbal fluency components in a sample of adults with HIV-infection. Switching and clustering have been identified as dissociable components that contribute to performance on tests of phonemic and semantic verbal fluency. Advanced HIV-infection was predicted to differentially impair switching. Switching has been shown to be reduced in disorders affecting frontal-striatal systems (e.g., Parkinson's disease). Verbal fluency protocols (FAS and Animals) of 217 adults with HIV-infection were scored for total switches and average cluster size following the method of Troyer, et al. (1998). Component scores were compared to published norms. Analysis of variance (ANOVA) was used to examine the impact on switching and clustering performance of (1) HIV disease severity (presence of AIDS diagnosis) and depressed mood, and (2) AIDS diagnosis and medication status (current HAART therapy). FAS switching was more often impaired in participants with AIDS. Depressed mood did not affect switching. Neither AIDS diagnosis nor depressed mood was associated with clustering performance. Participants with an AIDS diagnosis who were receiving HAART showed better performance on FAS switching relative to participants with AIDS who were not taking antiretroviral medication. FAS switching appears to be sensitive to cognitive changes associated with advanced HIV-infection. Further research is needed to determine if switching is a specific marker of frontal-striatal dysfunction in this population.

ACKNOWLEDGEMENTS

This work was supported by grants from the Canadian Foundation for AIDS Research (CANFAR) and the Ontario HIV Treatment Network (OHTN) and a Career Scientist Award from the OHTN to Sean B. Rourke. Colleen Millikin was supported by a Post-Doctoral Fellowship from the OHTN. This work was presented, in part, at the 31^st Annual Meeting of the International Neuropsychological Society, Honolulu, Hawaii, February 2003.

Notes

1 For the purposes of the present study, individuals who were asymptomatic but had a history of a CD4 lymphocyte count below 200 (CDC93 A3) were not classified as having AIDS because research suggests that the neuropsychological test performance of the A3 subgroup is similar to that of other asymptomatic individuals (Basso, M. R., & Bornstein, R. A. (2000). Effects of immunosuppression and disease severity upon neuropsychological function in HIV infection. Journal of Clinical & Experimental Neuropsychology, 22 (1), 104–14.)

2 A score > 10 on the BDI cognitive-affective scale was chosen as the cutoff for depression since this score has demonstrated sensitivity (Beck, A. T., & Steer, R. A. (1993). Beck Depression Inventory Manual. San Antonio, TX: The Psychological Corporation.) and avoids possible confounding effects of somatic symptoms of HIV infection.