Abstract
We propose 4 objective hearing tests requiring only short hospitalization for difficult-to-test infants and young children: ABR, auditory steadystate response (ASSR), electrocochleography (ECoG), and electrically induced ABR (EABR) via the ear canal. Both ASSR and ECoG have an advantage in that the use of frequency-specific test tones produces frequency specific thresholds. We used this system to examine 9 infants and young children with profound deafness. The results were as followas; 1) Fourteen ears of 17 ears with no response to ABR responded to ASSR and/or ECoG in the lower frequency areas. 2) Thresholds determined by ECoG test were 5 to 15dB lower than the thresholds predicted by ASSR. The difference was bigger at the low frequency. 3) Detection rate of the response was also twice higher in ECoG (52%) than ASSR (26%). 4) EABR was useful to determine suitable candidates for a cochlear implant. In conclusion, the use of these objective hearing tests during a short hospital stay was useful to predict the remaining hearing ability, the efficacy of hearing aids and also the eventual possibility for a cochlear implant in difficult-to-test infants and young children.
