Correlation between the laryngeal brain stem evoked response and the laryngeal chemoreflex in the porcine model

The laryngeal brain stem evoked response (LBR) represents the neural activity involved in laryngeal reflex pathways. The laryngeal chemoreflex (LCR) is a centrally mediated response consisting of apnea and hemodynamic changes that result from laryngeal stimulation. The purpose of this study is to determine the characteristics of the LBR that are predictive of LCR severity in the porcine model. The duration of apnea resulting from stimulation of the supraglottic larynx defined LCR severity. The LBR tracings were recorded from electrodes flanking the brain stem following direct electrical stimulation of the superior laryngeal nerve. The LBR peak latencies from piglets demonstrating prolonged LCR apnea were compared to those without an exaggerated LCR response. Two LBR peak latencies demonstrated a statistically significant difference between the two piglet groups. These peak latencies appear to be indicators of susceptibility to exaggerated laryngeal reflex sensitivity. Thus, the LBR may prove useful in identifying and evaluating subjects predisposed to conditions associated with dysfunctional laryngeal reflex activity.