Auditory steady-state responses in babies with normal hearing and with temporary conductive hearing loss

AbstractObjectives: To investigate whether test age and middle ear dysfunction had a significant effect on the variability of Auditory Steady-State Response (ASSR) thresholds when this test was undertaken on referrals from the newborn hearing screen. Methods: ASSR thresholds were measured at octave intervals from 500 Hz to 4000 Hz. They were recorded in 389 ears with normal hearing and middle ear function, and in a further 189 ears with temporary middle ear dysfunction. The modal corrected age at which the tests were undertaken was four weeks, with a minimum of one week and maximum corrected age of 26 weeks. Results: The mean ASSR thresholds of those with normal hearing were 47dB HL at 500 Hz, 36dB HL at 1000 Hz, and 34dB HL at both 2000 Hz and 4000 Hz. Standard deviations (SDs) from the mean ranged from 7.7 to 9.9dB. For those with middle ear dysfunction the mean ASSR thresholds were significantly greater at each frequency, with thresholds of 65dB HL at 500 Hz, 55dB HL at 1000 Hz, 53dB HL at 2000 Hz and ...