Effects of tobacco exposure on auditory function in newborns

In chapter 9, we discussed sensation and perception.  This study looks at how tobacco use of pregnant mothers can impair auditory processes in their unborn children.  Tobacco use by mothers during pregnancy has been consistently associated with negative effects in newborns.  Intrauterine tobacco exposure may lead to deficits in motor, sensory, and cognitive function.  New research is now showing that it can also impair the auditory processes.  This research, however, has received little attention.  This article discusses a study that was performed on pregnant women to determine the effects of tobacco use on newborns' auditory function.  The study began with a sample size of 110 pregnant women from a low socioeconomic population.  Researchers gathered information from these women such as self-reported smoking status, how many cigarettes smoked per day, and urine samples.  Of the 110 participants, 78 live-births were identified.  Some pregnancies resulted in spontaneous abortion while others did not return to the hospital for care or were transferred to another facility.  Auditory brain-stem evoked responses (ABRs) were measured in both ears of 62 of the newborns.  ABR waveforms are measures of the neuro-electrical activity produced by the auditory nerve and auditory brainstem in response to sound stimuli.  Researchers also looked at the levels of continine, which is found in both tobacco and nicotine, in the mothers' urine.  Researchers found that the infants of mothers with high continine levels (heavy smokers) responded at a much faster rate during the ABR testing than infants of mothers with low levels of continine (non-smokers).  ABRs that occur too quickly can possibly disrupt auditory processes related to speech perception, as well as negatively affect reading and language development.  Therefore, these findings suggest that smoking during pregnancy can possibly lead to impairment of auditory function in newborns.

References:
PECK, J., NEAS, B., ROBLEDO, C., SAFFER, E., BEEBE, L., & WILD, R. A. (2010). Intrauterine tobacco exposure may alter auditory brainstem responses in newborns. Acta Obstetricia et Gynecologica Scandinavica, 89(4), 592-596. doi:10.3109/00016340903511068