Script Generation and Multitasking in HIV - 1 Infection : Implications for Everyday Functioning

It is well established that 30-50% of persons infected with HIV-1 exhibit neuropsychological impairment. A subset of individuals with HIV-associated neurocognitive impairment experience related deficits in "real world" functioning (i.e., independently performing instrumental activities of daily living \[IADL\]). While performance-based tests of everyday functioning are reasonably sensitive to HIV-associated IADL declines, questions remain regarding the extent to which these tests' highly structured nature fully captures the inherent complexities of daily life. Script generation and multitasking are two constructs that may be of particular relevance to the prediction of everyday functioning in HIV, which ostensibly requires the efficient generation and execution of script-based action schemas to achieve specific goals, as well as the ability to plan, prioritize, and manage multiple activities. The present study examined script generation and multitasking performance in 60 individuals with HIV-1 infection (HIV+) and 26 demographically comparable seronegative healthy adults (HIV-). HIV+ individuals demonstrated worse overall multitasking performance and an elevated number of script generation errors as compared to the HIV-sample. Within the HIV+ sample, script generation errors and multitasking impairments were modestly associated with deficits on standard clinical measures of executive functions, episodic memory, and information processing speed, providing preliminary evidence for convergent validity. More importantly, multivariate prediction models revealed that multitasking, but not script generation, deficits were uniquely predictive of dependence in IADL, independent of depression and global cognitive impairment. Classification accuracy statistics showed that multitasking provided excellent sensitivity (86%) but modest specificity (57%) in predicting IADL declines. Taken together, these data indicate that the assessment of multitasking ability may ultimately provide an important adjunct to traditional neuropsychological testing in the evaluation of everyday functioning in HIV+ individuals. Findings may also inform the development of compensatory strategies to minimize the functional impact of cognitive deficits in persons living with HIV infection. eScholarship provides open access, scholarly publishing services to the University of California and delivers a dynamic research platform to scholars worldwide. 2009 iii The Dissertation of James Cobb Scott is approved, and it is acceptable in quality and form for publication on microfilm and electronically.