SOME forty years ago a series of observations by Liebmann1 disproved the opinion that all children are born deaf. This supposition had been generally accepted and was expressed by authors such as J. Meyer.2 Others, among them Alexander,3 were of the opinion that newborn infants had a certain hearing capacity.
The ability of hearing in the new born is very deficient. The external auditory meatus is not permeable, and the spaces of the middle ear are nearly filled with gelatinous tissue. The surface of the tympanic membrane is uneven and the membrane itself is thick.... Sound conduction is, therefore, considerably interfered with in both the external and middle ear. Such an impediment occurring in the adult from disease conditions would considerably diminish the auditory acuity, reducing it to perhaps one or two meters in ordinary conversation and this distance will probably represent the auditory acuity of the newborn....4
FROESCHELS E, BEEBE H. TESTING THE HEARING OF NEWBORN INFANTS. Arch Otolaryngol. 1946;44(6):710–714. doi:10.1001/archotol.1946.00680060739006