Tympanometry and the stapedial reflex in the first five days of life

Tympanometry was carried out on 45 full term neonates. It proved to be a straightforward procedure. The acoustic reflex was elicited using contralateral white noise stimulation at 70-85 dB and with a probe tone of 600 Hz. It was not detectable in the first hours of life, but was present in 100% of cases over 12 h of age. The initial absence of the reflex may be due to a transient conductive loss which resolves rapidly or, more likely, immaturity of the reflex itself at birth.