Further comparisons of ABR response amplitudes,test time,and estimation of hearing threshold using frequency-specific chirp and tone pip stimuli in newborns: Findings at 0.5 and 2 kHz

Objective: To compare auditory brainstem response (ABR) amplitudes evoked by 0.5 and 2 kHz tone pip and narrowband chirp (NB CE-Chirp) stimuli when testing post-screening newborns. To determine the difference in ‘estimated hearing level’ correction values. Design: Tests were performed with tone pips and NB CE-Chirps at 0.5 or 2 kHz and the ABR threshold for each stimulus defined. Response amplitude, response quality (Fmp), and residual noise were compared for both stimuli. Study sample: Thirty-nine babies (42 ears) who passed our ABR discharge criterion at 4 kHz following referral from their newborn hearing screen. Results: NB CE-Chirp responses were, on average, 31% larger than the tone pip responses at 0.5 kHz and were 52% larger at 2 kHz. Fmp was significantly higher for NB CE-Chirps. Conclusions: The advantages of NB CE-Chirps over tone pips we previously identified at 4 and 1 kHz extends to 0.5 and 2 kHz, which supports the use of NB CE-Chirps when testing newborns. We propose that ABR nHL threshold to eHL corrections for NB CE-Chirps should be approximately 5 dB less than corrections for tone pips at 0.5 and 2 kHz, mirroring our recommendation at 4 and 1 kHz.