Longitudinal study of cognitive function in people with HIV and toxoplasmic encephalitis or latent toxoplasma infection.

Background: Neurocognitive impairment (NCI) may occur during and persist even after recovery from HIV-related central nervous system (CNS) co-infections such as toxoplasmic encephalitis (TE). The long-term cognitive effects of TE and latent toxoplomasmic infections (LTI) among persons with HIV (PWH) are unknown. We measured longitudinal effects on neurocognitive functioning in PWH with TE compared to LTI or no toxoplasmal infection.

Methods: PWH (n = 345) followed in two longitudinal cohort studies underwent comprehensive neurocognitive assessments and an anti- toxoplamic immunoglobulin G (IgG) assay. Participants were classified into one of three groups: TE+ ( n  = 39), LTI+ ( n  = 34), LTI- ( n  = 272). The primary outcome was change in neurocognitive function between baseline and 7-year visit.

Results: The mean age was 48 ± 11 years, mean educational level 13 ± 3 years, and 13% were female. TE+ patients were less likely to have undetectable viral loads (≤50 copies/ml) and had lower absolute CD4 + cell count. The TE+ group had the highest prevalence of NCI globally and in domains of verbal, executive function, learning, recall, working memory, processing speed and motor at baseline and at 7-year follow-up. Changes in longitudinal NC function over 7 years were small and did not differ significantly among all groups, except that speed of information processing improved more in TE+ compared with LTI- participants.

Conclusions: PWH with a history of TE had cognitive impairment over a broad range of severity at both baseline and last follow-up. Changes in cognition from baseline to last examination in all groups were minimal and did not differ significantly among the groups with the exception of speed of information processing.