Induction and HIV-Associated Neurocognitive Disorders

Antiretroviral medication has improved HIV-related prognosis. Yet HIV-associated neurocognitive disorders (HAND) have substantially increased, leading to decreased quality of life, increased illness severity and mortality. In the research literature, executive dysfunction (e.g. planning difficulties and cognitive inflexibility) has been identified as prominent in HAND, but there has been little analysis of the componential and qualitative aspects underpinning these deficits. Targeted and theory-driven neurorehabilition for HAND is limited due to the lack of this type of detailed information. This study aimed to explore whether induction, a key aspect of executive function, is impaired in HAND, and if so, the underpinning processes causing impairment.

Thirteen participants with HAND and thirteen HIV-negative participants were matched for gender, age, education and reading ability. The HAND population were assessed for current functioning, and compared to the control group on verbal and non-verbal tests of induction. Qualitative analysis was used to derive a componential scoring system for the Brixton Spatial Anticipation Test (non-verbal measure of induction) to qualitatively and quantitatively characterise performance in the HAND group compared to the non-clinical sample.

Results suggest that induction is impaired in HAND. However, initial rule detection appears spared. Processes such as slowed information processing, and lapses in attention and working memory affected induction across the HAND group. Other deficits appeared idiosyncratically: accordingly, no single profile of impairment was identified. This study showed that taking simple measures of executive function at face value does not provide an accurate description of individual performance in HAND. The results are interpreted in the context of a need for componential analyses of neuropsychological tests, generally in research and when interpreting scores in practice