Clinical experience with the active middle ear implant Vibrant Soundbridge in sensorineural hearing loss

To evaluate gain at threshold level and speech recognition performance of 54 subjects with mild-to-severe symmetrical sensorineural hearing loss (SNHL) that received the active middle ear implant system Vibrant Soundbridge (VSB).

Pre- and postoperative assessments of hearing thresholds and monosyllabic word discrimination were performed in a homogeneous group of 54 adults who received a VSB system (VORP 502/AP 404) in an active middle ear implant (AMEI) program in a tertiary referral hospital. All subjects included in this study had mild-to-severe, predominately sloping SNHL. Gain at threshold level and speech recognition results were assessed for unaided and aided conditions using the patient's walk-in hearing aid (HA) and the VSB in a retrospective study design.

A comparison of pre- and postoperative unaided air conduction thresholds revealed a mean decrease in pure tone averages of 3.9 dB (0.25-8 kHz). Gain at threshold level (unaided thresholds minus AMEI-aided thresholds) was, on average, 20.9 dB at 0.5 kHz, 20.5 dB at 1 kHz, 23.8 dB at 2 kHz, 30.2 dB at 3 kHz, 36.1 dB at 4 kHz, 37.6 dB at 6 kHz and 37.9 dB at 8 kHz. Monosyllabic word discrimination at 65 dB SPL improved from a mean of 30% in the unaided condition to 44% for the HA-aided condition (p<0.05), with a further increase to 57% for the VSB-aided condition (p<0.05, compared to the HA).

The AMEI system VSB can be considered as an effective rehabilitation alternative in subjects with mild-to-severe SNHL and unsatisfying benefit from conventional hearing aids.