Verbal list learning and memory profiles in HIV-infected adults, Alzheimer’s disease, and Parkinson’s disease: An evaluation of the “cortical hypothesis” of NeuroAIDS

HIV+population is getting older because of progress in treatments. Yet, there are concerns that Older HIV+individuals (OHIV+) may be more vulnerable for developing a cortical dementia such as Alzheimer Disease (AD). Our aim was to explore the hypothesis that the cognitive deficit extends to cortical'' functions in OHIV+by comparing serial position effects (SPE) in different groups of participants affected by cortical or subcortical damage. We enrolled a total of 122 subjects: 22 OHIV+ (60 years of age), 31 Younger HIV+ (YHIV+) (<60 years of age), 18 participants with AD, 23 subjects with Parkinson Disease (PD), and 28 healthy subjects. All subjects performed verbal learning tasks (VLT) to explore SPE. Factorial analysis of covariance showed a significant effect of group (p<0.001) and task (Primacy vs Recency) (p<0.001), but no significant group*task (p=0.257) interaction. Compared with healthy subjects (p=0.003), AD had the most severe reduction of Primacy, confirming a primary encoding deficit, while PD confirmed a frontal pattern. OHIV+showed a memory profile similar to that of PD with a worsening of the cognitive performance in comparison with YHIV+. In conclusion, we did not confirm the cortical hypothesis in OHIV+, at least in terms of learning and memory functions.