Auditory brain stem responses(ABR) in developmentally retarded infants and children

We recorded ABR in 65 infants and children with developmental retardation and analyzed the relationship between the incidence of abnormal findings and the degree of mental retardation, which was confirmed by follow-up observation and formal intelligence tests. There were 3 cases for whom no response could be obtained. In the 21 retardates with specific causes of retardation or complications, peripheral abnormalities were noted in 13 (62%) and central abnormalities in 11 (52%). The 41 cases of idiopathic retardates were divided into three categories according to the degree of mental retardation. Of 15 cases who were ascertained to be normal or borderline retardates, 3 (20%) showed some abnormal findings. Of 13 cases who were proven to be suffering from mild to moderate mental retardation, 5 (38%) showed abnormal findings. Of 13 cases who were confirmed to be suffering from severe to profound mental retardation, 5 (39%) showed central abnormalities. The high incidence of ABR abnormalities in retardates compared to in normal controls suggests that ABR measurement is a useful tool for evaluating infants who have possible developmental delay. It seems that disturbance of acoustic information processing can disturb language acquisition, and such a consideration is necessary for the education of children who show significant elevation of the response threshold.