Ear Implants Research Articles

The development of active middle ear implants: A historical perspective and clinical outcomes.

Objective (s)Energy emitting, active middle ear implants (aMEI) have taken more than two decades of research to reach technological sophistication, medical safety, and regulatory approval to become a powerful tool in treating sensorineural, conductive, and mixed hearing loss. The present review covers this era.Data SourceLiterature found from searching Pubmed (MEDLINE); EMBASE, SciSearch, German Medical Science Journals and Meetings, and The Cochrane Library; and published as of February 2017. Study bibliographies were hand‐searched to find further materials.MethodsA systematic literature review was conducted to identify studies evaluating the safety, efficacy, effectiveness, and subjective outcomes of partially implantable aMEIs. Data were extracted on systems with regulatory approval and summarized narratively. Meta‐analyses were conducted for aMEIs with more than 25 publications. Study selection, data extraction, and quality appraisal for quantitative data synthesis was carried out by two reviewers.ResultsFour hundred thirty‐one studies included in narrative synthesis describe that albeit good audiological outcomes, clinical safety and (dis)investment are major barriers to continued market access. The synthesised risk of adverse events was three fold with the MET than with the VIBRANT SOUNDBRIDGE. With the latter system, audiological outcomes were stable and similar for all indications and age groups.ConclusionTo date, the majority of the literature covers the clinical application of the VIBRANT SOUNDBRIDGE system as it is applicable to a wide range of otologic and audiological conditions, particularly with the introduction of couplers to extend its clinical reach. The MAXUM and MET still have to find their way into surgical routine.Level of Evidence:

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.

A reutilização de um implante de Norgestomet na manifestação de estro ovino

This study assessed the efficacy of the re-utilization of a Norgestomet ear implant in the sheep. Following body condition scoring (CC 3-4) and weight (50-60 Kg) evaluation 60 Texel ewe lambs were randomly assigned to two experimental groups: NorgN (new) control group (n=30), and NorgR (re-used) treatment group (n=30). The implants employed in the treatment group were previously used in estrus synchronization of cows. The ewe lambs were treated with 1/3 of the dosage of Norgestomet recommended for cows. The estrus synchronization protocol consisted of administration of an ear implant at day 0 (beginning of experiment) for 6 days. At implant removal (day 6) the animals received i.m. injections of a prostaglandin analogue (xxx mg) and eCG (400 IU). Teaser rams with brisket paint were used to mark the ewes in heat for 5 days after implant withdrawal. In total, 95% (57/60) of the ewes displayed estrus. 100% (30/30) and 90% (27/30) of the ewes in NorgN and NorgR groups, respectively, displayed estrus 36 hours after implant removal. In conclusion, Norgestomet ear implants associated with eCG and a prostaglandin analogue can be successfully reused to synchronize estrus in Texel ewe lambs.

Benefits of Bimodal Hearing With Cochlear and Middle Ear Implants: Preliminary Results in Four Patients

Conventional hearing aids have some limitations in overcoming a large air-bone gap or in cases of severe high-frequency hearing loss. The authors aimed to evaluate the benefit of a new bimodal hearing configuration combining cochlear implantation (CI) and middle ear implant (MEI) in patients with severe mixed conductive and ski-slope hearing loss. Retrospective case review. Tertiary referral center. Four patients with severe to profound hearing loss, who underwent CI in one ear and MEI in the other, were enrolled. Audiological outcomes were assessed at least 6 months after the MEI/CI operation. Pure-tone audiometry (PTA) in unaided, CI-aided, and MEI-aided conditions were measured. Average threshold changes in bands of frequencies (<1 kHz, ≥1 kHz) were compared between MEI-aided and HA-aided conditions. The Korean version of the Hearing-in-Noise Test (K-HINT), and speech perception score in noisy and quiet conditions were evaluated in the bimodal configuration (i.e., MEI with CI). MEI-aided PTA was especially increased in high-frequency areas (≥1 kHz). Speech perception in noisy and quiet conditions demonstrated better scores in the bimodal configuration. K-HINT also demonstrated better scores in the bimodal configuration. There is an increasing number of patients with unilateral CI and residual hearing in the contralateral ear. The benefits of a new bimodal hearing configuration with CI and MEI were demonstrated in patients with severe high-frequency hearing loss or mixed conductive hearing loss in the contralateral ear.

The Impact of Two-Stage Subtotal Petrosectomy and Round Window Vibroplasty on Bone Conduction Thresholds

Objective: To evaluate possible increases in bone conduction (BC) hearing thresholds in patients undergoing subtotal petrosectomy (SP) with fat obliteration and blind sac closure of the outer ear canal and subsequent round window vibroplasty. Patients and Interventions: Between 1997 and 2013, 43 patients (45 ears) with combined hearing loss and recurrent chronic otitis or status post formation of a radical cavity underwent SP around 6 months prior to implantation of a Vibrant Soundbridge^TM. Pure tone audiograms (0.5, 1, 1.5, 2, 3, 4, and 6 kHz) prior to SP, after SP, prior to implantation, after implantation, and at first fitting around 5 weeks after implantation were collected and statistically analyzed. Results: The comparison between BC thresholds before SP and at first fitting showed an overall decline during the two-step procedure between 2.8 and 6 dB that was significant (p < 0.05, Student t test) at 2, 3, 4, and 6 kHz. Conclusion: In some cases, SP is the only way to eradicate chronic otitis and to achieve a suitable environment for the implantation of active middle ear implants. The present data demonstrate a relatively small but significant decline in BC thresholds throughout the whole procedure. Knowledge of its extent is mandatory for a correct indication for later implantation of a Vibrant Soundbridge^TM.

인공 중이 이식술의 최신 지견

난청은 가장 흔한 만성질환 중 하나이며, 사회적 고 립, 불안, 우울, 인지저하에 걸쳐 삶의 질에 지대한 영향 을 미치는 것으로 보고되고 있다.1,2) 이러한 난청의 높은 유병률과 악영향에도 불구하고 보청기 같은 청각재활이 필요한 대상자에서 15% 정도만 보청기를 꾸준히 사용 하고 있는 것으로 보고되고 있다.3) 대부분의 경도에서 중등도 난청 환자들이 고전적 보청기를 통해 충분한 청 각학적 이득을 얻을 수 있음에도 폐쇄 효과나 외이도의 불편감, 소리의 왜곡, 되울림 현상, 소음 속 청취의 어려 움 및 고주파의 증폭 제한 등의 이유로 보청기 사용을 꺼려하고 있는 실정이며, 고전적 보청기의 기술적 발달 에도 불구하고 소리의 왜곡과 되울림현상은 여전히 보 청기 구입 및 사용을 망설이게 하는 가장 큰 이유이다. 더불어 외이도의 자극이나 착용에 따른 불편감, 이루가 동반된 경우에 착용의 문제점 등 다양한 문제가 여전히 존재한다. 1970년대에 개발된 인공와우이식술은 난청 치료에 있어서 획기적인 전기가 되었다. 그러나 보청기 로 충분한 청각 이득을 얻지 못하는 많은 난청환자들이 인공와우이식의 기준을 충족시키지 못하는 경우가 많 다. 중이 이식술은 앞서 말한 고전적 보청기의 여러 문 제점을 해결하고 고전적 보청기로 충분한 청각 이득을 얻지 못하나 인공와우이식술의 대상이 되지 못하는 난 청환자, 즉 두 가지 청력 재활의 경계에 존재하는 중고 도 난청 환자들을 위해 개발되어 왔다. 본문에서는 현 재 국내 및 해외에서 사용 중인 중이 이식술 중에서 인공 중이 이식술(Active middle ear implant)을 소개하고자 한다.

Transtympanic Hearing Aid: exploratory study on a new device

In this paper, we present the preliminary results achieved with a transtympanic hearing aid (THA). This is a modified digital, open-fit external hearing aid (HA) designed for acute study only, which allows coupling with a pre-implanted ventilation tube. The THA conveys amplified sound directly onto the round window, bypassing the ossicular chain, in contrast with traditional HAs that convey sound onto the second or third portion of the external auditory canal. The THA has been developed as an alternative to standard HAs and active middle ear implants for patients who are unsatisfied with traditional HA outcomes and want to avoid middle-ear implantation. The results achieved using the THA were compared to those obtained with an equivalent device, the Latitude 8 Moxi 13 (Moxi), uncoupled from the ventilation tube, and placed onto the outer ear. For this purpose, 12 patients with conductive (1/12), sensorineural (3/12), or mixed (8/12) hearing loss from moderate to severe, with a pre-implanted ventilation tube, underwent audiological evaluation with both the THA and the Latitude 8 Moxi 13 (Moxi). Our initial results showed that the THA provided significant improvement in the warble tone results in comparison to the Moxi. Moreover, patients with a PTA between 41 and 90 also achieved better results in terms of speech recognition using the THA in comparison to the Moxi. In conclusion, these outcomes provide the first evidence of the potential benefits of the THA over standard open-fit HAs. Nevertheless, these preliminary outcomes require further confirmation.

ZASTOSOWANIE ZACZEPU NA ODNOGĘ KRÓTKĄ KOWADEŁKA IMPLANTU UCHA ŚRODKOWEGO VIBRANT SOUNDBRIDGE W PRZEWLEKŁYM ZAROSTOWYM ZAPALENIU PRZEWODU SŁUCHOWEGO ZEWNĘTRZNEGO – OPIS PRZYPADKU

ObjectiveChronic obstructive inflammation of the external ear canal after different kinds of surgeries often leads to restenosis. There are different approaches to treatment of such cases, and one solution is a middle ear implant. Here we analyze the efficacy of using the Vibrant Soundbridge middle ear implant with a new incus short process (SP) coupler in this type of case.Material and MethodsWe present a case study of a 29-year old patient with bilateral mixed hearing loss caused by bilateral obstructive inflammation of the external ear canals. He had undergone meatoplasty with very short-lived improvement. Afterwards he qualified for middle ear implantation to restore hearing, and the Vibrant Soundbridge was implanted with a new SP coupler to which the floating mass transducer (FMT) is attached. Postoperative hearing tests included pure tone audiometry, free field audiometry, speech recognition, and APHAB questionnaire.ResultsSpeech recognition after implantation improved to 100%. Pre- and postoperative bone conduction thresholds were unchanged. Vibrometry thresholds 10 months after surgery did not deteriorate. There was a decrease in global APHAB score by 61% from 2 to 10 months after implantation.ConclusionsApplication of the Vibrant Soundbridge middle ear implant can be an effective treatment in cases of hearing loss caused by obstructive inflammation of the external ear canals. The new incus SP coupler seems to be an effective method of stimulating the middle ear in mixed hearing loss.

Ten years of active middle ear implantation for sensorineural hearing loss

Objectives: To evaluate long-term benefits of a totally implantable active middle ear implant (AMEI) that has been used in a single implanting center for over 10 years.Methods: Forty-one subjects who underwent implantation with an Esteem® AMEI during a 10-years period were evaluated on the auditory benefits, as derived from pure tone and speech audiometry tests. The analysis included a comparison with a conventional hearing aid, the problematics related to the battery duration and surgical replacement and, finally, the complication rate.Results: Over 80% of the implanted subjects maintained over time a satisfactory auditory gain, ranging from 10 to over 30 dB in respect to the unaided situation, as mean at 0.5, 1, 2 and 4 kHz. In more than 60% of them, an improvement has also been found at 4 and 8 kHz. Battery duration varied according to the severity of the hearing loss and to the daily use of the device. No major post-operative complications were recorded, whilst explantation was necessary in five subjects, although none for device failure.Conclusions: The Esteem® can be considered a reliable device for rehabilitation of sensorineural hearing loss in alternative to conventional hearing aids.

Physical outcome measures for conductive and mixed hearing loss treatment: A systematic review.

The number of potential options for rehabilitation of patients with conductive or mixed hearing loss is continually expanding. To be able to inform patients and other stakeholders, there is a need to identify and develop patient-centred outcomes for treatment of hearing loss. To identify outcome measures in the physical core area used when reporting the outcome after treatment of conductive and mixed hearing loss in adult patients. Systematic review. Systematic review of the literature related to reported physical outcome measures after treatment of mixed or conductive hearing loss without restrictions regarding type of intervention, treatment or device. Any measure reporting the physical outcome after treatment or intervention of mixed or conductive hearing loss was sought and categorised. The physical outcome measures that had been extracted were then grouped into domains. The literature search resulted in the identification of 1434 studies, of which 153 were selected for inclusion in the review. The majority (57%) of papers reported results from middle ear surgery, with the remainder reporting results from either bone conduction hearing devices or middle ear implants. Outcomes related to complications were categorised into 17 domains, whereas outcomes related to treatment success was categorised into 22 domains. The importance of these domains to patients and other stakeholders needs to be further explored in order to establish which of these domains are most relevant to interventions for conductive or mixed hearing loss. This will allow us to then assess which outcome measures are most suitable for inclusion in the core set.

Different estrus induction protocols and fixed time artificial insemination during the anoestrous period in non-lactating Kivircik ewes

The efficiency of medroxyprogesterone acetate (MAP) sponges or norgestomet ear implants (half or entire) for synchronizing and inducing the estrous cycle in non-lactating Kivircik ewes was investigated during the natural non-breeding period. Ewes were treated for 11 days either with 60 mg MAP sponges (group 1, n=27) or with 1.5 mg norgestomet (group 2, n=25) or with 3 mg norgestomet (group 3, n=27) ear implants. In addition, each ewe received an intramuscular injection of 500 IU of equine chorionic gonadotropin (eCG) and 125 μg cloprostenol (PGF2α), 48 h prior to progestagen removal. Double Cervical Artificial Insemination (AI) with diluted fresh semen was performed at a fixed time (36 and 48 h) following progestagen withdrawal. Mean values for estrous detection rates at the first 12 ± 6 h and within 72 h, the time from progestagen removal to the onset of estrous, the duration of the induced estrous and pregnancy rate were found to be 46.8%, 86.1%, 26.1 ± 7.3 h, 27.0 ± 10.7 h and 27.8%, respectively. There were significant differences between groups 2 and 3 in the time of induced estrous onset (P&lt;0.05). These results indicate that, each of the three protocols was equally efficient in inducing and synchronizing estrus in non-lactating Kivircik ewes during the natural non-breeding period.

Acoustic stimulation on the round window for active middle ear implants

Many clinical reports have discussed the effectiveness of stimulating the ear's round window (RW) with a tool to mitigate conductive and mixed hearing loss. The RW is one of the two openings from the middle ear into the inner ear. Various methods have been proposed to construct a highly efficient, easily implanted, and reliable RW transducer. Devices, however, such as floating mass transducers, have difficulty establishing proper contact without some degree of bone incision around the RW. Additionally, vibration energy may not be fully transmitted to the cochlea, but instead will be spread through the soft tissue around the transducer. We propose a more direct RW stimulation with very high acoustical impedance using a receiver that is a volume velocity source. We expect this source to overcome large acoustic impedance by maximizing sound pressure in a confined space, the RW niche. To verify the effectiveness of the proposed method, ear canal pressure, RW pressure, and stapes velocity are measured by acoustic RW stimulation of human temporal bones.

A clinical guidance to DFNA22 drawn from a Korean cohort study with an autosomal dominant deaf population: A retrospective cohort study.

The MYO6 gene, if altered, can cause nonsyndromic hearing loss (NSHL) either in an autosomal dominant (AD) (DFNA22) or recessive form. The present study identified MYO6 variants in the cohort of Korean AD NSHL families and investigated the audiological phenotypes of DFNA22 with respect to suggesting clinical guides for the counseling of DFNA22. A retrospective cohort study was performed on 81AD NSHL families in two hospitals. Among them, five families (SH21, SB60, SB247, SB290 and SB305) segregating with MYO6 variant were genetically and clinically assessed. We identified two novel missense variants of MYO6: p.G223R (SB290) and p.T158R (SB305). A known heterozygous truncation variant, p.R205X, reported previously (SH21, SB60), was identified (SB247). The overall frequency of DFNA22 among such cases was 6.2%. Specifically, we found p.R205X from three of five DFNA22 families (60%). Five DFNA22 families demonstrated extremely diverse audiogram configurations and age of onset with even intrafamilial variations, whereas the severity of hearing loss mostly ranged within moderate. We report a recurring predominant allele and two new missense variants of MYO6, highlighting the significant contribution of MYO6 to AD NSHL in the Korean population. Extremely diverse audiological configurations of DFNA22 suggest that MYO6 should be considered in future genetic studies of patients with AD NSHL. Gradual progression with a good speech audiometry score could provide physicians with clinical insight with respect to advising patients to use hearing aids or consider middle ear implants, whereas, in the case of certain exceptional circumstances, physicians could provide patients with the option to consider a cochlear implant.

Hearing Rehabilitation with Active Middle Ear Implants.

Hearing implant technology is evolving at a rapid rate and more than ever patients with hearing loss are benefiting from these emerging hearing devices. Active middle ear implants are alternatives to hearing aids and bone conducting devices, offering patients an expanded range in improving their hearing. This chapter looks at the devices currently available, their indications and the literature regarding their outcomes.

Hearing Rehabilitation in Congenital Middle Ear Malformation.

Microtia and atresia cause significant conductive hearing loss of up to 60 dB HL. The bilateral cases suffer from severely restricted communication abilities and require immediate acoustic stimulation. There is also growing evidence that unilateral cases benefit from an early and selective stimulation of the affected side. Hearing restoration can be performed in selected cases of minor malformation by classic middle ear reconstruction. However, the majority of patients presumably benefit better from a hearing aid. There are 3 main types: active middle ear implants, active bone conduction implants and passive bone conduction implants. All implants improve speech perception, speech recognition, the signal-to-noise ratio and directional hearing. The extent varies among implants and requires further studies. Decision making on the implant type depends on the extent of malformation and hence the preoperative imaging. New scoring systems provide reliable risk stratification. Second it depends on the age of the patient. The active middle ear implants provide a selective stimulation of the affected side and are beneficial if implanted in the first years of life during the maturation period of the auditory system. In conclusion, hearing rehabilitation of congenital atresia should be performed as early as possible. This includes not only the bilateral but also the unilateral affected patients.

Comparison of the Effects of Middle Ear Implants and Conventional Hearing Aids on Cognitive Function

Background and Objectives The association between hearing impairment and cognitive function has been established in previous studies. The aim of this study was to compare the effects of conventional hearing aids and middle ear implants on cognitive function. Subjects and Method This study included 22 participants who underwent middle ear implantation between October 2013 and September 2016. Their mean age at surgery was 70 years. Using Pure tone audiometry (PTA), the Speech discrimination test (SDT), and the Abbreviated Profile of Hearing Aid Benefit (APHAB) questionnaire, we compared audiologic benefits of three conditions [without hearing aids, with conventional hearing aids, or with Vibrant Sound bridge (VSB)]. Cognitive ability was evaluated using neuropsychological testings (Seoul Neuropsychological Screening Battery) at intervals of approximately eight weeks. Results The results of PTA showed a 7.96 dB HL gain with conventional hearing aids and a 10.00 dB HL gain with the use of VSB. SDT results showed a 4.10% gain with conventional hearing aids and a 10% gain with the use of VSB. Results of the APHAB questionnaire showed a significant increase with the use of VSB compared to conventional hearing aids. In the Korean Mini-Mental State Examination, a slight improvement was observed after middle ear implantation. In the Digit Span Test and Korean-Boston Naming Test, a significant improvement was seen with the use of VSB compared to conventional hearing aids. Conclusion The use of middle ear implants in rehabilitation of hearing communication in patients showed improvements in cognitive abilities, compared to the use of conventional hearing aids. Key words: Hearing loss ㆍ Cognition ㆍ Middle ear implant ㆍ Hearing aids

Validation of methods for prediction of clinical output levels of active middle ear implants from measurements in human cadaveric ears

Today, the standard method to predict output levels of active middle ear implants (AMEIs) before clinical data are available is stapes vibration measurement in human cadaveric ears, according to ASTM standard F2504-05. Although this procedure is well established, the validity of the predicted output levels has never been demonstrated clinically. Furthermore, this procedure requires a mobile and visually accessible stapes and an AMEI stimulating the ossicular chain. Thus, an alternative method is needed to quantify the output level of AMEIs in all other stimulation modes, e.g. reverse stimulation of the round window. Intracochlear pressure difference (ICPD) is a good candidate for such a method as it correlates with evoked potentials in animals and it is measurable in cadaveric ears. To validate this method we correlated AMEI output levels calculated from ICPD and from stapes vibration in cadaveric ears with outputs levels determined from clinical data. Output levels calculated from ICPD were similar to output levels calculated from stapes vibration and almost identical to clinical data. Our results demonstrate that both ICPD and stapes vibration can be used as a measure to predict AMEI clinical output levels in cadaveric ears and that ICPD as reference provided even more accurate results.

Les dispositifs médicaux correcteurs de la surdité : prothèses et implants auditifs

The management of deafness has become a major public health issue as their lack of detection has a deleterious effect in children and increases the risk factors for aggravation of other pathologies in adults. The detection of deafness remains a real challenge: in the newborn, systematic screening at birth is a good strategy, in adults, much remains to be done. The functional rehabilitation of deafness is based on the use of hearing aids by aerial or bone conduction or of auditory implants. There are three types of auditory implants available: bone anchored hearing implants, middle ear implants and cochlear implants. Many actors, in particular social organizations, can intervene in the financial management of these medical devices.

Auditory and cognitive development in a partially deaf child with bilateral electro-acoustic stimulation: a case study

Objective: To study the long-term evolution of speech and intelligence in a child with partial deafness and normal hearing in the low frequencies after sequentially receiving cochlear implants in both ears. Design: Retrospective chart review. Study sample: Male child aged 6 years was followed over a time period of four years. Results: The paediatric patient had normal hearing up to 1 kHz and profound hearing loss at all higher frequencies symmetrical in both ears. Deprivation of high-frequency sounds resulted in retarded development of speech, language and cognitive skills. The choice for rehabilitation was cochlear implantation with the aim of preserving a considerable amount of low-frequency hearing. With natural hearing at low frequencies and electrical stimulation at high frequencies, the child was able to compensate most of his developmental deficits. Moreover, spatial hearing was almost normal. Conclusions: Electro-natural stimulation without amplification of the low frequencies (electro-natural hearing) provides access to the whole audible frequency range for children, who suffer from partial deafness in the high frequencies and are normal hearing at low frequencies. Such provision allows for regular speech development and favours the development of spatial hearing. The case report also demonstrates a strong impact on intellectual performance.

Audiological Outcomes and Map Characteristics in Children With Perimodiolar and Slim Straight Array Cochlear Implants in Opposite Ears.

To identify differences in outcomes and map characteristics in pediatric bilateral cochlear implants with modiolar conforming and lateral wall arrays in opposite ears. Retrospective case series. Tertiary care pediatric referral center. Fourteen children who received a perimodiolar array in one ear and a slim straight array in the opposite ear in sequential surgeries. None. Consonant-nucleus-consonant test (CNC) word recognition score, battery life, power levels, electrical compound action potential (ECAP) thresholds, and electrical threshold and comfort charge levels. Speech perception outcomes were poorer in the lateral wall ears than the perimodiolar ears, and scores in the bilateral condition were better than with the lateral wall device alone. Sequential placement was a factor with differences in preoperative candidacy time correlating with greater difference in speech perception. There was no difference in charge levels between ears, in spite of higher ECAP threshold values for the lateral wall devices. While bilateral speech perception was good, speech perception with the lateral wall device alone was poorer. This cannot be explained solely by the device, as differences in preoperative candidacy time were a significant factor. ECAP thresholds are significantly higher for lateral wall electrodes, but that did not translate in to higher psychophysical measurements.