Normal reference values of low frequency specific air-conducted auditory brainstem responses among normal hearing children of different ages: A retrospective observational study.

Abstract

To explore and compare the normal reference values (NRV) for low frequency specific air-conducted tone-burst auditory brainstem response (tb-ABR) among children of different ages and with normal hearing, because tb-ABR is often used to supplement the lack of click-evoked ABR (click-ABR) frequency but the NRV of this response threshold in different populations remain inconclusive. This retrospective observational study included children younger than 5 years of age with normal hearing in Hubei Province between November 2020 and September 2021. These children came to center of audiology for audiological examination including click-ABR due to different purposes and had accepted suggestion of tb-ABR test (0.5kHz, 1kHz). The children were divided into 5 groups according to age (0-12, 13-24, 25-36, 37-48, and 49-60 months of age), and 20 children (40 ears) met the inclusion criteria were selected from each group. The responding thresholds, peak latencies (PL), and inter-peak latencies (IPL) of the major waves were counted and compared in each group. NRV of responding thresholds (dBnHL) in children aged 0-12, 13-24, 25-36, 37-48, and 49-60 months were 27.25±9.47, 22.63±5.31, 21.5±5.33, 18.25±5.83, and 21.63±6.24at 0.5kHz, and 23.63±7.16, 20.88±7.06, 22±4.21, 17.75±6.09, and 21.38±4.53at 1kHz, respectively. The response thresholds of children aged 0-12 months were significantly higher compared to children in other age groups at 0.5kHz (all P<0.05) and significantly higher than in children aged 37-48 months at 1kHz(P<0.05). There were significant differences among children of different ages in Wave III (P<0.001) and Wave V (P<0.001) in the peak latencies, and Waves I-III (P=0.003) and Waves I-V (P<0.001) in the inter-peak latencies at 0.5kHz. Also, there were significant differences among children of different ages in Wave III and Wave V in the PL, and Waves I-III, Waves III-V, and Waves I-V in the IPL at 1kHz (all P<0.001). The NRV of tb-ABR at 0.5kHz and 1kHz might differ among children of different ages. Newborn infants (<12 months old) might have a higher response threshold, while children aged 37-48 months might have a lower response threshold. However, it was a retrospective analysis with a small sample size, prospective contrast studies with larger samples are needed in the future.