Delayed visual evoked potentials in children with Plasmodium falciparum malaria and reduced consciousness

Abstract

We aimed to investigate the visual evoked potential (VEP) in children unconscious with Plasmodium falciparum malaria, a common cause of death in Africa. Flash VEPs were carried out in Malawi during one peak malaria season. Children were included in the study if they had P. falciparum malaria and reduced consciousness – Blantyre Coma Score (BCS) 4 or less out of 5. Initial VEPs were performed after stabilising the patient and commencing treatment. To investigate optimal VEP protocols, varying stimulus parameters were tested. Where possible, VEPs were repeated daily until the child recovered full consciousness (BCS 5). The initial traces of 40 children were included in the study and serial traces were obtained in 30 of these. Mean VEP latency was greater on admission than either on day 1 or at BCS 5 (paired t-test, P < 0.05) for all test protocols. There was a positive correlation between VEP latency on admission and parasite count and a negative correlation with blood glucose on admission (Spearman's rank correlation, P < 0.05 for all test protocols). Children with severe P. falciparum malaria have delayed VEP responses and recovery occurs in parallel with return to normal consciousness. VEP recordings are quick and reproducible and may find a place in assessing levels of coma and cerebral function in severe malaria.

Keywords

Coma - malaria - visual evoked potential - children