Benefits of active middle ear implants over hearing aids in patients with sloping high tone hearing loss: comparison with 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.

Totally implantable active middle-ear implants: a large, single-surgeon cohort

OBJECTIVES

This study aimed to evaluate hearing outcomes and device safety in a large, single-surgeon experience with the totally implantable active middle-ear implants.

METHODS

This was a retrospective case series review of 116 patients with moderate-to-severe sensorineural hearing loss undergoing implantation of active middle-ear implants.

RESULTS

Mean baseline unaided pure tone average improved from 57.6 dB before surgery to 34.1 dB post-operatively, signifying a mean gain in pure tone average of 23.5 dB (p = 0.0002). Phonetically balanced maximum word recognition score improved slightly from 70.5 per cent to 75.8 per cent (p = 0.416), and word recognition score at a hearing level of 50 dB values increased substantially from 14.4 per cent to 70.4 per cent (p < 0.0001). Both revision and explant rates were low and dropped with increasing surgeon experience over time.

CONCLUSION

This study showed excellent post-operative hearing results with active middle-ear implants with regard to pure tone average and word recognition score at a hearing level of 50 db. Complication rates in this case series were significantly lower with increasing experience of the surgeon. Active middle-ear implants should be considered in appropriate patients with moderate-to-severe sensorineural hearing loss who have struggled with conventional amplification and are good surgical candidates.

Revision of active middle ear implants (AMEI): causes, surgical issues and rehabilitative transition at a single implanting center

PURPOSE

To report on failures related to active middle ear implants (AMEI) surgery, within a series of subjects treated at a single Implanting Center.

METHODS

A retrospective review of 79 cases of implanted AMEI has been performed to report the failure ratio, the causes for the failure and the selected rehabilitative solution. The AMEI included 25 Vibrant Soundbridge^® (Medel, Innsbruck, Austria), 20 as round window vibroplasty (RW-VSB) for mixed hearing loss, 5 as incus-vibroplasty for sensorineural hearing loss; 7 MET/Carina^® (Cochlear, Melbourne, Australia), 2 MET for mixed and sensorineural hearing loss, 5 Carina for sensorineural hearing loss; 43 Esteem^® (EnvoyMedical, St Paul, USA) for sensorineural hearing loss; 3 Maxum^® (Ototronics, Texas, USA) for sensorineural hearing loss; 1 Codacs^® (Cochlear, Melbourne, Australia) for severe mixed hearing loss.

RESULTS

The overall complication rate affected 20% of the implanted devices, individually ranging from 6.9 to 100%. Hardware system failures were recorded in all the AMEI, ranging from 10 to 50%. The alternative auditory rehabilitation included replacement of the same system in 2 cases, use of a conventional hearing aid in 3 cases, Cochlear implantation in 4 cases and implantation in the contralateral ear in 2 cases.

CONCLUSION

The present clinical experience showed that, in spite of the successful functional rate displayed by the majority of the AMEI implantees, complications may occur to a certain percentage of cases and should prompt the professionals to select alternative solutions, starting from the (re)adoption of a conventional hearing aid and ending up to Cochlear implantation.

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.

Concept and Evaluation of a New Piezoelectric Transducer for an Implantable Middle Ear Hearing Device

Implantable middle ear hearing devices (IMEHDs) have been developed as a new technology to overcome the limitations of conventional hearing aids. The piezoelectric cantilever transducers currently used in the IMEHDs have the advantages of low power consumption and ease of fabrication, but generate less high-frequency output. To address this problem, we proposed and designed a new piezoelectric transducer based on a piezoelectric stack for the IMEHD. This new transducer, attached to the incus body with a coupling rod, stimulates the ossicular chain in response to the expansion-and-contraction of its piezoelectric stack. To test its feasibility for hearing loss compensation, a bench testing of the transducer prototype and a temporal bone experiment were conducted, respectively. Bench testing results showed that the new transducer did have a broad frequency bandwidth. Besides, the transducer was found to have a low total harmonic distortion (<0.75%) in all frequencies, and small release time (1 ms). The temporal bone experiment further proved that the transducer has the capability to produce sufficient vibrations to compensate for severe sensorineural hearing loss, especially at high frequencies. This property benefits the treatment of the most common sloping high-frequency sensorineural hearing loss. To produce a 100 dB SPL equivalent sound pressure at 1 kHz, its power consumption is 0.49 mW, which is low enough for the transducer to be utilized in the IMEHD.