V-wave detection threshold of click-evoked ABR- and ASSR-estimated hearing level performed on the same day in infants

Abstract

　　We determined, within 6 months of birth, the V-wave detection threshold for 163 ears of 82 infants who underwent click-evoked ABR and ASSR on the same day, and also examined the estimated hearing level by ASSR. There was a strong correlation between the V-wave threshold and the estimated hearing at 0.5kHz, 1kHz, 2kHz, 4kHz and the average hearing of its estimated hearing by ASSR. Out of the 105 ears with a V wave threshold of within 20dBnHL the estimated hearing by ASSR, 95 was within 35dB at all four frequencies. All three ears with a V wave threshold of 30dBnHL showed abnormalities, including mild to moderate hearing loss in one ear, and exudative otitis media in the remaining two ears. The hearing level estimated by ASSR in all 18 ears with a V-wave threshold of 40dBnHL was ≥45dB at 2 or more frequencies. Of these 18 ears, 11 showed mild to moderate hearing loss, 1 showed severe stenosis of the external auditory canal, 5 showed otitis media with effusion, and 1 ear was normal. Thus, in cases with a V-wave threshold is ≥40dBnHL, there is a high possibility of some hearing impairment, and it is necessary to quickly evaluate the hearing, including by ASSR.