Hearing loss trajectory and prediction model for children with enlarged vestibular aqueduct

Purpose: To explore how hearing changes over time and the characteristics associated with progressive hearing loss in children with enlarged vestibular aqueduct (EVA), and develop a prediction model for anticipation of hearing progression probability.

Methods: A retrospective analysis was conducted on 48 children (92 ears) diagnosed with EVA. A total of 314 audiograms were included in the analysis of hearing loss trajectories using linear mixed-effects model. Progressive hearing loss was defined based on the difference between the initial and final hearing threshold. All participants had underwent one or two gene detection methods, including deafness gene screening and SLC26A4 whole coding exon sequencing.

Results: The pure-tone thresholds (PTTs) at frequencies of 500 Hz, 1000 Hz, 2000 Hz, 4000 Hz and the average are expected to increase by 0.34, 0.49, 0.54, 0.57, and 0.55 dB HL per each additional month. Age and genotypes have an interactive effect on PTT at frequencies of 500 Hz, 1000 Hz, and the average. The hazard ratio for the genotype without SLC26A4 c.919-2 A > G mutation was 4.91 (95 % confidence interval 1.76-13.7, P < 0.01). This prediction model fitted using age, initial average PTT, midpoint size of vestibular aqueduct, incomplete partition type II, and genotypes of SLC26A4 showed strong consistency and differentiation.

Conclusion: These findings reveal that the PTT would deteriorate over time in patients with EVA. The hearing threshold at high frequency and genotype without c.919-2 A > G heterozygous mutation deteriorated relatively fast. Genotype is an important predictive factor and the nomogram helps to predict progressive hearing loss.