Chronic in utero alcohol exposure affects auditory function in rats and in humans.

In one experiment, brainstem auditory evoked potentials (BAEPs) were used to study the postnatal development of the peripheral and brainstem auditory pathways in rat pups prenatally exposed to alcohol. The results indicated that prenatal alcohol exposure retards development of the peripheral and brainstem auditory pathways and that prolonged auditory transmission times, despite a "catch-up" trend, persist in maturity. BAEP latency-intensity profiles demonstrated that a significant proportion (19%) of the alcoholized rats had recruitment-type sensorineural hearing loss. In a second study, a group of 12 fetal alcohol syndrome (FAS) children were evaluated for auditory function. These children showed unusually high incidence rates of sensorineural hearing loss (33%) and conductive hearing loss secondary to recurrent serous otitis media (92%). A final study used the cortical auditory evoked potential (CAEP) and found evidence of dysfunctional processing of auditory information at the cortical level in rats prenatally exposed to alcohol. The implications of these findings for the evaluation and treatment of FAS children and for evoked potential studies on children of alcoholics and learning disabled children are discussed.