Investigation of saccadic eye movement abnormalities in children with HIV/AIDS on HAART

Abstract

Reading is a complex psychological task that involves rapid movements of both eyes in the same direction (saccades) from one word to the next, or, occasionally, backwards to previously encountered text. Eye movement provides a sensitive window into cognitive processing during reading and reading skills are associated with various eye movement parameters, total number of saccades and saccadic amplitudes. This is due to the knowledge that brain areas compromised by HIV infection also control saccadic eye movements. The aim of this study was to investigate the relationship between saccadic eye movements in children with HIV/AIDS on Highly Active Antiretroviral Therapy (HAART). With a descriptive cross-sectional design, 128 conveniently accessed male and female participants of ages 6 years to 13 years 11 months had their saccadic eye movements evaluated. The tool used to screen for saccadic eye movement abnormalities was a numerical reading test called the Development Eye Movement (DEM) test. Descriptive and inferential statistics was developed using SAS. Seventy-eight percent (78%) of participants had minimal immunosuppression and 65% had undetectable viral loads. The DEM test classified participants into four Behaviour Types based on their performances in this timed reading test. Ninety-three percent (93%) had vertical times and 92% had horizontal times that were outside of the specified test norms. The Behaviour Types revealed that 53% had automaticity problems (Type 3), 22% had both eye movement and automaticity problems (Type 4), 8% had no problems (Type 1) and only 3% had eye movement problems (Type 2). The association between the viral load with Behaviour Types (p=0.2) and the CD4 count against the behaviour types (p=0.17) were not statistically significant, hence no relationship could be established. More than half of the sample population manifested automaticity problems. What could not be determined was whether the automaticity problems found in this population were related to the neurocognitive functioning or neurodevelopmental delays which are known to exist in children with HIV/AIDS despite being on HAART, or if it was due to other factors. No relationship could be established between the Behaviour Types specified in the DEM test and the HIV biomarkers despite the DEM performances being largely outside of the standardised norms.