Indications and candidacy for active middle ear implants

Influence of Age on Speech Recognition in Noise and Hearing Effort in Listeners with Age-Related Hearing Loss

The aim of this study was to measure how age affects the speech recognition threshold (SRT50) of the Oldenburg Sentence Test (OLSA) and the listening effort at the corresponding signal-to-noise ratio (SNRcut). The study also investigated the effect of the spatial configuration of sound sources and noise signals on SRT50 and SNRcut. To achieve this goal, the study used olnoise and icra5 noise presented from one or more spatial locations from the front and back. Ninety-nine participants with age-related hearing loss in the 18-80 years age range, specifically in the 18-30, 31-40, 41-50, 51-60, 61-70, and 71-80 age groups, participated in this study. Speech recognition and listening effort in noise were measured and compared between the different age groups, different spatial sound configurations and noise signals. Speech recognition in noise decreased with age and became significant from the age group of 50-51. The decrease in SRT50 with age was greater for icra5 noise than for olnoise. For all age groups, SRT50 and SNRcut were better for icra5 noise than for olnoise. The measured age-related reference data for SRT50 and SNRcut can be used in further studies in listeners with age-related hearing loss and hearing aid or implant users.

New technology can benefit established middle ear implant users: Samba 2 vs previous models of audio processors for Vibrant Soundbridge

Introduction

The Vibrant Soundbridge (VSB) is a semi-implantable hearing aid for patients with various types of hearing loss and has been available for over 25 years. Recently, new audio processors with advanced signal processing, noise reduction, and multi-microphone technology have appeared. The aim of this study is to compare the benefits of using the newest Samba 2 processor to the previous generation processors in a group of experienced VSB users.

Methods

There were 22 experienced VSB users (mean time of using VSB was 9 years, SD = 2) who had their processor (D404 or Amadé) upgraded to the newest model (Samba 2). The mean age of the subjects was 56 years (SD = 20). Assessments were made by free-field audiometry, speech reception in quiet and noise, and Patient-Reported Outcome Measures (PROMs).

Results

Hearing tests in free field showed statistically significant improvements in hearing sensitivity and speech discrimination in quiet and noise with the Samba 2 audio processor compared to the earlier technology. PROMs confirmed the benefits of using the newest audio processor and there was more satisfaction in terms of usability.

Conclusions

Access to modern technology for VSB patients provides measurable benefits.

Battery Lifespan of an Implantable Middle Ear Device

Background: The Carina system (Cochlear Ltd., Sydney, Australia) is a totally implantable device providing acoustic amplification in adult patients with moderate-to-severe sensorineural or mixed hearing loss. One of the main concerns about such a totally implantable device has been represented by the subcutaneous battery lifespan. The aim of this article is to report the analysis of battery performances in a series of Carina-implanted patients after a long follow up. Methods: In this retrospective study, the technical data of a series of patients implanted with the Carina middle ear implant in our clinic have been analysed, extracting the data from the log of telemetric measures. Results: The mean lifespan cutback was 0.43 h/years (from 0 to 0.71 h/year), with a strong negative significant correlation between the follow-up period and the percentage of battery residual lifespan. Conclusion: The lifespan of the Carina’s battery seems consistent with the manufacturer statement of a pluri-decennial lifespan, avoiding the need of an early surgical substitution and providing a full day of use of the system even after up to 12 years from the implantation.

Long-Term Follow-Up of the Auditory Threshold After a Fully Implantable Middle Ear Implant

A fully implantable active middle ear device has been proposed and indicated for the rehabilitation of bilateral moderate or moderate-to-severe sensorineural hearing loss, assuming it would overcome the disadvantages of a conventional hearing aid. The indications have further been extended to severe or severe-to-profound forms of hearing loss in the case of an expected limited or null efficacy of hearing aids. While the literature has highlighted several positive aspects of the device, including a better quality of life related to its invisibility, the improvement of auditory and perceptual functions has not been controlled for throughout a long period of follow-up. The present study aimed to verify the behavior of the auditory threshold, especially the bone conduction (BC) component, in the implanted ear in a group of implantees affected by initial bilateral symmetric hearing loss of different severity grades. The BC threshold was assessed preoperatively at activation and at the last follow-up (ranging from 4 to 12 years) in the implanted ear, and preoperatively and at the last follow-up in the contralateral ear, to monitor eventual deteriorated values in both ears over time. The pure tone average (PTA; 250–4,000 Hz), speech reception threshold (SRT) and the maximum word recognition score as a percentage (% WRS) and in dB HL were measured in the implanted ear to verify the efficacy of the device after the first fitting at device activation. A significant worsening of the BC threshold with respect to the baseline threshold was noticed during further follow-up. When comparing the implanted ear with the contralateral ear, a significant worsening of the bone PTA was assessed in the former with respect to the contralateral ear. Despite the worsened hearing found in the implanted ears, the beneficial gains in PTA and speech audiometry observed at the first activation remained constant at the follow-up, thus showing an extension of the efficacy of this device in aiding those with up to the most severe forms of sensorineural hearing loss.

Speech perception and hearing effort using a new active middle ear implant audio processor

Purpose

The Vibrant Soundbridge (VSB) was introduced in 1996, and the fourth generation of the audio processor recently released. This clinical study evaluates the audiological performance and subjective satisfaction of the new SAMBA 2 audio processor compared to its predecessor, SAMBA.

Method

Fifteen VSB users tested both audio processors for approximately 3 weeks. Air conduction and bone conduction thresholds and unaided and aided sound field thresholds were measured with both devices. Speech performance in quiet (Freiburg monosyllables) and noise (OLSA) was evaluated as well as subjective listening effort (ACALES) and questionnaire outcomes (SSQ12 and APSQ). In addition, data from 16 subjects with normal hearing were gathered on sound field tests and ACALES.

Results

Both audio processors showed substantial improvement compared to the unaided condition. The SAMBA and SAMBA 2 had comparable performance in sound filed thresholds, while the SAMBA 2 was significantly better in speech in quiet, speech in noise, reduced listening effort, and improved subjective satisfaction compared with the SAMBA.

Conclusion

The SAMBA 2 audio processor, compared to its predecessor SAMBA, offers improved performance throughout the parameters investigated in this study. Patients with a VSB implant would benefit from an upgrade to SAMBA 2.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00405-021-07207-4.

Audiological Results with the SAMBA Audio Processor in Comparison to the Amadé for the Vibrant Soundbridge

BACKGROUND

Since its introduction in 1996, the Vibrant Soundbridge (VSB) has been upgraded with several improved generations of processors. As all systems are compatible, implanted patients can benefit from new technologies by upgrading to the newest processor type available.

OBJECTIVES

The aim of this study was to compare the performance of the new (current) SAMBA processor with the previous Amadé processor.

METHODS

Twenty subjects monaurally implanted with a VSB and the Amadé processor tested the new SAMBA processor for a trial period of 4 weeks. We measured air conduction and bone conduction thresholds, unaided thresholds, and aided free field thresholds with both devices. Speech performance in quiet using the Freiburg monosyllabic test at 65 dB SPL (S0) was compared. The speech intelligibility in noise was determined using the Oldenburg sentence test measured in different listening conditions (S0NVSB/S0Ncontra) and microphone settings (omni/directional vs. adaptive directivity).

RESULTS

Word recognition scores in quiet with the SAMBA were still significantly lower than with the Amadé after the 4 weeks trial period but improved over the following year. Speech intelligibility with the SAMBA was significantly better than with the Amadé in omnidirectional mode and comparable with the Amadé in directional mode. Hence, the adaptive directionality provides an advantage in difficult hearing situations such as noisy environments. The subjective benefit was evaluated using the Abbreviated Profile of Hearing Aid Benefit and the Speech, Spatial and Qualities-C questionnaire. Results of the questionnaires demonstrate an overall higher level of satisfaction with the new SAMBA speech processor than with the older processor.

CONCLUSION

The SAMBA enables similar speech perception in quiet but more flexible adaptation in acoustically challenging environments compared to the previous Amadé processor.

Air- and Bone-Conducted Sources of Feedback With an Active Middle Ear Implant

OBJECTIVES

Active middle ear implants (AMEI) have been used to treat hearing loss in patients for whom conventional hearing aids are unsuccessful for varied biologic or personal reasons. Several studies have discussed feedback as a potential complication of AMEI usage, though the feedback pathway is not well understood. While reverse propagation of an acoustic signal through the ossicular chain and tympanic membrane constitutes an air-conducted source of feedback, the implanted nature of the device microphone near the mastoid cortex suggests that bone conduction pathways may potentially be another significant factor. This study examines the relative contributions of potential sources of feedback during stimulation with an AMEI.

DESIGN

Four fresh-frozen, hemi-sectioned, human cadaver specimens were prepared with a mastoid antrostomy and atticotomy to visualize the posterior incus body. A Carina active middle ear implant actuator (Cochlear Ltd., Boulder, CO) was coupled to the incus by two means: (1) a stereotactic arm mounted independently of the specimen and (2) a fixation bracket anchored directly to the mastoid cortical bone. The actuator was driven with pure-tone frequencies in 1/4 octave steps from 500 to 6000 Hz. Acoustic sound intensity in the ear canal was measured with a probe tube microphone (Bruel & Kjær, Nærum, Denmark). Bone-conducted vibration was quantified with a single-axis laser Doppler vibrometer (Polytec Inc., Irvine, CA) from both a piece of reflective tape placed on the skin overlying the mastoid and a bone-anchored titanium screw and pedestal (Cochlear Ltd., Centennial, CO) implanted in the cortical mastoid bone.

RESULTS

Microphone measurements revealed ear-canal pressures of 60-89 dB SPL, peaking in the frequency range below 2 kHz. Peak LDV measurements were greatest on the mastoid bone (0.32-0.79 mm/s with mounting bracket and 0.21-0.36 mm/s with the stereotactic suspension); peak measurements on the skin ranged from 0.05 to 0.15 mm/s with the bracket and 0.03 to 0.13 mm/s with stereotactic suspension.

CONCLUSION

AMEI produce both air- and bone-conducted signals of adequate strength to be detected by the implanted device microphone, potentially resulting in reamplification. Understanding the relative contribution of these sources may play an important role in the development of targeted mitigation algorithms, as well as surgical techniques emphasizing acoustic isolation.

Vibrant Soundbridge Implantation: Floating Mass Transducer Coupled with the Stapes Head and Embedded in Fat

Subtotal petrosectomy may be performed for refractory chronic middle ear diseases, such as massive cholesteatoma or recurrent otitis media. It involves permanent obliteration of the operative cavity, thus precluding the chance to restore conductive hearing via traditional inertial ossicular prostheses. The Vibrant Soundbridge (VSB) is an alternative option for hearing rehabilitation. Vibrant energy is delivered into the inner ear via a floating mass transducer (FMT), which can be coupled with any part of the middle ear acoustic transmission structure. To restore the hearing of a young woman with cholesteatoma, we combined subtotal petrosectomy with obliteration of the cavity and VSB implantation with an FMT coupled to the stapes head. Two years of follow-up demonstrated excellent auditory rehabilitation, improved sound source localization ability, and a lower speech recognition threshold. This study showed that the FMT works well in an obliterated cavity, and the experience acquired through this successful exploration is worth disseminating.

Contemporary imaging of auditory implants

There have been significant advances in the diversity and effectiveness of hearing technologies in recent years. Implanted auditory devices may be divided into those that stimulate the cochlear hair cells (bone conduction devices and middle ear implants), and those that stimulate the neural structures (cochlear implants and central auditory implants). Contemporary preoperative and postoperative imaging may be used to help individualise implant selection, optimise surgical technique and predict auditory outcome. This review will introduce the concepts behind auditory implants, and explains how imaging is increasingly used to aid insertion and evaluation of these devices.

Comparison of Alternative Coupling Methods of the Vibrant Soundbridge Floating Mass Transducer

The active middle ear implant Vibrant Soundbridge© provides a variety of coupling modalities of the floating mass transducer (FMT) to various structures of the ossicular chain and the round window. A retrospective analysis was performed on 125 subjects (n = 137 ears) (1) to compare the efficacy of the different FMT coupling modalities with increasing degree of hearing loss, (2) to compare the performance in speech outcome and the effective gain between the coupling types, and (3) to evaluate the risk of additional hearing loss of each coupling procedure. The patients were grouped according to their type of FMT coupling into incus vibroplasty (incus group, n = 59), round window vibroplasty with coupler (RWC group, n = 23), round window vibroplasty without coupler (RW group, n = 22), and oval window vibroplasty with coupler (OWC group, n = 33). For each coupling group, pre- and postoperative thresholds, the results of the Freiburg monosyllable test at 65 dB SPL, and the effective gain across frequencies (0.5-6 kHz) were evaluated. A logistic regression function was used to describe the relationship between word recognition scores (WRS, in % correct) and the mean bone conduction (BC) hearing loss. The surgical procedure had no clinically relevant effect on BC thresholds of patients in each coupling group. The BC pure tone average (PTA4) for 50% WRS predicted by the model function was similar for the incus (48.2 dB nHL), RW (47.8 dB nHL), and OWC (49.0 dB nHL) groups, but higher for the RWC group (67.9 dB nHL). However, the median WRS was 80% or better with no significant differences in speech perception between coupling types (Kruskal-Wallis test, p = 0.229). The effective gain shows an advantage for the incus coupling between 0.5 and 2 kHz over the other coupling types. The performance of the FMT coupling modalities is equally good for patients with a mild-to-moderate hearing loss, but the efficacy of coupling types differs for patients with greater hearing loss (>48 dB BC HL).