Respiratory-related evoked potentials in children with life-threatening asthma

Respiratory-related evoked potentials (RREPs) have been elicited by inspira tory occlusion and recorded over the somatosensory cortex. The first positi ve peak (P-1) amplitude has been correlated with the magnitude of inspirato ry loads. Since children with life-threatening asthma (LTA) have a decrease d perceptual sensitivity of inspiratory loads, we hypothesized that a subpo pulation of patients with LTA have an impaired ability to sense mechanical loads, and that these patients would have an abnormal RREP. The RREP was re corded from C-Z-C-3 and C-Z-C-4 in three groups: LTA asthmatic, control ast hmatic, and nonasthmatic children. Two inspiratory-interruption occlusions trials and a control trial were recorded. All the evoked potentials were an alyzed after the averaged control trial was subtracted from the averaged oc clusion trials. The RREP P-1 peak was observed in all 14 nonasthmatic child ren and in 14 of 15 control asthmatic children. The RREP was absent in 6 of 11 patients with LTA. When present, there were no between-group significan t differences in P-1 peak latency or amplitude. These results demonstrate t hat the RREP elicited by inspiratory occlusion is present bilaterally in no nasthmatic and asthmatic children. There is a subpopulation of LTA children in which inspiratory occlusion fails to elicit the pi peak of the RREP, su ggesting an altered neural processing of inspiratory load information.