Comparison of threshold estimation in infants with hearing loss or normal hearing using auditory steady-state response evoked by narrow band CE-chirps and auditory brainstem response evoked by tone pips.

Objective: The objective of this study is to compare air-conduction thresholds obtained with ASSR evoked by narrow band (NB) CE-chirps and ABR evoked by tone pips (tpABR) in infants with various degrees of hearing loss.

Design: Thresholds were measured at 500, 1000, 2000 and 4000 Hz. Data on each participant were collected at the same day. Study sample: Sixty-seven infants aged 4 d to 22 months (median age = 96 days), resulting in 57, 52, 87 and 56 ears for 500, 1000, 2000 and 4000 Hz, respectively.

Results: Statistical analysis was performed for ears with hearing loss (HL) and showed a very strong correlation between tpABR and ASSR evoked by NB CE-chirps: 0.90 (n = 28), 0.90 (n = 28), 0.96 (n = 42) and 0.95 (n = 30) for 500, 1000, 2000 and 4000 Hz, respectively. At these frequencies, the mean difference between tpABR and ASSR was -3.6 dB (± 7.0), -5.2 dB (± 7.3), -3.9 dB (± 5.2) and -5.2 dB (± 4.7). Linear regression analysis indicated that the relationship was not influenced by the degree of hearing loss.

Conclusion: We propose that dB nHL to dB eHL correction values for ASSR evoked by NB CE-chirps should be 5 dB lower than values used for tpABR.