Cognitive mechanisms of switching in HIV-associated category fluency deficits

Abstract

HIV infection is associated with deficits in category fluency, but the underlying cognitive mechanisms of such impairments have not been determined. Considering the preferential disruption of the structure and function of frontostriatal circuits in HIV disease, the present study evaluated the hypothesis that HIV-associated category fluency deficits are driven by impaired switching. Study participants were 96 HIV-infected individuals and 43 demographically comparable healthy comparison volunteers who were administered a standard measure of animal fluency and an alternating category fluency task (i.e., fruits and furniture) in a randomized order. Consistent with prior research on letter fluency, HIV infection was associated with greater impairments in switching, but not semantic clustering within the animal fluency task. Moreover, a significant interaction was observed whereby the HIV-associated deficits in switching were exacerbated by the explicit demands of the alternating fluency task. Across both fluency tasks, switching demonstrated generally small correlations with standard clinical measures of executive functions, working memory, and semantic memory. Collectively, these findings suggest that HIV-associated category fluency deficits are driven by switching impairments and related cognitive abilities (e.g., mental flexibility), perhaps reflecting underlying neuropathology within prefrontostriatal networks.

Keywords:

• Cognitive processes
• Human immunodeficiency virus
• Neuropsychological assessment
• Nouns
• Verbal fluency

This research was supported by National Institute of Mental Health Grants R01-MH73419 to S. P. Woods and P30-MH62512 to I. Grant. 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. The authors extend their gratitude to Nancy Anderson for her assistance with the data entry and to Ofilio Vigil, Lisa M. Moran, Sarah Gibson, and Shannon LeBlanc for their help with data collection and coding. The 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 it 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, David J. Moore, Steven Paul Woods; Neuroimaging component: Terry Jernigan, Christine Fennema-Notestine, Sarah L. Archibald, John Hesselink, Jacopo Annese, Michael J. Taylor, Brian C. 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), Daniel R. Masys (Senior Consultant); Statistics Unit: Ian Abramson, Christopher Ake, Florin Vaida.