Study of the factors related to air-bone gap in enlarged vestibular aqueduct.

Background: Over half of patients with enlarged vestibular aqueducts (EVA) will have an air-bonr gap (ABG), however, current research on audiology has focused on the influencing factors of air-conducted.

Objective: To retrospectively analyse the influencing factors and clinical manifestations of the bone-conduction threshold and ABG in patients with EVA.

Materials and methods: We included 286 patients with EVA; among them, 126 had full SLC26A4 gene sequence results. We performed a descriptive analysis of the bone-conduction threshold and explored the effect of age. Finally, we analyzed the relationship of ABG and SLC26A4 genes with the degree of vestibular aqueduct (VA) enlargement.

Results: Among 555 ears, 312 (57.8%) ears had ABG; approximately 94% of the patients' bone-conduction hearing is almost completely lost at frequencies of 2 and 4 kHz. There was no linear correlation between age and bone-conduction threshold (p > 0.05). ABG did not significantly differ according to the degree of VA enlargement and number of SLC26A4 allele mutations (p > 0.05).

Conclusions and significance: Among patients with EVA, ABG is mainly produced at low frequencies and is not significantly correlated with age, size of the VA opening or SLC26A4 genes, which could be attributed to the biomechanical effects.