Narrow band CE-Chirp stimulus in auditory steady state response threshold estimation in normal hearers and patients with various degrees of sensorineural hearing loss

Abstract

Background: Auditory steady-state responses (ASSRs) are periodic scalp potentials that arise in response to auditory stimuli. Narrow-band (NB) CE-Chirps stimuli have been developed to combine the advantages of compensation for the cochlear traveling wave delay and frequency specificity.

Objectives: To measure the hearing threshold objectively using ASSR in adults with normal behavioural hearing thresholds and adult patients with different degrees of sensorineural hearing loss (SNHL) and its comparison to the behavioural thresholds.

Methods: In the present study, 35 subjects (70 ears) were enrolled. Ears were grouped according to the level of hearing obtained by pure tone audiometry (PTA) into 7 equal groups. NB-CE-Chirp ASSR was done for all groups by means of auditory-evoked potential device.

Results: The estimated ASSR audiograms configuration matched the behavioural curves. ASSR was equally accurate at all frequencies tested except for 1 kHz in the normal-hearing group who showed less accuracy compared to 500 and 4000 Hz in air conduction (AC) and in bone conduction (BC). Although the AC estimation was not equal among the different degrees of hearing compared to the BC estimation, the AC PTA-ASSR thresholds difference range was small. BC PTA-ASSR threshold difference was statistically significantly less than AC at all tested degrees of hearing loss, in most of the frequencies; which reflects that the ASSR was more accurate in estimating BC than the AC thresholds. There was a negative correlation regarding behavioural BC PTA thresholds with PTA-ASSR threshold difference and PTA-estimated audiograms threshold difference at all tested frequencies.

Conclusion: ASSR using either AC or BC NB-CE-Chirp is a reliable objective method in estimating the behavioural threshold in normal hearers and patients with various degrees of SNHL, so it can be used in difficult-to-test cases where accurate behavioural thresholds could not be obtained.

Keywords:

• Air conduction
• auditory steady-state response
• bone conduction
• hearing threshold
• narrow-band CE-Chirps
• sensorineural hearing loss

Disclosure statement

No potential conflict of interest was reported by the authors.