Factors influencing auditory brainstem response changes in infants.

Background: To elucidate the factors influencing auditory brainstem response (ABR) threshold improvement in infants.

Methods: This retrospective study included 626 infants who underwent ABR at the our Health and Medical Center between 2016 and 2020. Preliminary assessment indicated that 352 infants had an ABR threshold ≥40 dBnHL in both ears. A second ABR examination was conducted 5 months after delivery. The participants were divided into the improved (improvement ≥20 dBnHL) and unchanged (improvement <20 dBnHL) groups. The associations between risk factors were evaluated. Furthermore, we measured and compared the latencies of waves I, III, and V between participants with normal hearing and those in the improved and unchanged groups.

Results: The improved and unchanged groups consisted of 185 and 167 participants, respectively. ABR deterioration occurred in one infant with unilateral congenital cytomegalovirus-associated hearing loss. Binary logistic regression analysis revealed that the presence of otitis media with effusion and Down syndrome were factors contributing to ABR threshold improvement. In the ABR waveform analysis, patients in the improved group who had otitis media with effusion exhibited prolonged latencies of waves I, III, and V. Conversely, patients in the unchanged group who had Down syndrome showed shortened I-V interval.

Conclusions: Half of the infants tested the second time showed improvement in ABR threshold. Children with congenital syndromes (such as Down syndrome) or otitis media with effusion should undergo a second ABR examination or other auditory assessments to ensure an accurate diagnosis of hearing loss.