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.

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Background: In benign paroxysmal positional vertigo (BPPV), the otoconia are dislodged from their usual position within the utricle and migrated into one of the semicircular canals. Utricular dysfunction in BPPV has been reported. Residual dizziness (RD) is common after the treatment. Objective: To assess the utricular function in patients with posterior canal BPPV after canalith repositioning maneuver (CRM) using ocular vestibular evoked myogenic potential (oVEMP) and to correlate the findings with any RD after CRM. Methods: Thirty adult patients with posterior canal BPPV (6 males and 24 females) were compared to well-matched controls. The oVEMP and Dizziness Handicap Inventory (DHI) Questionnaire were administrated before and after successful CRM. Results: Before CRM, the affected ear showed a significant delay in latency of N1 in the affected ear oVEMP and a significantly decreased in N1–P1 amplitude compared to controls and to the non-affected ears. After CRM their amplitudes were comparable. The BPPV group had a greater interaural amplitude difference percent (IAAD%) compared to controls before and after CRM. The non-affected ear showed only decrease in N1–P1 amplitude compared to controls. After CRM the affected ear amplitude increased and became comparable to the controls. The IAAD% was larger in RD group than non-RD group before and after CRM. The dizziness handicap severity decreased after CRM. But the occurrence of RD could not be predicted from DHI scores. Conclusion: Utricular function measured by oVEMP in the affected ear improved after CRM, and contralateral ear showed sub-clinical affection. Persistent VEMP abnormality reflecting persistent utricular dysfunction was related to residual dizziness.

Background: Various auditory evoked potential techniques have been explored as a means of objectively predicting the behavioral audiogram in groups of subjects who cannot provide reliable or accurate behavioral results. The tone-evoked auditory brainstem response (ABR) cannot differentiate between severe and profound SNHL, whereas the auditory steady state response (ASSR) can provide threshold information in a frequency-specific manner at intensity levels of 120 dBSPL. The cortical auditory evoked potential (N1P2 CAEP) has shown advantages over the ABR and ASSR.Objectives: To assess the ability of the N1P2 cortical auditory evoked potential (CAEP) to estimate the hearing threshold level at different frequencies, in normal hearing adults and adults with different degrees of sensorineural hearing loss (SNHL); and to compare it to the auditory steady state response (ASSR).Methods: This study included 90 subjects (180 ears), grouped into 6 groups according to the degree of hearing obtained by pure tone audiometry (PTA). Hearing threshold was then measured using N1P2 CAEP and ASSR.Results: N1P2 CAEP and ASSR were highly correlated to PTA at all frequencies. However, N1P2 CAEP predicted behavioral thresholds more accurately than ASSR at all frequencies, especially at 500 and 1000 Hz in the normal hearing group and for all degrees of SNHL. N1P2 CAEP was equally accurate at all frequencies and predicted behavioral thresholds better at more severe degrees of SNHL at 1, 2, and 4 kHz. Conclusion:The N1P2 CAEP can be reliably used as an objective method for estimating the behavioral hearing threshold, yielding more accurate results than the ASSR, especially at lower frequencies and with more severe degrees of hearing loss. We therefore recommend using the N1P2 CAEP in estimating the behavioral threshold in difficult-to-test adults.

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