Patient selection for incus body coupling of a totally implantable middle ear implant

Objective-To evaluate audiologic selection criteria for incus body coupling (IBC) of a totally implantable middle ear implant (TI-MEI) for the treatment of sensorineural hearing loss (SNHL). Material and Methods-The protocol is specified in the Investigational Device Exemption of a Food and Drug Administration-approved multicenter clinical trial. The prospective study compared pre- and postoperative hearing levels using each patient as their own control. In addition, an implant on/off comparison was made. All patients had a follow-up interval of at least 6 months. Audiologic assessment tests included speech discrimination in quiet as the primary efficacy variable and pure-tone audiometry (aided thresholds), gain, speech recognition in noise and subject satisfaction using standardized questionnaires and visual analog scales (VASs) as secondary efficacy variables. The study group of patients (n = 13) was divided into 3 subgroups based on their pure-tone and speech discrimination scores: Group A consisted of 6 patients, Group B 9 patients and Group C of all 13 patients. All patients suffered from long-standing bilateral moderate to severe SNHL. Five patients were dissatisfied hearing aid (HA) users and eight subjects could not wear HAs. All patients were implanted with a TI-MEI which was coupled to the incus body. The amplification level of the device was set postoperatively using inductive digital fitting based on "most comfortable loudness" specifications. Results-The implant produced median improvements from 30% (optimally fit bilateral HAs; n = 5) and 50% (HA non-users; n = 8) to 70% word recognition at 60 dB SPL. Average word recognition scores at 60, 80 and 90 dB SPL in Groups A and B showed increases from 42% (interquartile range +27%, -12%) to 93.5% (+3%, -5%) and 92.5% (+3%, -7%), respectively. In the presence of background noise, the sentence recognition threshold ranged from -2 to 1 dB signal-to-noise ratio. Maximum amplification was 50 dB at 3 kHz and 55 dB at 4 kHz. In Groups A and B, VASs revealed improvements in both natural sound impression and clarity from 62-70% of a natural sound impression to maximum scores of 100%. Using the standardized Gothenburg profile, subjective evaluations of hearing, orientation, social behavior and self-confidence reached 96-98%, 92-96% and 84-92% of the maximum score for Groups A-C, respectively. Conclusions-In selected cases, IBC of the TI-MEI investigated herein may be indicated for the treatment of SNHL, prov