Factors associated with benefit of active middle ear implants compared to conventional hearing aids

Results and Quality of Life after Implantation of Active Middle Ear Implants

The provision of implantable hearing aids represents an area with high development and innovation potential. On the one hand, this review article provides an overview of current indication criteria for the treatment with active middle ear implants. On the other hand, outcome parameters as well as functional results after implantation of active middle ear implants are demonstrated and discussed. The focus is mainly placed on audiological results as well as the subjective health status. "Patient Reported Outcome Measures" (PROMs) have become an integral part of the evaluation of hearing implant treatment. Due to low evidence level criteria, the study situation regarding audiological as well as subjective outcome parameters is not satisfactory. The lack of an international consensus on accepted outcome parameters makes a meta-analytical analysis of results immensely difficult. In the studies published to date, patients with sensorineural hearing loss and patients with conductive or mixed hearing loss offered better speech recognition after implantation of an active middle ear implant compared to conventional hearing aids. Current analyses show a significant improvement in general as well as hearing-specific quality of life after implantation of an active middle ear implant. To date, no validated, hearing-specific quality-of-life measurement instruments exist for assessing the success of fitting in children. Especially in children with complex malformations of the outer ear and the middle ear, excellent audiological results were shown. However, these results need to be substantiated by quality-of-life measurements in future.

New Considerations for a Totally Implantable Active Middle Ear Implant

Totally implantable active middle ear implants (AMEI) provide full-time hearing amplification to those with moderate to severe sensorineural hearing loss. While technology in conventional hearing aids (CHA) has advanced greatly, limitations remain for people with active lifestyles, limited vision or dexterity, and hearing aid fit issues. Furthermore, direct-drive properties of AMEI are thought to provide those with inefficient middle ear transfer functions a distinct advantage in delivering prescribed sound to the cochlea, ultimately improving speech understanding with less distortion. AMEI safety, stability, and efficacy outcomes are well documented and fitting strategies continue to improve. Recent studies show how simple aided speech testing can help predict whether a patient struggling with CHA may instead benefit from an AMEI. Totally implantable AMEI continue to be a viable option for patients who cannot or will not utilize traditional hearing aids.

Design Study of a Round Window Piezoelectric Transducer for Active Middle Ear Implants

This report describes the design of a new piezoelectric transducer for round window (RW)-driven middle ear implants. The transducer consists of a piezoelectric element, gold-coated copper bellows, silicone elastomer (polydimethylsiloxane, PDMS), metal cylinder (tungsten), and titanium housing. The piezoelectric element is fixed to the titanium housing and mechanical resonance is generated by the interaction of the bellows, PDMS, and tungsten cylinder. The dimensions of PDMS and the tungsten cylinder with output characteristics suitable for compensation of sensorineural hearing loss were derived by mechanical vibrational analysis (equivalent mechanical model and finite element analysis (FEA)). Based on the results of FEA, the RW piezoelectric transducer was implemented, and bench tests were performed under no-load conditions to confirm the output characteristics. The transducer generates an average displacement of 219.6 nm in the flat band (0.1–1 kHz); the resonance frequency is 2.3 kHz. To evaluate the output characteristics, the response was compared to that of an earlier transducer. When driven by the same voltage (6 V_p), the flat band displacement averaged 30 nm larger than that of the other transducer, and no anti-resonance was noted. Therefore, we expect that the new transducer can serve as an output device for hearing aids, and that it will improve speech recognition and treat high-frequency sensorineural hearing loss more effectively.

Implantable Hearing Aids: Where are we in 2020?

Beginning in the late 20th century, implantable hearing aids were developed and used as an alternative for individuals who were unable to tolerate conventional hearing aids. Since that time, several devices have been developed, with four currently remaining on the international market (Med-el Vibrant Soundbridge, Envoy Esteem, Ototronix MAXUM, and Cochlear Carina). This review will briefly examine the history of middle ear implant development, describe current available devices, evaluate the benefits and limits of the technology, and consider the future directions of research in the field of implantable hearing aids.

Speech Perception Gap Is Predictive of an Active Middle Ear Implant Advantage

OBJECTIVE

Evaluate whether the difference between word recognition score (WRS) obtained unaided under earphone and with a hearing aid (HA), the speech perception gap (SPgap), is predictive of performance with a totally implantable active middle ear implant (AMEI).

STUDY DESIGN

Retrospective review of systematically collected data.

SETTING

Private otologic practice.

PATIENTS

One hundred thirty six ears (133 patients) with sensorineural hearing loss implanted with an AMEI. Subjects were 73.5% men, with mean age = 61.3 years.

INTERVENTION

Previous AMEI.

MAIN OUTCOME MEASURES

WRS with earphone at phonetically balanced maximum (PB-MAX), and with HA and AMEI at 50 dB HL. Differences between earphone, HA and AMEI word recognition, grouped as positive or negative speech perception gap (+SPgap/-SPgap) between two devices.

RESULTS

A +SPgap (WRS poorer with device than earphone) occurred in 86.0% of patients with HA and 42.3% with the AMEI. Mean SPgap = 24.7% with HA and 3.0% with AMEI (p ≤ 0.001). With a HA +SPgap, AMEI performance was better than HA by an average difference of 23.2% WRS, with AMEI more than HA in 82.9% of subjects. With HA -SPgap, the mean difference was 1.1% correct and AMEI more than HA in 47.4% of subjects (p ≤ 0.001 and p ≤ 0.002, for mean difference and percent of subjects, respectively). The larger the +SPgap (earphone-HA), the greater the advantage of AMEI over HA (r = 0.62, p ≤ 0.001).

CONCLUSION

A speech perception gap between earphone PB-MAX and aided word recognition score suggests a patient may have better speech perception with an AMEI than with his/her hearing aid. This information is useful for counseling patients who are not performing well or are unsatisfied with their hearing aid.

Three-year audiological outcomes of the latest generation middle ear transducer (MET) implant

PURPOSE

To evaluate the long-term audiological outcomes and safety of the latest generation of middle ear transducer (MET) among a group of Polish patients.

METHODS

Ten patients aged 48-72 years with bilateral sensorineural hearing loss (n = 8) and mixed hearing loss (n = 2) were included in this study. Pure tone audiometry, sound thresholds, word recognition scores in quiet and speech reception thresholds in noise were assessed. Medical and technical complication information was gathered.

RESULTS

All the patients underwent unilateral implantation with the latest generation Cochlear MET between 2014 and 2016. Mean length of follow-up was 3.7 years. Compared to the unaided condition, the implant provided significant functional gain (mean M = 26.1 dB) at 12 months follow-up. Compared to before surgery, average word recognition in quiet at 65 dB and at 80 dB SPL, as well as speech reception threshold in noise, were significantly better at 12 months. However, postoperative air conduction thresholds 6 months after implantation worsened by 10.3 dB (standard deviation SD = 5.8 dB). Postoperatively, three patients had skin problems around the processor, and one of them completely resigned from using the device 5 months after activation. Technical failures occurred in 4 cases. There were 9 out of 10 patients who still used the MET, but only 5 of them used the processor regularly (every day).

CONCLUSION

Despite changes in the transducer implemented by the manufacturer, we observed a significant number of adverse events in users of the latest generation of MET.

Earphone and Aided Word Recognition Differences in Cochlear Implant Candidates

OBJECTIVE

Compare word recognition scores for adults undergoing cochlear implant evaluations (CIE) measured using earphones and hearing aids.

STUDY DESIGN

Retrospective review of data obtained during adult CIEs.

SETTING

Tertiary cochlear implant center.

PATIENTS

Two hundred eight ears in 183 subjects with greater than 10% word recognition scores measured with earphones.

INTERVENTIONS/MAIN OUTCOMES MEASURED

Preoperative pure-tone thresholds and word recognition scores measured with earphones and hearing aids.

RESULTS

A review of audiological data obtained from 2012 to 2017 during adult CIEs was conducted. Overall, a weak positive correlation (r = 0.33, 95% confidence interval 0.17-0.40, p < 0.001) was observed between word recognition scores measured with earphones and hearing aids. Earphone to aided differences (EAD) ranged from -38 to +72% (mean 14.3 ± 19.9%). Consistent with EADs, 108 ears (51.9%) had earphone scores that were significantly higher than aided word recognition scores (+EAD), as determined by 95% confidence intervals; for 14 ears (6.7%), earphone scores were significantly lower than aided scores (-EAD). Moreover, of the patients with earphone word recognition scores ≥50%, 82.6% were CI candidates based on aided AzBio+10 dB SNR scores.

CONCLUSION

These results demonstrate the limited diagnostic value of word recognition scores measured under earphones for patients undergoing CIE. Nevertheless, aided word recognition is rarely measured before CIEs, which limits the information available to determine CI candidacy and referral for CIEs. Earlier and routine measurement of aided word recognition may help guide clinical decision making by determining the extent to which patients are achieving maximum benefit with their hearing aids or should consider cochlear implantation.