Browsing by Author "Zondo, Sizwe"

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Executive Functioning in a HIV-positive Paediatric Sample
(University of the Witwatersrand, Johannesburg, 2024) Mes, Nike; Cockcroft, Kate; Zondo, Sizwe
High prevalence of Human Immunodeficiency Virus (HIV) poses significant public health challenges in regions like Sub-Saharan Africa, especially among children and adolescents. Despite advancements in reducing vertical mother-to-child transmission and increasing access to antiretroviral therapies, paediatric populations continue to face substantial neurocognitive challenges associated with HIV infection. This study aimed to establish a profile of executive functioning in a South African paediatric population using cognitive measures (the NEPSY-II) and a behavioural rating scale (the BRIEF) to elucidate the cognitive impact of HIV. Assessing executive functions in children presents challenges due to their multifaceted nature, with cognitive measures and behavioural rating scales offering differing insights. As such, a secondary aim of this paper was to examine the inter-correlations between these measures. The participant group was comprised of 40 children living with HIV in Johannesburg, South Africa, aged 10-16. Normative data for comparisons were obtained from the NEPSY-II and BRIEF manuals, as well as a sample of NEPSY-II raw scores for South African youth without a central nervous system disease (Truter et al., 2017). Significant differences were found between the HIV+ group and comparison samples. Specifically, HIV+ children showed poorer performance in working memory, inhibitory control and cognitive flexibility compared to their typically developing peers. These results provide insights into executive function challenges faced by HIV+ children and adolescents, emphasising the importance of early intervention and support.
Neurocognitive Rehabilitation for an Adolescent HIV Population: The Case of Sustained Attention
(University of the Witwatersrand, Johannesburg, 2024) Zondo, Sizwe
The Human Immunodeficiency Virus (HIV) continues to be a significant disease burden. In terms of neurocognitive health, HIV crosses the blood-brain barrier, resulting in neuronal dysregulation and compromised neurocognition. Of further import, antiretroviral drugs are indicated to have limited permeability in the central nervous system and do not reverse compromised neurocognition, sequent HIV neuroinvasion. The objectives of the study were to investigate the efficacy of HIV cognitive rehabilitation therapy (HIV-CRT) in adolescent HIV. The first aim was to investigate the evidence for the cognitive rehabilitation of HIV in adolescent and geriatric samples, sequent neuroHIV. This investigation resulted in the publication of a meta-analysis detailing the efficacy of attention remediation in neuroHIV. The second aim was to examine the efficacy of fNIRS neuroimaging in measuring hemodynamic responses in the prefrontal cortex in adolescents neuroHIV. This investigation resulted in the publication of an article detailing the efficacy of fNIRS in detailing changes in oxygenated haemoglobin in adolescents living with neuroHIV. The third aim was to pair fNIRS optical neuroimaging with behavioural data to investigate changes associated with brain training at a cortical and behavioural level. The execution of the above aim resulted in the publication of an article detailing the procedures and methods to achieve the enquiry. The fourth article, under review, details findings related to neural efficiency and attention training. The final manuscript, under preparation, details functional connectivity outcomes related to attention training. To enable the analysis of the published articles, an initial cohort of 42 adolescents (mean age = 17.28) living with HIV participated in the study. Following attrition, the sample was reduced to 26 participants. Thirteen participants were assigned to the treatment group (n = 13; mean age = 16; SD = 1.2), which received cognitive rehabilitation to remediate attention. Thirteen children acted as controls (mean age = 17; SD = 1.3). Pre- and post-intervention data were analysed using behavioural and optical imaging data. 5 Findings indicated that HIV-CRT (attention) is associated with decreased oxygenated haemoglobin (HbO) and increased functional connectivity in the Central Executive Network (CEN). Contrary to expectation, HIV-CRT was associated with minimal behavioural gains, as indicated by neuropsychological assessments. Taken together, findings seem to suggest that in adolescent neuroHIV, customised HIV-CRT promotes cortical efficiency. However, brain training does not translate to immediate behavioural improvements at post-assessment. Summarily, findings suggest that cortical plasticity may precede near-and-far cognitive transfer gain in adolescents neuroHIV.