Narcotic and nicotine effects on the neonatal auditory system.

To evaluate narcotic and nicotine effects on the neonatal auditory system, brain stem auditory evoked responses were recorded in 15 infants prenatally exposed to both narcotics and nicotine (median gestational age 38.4 weeks, median birth weight 2820 g), in 15 nicotine exposed infants (gestational age 40.0 weeks, birth weight 3000 g) and in 24 healthy term infants (gestational age 40.1 weeks, birth weight 3310 g) who served as controls. Whereas nicotine-exposed and control infants were similar in all brain stem auditory evoked response measurements, narcotic/nicotine infants had bilaterally increased wave V latencies (left: p = 0.005; right: p = 0.04) and I-V intervals (left: p = 0.02; right: p = 0.01) when compared to controls. Our findings suggest that prenatal narcotic but not nicotine exposure negatively affects maturation or integrity of the neonatal auditory brain stem tract and that neither narcotic nor nicotine exposure is associated with hearing loss in the neonate.