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 if processing speed mediated any of the relationships between cognitive and non-cognitive 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.

Working Memory, Reading and Math Fluency in Children with the Human Immunodeficiency Virus (HIV+)

“…Cohen's d = .64, a 'medium' effect. These findings agree with those of Fellows et al (2014) who found that information processing skills in persons living with HIV were poorer for than controls who where HIV negative.…”

Multicomponent analysis of a digital Trail Making Test

“…Researchers have also developed and utilized derived scores in an attempt to better isolate cognitive processes associated with TMT-B performance (Lamberty et al, 1994; Lange, Iverson, Zakrzewski, Ethel-King, & Franzen, 2005; Salthouse, 2011). The three most common methods are subtracting total time to complete TMT-A from total time to complete TMT-B (B–A); the ratio of B to A (B:A), or the residual of TMT-B after it has been regressed on Part A (BrA; Fellows, Byrd, & Morgello, 2014; Fellows & Schmitter-Edgecombe, 2015; Salthouse, 2011). In a principal components analysis, the BrA derived score loaded on the same component as CLOX (Royall, Cordes, & Polk, 1998) and the Behavioral Assessment of the Dysexecutive Syndrome Zoo map subtest (Wilson, Alderman, Burgess, Emslie, & Evans, 1996), which provides further support for this index as a measure of more complex executive functions (Fellows & Schmitter-Edgecombe, 2015).…”

Cognitive impairment in HIV and HCV co-infected patients: a systematic review and meta-analysis

“…A possible explanation for greater impairment in the coinfected patients may be the higher risk of neurotoxicity due to CNS insults by both viruses in fronto-striatal areas. Particularly, high levels of HIV have been found in the basal ganglia (notably the substantia nigra) and fronto-cortical areas (Kumar, Borodowsky, Fernandez, Gonzalez, & Kumar, 2007), and it has been shown that fronto-striatal neuronal circuitry mediates processing speed (e.g., Fellows, Byrd, & Morgello, 2014;Kumar, Ownby, Waldrop-Valverde, Fernandez, & Kumar, 2011;Salthouse, 1996). Additionally, there is evidence that fronto-striatal circuits are rich in dopaminergic activity and it is hypothesised that dopamine depletion exacerbates processing speed impairment in HIV (Kumar et al, 2011).…”