Detectability of newborn chirp-evoked ABR in the frequency domain at different stimulus rates

Abstract

Objective: The present paper reports the results of a study on a group of newborns whose chirp-evoked auditory brainstem responses (ABR) were recorded at different repetition rates. The study was aimed at finding an optimum repetition rate for the chirp stimulus that facilitates a short response detection time in the frequency domain. Design: Chirp-evoked ABR were recorded at six different stimulation rates between 20/s and 100/s. The stimulation level was 35 dB nHL. The mean harmonic related SNR was calculated, and the response detection time and rate were assessed using a detection algorithm. Study sample: A group of 80 sleeping and 27 awake newborns with normal hearing were included. Results: The highest mean harmonic-related SNR in both groups was found at 60/s. The signal-to-noise ratio (SNR) was significantly smaller for the awake newborns. A significantly shorter detection time can be achieved for both newborn groups at 60/s compared to the other rates tested. Response detection in the group of awake newborns profited more from the change to 60/s compared to the sleeping newborns. Conclusions: It can be expected that with this optimized stimulus paradigm a shorter test time and a higher specificity of the hearing screening can be reached.

Key Words::

• ABR
• auditory steady state response
• chirp stimulus
• hearing screening
• stimulus rate

Acknowledgements

The authors wish to acknowledge Eva Jüngling and Enrique Murillo, Department of Audiology, Würzburg University Hospitals, for their significant contribution to the collection of the electrophysiological data. Furthermore, the authors want to thank Manuel Don, House Ear Institute, Los Angeles, USA, for his helpful discussions.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.