Advantages of Narrow Band CE-Chirp ABR Compared to Tone Burst ABR in Adults with Normal Hearing

Objectives: In this study, we aimed to compare the ABR’s (Auditory Brainstem Response) estimated behavioral thresholds, wave V latencies, and amplitudes, obtained using Tone Burst and Narrow Band (NB) CE-Chirp stimuli in adults with normal hearing. Design: A prospective study was designed. Setting: Otorhinolaryngology and Audiology Clinic of the tertiary university. Participants: Twenty-four adults with normal hearing (17 males, 7 females) participated in this study. Main outcome measures: ABR was recorded using Narrow Band (NB) CE-Chirp and Tone Burst (TB) for four frequencies (0.5, 1, 2, 4 kHz). Wave V obtained for 60, 40, and 20 dB nHL intensity levels for both two procedures. Behavioral hearing thresholds (BHT) were identified at 0.5, 1, 2, 4 kHz. Duration of TB and NB CE Chirp ABR tests for each ear was recorded. Wave V latencies, amplitudes, BHTs, duration of tests were compared. Results: The thresholds obtained from NB CE-Chirp stimulus (20, 19, 16, 15 dB nHL) at 0.5, 1, 2 and 4 kHz were significantly closer to the behavioral hearing thresholds (11, 10, 9, 9 dB HL) compared to Tone Burst ABR thresholds (25, 23, 20, 19 dB nHL) (at all frequencies p < 0.001, CI = 2.0- 5.9). The absolute latencies of peak V with TB stimuli were significantly longer than latencies obtained with NB CE Chirp stimuli at 0.5, 1, and 2 kHz at all sound intensity levels (p<0.001). The mean test time for NB CE-Chirp ABR was 23.6 ± 3.9 minutes and significantly shorter than the TB ABR test time (28.2 ± 4.5), (p=0.011). Conclusion: Frequency-specific behavioral thresholds are estimated better with NB CE-Chirp than TB ABR.