[Transient evoked otoacoustic emission measurement in infants]

Transient evoked otoacoustic emissions (TEOAEs) were measured and evaluated in 194 ears of 101 subjects under 4 years old who were suspected of hearing loss, using a ILO88 Otoacoustic Emission Analyzer, to study the basic characteristics of this measure and its utility for hearing screening. The mean time necessary to record TEOAEs in both ears was short, about 3 minutes. In 58 ears judged as normal hearing within 30 dB in ABR, TEOAE levels in infants aged less than 2 months were significantly higher than in those aged more than 1 year, especially in the high frequency bands (4-kHz and 5-kHz bands). One case which had been judged as bilateral moderate-to-profound hearing impairment in initial ABR testing showed good responses in TEOAEs, indicating normal cochlear function, and obvious wave Vs in follow-up ABRs recorded at 30 dB nHL confirmed normal auditory function. Therefore, in a case like this one, suspected of retardation in brain stem maturation, TEOAE is more useful than ABR as a hearing screening technique. Since external and middle-ear factors caused poor TEOAE responses in some cases which had been judged as normal hearing by ABR. TEOAE seems to be more sensitive in detecting external and middle ear problems than ABR. Moreover, TEOAE measurement of infants was easy and noninvasive. We conclude that TEOAE is an excellent tool for screening auditory function in infants.