Working Memory Structure in Atypical Development: HIV-infected and HIV-exposed, Uninfected School Beginners

Cognitive impairment in children and adolescents living with perinatal HIV disease in the ART era: a meta-analysis

Background

Despite improved survival and overall health outcomes from modern antiretroviral therapy (ART), children and adolescents living with HIV are facing pervasive impairments in neurodevelopment including cognitive impairment, but there remains a lack of consensus on the cognitive domains that are affected in those children and adolescents. The objective of this meta-analysis was to evaluate the impact of perinatal HIV-infection on executive function, working memory, and speed of information processing in the ART era.

Methods

The PubMed database was searched for studies published between 1997 and 2024, plus additional search with the ScienceDirect, bioRxiv, and medRxiv databases. A meta-analysis was conducted on thirty-five studies published between 2012 and 2023 that encompassed a total of 4066 perinatally-infected HIV patients, 2349 HIV-exposed uninfected (HEU) controls, and 2466 HIV-unexposed, uninfected (HUU) controls. Performance scores on executive function, working memory, and processing speed were pooled using random-effects meta-analysis.

Findings

Compared to HEU and HUU controls, perinatally HIV-infected children and adolescents presented with significant impairments in processing speed (Hedges g = -0.64, p < 0.00001), working memory (Hedges g = -0.69, p < 0.00001), and to a lesser degree, executive function (Hedges g = -0.35, p = 0.02). Meta-regression analysis suggested that the effect estimate of processing speed impairment negatively correlated with Gross National Income (GNI) per capita of the study countries (CALHIV vs HUU, p = 0.0016; CALHIV vs HEU, p = 0.0019), even though HIV-infected cases were compared to sociodemographically matched HUU controls from the same countries. Sub-group meta-analyses with participants from high-income or low-/middle-income countries provided further evidence suggesting that the performance gap between HIV-infected cases and HUU/HEU controls may be larger in low-/middle-income countries than high-income countries.

Interpretation

In the ART era, cognitive impairment (especially reduced processing speed and working memory) persists in children and adolescents living with HIV. These impairments may be more pronounced among those children and adolescents living with HIV in low-income countries, suggesting that there may be global health inequities in treatment outcomes with perinatal HIV-infection. However, meta-analysis and meta-regression analysis have their limitations, which calls for future collaborative multi-country international studies to directly investigate this important topic. Nevertheless, there is an unmet need to assure equity in timely assessments and interventions to optimize neurocognitive development and outcomes among children and adolescents with perinatal HIV globally.

Funding

This research was supported in part by NIH R01MH108466, NIH R56NS124422, and NIH R01NS124422.

Perinatal exposure to atazanavir-based antiretroviral regimens in a mouse model leads to differential long-term motor and cognitive deficits dependent on the NRTI backbone

Background

Combination antiretroviral therapy (ART) use in pregnancy has been pivotal in improving maternal health and reducing perinatal HIV transmission. However, children born HIV-exposed uninfected fall behind their unexposed peers in several areas including neurodevelopment. The contribution of in utero ART exposure to these deficits is not clear. Here we present our findings of neurocognitive outcomes in adult mice exposed in utero to ART.

Methods

Dams were treated with a combination of ritonavir-boosted atazanavir with either abacavir plus lamivudine (ABC/3TC + ATV/r) or tenofovir disoproxil fumarate plus emtricitabine (TDF/FTC + ATV/r), or water as a control, administered daily from day of plug detection to birth. Offspring underwent a battery of behavioral tests that investigated motor performance and cognition starting at 6-weeks of age and ending at 8 months. Changes in brain structure were assessed using magnetic resonance imaging and immunohistochemistry. Expression of genes involved in neural circuitry and synaptic transmission were assessed in the hippocampus, a region strongly associated with memory formation, using qPCR.

Findings

Pups exposed to TDF/FTC + ATV/r showed increased motor activity and exploratory drive, and deficits in hippocampal-dependent working memory and social interaction, while pups exposed to ABC/3TC + ATV/r showed increased grooming, and deficits in working memory and social interaction. Significant volumetric reductions in the brain were seen only in the ABC/3TC + ATV/r group and were associated with reduced neuronal counts in the hippocampus. Altered neurotransmitter receptor mRNA expression as well as changes in expression of the neurotrophic factor BDNF and its receptors were observed in both ART-exposed groups in a sex-dependent manner.

Interpretation

In our model, in utero ART exposure had long-term effects on brain development and cognitive and motor outcomes in adulthood. Our data show that neurological outcomes can be influenced by the type of nucleoside reverse transcriptase inhibitor backbone of the regimen and not just the base drug, and display sex differences.

Working with memory: Computerized, adaptive working memory training for adolescents living with HIV

This study investigated working memory (WM) training for adolescents with perinatal HIV infection, since WM is negatively impacted by the virus, and adolescence is a time of considerable brain reorganization, during which WM functioning reaches maturation. We posed three main questions: 1) whether WM could be trained in adolescents living with HIV, and if so, whether these effects were maintained over a six-month period during which no further training was received; 2) whether there were differential effects of training on the components of WM (verbal and visuospatial storage, verbal and visuospatial processing); 3) whether the WM training transferred to cognate tasks, and if so, whether these transfer effects were maintained over six months. Sixty-three HIV+ adolescents (10-16 years) from two children's homes were assigned to the training (n = 31) or control (n = 32) group. The training group received 32 hours of supervised training in an adaptive, computerized WM intervention, while the control group received a supervised, placebo computerized program for the same hours. Comprehensive WM and neuropsychological batteries were administered to both groups at pretest, immediately following the intervention, and six months later. Significant improvements were found in verbal WM for the training group, which were maintained six months later. Transfer effects were evident in attention, executive function, memory, language and fluid intelligence. There were no significant posttest improvements in visuospatial storage, and minimal changes in verbal storage and visuospatial WM. These findings represent an important step in exploring ways to improve cognitive functioning in an at-risk population.