Retrospective audiological analysis of bone conduction versus round window vibratory stimulation in patients with mixed hearing loss.

Objective: To compare audiological outcomes in mild-to-moderate mixed hearing loss patients treated with a bone-anchored hearing aid or an active middle-ear implant. Analysis aimed to refine criteria used in preoperative selection of implant type.

Design: Retrospective comparative analysis of audiological data. Follow-up time ranged between 0.55 and 8.8 years.

Study Sample: For detailed comparative analysis, 12 patients (six in each group) with comparable bone conduction thresholds and similar clinical characteristics were selected. A larger cohort of 48 patient files were used to evaluate overall audiological indication criteria (24 per group).

Results: In free-field tone audiometry, Baha patients showed mean aided thresholds between 40-48 dB, whereas hearing thresholds for VSB patients were 25-43 dB. Baha and VSB users had mean WRS of 56% and 82%, respectively, at 65 dB. Better speech understanding in noise was seen with the VSB.

Conclusion: Analysis of the main cohort (n = 48) showed that treatment with round window vibroplasty leads to better hearing performance than treatment with a bone-anchored hearing device, if the bone conduction pure-tone average (0.5 to 4 kHz) is poorer than 35 dB HL. Audiological analysis in the smaller comparative analysis showed similar findings.