Somatosensory discrimination deficits following pediatric cerebral malaria.

Abstract

Abstract. Pathologic studies of central nervous system damage in human falciparum malaria indicate primary localization in the cerebral white matter. We report a sensory-perceptual investigation of 20 Ghanaian children with a recent history of cerebral malaria who were age-, gender-, and education-matched with 20 healthy control subjects. Somatosensory examinations failed to show any evidence of hemianesthesia, pseudohemianesthesia, or extinction to double simultaneous tactile stimulation. While unilateral upper limb testing revealed intact unimanual tactile roughness discrimination, bimanual tactile discrimination, however, was significantly impaired in the cerebral malaria group. A strong negative correlation (r ϭ Ϫ0.72) between coma duration and the bimanual tactile roughness discrimination test was also found. An inefficiency in the integrity of callosal fibers appear to account for our findings, although alternative subcortical mechanisms known to be involved in information transfer across the cerebral hemispheres may be compromised as well.An estimated 40% of the world's population is exposed to malaria.1 In Africa, children are at particular risk of developing the imminently lethal complications of Plasmodium falciparum infection, with 90% of all malaria deaths being pediatric cases. 2 We are far from understanding why some children in malaria endemic areas who develop symptomatic manifestations of falciparum malaria progress to the more severe cerebral malaria while others do not.3 There is also scant, but increasing evidence of neurologic deficits in both uncomplicated falciparum malaria 4-6 and cerebral malaria, 7-9 with an estimated 5-10% of African children developing significant and neurologic sequelae following cerebral malaria. These include sensory (i.e., hearing deficits, cortical blindness, and other visual field defects) and motor (i.e., ataxic and paretic) disorders.Recent advances in neuroradiologic imaging technologies have improved the diagnostic accuracy of detecting neuropathological changes in cerebral malaria 10,11 over earlier, lower resolution methods.12 Unfortunately, however, neuropsychologic aspects of cerebral malaria have received very little clinical or research attention. Cerebral white matter lesions have been strongly associated with cerebral malaria, 13,14 with axonal demyelination 15 and local cerebral hypoxic effects 14 thought to be among its pathologic sequelae. The human corpus callosum is the largest neocortical fiber tract in the brain, and along with other forebrain commissures, facilitates efficient communication between the cerebral hemispheres. If indeed cerebral malaria shows a predilection for cerebral white matter, one can hypothesize interhemispheric transfer inefficiencies on neuropsychologic evaluation. To investigate this possibility, the efficiency in transmission of tactile somesthetic information across the cerebral hemispheres was studied in a sample of Ghanaian children. MATERIALS AND METHODSStudy area and study population. Accra, the capital of Ghana...

Cognitive Impairment After Cerebral Malaria in Children: A Prospective Study

“…[4][5][6][7][8] However, the enrollment of a control cohort from the same neighborhoods as children with CM or UM permitted assessment of changes over time for this comparison group and helped to ensure that comparison children were not significantly different from children with CM in several important areas that might affect cognitive function. Age, gender, nutrition, home environment, and school level were also adjusted for in our statistical analyses.…”

“…3 However, several retrospective studies suggested that cognitive deficits in children with CM are more frequent (occurring in 11%-28% of children with CM) and persist for a far longer time (3-9 years after the CM episode) than neurologic deficits. [4][5][6][7][8] The data from those studies were strong and generally consistent, but one study found no evidence of increased cognitive deficits. 9 Furthermore, the original clinical and social assessments of those children were performed as part of studies investigating other aspects of CM and not as part of a study designed specifically to address the question of cognitive deficits in children with CM.…”

Cerebral Malaria in Children Is Associated With Long-term Cognitive Impairment

“…[4][5][6][7][8]12 These important studies broadened understanding of the potential long-term morbidity of CM; however, although the children with CM were part of a well-studied cohort in several of these studies, control subjects were chosen retrospectively, at the time of cognitive testing (3-9 years after the CM episode). Importantly, assessment of potential confounding factors such as nutrition, home environment, and education level, which can change over time and may be related to long-term cognition, could not be assessed in the studies in the "control" child at the time when the "case" child had CM.…”

Involvement of nitric oxide and its up/down stream molecules in the immunity against parasitic infections

“…Experiments conducted to confirm or deny the involvement of NO and RNI in infections, using experimental NOS knockout animals have been contradictory or inconclusive [36][37][38]. However, it is possible that iNOS deficient mice develop alternative pathways to overcome in-born deficiencies [36,39].…”