Is HIV disease associated with a discrepancy between premorbid verbal IQ and neurocognitive functions?

Introduction: There is debate about the optimal approach to diagnose neurocognitive impairment in people with HIV disease. The current "gold-standard" uses normative data to determine whether performance is below that of demographically comparable peers. This study investigated the utility of a discrepancy analysis approach, which compares normative neurocognitive performance directly to estimated premorbid intellectual functioning. Method: A total of 570 adults with and without HIV disease completed a comprehensive neurocognitive battery and the Wechsler Test of Adult Reading (WTAR), an oral word reading measure that was used to estimate premorbid verbal IQ. Normative scores for six neurocognitive domains were subtracted from the WTAR standardized score to calculate discrepancy scores where higher scores indicated greater discrepancies. Results: In models adjusting for relevant confounds, an interaction between HIV serostatus and domain discrepancy scores emerged such that persons with HIV had significantly higher discrepancy scores than seronegative participants, specifically in the domains of attention and episodic memory. Of clinical relevance, persons with HIV were two to three times more likely than their seronegative counterparts to have clinically discordant performance relative to premorbid verbal IQ in these domains. Additionally, the standard normative approach and discrepancy analysis method had fair to moderate agreement for classifying attention and episodic memory impairment in the participants with HIV disease. Conclusions: HIV disease is associated with discrepancies between premorbid IQ estimates and the domains of attention and memory, consideration of which may be a clinically useful complement to standard normative approaches to diagnosing HIV-associated neurocognitive disorders.