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

Abstract

Introduction: It is unclear whether or to what degree literacy, aging, and other neurologic abnormalities relate to cognitive deficits among people living with HIV/AIDS in the combined antiretroviral therapy (CART) era. The primary aim of this study was to simultaneously examine the association of age, HIV-associated motor abnormalities, major depressive disorder, and reading level with information processing speed, learning, memory, and executive functions, and to determine whether processing speed mediated any of the relationships between cognitive and noncognitive variables. Method: Participants were 186 racially and ethnically diverse men and women living with HIV/AIDS who underwent comprehensive neurological, neuropsychological, and medical evaluations. Structural equation modeling was utilized to assess the extent to which information processing speed mediated the relationship between age, motor abnormalities, major depressive disorder, and reading level with other cognitive abilities. Results: Age, motor dysfunction, reading level, and current major depressive disorder were all significantly associated with information processing speed. Information processing speed fully mediated the effects of age on learning, memory, and executive functioning and partially mediated the effect of major depressive disorder on learning and memory. The effect of motor dysfunction on learning and memory was fully mediated by processing speed. Conclusions: These findings provide support for information processing speed as a primary deficit, which may account, at least in part, for many of the other cognitive abnormalities recognized in complex HIV/AIDS populations. The association of age and information processing speed may account for HIV/aging synergies in the generation of CART-era cognitive abnormalities.

Keywords:

• Information processing speed
• Memory
• Executive function
• Structural equation model
• Human immunodeficiency virus

The authors thank the staff and participants of the Manhattan HIV Brain Bank.

This research was supported by the National Institutes of Health [grant number U01MH083501], [grant number U24MH100931]. Statistical consultation was provided by Conduits, the Biostatistics, Ethics and Research Design Core at the Icahn School of Medicine at Mount Sinai. Conduits is supported by the National Center for Research Resources and the National Center for Advancing Translational Sciences of the National Institutes of Health [grant number UL1TR000067].