The developmental origins of fetal responsiveness to an acoustic stimulus

Abstract

There is now little doubt that the fetus responds to sound during its development. Whilst many studies, based upon the observation of a response on the pan of the fetus to the presentation of a sound stimulus, have demonstrated fetal responsiveness to sound during the third trimester, few have looked in any systematic fashion at the developmental origins of this response in the fetus. To investigate the origins of fetal responsiveness to an acoustic stimulus the following study examined the response of the fetus from 15 weeks gestation to 25 weeks gestation, comparing the number of fetal movements before, during and after the presentation of an acoustic broad-band stimulus. The results of these experiments indicate that the human fetus first responds to acoustic stimulation at 20 weeks of gestation. At this age the fetus responds with a diffuse response of slow latency; however, by 25 weeks of gestation the response is an immediate auditory startle-type response. The difference in the type of response observed at 20 and 25 weeks of age is probably the result of maturational changes in the auditory startle response.