Asymmetric brain stem auditory evoked responses in infants treated with extracorporeal membrane oxygenation

Brain stem auditory evoked responses (BAERs) were obtained in 25 infants who received extracorporeal membrane oxygenation (ECMO) for severe respiratory failure. Tracings were obtained by means of a Nicolet CA-2000 averager, using a conventional paradigm. The presence or absence of replicated responses at 35 and 75 dB nHL were recorded for each ear. Interpeak latencies I-III, III-V, and I-V were measured and differences between right and left ears were compared, using a matched pair t-test. Wave III-V latencies were longer on the left than right (p less than 0.05), but no significant right-left differences for latencies I-III were noted. Sixteen percent of the infants failed hearing sensitivity criteria, 45% (10/23) had prolonged I-V latencies. At follow-up (age 4 to 12 months) 6/10 infants with prolonged I-V latencies had additional neurologic abnormalities. In this population left ear III-V latencies are prolonged versus right, and the incidence of abnormal BAERs is high. Relative prolongation of left ear III-V latencies (generated from the right brain stem) may be result of right carotid artery and/or jugular vein ligation for ECMO, and abnormal I-V latencies prognosticate future neurologic abnormalities in this population.