Clinical apnea and brain-stem neural function in preterm infants.

We assessed the relation between clinical apnea and brain-stem neuronal function in 58 preterm babies. The brain-stem conduction time of the auditory evoked response (Wave V-I interval) was longer in babies with apnea than in those without it at a similar postconceptional age (at 32 to 33 weeks: mean, 6.16 vs. 5.35 msec, P less than 0.001; at 34 to 35 weeks: mean, 5.98 vs. 5.33 msec, P less than 0.002). The number of apneas per day decreased over a period that was similar to the period during which brainstem conduction time decreased. In general, apneas ceased when the conduction time decreased to the levels observed in babies of a similar age who did not have apnea. Short brain-stem conduction times were observed in some infants who had prenatal stress, such as intrauterine growth retardation or maternal hypertension. These results suggest that the occurrence of apnea in preterm infants is correlated with neural function in the brain stem.