Systematic and audiological indication criteria for bone conduction devices and active middle ear implants

Certain patients with conductive or mixed hearing loss can benefit from bone-conduction hearing devices or active middle ear implants. Available devices differ in coupling site, energy transfer from the sound processor to the implant, and the active or passive actuator technology. The audiological benefit of those devices depends on the maximum stable power output and the noise floor of the device, the degree and expected stability of the sensorineural hearing loss and the coupling efficiency with the aim on achieving a minumum of 30-35 dB effective dynamic range. The choice of the device is often a trade-off between the optimal audiological solution with respect to the hearing loss, technical device-related parameters and the expected coupling efficiency, the optimal surgical solution with respect to patho-anatomical aspects, device dimensions and the coupling site, invasiveness or surgical risks, and other patient factors with respect to the patients' wish and expectations, social aspects, device usability and connectivity. This review article lists all currently available implantable and conventional bone-conduction hearing devices and active middle ear implants with respect to technical features like maximum power output, market availability, and the expected effective output dynamic range.

Safety of active auditory implants in magnetic resonance imaging

Magnetic resonance imaging (MRI) has become the gold standard for the diagnosis of many pathologies. Using MRI in patients with auditory implants can however raise concerns due to mutual interactions between the implant and imaging device, resulting in potential patient risks. Several implant manufacturers have been working towards more MRI safe devices. Older devices are however often labelled for more stringent conditions, possibly creating confusion with patients and professionals. With this myriad of different devices that are implanted in patients for lifetimes of at least 20 years, it is crucial that both patients and professionals have a clear understanding of the safety of their devices. This work aims at providing an exhaustive overview on the MRI safety of active auditory implants. The available industry standards that are followed by manufacturers are outlined and an overview of the latest scientific developments focusing on the last five years is provided. In addition, based on the analysis of the adverse events reported to the Food and Drug Administration (FDA) and in literature within the past ten years, a systematic review of the most commonly occurring issues for patients with auditory implants in the MRI environment is provided. Results indicate that despite the release of more MRI conditional active hearing implants on the market, adverse events still occur. An extensive overview is provided on the MRI safety of active auditory implants, aiming to increase the understanding of the topic for healthcare professionals and contribute to safer scanning conditions for patients.

Outcomes after Application of Active Bone Conducting Implants

BACKGROUND

A bone conducting implant is a treatment option for individuals with conductive or mixed hearing loss (CHL, MHL) who do not tolerate regular hearing aids, and for individuals with single-sided deafness (SSD). An active bone conducting implant (ABCI) was introduced in 2012 with indication in CHL, MHL, and SSD, and it is still the only ABCI available. With complete implantation of the active transducer and consequent intact skin, a decrease in infections, skin overgrowth, and implant losses, all common disadvantages with earlier passive bone conducting implants, could be expected. Our Ear, Nose and Throat Department, a secondary care center for otosurgery that covers a population of approximately 365,000 inhabitants, was approved to implant ABCIs in 2012.

OBJECTIVES

Our aim was to conduct an evaluation of audiological and subjective outcomes after ABCIs.

METHOD

A cohort study with retrospective and prospective data collection was performed.The first 20 consecutive patients operated with an ABCI were asked for informed consent. The main outcome measures werepure tone and speech audiometry and the Glasgow Benefit Inventory (GBI).

RESULTS

Seventeen patients accepted to participate and 15 were able to complete all parts. Six patients had CHL or MHL. In this group the pure tone audiometry tests are comparable with an average functional hearing gain of 29.8 dB HL. With bilateral hearing, the mean Word Recognition Score (WRS) in noise was 35.7% unaided and 62.7% aided. Ten patients had the indication SSD. With the hearing ear blocked, the pure tone average was >101 dB HL, compared to 29.3 dB HL in sound field aided. With bilateral hearing, the mean WRS in noise was 59.7% unaided and 72.8% aided. The mean of the total GBI score was 42.1 in the group with CHL or MHL and 20.6 in the group with SSD.

CONCLUSIONS

The patients benefit from their implants in terms of quality of life, and there is a substantial hearing gain from the implant for patients with conductive or MHL. Patients with SSD benefit less from the implant than other diagnoses but the positive outcomes are comparable to other options for this group.