Abnormally increased semantic priming in children with symptomatic HIV-1 disease: Evidence for impaired development of semantics?

Language deficits are a major characteristic of neurobehavioral dysfunction in pediatric HIV disease. An object decision task, which assessed reaction time facilitation following a semantic or identical prime in comparison to an unrelated prime, was used to investigate whether semantic processing ab normalities could be responsible, in part, for these deficits. Thirty child ren with vertically acquired HIV infection (M age 9.0 years; range 6-13) pa rticipated. Either a picture of the same object (repetition prime), a seman tically related object (semantic prime), a semantically unrelated object, o r a nonsense object preceded a target picture, which in 50% of the cases wa s a real object. Brain scans of children were rated and used together with neurobehavioral functioning to classify children as having HIV-related CNS abnormalities (n = 13) or not (n = 17). increased semantic priming but not repetition priming was associated with a greater degree of cortical atrophy . Furthermore, CNS compromised children had significantly faster reaction t imes following a semantic prime compared to an unrelated prime than non-com promised patients. This facilitation following semantic priming for the CNS compromised patients (13.3%) almost equaled the facilitation following rep etition priming (15.3%) while for the non-compromised patients facilitation following semantic priming (7.9%) was clearly smaller than following repet ition priming (14.6%). These data suggest that HIV infection in children ma y result in a reduced neural network leading to impoverished semantic repre sentations characterized by poor differentiation between closely related ob jects.