Normative Values for Click and 4000 Hz NB CE-Chirp Auditory Brainstem Responses in Neonates

Background: Auditory Brainstem Response (ABR) is essential for assessing neural integrity and hearing thresholds in infants. While CE-Chirp stimuli are increasingly popular for their superior morphology , there is a critical need for updated normative data using contemporary protocols of high rate modern stimuli.

Methods: We evaluated 165 neonates and infants (91 males, 74 females), stratified into five post-conceptional age (PCA) groups (40–64 weeks). Adhering to strict inclusion criteria, only subjects with normal hearing thresholds (≤15 dBnHL) were included. ABRs were recorded using air-conduction clicks and Narrow Band (NB) CE-Chirp LS stimuli.

Results: Detailed normative data were established for each of the five PCA groups, covering absolute latencies and interpeak intervals for all analyzed waves. Click stimuli revealed significantly prolonged latencies in males compared to females across all ages. Conversely, 4000 Hz NB CE-Chirp parameters showed no gender effects but demonstrated clear intensity and maturation-dependent shifts. As PCA increased, latencies and standard deviations decreased, reflecting neural maturation.

Conclusions: This study provides more detailed norms than previous research by utilizing a larger sample size, granular age-groupings, and a stricter threshold for normal hearing. The findings underscore the necessity of sex-specific norms for click-evoked ABR. These updated values offer a reliable clinical foundation to assist audiologists in accurate waveform identification and interpretation