A total of 70 infants, complaining of hearing loss or speech retardation, were employed in this study. Evoked Response Audiometry (ERA) was carried out for 63 infants, Electro- cochleography (ECoG) for 26 infants and Brain Stem Response (BSR) for 41 infants. The role of these objective audiological examinations in ped-audiology was evaluated.
The results were as follows:
1) ERA is the best method to judge whether the infant is total deaf or not.
2) Response thresholds of electrocochleographical AP and BSR were lower than those of ERA.
3) Thresholds of AP responses to tone pips of 2kHz, 4 kHz and 8 kHz were in relatively good agreement with the behavioral hearing thresholds for pure tones of each frequency.
4) Response threshold of BSR to click was generally in good agreement with the sub- jective threshold for the same stimuli. In case of sharp-cut type high tone hearing loss (above 2 kHz), however, there was a great difference between them.
5) Latencies of AP in infants differ from those in adults.
6) Since standard deviations of BSR-latency were much greater than those of AP-latency, the measurement of BSR latency is not useful in differential diagnosis of hearing losses.
