Comparative study of objective hearing thresholds in adults using Auditory Steady State Response and Auditory Brainstem Response with Pure Tone Audiometry

 Pure-tone audiometry (PTA) is the most common audiological test to determine hearing thresholds. However, accurate assessment of hearing in difficult-to-test populations has always remained an audiological challenge as it gives inconsistent responses in PTA.

 The aim of this study was to evaluate the reliability of the Auditory Steady State Response (ASSR) and Auditory Brainstem Response (ABR) in determining the frequency specific hearing thresholds by establishing a correlation between the thresholds determined by subjective test- PTA and objective test - ASSR and ABR at 500 Hz, 1 kHz, 2 kHz and 4 kHz.

 In this prospective study we have included 40 adult subjects (n = 80 ears) of both genders. All subjects underwent ASSR, tone burst ABR and PTA to record frequency specific hearing thresholds at 500 Hz, 1 kHz, 2 kHz and 4 kHz. Data were recorded and analyzed with SPSS IBM software version 22.

 Mean difference between PTA - ASSR was 14.2 dB and between PTA - ABR was 18.8 dB in the study population. We found a strong correlation between PTA-ASSR and PTA-ABR across all frequencies. We also confirmed that correlation was better in the sensorineural hearing loss and conductive hearing loss group in comparison with the normal hearing group. The overall reliability was better in high frequency for both ASSR and ABR.

 Results of this study concluded that both ABR and ASSR can be used to predict frequency specific hearing thresholds. ASSR was more reliable than ABR for accurate prediction of frequency specific hearing threshold as the mean difference between ASSR and PTA was smaller than the mean difference between ABR and PTA.