Bone Conduction Devices Research Articles

Comparison of Aided and Unaided Thresholds and Selection Processes of Contralateral Routing of Signal Hearing Aids and Implantable Bone Conduction Devices in Patients with Asymmetric Hearing Loss

Background and Objectives We reviewed the selection processes of contralateral routing of signal (CROS) hearing aids (HAs) and bone-conduction (BC) Has, and compared aided and unaided hearing thresholds. Subjects and Method Twenty-four patients with asymmetrical hearing loss who used BC HAs (n=12) and CROS HAs (n=12) were enrolled. The choice of two different HAs were compared with respect to the degree of hearing loss, the unaided hearing thresholds and functional gains. Results When the hearing thresholds of the better hearing ears were ＞30 dB HL, most (92%, 11 of 12) chose CROS rather than BC HAs, with significant difference (p=0.001). Both CROS and BC HAs groups showed significantly improved functional gains (46.6 dB and 53.4 dB, respectively). Aided air-conduction (AC) thresholds (40.2 dB HL) in the CROS group were similar to the AC thresholds (43.1 dB HL) of better hearing ears. However, the hearing threshold of Aided AC thresholds (35.8 dB HL) in BC HAs group were less than the BC thresholds (17.3 dB HL) of better hearing ears by 19 dB (p＜0.001). Conclusion Both groups showed significantly increased functional gains. CROS HAs were preferred when hearing thresholds in better hearing ears were ＞30 dB HL. The CROS group showed aided thresholds similar to the thresholds of better hearing ears, but the BC HAs group showed poorer aided thresholds than the thresholds of better hearing ears. For patients with asymmetric hearing loss, HAs should be selected based on the degree and types of hearing loss and the maximum output level of the selected device. Key words: Bone conduction ㆍ Contralateral routing of signal ㆍ Deafness ㆍ Hearing aids ㆍ Hearing loss ㆍ Single-sided

Cochlear implantation as a treatment for single-sided deafness and asymmetric hearing loss: a randomized controlled evaluation of cost-utility

BackgroundSingle-sided deafness (SSD) and asymmetric hearing loss (AHL) have recently been proposed as a new indication for cochlear implantation. There is still no recommended treatment for these hearing deficits, and most options considered rely on the transfer of sound from the poor ear to the better ear, using Contralateral Routing of the Signal (CROS) hearing aids or bone conduction (BC) devices. In contrast, cochlear implantation allows the poor ear to be stimulated and binaural hearing abilities to be partially restored. Indeed, most recently published studies have reported an improvement in the spatial localisation of an incoming sound and better speech recognition in noisy environments after cochlear implantation in SSD/AHL subjects. It also provides consistent relief of tinnitus when associated. These encouraging hearing outcomes raise the question of the cost-utility of this expensive treatment in an extended indication.MethodsThe final endpoint of this national multicentre study is to determine the incremental cost-utility ratio (ICUR) of cochlear implantation in comparison to the current standard of care in France through simple observation, using a randomised controlled trial. Firstly, the study comprises a prospective and descriptive part, where 150 SSD/AHL subjects try CROS hearing aids and a BC device for three weeks each. Secondly, the choice is made between CROS hearing aids, BC implanted device and cochlear implantation. Hearing outcomes and quality of life measurements are described after 6 months for the subjects who chose CROS, BC or declined any option. The subjects who opt for cochlear implantation are randomised between one group where the cochlear implant is inserted without delay and one group of simple initial observation. Hearing outcomes and quality of life measurements are compared after 6 months.DiscussionThe present study was designed to assess the efficiency of cochlear implantation in SSD/AHL. A favourable cost-utility ratio in this extended indication would strengthen the promising clinical results and justify a reimbursement by the health insurance. The efficiency of other options (CROS, BC) will also be described.Trial registrationThis research has been registered in ClinicalTrials.gov (http://www.clinicaltrials.gov/), the 29th July 2014 under the n°NCT02204618.

Feasibility of direct promontory stimulation by bone conduction: A preliminary study of frequency-response characteristics in cats

BackgroundAs an alternative pathway to air conduction, bone conduction is a multipathway process that transmits sound energy to the inner ear through the skull in general. Based on this mechanism, bone conduction devices (BCDs) have been used widely in the rehabilitation of hearing loss. Although great efforts have been devoted to improving BCDs, drawbacks still exist in most categories of BCDs due to the complicated process of bone conduction. We hypothesized that if a bone conduction transducer was placed on the cochlea to stimulate it directly, the attenuation would be minimized, and the frequency dependency would be different from that of the vibratory response induced by traditional BCDs. This study aimed to explore the feasibility of direct promontory stimulation and to investigate its frequency-response characteristics. MethodsMeasurements were conducted in twelve cat ears. To stimulate the promontory directly, the floating mass transducer (FMT) of the Vibrant Soundbridge© (VSB) implant was glued to the promontory coupled with an oval window (OW) coupler. Auditory brainstem response (ABR) and laser Doppler vibrometry (LDV) measurements were used to evaluate the auditory response induced by the FMT. In both measurements, the FMT was driven by direct voltage stimuli. ResultsABR waves could be induced under direct promontory stimulation by the FMT. In the frequency range of 1–12 kHz, the variation in the voltage threshold level were limited to 16 dB SPL with a maximum of 0.2 V at 1 kHz and a minimum of 0.04 V at 10 kHz. In the LDV measurements and the relative motion of the round window membrane (RWM) and the promontory were used to evaluate the cochlear response. The LDV results indicated a weak frequency dependency from 1 to 12 kHz. ConclusionDifferent from traditional stimulation via transcranial bone conduction, direct promontory stimulation is a new method in which a small bone conduction transducer stimulates the cochlear shell directly. The current experimental data demonstrate that it is feasible to generate sensations through bone conduction by stimulating the cochlea directly. Furthermore, the cochlear response induced by this type of stimulus in cats was weakly frequency dependent at frequencies ranging from 1 to 12 kHz. This study may provide a basis for the design of new transducers that can perform well over a wide range of frequencies.

Characteristics of Bone-Conduction Devices Simulated in a Finite-Element Model of a Whole Human Head.

Nowadays, many different kinds of bone-conduction devices (BCDs) are available for hearing rehabilitation. Most studies of these devices fail to compare the different types of BCDs under the same conditions. Moreover, most results are between two BCDs in the same subject, or two BCDs in different subjects failing to provide an overview of the results between several of the BCDs. Another issue is that some BCDs require surgical procedures that prevent comparison of the BCDs in the same persons. In this study, four types of skin-drive BCDs, three direct-drive BCDs, and one oral device were evaluated in a finite-element model of the human head that was able to simulate all BCDs under the same conditions. The evaluation was conducted using both a dynamic force as input and an electric voltage to a model of a BCD vibrator unit. The results showed that the direct-drive BCDs and the oral device gave vibration responses within 10 dB at the cochlea. The skin-drive BCDs had similar or even better cochlear vibration responses than the direct-drive BCDs at low frequencies, but the direct-drive BCDs gave up to 30 dB higher cochlear vibration responses at high frequencies. The study also investigated the mechanical point impedance at the interface between the BCD and the head, providing information that explains some of the differences seen in the results. For example, when the skin-drive BCD attachment area becomes too small, the transducer cannot provide an output force similar to the devices with larger attachment surfaces.

The Bonebridge implant in older children and adolescents with mixed or conductive hearing loss: Audiological outcomes

IntroductionFor children with conductive or mixed hearing loss, in whom use of conventional hearing aids is impossible or limited, use of bone conduction devices is recommended. The choice between the available types of devices depends mostly on the degree of hearing loss, age, and anatomical conditions. One device application in children older than 5 years is the Bonebridge implant. The aim of this study is to assess the benefits and safety of this device in children. MethodsThe material was a group of 11 older children and adolescents aged 10–17 years (mean = 14.7, SD = 2.45) with single-sided or bilateral conductive or mixed hearing loss, implanted unilaterally with the Bonebridge system at the World Hearing Center in Kajetany near Warsaw between 2014 and 2016. Benefits of the Bonebridge were assessed with warble tone audiometry and word audiometry in free field, as well as an APHAB (Abbreviated Profile of Hearing Aid Benefit) questionnaire before and after implantation. ResultsHearing tests showed a statistically significant improvement in hearing sensitivity and speech discrimination. Results of the questionnaire confirm the benefits of Bonebridge implantation to the older children in terms of their auditory performance under various acoustic conditions. ConclusionsAt a one-year follow up the Bonebridge system was found to be a safe, efficient, and effective tool for compensating for conductive or mixed hearing loss in older children and adolescents. For good anatomical conditions the Bonebridge implant provides a safe alternative to other popular bone conduction systems.

Development of a Novel Bone Conduction Verification Tool Using a Surface Microphone: Validation With Percutaneous Bone Conduction Users.

Objectives:To determine if a newly-designed, forehead-mounted surface microphone would yield equivalent estimates of audibility when compared to audibility measured with a skull simulator for adult bone conduction users.Design:Data was analyzed using a within subjects, repeated measures design. There were two different sensors (skull simulator and surface microphone) measuring the same hearing aid programmed to the same settings for all subjects. We were looking for equivalent results.Patients:Twenty-one adult percutaneous bone conduction users (12 females and 9 males) were recruited for this study. Mean age was 54.32 years with a standard deviation of 14.51 years. Nineteen of the subjects had conductive/mixed hearing loss and two had single-sided deafness.Methods:To define audibility, we needed to establish two things: (1) in situ–level thresholds at each audiometric frequency in force (skull simulator) and in sound pressure level (SPL; surface microphone). Next, we measured the responses of the preprogrammed test device in force on the skull simulator and in SPL on the surface mic in response to pink noise at three input levels: 55, 65, and 75 dB SPL. The skull simulator responses were converted to real head force responses by means of an individual real head to coupler difference transform. Subtracting the real head force level thresholds from the real head force output of the test aid yielded the audibility for each audiometric frequency for the skull simulator. Subtracting the SPL thresholds from the surface microphone from the SPL output of the test aid yielded the audibility for each audiometric frequency for the surface microphone. The surface microphone was removed and retested to establish the test–retest reliability of the tool.Results:We ran a 2 (sensor) × 3 (input level) × 10 (frequency) mixed analysis of variance to determine if there were any significant main effects and interactions. There was a significant three-way interaction, so we proceeded to explore our planned comparisons. There were 90 planned comparisons of interest, three at each frequency (3 × 10) for the three input levels (30 × 3). Therefore, to minimize a type 1 error associated with multiple comparisons, we adjusted alpha using the Holm–Bonferroni method. There were five comparisons that yielded significant differences between the skull simulator and surface microphone (test and retest) in the estimation of audibility. However, the mean difference in these effects was small at 3.3 dB. Both sensors yielded equivalent results for the majority of comparisons.Conclusions:Models of bone conduction devices that have intact skin cannot be measured with the skull simulator. This study is the first to present and evaluate a new tool for bone conduction verification. The surface microphone is capable of yielding equivalent audibility measurements as the skull simulator for percutaneous bone conduction users at multiple input levels. This device holds potential for measuring other bone conduction devices (Sentio, BoneBridge, Attract, Soft headband devices) that do not have a percutaneous implant.

Performance evaluation of a novel piezoelectric subcutaneous bone conduction device

ObjectivesEvaluation of the transfer function efficiency of a newly-developed piezo-electric actuator for active subcutaneous bone conduction hearing aid. MethodsThe experiments were conducted on four Thiel embalmed whole head cadaver specimens. A novel actuator based on piezo-electric transduction (PZTA), part of a subcutaneous bone conduction hearing aid device, was sequentially implanted on three locations: 1) Immediately posterior to pinna; 2) 50–60 mm posterior to pinna, approximately the same distance as between the BAHA (bone anchored hearing aid) location and the ear canal, but the same horizontal level as location 1; 3) the traditional BAHA location. Using a single point 3-dimensional laser Doppler vibrometer (LDV) system, three types of motion measurements were performed at the cochlear promontory for each stimulation location: 1) ipsilateral side, 2) contralateral side, 3) measurements 1 and 2 were repeated after mastoidectomy on the ipsilateral side. ResultsOn average, stimulation at locations 1 and 2 show a trend for higher promontory motion relative to location 3 (BAHA location) above 1 kHz. Stimulation at location 1 had an average improvement of 1–6 dB at 2–4 kHz, and 1–18 dB at 6–8 kHz. The spatial composition of the motion showed significant contributions from both in-plane and out-of-plane (along ear canal) motion components, with in-plane components being dominant at mid and high frequencies for locations 2 and 3. Stimulation at locations 1 and 3 produced similar transcranial attenuation at mid frequencies (0.6–4 kHz), with a potential trend of higher attenuation (seen in 3 or the 4 samples) for location 1 at higher frequencies (>4 kHz). The mastoidectomy affected negatively mostly the high frequencies (6–8 kHz) for stimulation at location 1, with no significant change for location 3. ConclusionThe sound transfer function efficacy of a novel subcutaneous bone conduction device has been quantified, and the influence of stimulation location and mastoidectomy have been analyzed based on promontory motion in Thiel-preserved cadaver heads.

Unilateral and Bilateral Audiological Benefit With an Adhesively Attached, Noninvasive Bone Conduction Hearing System.

To assess the audiological benefit of a noninvasive, adhesively attached bone conduction device (BCD1) in subjects with induced bilateral conductive hearing loss. Secondary objectives were to evaluate the additional benefit of bilateral fitting compared with unilateral fitting and to compare the outcomes with bone conduction devices attached to a softband (BCD2). Prospective nonrandomized crossover study. Tertiary referral center. Fifteen subjects with induced bilateral conductive hearing loss. Sound field thresholds, speech understanding in quiet and in multinoise were assessed in unaided, unilateral, and bilateral treatment conditions. In addition, sound localization was evaluated in uni- and bilateral treatment conditions. The outcomes of BCD1 and BCD2 were comparable. Sound field thresholds improved by 24.6 dB (BCD1) and 24.8 dB (BCD2) in the unilateral and 26.8 dB (BCD1) and 25.1 dB (BCD2) in the bilateral treatment condition. Speech reception thresholds (SRTs) in quiet improved by 20.0 dB (BCD1) and 21.7 dB (BCD2) in the unilateral and by 22.7 dB (BCD1) and 21.5 dB (BCD2) in the bilateral condition. If speech was presented from the front, SRTs in noise were improved by 3.6 dB and 4.2 dB (unilateral) and by 4.5 dB and 4.4 dB (bilateral) for BCD1 and BCD2, respectively. With speech presented from the unilateral side, SRTs were improved by 4.0 dB and 4.7 dB (unilateral) and 3.8 dB and 4.8 dB (bilateral) compared with the unaided situation. If noise was presented from the contralateral side, small differences (-0.6 dB and -0.1 dB) were observed. Bilateral fitting brought additional benefits for speech understanding in noise and sound localization. Both bone conduction devices seem to be a valid treatment for patients with conductive hearing loss and minor sensorineural hearing loss component.

Improved directional hearing of children with congenital unilateral conductive hearing loss implanted with an active bone-conduction implant or an active middle ear implant

Different amplification options are available for listeners with congenital unilateral conductive hearing loss (UCHL). For example, bone-conduction devices (BCDs) and middle ear implants. The present study investigated whether intervention with an active BCD, the Bonebridge, or a middle ear implant, the Vibrant Soundbridge (VSB), affected sound-localization performance of listeners with congenital UCHL. Listening with a Bonebridge or VSB might provide access to binaural cues. However, when fitted with the Bonebridge, but not with a VSB, binaural processing might be affected through cross stimulation of the contralateral normal hearing ear, and could interfere with processing of binaural cues. In the present study twenty-three listeners with congenital UCHL were included. To assess processing of binaural cues, we investigated localization abilities of broadband (BB, 0.5–20 kHz) filtered noise presented at varying sound levels. Sound localization abilities were analyzed separately for stimuli presented at the side of the normal-hearing ear, and for stimuli presented at the side of the hearing-impaired ear. Twenty-six normal hearing children and young adults were tested as control listeners. Sound localization abilities were measured under open-loop conditions by recording head-movement responses. We demonstrate improved sound localization abilities of children with congenital UCHL, when listening with a Bonebridge or VSB, predominantly for stimuli presented at the impaired (aided) side. Our results suggest that the improvement is not related to accurate processing of binaural cues. When listening with the Bonebridge, despite cross stimulation of the contralateral cochlea, localization performance was not deteriorated compared to listening with a VSB.

The current status and applications of implantable bone-conduction devices

Implantable bone-conduction devices are characterized by the fact that the vibration is transmitted through bone conduction. The technology and surgical techniques in the application of implantable bone-conduction devices have developed considerably in recent years, experiencing a transformation from percutaneous to transcutaneous implantation. This article reviewed current developments in the types, surgical indications, and complications, as well as compared between the various bone-conduction devices to provid references for clinical application.

Sound-localization performance of patients with single-sided deafness is not improved when listening with a bone-conduction device

An increased number of treatment options has become available for patients with single sided deafness (SSD), who are seeking hearing rehabilitation. For example, bone-conduction devices that employ contralateral routing of sound (CROS), by transmitting acoustic bone vibrations from the deaf side to the cochlea of the hearing ear, are widely used. However, in some countries, cochlear implantation is becoming the standard treatment. The present study investigated whether CROS intervention, by means of a CROS bone-conduction device (C-BCD), affected sound-localization performance of patients with SSD. Several studies have reported unexpected moderate to good unilateral sound-localization abilities in unaided SSD listeners. Listening with a C-BCD might deteriorate these localization abilities because sounds are transmitted, through bone conduction to the contralateral normal hearing ear, and could thus interfere with monaural level cues (i.e. ambiguous monaural head-shadow cues), or with the subtle spectral localization cues, on which the listener has learned to rely on. The present study included nineteen SSD patients who were using their C-BCD for more than five months. To assess the use of the different localization cues, we investigated their localization abilities to broadband (BB, 0.5–20 kHz), low-pass (LP, 0.5–1.5 kHz), and high-pass filtered noises (HP, 3–20 kHz) of varying intensities. Experiments were performed in complete darkness, by measuring orienting head-movement responses under open-loop localization conditions. We demonstrate that a minority of listeners with SSD (5 out of 19) could localize BB and HP (but not LP) sounds in the horizontal plane in the unaided condition, and that a C-BCD did not deteriorate their localization abilities.

Evaluation of an abutment-level superpower sound processor for bone-anchored hearing.

Performance of an abutment-level superpower sound processor for bone-anchored hearing, the Ponto 3 SuperPower from Oticon Medical (BCD2), was compared to an earlier model from Oticon Medical (BCD1). A comparative study in which each patient serves as its own control. Tertiary clinic. Eighteen experienced BCD1 users with profound mixed hearing loss. Speech reception thresholds in noise; APHAB and SSQ questionnaires. In a group of 18 patients with severe mixed hearing loss, the performance of a recently introduced bone conduction device (BCD2) is evaluated relative to that of an earlier model (BCD1). Speech reception thresholds for the sentence-in-noise test in the speech and noise frontal condition are not significantly different (P>.05) for BCD1 and BCD2. Speech reception thresholds for frontal speech and three identical noise sources are 1.7 dB lower for BCD2 than for BCD1 (P<.05). With the APHAB questionnaire, the score for background noise is significantly lower (P<.01), that is more favourable, for BCD2 than for BCD1 with an effect size of 0.91. The APHAB domain scores for ease-of-communication, reverberation and aversiveness of loud sounds are not significantly different for both devices (P>.05). Scores for the speech, spatial and quality of hearing domains of the SSQ questionnaire are significantly higher (P<.01), that is more favourable, for BCD2 than for BCD1 with effect sizes of 1.22, 0.71 and 1.05, respectively. Scores for the SSQ-factors "speech understanding," "spatial," "clarity, separation and identification" and "listening effort and concentration" were all significantly higher (P<.05) for BCD2 than for BCD1, with effect sizes of 1.28, 0.64, 0.98 and 0.78, respectively. On a proprietary questionnaire, 16 patients indicate a preference for BCD2 over BCD1 for conversations in a small group and two patients have no preference for either device. In a large group, one patient prefers BCD1, six patients have no preference, and eleven patients prefer BCD2. When listening to music, all patients prefer BCD2 over BCD1, with a strong preference for BCD2 for seven patients. When asked for an overall preference, all patients prefer BCD2 over BCD1, with nine patients strongly preferring BCD2. The lower speech reception thresholds in noise with BCD2 relative to BCD1 can be attributed to the "speech omni" directionality mode of BCD2. The combination of an improved directionality for primarily low-level inputs and a higher maximum force output, relevant for mid- and high-level inputs, results in a clear preference for BCD2 over BCD1.

Transmastoid implantability of an active transcutaneous bone conduction implant in adults with regard to the underlying pathology: a radiological simulation study

Objectives: To compare the feasibility of transmastoid implantation of an active transcutaneous bone conduction device (BCD) in the most important pathologies of the temporal bone and the impact of implant lifts in adulthood.Methods: First, clinical predominant pathologies for implantation of this BCD were evaluated by a literature review. Then, high-resolution CT of 240 temporal bones with neuro-otologic diseases (NOD), chronic otitis media (COM), or cholesteatoma, respectively, were investigated regarding their implantability, using a radiological simulation program.Results: Chronic inflammatory diseases (CID) of the temporal bone with or without cholesteatoma account for most adults scheduled for an active BCD. Complete implantation was possible in almost all cases with NOD as well as COM, requiring an implant lift in 50% of COM and 20% of NOD (p = .025) cases. In contrast, in subjects with cholesteatoma, implantation required an additional tool in 92% of cases, leading to 59% implantability rate in these temporal bones.Conclusion: Adult subjects with CID of the temporal bone show more limiting anatomical conditions for transmastoid placement of an active transcutaneous BCD than those with single-sided deafness. Implant lifts increase the implantability significantly in subjects with COM and particularly in those with cholesteatoma.

Direct bone conduction stimulation: Ipsilateral effect of different transducer attachments in active transcutaneous devices

Active transcutaneous bone conduction devices, where the transducer is implanted, are used for rehabilitation of hearing impaired patients by directly stimulating the skull bone. The transducer and the way it is attached to the bone play a central role in the design of such devices. The actual effect of varying the contact to bone has not been addressed yet. The aim of this study is therefore to compare how different attachment methods of the transducer to the bone for direct stimulation affect the ear canal sound pressure and vibration transmission to the ipsilateral cochlea.Three different attachments to the bone were tested: (A) via a flat small-sized surface, (B) via a flat wide surface and (C) via two separated screws. Measurements were done on four human heads on both sides. The attachments were compared in terms of induced cochlear promontory velocity, measured by a laser Doppler vibrometer, and ear canal sound pressure, measured by a low noise microphone. A swept sine stimulus was used in the frequency range 0.1–10 kHz.On an average level, the attachment method seems to affect the transmission mainly at frequencies above 5 kHz. Furthermore, the results suggest that a smaller contact surface might perform better in terms of transmission of vibrations at mid and high frequencies. However, when considering the whole frequency range, average results from the different attachment techniques are comparable.

Single-center Experience of Over a Hundred Implantations of a Transcutaneous Bone Conduction Device.

To assess outcomes with a novel passive transcutaneous bone conduction device (t-BCD). Prospective data collection and patient review. Tertiary referral center. Patients who underwent implantation with the t-BCD between November 2013 and September 2016. Implantation of BAHA Attract. Surgical outcome, patient reported outcomes including the "Glasgow Benefit Inventory" and the "Client Oriented Scale of Improvement" for adults and the "Speech, Spatial and Qualities of Hearing scale" (SSQ-12) for children. One hundred five patients were implanted. Numbness superior to the incision was commonly noticed. Four patients (3.8%) developed skin tenderness and redness that settled with conservative measures. Among those patients who had a conversion from a percutaneous Bone Conduction Hearing Device (BCHD) to the t-BCD (n=15), 1 (0.9%) developed seroma and 2 (1.9%) developed skin dehiscence at the edge of the implant magnet. Significant improvement in Client Oriented Scale of Improvement and Glasgow Benefit Inventory scores with a global satisfaction of 84% and 77.4% was observed for those previously aided and unaided respectively, with use of the device. A 22% improvement in SSQ-12 mean score was observed in the pediatric population. This is the largest single-center series reported on this t-BCD. The complication rate is small but caution is required in patients of conversion from a percutaneous BCHD. The patients' satisfaction is high and the need for aftercare is minimal. Cost-effectiveness evaluation of these devices, development of core outcome sets and well-designed, prospective trials to compare the different BCHDs should be the focus of future research.

The IPS-scale: A new soft tissue assessment scale for percutaneous and transcutaneous implants for bone conduction devices.

Percutaneous titanium implants for bone conduction devices (BCDs) have offered, since 1977, a solution for patients with hearing loss not treatable by conventional hearing aids, such as patients with chronic ear infections or microtia and/or ear canal atresia. Percutaneous implants imply a continuous breach in the mechanical defensive barrier of the skin. To compensate for this breach, immunological mechanisms in the subcutaneous tissue surrounding the implant become more active. This article is protected by copyright. All rights reserved.

Systematic Review on the Trial Period for Bone Conduction Devices in Single-Sided Deafness: Rates and Reasons for Rejection.

To systematically review the literature to evaluate the trial period of bone conduction devices (BCDs) for adult patients with single-sided deafness (SSD). The PubMed, Embase, and Cochrane Library databases were searched from their inception up to August 15, 2016 for SSD, BCD, and their synonyms. In total, 523 articles were retrieved, of which 12 satisfied the eligibility quality criteria. Our outcomes of interest were: 1) the BCD implantation rejection percentage, 2) reasons to reject BCD implantation, and 3) possible prognostic factors predicting the trial outcome. At critical appraisal, six studies (n = 471 patients) scored a moderate to high directness of evidence and a medium or low risk of bias and were selected for data extraction. Due to heterogeneity between studies, pooling of data for meta-analysis was not feasible. Therefore, results of studies were summarized per outcome: 1) after the BCD trial, 32.0 to 69.6% of SSD patients rejected BCD implantation, 2) the three main reasons for rejection were experiencing limited benefit from the device, patients fearing or being unfit for surgery and cosmetic aspects, 3) no clear prognostic factors predicting the trial outcome could be identified. Roughly half of patients rejected BCD implantation after a trial period. From the current literature it is unclear which patients could benefit most from BCD implantation. High level of evidence studies should be conducted to investigate possible prognostic factors that predict the BCD trial outcome.

Determining fitting ranges of various bone conduction hearing aids.

To define fitting ranges for nine bone conduction devices (BCDs) over different frequencies based on the device's maximum power output (MPO) and to validate the assessment of MPO of BCDs in the ear canal. Maximum power output (MPO) is an important characteristic when fitting BCDs. It is the highest output level a device can deliver and is one of the major determinants of a device's fitting range. A skull simulator can be used to verify MPO of percutaneous BCDs. No such simulator is available for active and passive transcutaneous devices. The MPO of nine different BCDs was assessed either by real-ear measurements and/or with skull simulator measurements. MPO and cross-validation of the methods using the Bland-Altman method. Percutaneous BCDs have higher MPO levels compared to active and passive transcutaneous devices. This results in a wide dynamic range of hearing for percutaneous devices. Moreover, the assessment of MPO by real-ear measurements was validated. Based on MPO data, fitting ranges were defined for nine BCDs over seven frequencies.

Influence of Behavior on Complications of Osseointegrated Bone Conduction Devices in Children.

Compare incidences of complications following implantation of osseointegrated bone conduction devices (OBCD) between children with and without behavioral disorders. Case series with chart review. Tertiary referral center otology and neurotology practice. Pediatric patients who underwent implantation of OBCD between May 2009 and July 2014 at Arkansas Children's Hospital. Implantation with Cochlear BAHA 200 series, Cochlear BAHA BI300, or Oticon OBCD. Osseointegration failure (OIF) with resulting loss of flange-fixture and/or skin and soft tissue reactions. The total rate of complications was 66.2%, with the majority being minor complications (39.4%). There was no difference in the total rate of complication (p = 0.461), minor complications (p = 0.443), major complications (p = 0.777), and minor and major complications (p = 0.762) between the control group and children with behavioral disorders. Behavior was not observed to influence the incidence of OIF or skin/soft tissue reactions after implantation of OBCD in pediatric patients.

Towards a Unified Testing Framework for Single-Sided Deafness Studies: A Consensus Paper

Background: While hearing aids for a contralateral routing of signals (CROS-HA) and bone conduction devices have been the traditional treatment for single-sided deafness (SSD) and asymmetric hearing loss (AHL), in recent years, cochlear implants (CIs) have increasingly become a viable treatment choice, particularly in countries where regulatory approval and reimbursement schemes are in place. Part of the reason for this shift is that the CI is the only device capable of restoring bilateral input to the auditory system and hence of possibly reinstating binaural hearing. Although several studies have independently shown that the CI is a safe and effective treatment for SSD and AHL, clinical outcome measures in those studies and across CI centers vary greatly. Only with a consistent use of defined and agreed-upon outcome measures across centers can high-level evidence be generated to assess the safety and efficacy of CIs and alternative treatments in recipients with SSD and AHL. Methods: This paper presents a comparative study design and minimum outcome measures for the assessment of current treatment options in patients with SSD/AHL. The protocol was developed, discussed, and eventually agreed upon by expert panels that convened at the 2015 APSCI conference in Beijing, China, and at the CI 2016 conference in Toronto, Canada. Results: A longitudinal study design comparing CROS-HA, BCD, and CI treatments is proposed. The recommended outcome measures include (1) speech in noise testing, using the same set of 3 spatial configurations to compare binaural benefits such as summation, squelch, and head shadow across devices; (2) localization testing, using stimuli that rove in both level and spectral content; (3) questionnaires to collect quality of life measures and the frequency of device use; and (4) questionnaires for assessing the impact of tinnitus before and after treatment, if applicable. Conclusion: A protocol for the assessment of treatment options and outcomes in recipients with SSD and AHL is presented. The proposed set of minimum outcome measures aims at harmonizing assessment methods across centers and thus at generating a growing body of high-level evidence for those treatment options.