Comparison between ABR with click and narrow band chirp stimuli in children

Abstract

ObjectiveClick and chirp-evoked auditory brainstem responses (ABR) are applied for the estimation of hearing thresholds in children. The present study analyzes ABR thresholds across a large sample of children's ears obtained with both methods. The aim was to demonstrate the correlation between both methods using narrow band chirp and click stimuli. MethodsClick and chirp evoked ABRs were measured in 253 children aged from 0 to 18 years to determine their individual auditory threshold. The delay-compensated stimuli were narrow band CE chirps with either 2000Hz or 4000Hz center frequencies. Measurements were performed consecutively during natural sleep, and under sedation or general anesthesia. Threshold estimation was performed for each measurement by two experienced audiologists. ResultsPearson-correlation analysis revealed highly significant correlations (r=0.94) between click and chirp derived thresholds for both 2kHz and 4kHz chirps. No considerable differences were observed either between different age ranges or gender. Comparing the thresholds estimated using ABR with click stimuli and chirp stimuli, only 0.8–2% for the 2000Hz NB-chirp and 0.4–1.2% of the 4000Hz NB-chirp measurements differed more than 15dB for different degrees of hearing loss or normal hearing. ConclusionThe results suggest that either NB-chirp or click ABR is sufficient for threshold estimation. This holds for the chirp frequencies of 2000Hz and 4000Hz. The use of either click- or chirp-evoked ABR allows a reduction of recording time in young infants. Nevertheless, to cross-check the results of one of the methods, we recommend measurements with the other method as well.