Feasibility of hearing preservation for residual hearing with longer cochlear implant electrodes

Abstract

Background: Hearing preservation is thought to be achievable following atraumatic surgery with thin cochlear implant electrodes; therefore, the surgical approach and implant electrode design are crucial considerations.

Objective: To assess the feasibility of hearing preservation with long electrodes for patients meeting the criteria for conventional cochlear implantation.

Methods: One hundred and two patients (132 ears) who underwent cochlear implant surgery were analyzed. Inclusion criteria included measurable residual hearing in the low frequency before implantation and not meeting the criteria for electric acoustic stimulation (EAS).

Results: Of the 18 patients with residual hearing in the low frequency enrolled, 17 subjects (94.4%) retained low frequency hearing. A younger age at surgery tended to contribute to better hearing preservation than that observed in older patients. There was no clear trend regarding the influence of insertion depth angle of the electrode on hearing preservation.

Conclusion: It is possible to achieve hearing preservation in the lower frequency by the use of longer electrodes. This study underscores the importance of atraumatic surgery, even for patients with only limited residual hearing, and longer electrodes should be adopted for EAS.     

An evaluation of hearing preservation outcomes in routine cochlear implant care: Implications for candidacy

Introduction: A retrospective evaluation of pre- and post-operative audiometric data at a single large UK cochlear implant centre over 25 years was undertaken.

Methods: Analysis of pre-operative hearing levels showed that there was a modest but significant reduction in average pre-operative hearing thresholds among patients referred between 1990 and 2015, particularly in the low frequencies.

Outcomes: The proportion of those referred who would meet widely-accepted candidacy criteria for electro-acoustic stimulation (EAS) grew significantly over time but in the period 2011-2015 just 9% of those referred had sufficient residual hearing for EAS. On average, implant recipients lost 20 dB hearing at frequencies ≤1000 Hz as a result of the surgery.

Conclusions: The findings suggest that hearing preservation is now widely achievable, and that both candidacy criteria and referrer education should take into account potential EAS benefit.     

Hearing preservation and cochlear implants according to inner ear approach: multicentric evaluation

IntroductionElectroacoustic stimulation is an excellent option for people with residual hearing in the low frequencies, who obtain insufficient benefit with hearing aids. To be effective, the subject's residual hearing should be preserved during cochlear implant surgery.ObjectivesTo evaluate the hearing preservation in patients that underwent implant placement and to compare the results in accordance with the approach to the inner ear.Methods19 subjects underwent a soft surgical technique, and the electrode MED-EL FLEX™ EAS, designed to be atraumatic, was used. We evaluated pre- and postoperative tonal audiometric tests with an average of 18.4 months after implantation, to measure the rate of hearing preservation.Results17 patients had total or partial preservation of residual hearing; 5 had total hearing preservation and two individuals had no preservation of hearing. The insertion of the electrode occurred through a cochleostomy in 3 patients, and in 2 of these there was no hearing preservation; the other 16 patients experienced electrode insertion through a round window approach. All patients benefited from the cochlear implant, even those who are only using electrical stimulation.ConclusionThe hearing preservation occurred in 89.4% of cases. There was no significant difference between the forms of inner ear approach.     

Electric-acoustic stimulation with longer electrodes for potential deterioration in low-frequency hearing

Abstract

Background: Electric-acoustic stimulation (EAS) has emerged as a standard treatment for patients with high-frequency hearing loss. EAS is usually performed with shorter electrodes of 16–24?mm in length. As most EAS recipients gradually lose residual acoustic hearing in the implanted ear over time, EAS with longer electrodes without causing significant intra-cochlear damage might be ideal.

Objective: The aim of this study was to investigate hearing preservation (HP) results after EAS surgery with longer electrodes.

Methods: Ten patients (11 ears) with partial deafness that met the indications for EAS with a MED-EL FLEX28 electrode were included in this study. Auditory thresholds before and at 6?months after activation were examined.

Results: In 100% of cases, HP was comfortably achieved, indicating that all patients could utilize acoustic amplification combined with electric stimulation.

Conclusion: EAS with longer electrodes can offer broader cochlear coverage, resulting in natural frequency matching in comparison with shorter electrodes, even in EAS cases. The combination of advanced surgical techniques and flexible, long, straight electrodes permits deep insertion that reaches the apical region with little or no insertion trauma.     

A new electrode for residual hearing preservation in cochlear implantation: first clinical results

Conclusion. A so far unattained high rate (100%) of residual hearing preservation in cochlear implantation for electric-acoustic stimulation could be achieved using sophisticated surgical techniques in combination with the MedEl Flex EAS electrode. Objectives. This study aimed to gather first audiological and surgical results from the experience gained with the new MedEl Flex EAS electrode array. Patients and methods. Nine patients (aged 7.62–71.32 years) with profound high frequency hearing loss were supplied with this atraumatic electrode, which was designed to preserve residual hearing despite intracochlear insertion of an electrode array. All patients were implanted by the same surgeon. Results. Hearing preservation was achieved in all patients (complete preservation 44.44%) after a mean follow-up period of 9.73 months. Mean monosyllabic test scores improved from 9% correct with the hearing aid alone to 48% with the cochlear implant and to 65% in the electric-acoustic mode.     

Prevalence of potential candidates for electric-acoustic stimulation implant in a hearing-impaired population

ObjectiveTo estimate the prevalence of potential electric-acoustic stimulation (EAS) implant candidates in a hearing-impaired population through a review of auditory examinations.MethodsIn total, 7356 patients underwent audiometric examination in our department between 2011 and 2014. The prevalence of patients meeting the audiometric criteria for EAS and standard cochlear implant (CI) was assessed.ResultsThe percentage of EAS implant candidates meeting the pure-tone audiometric criteria was 0.71% (n = 34) among the hearing-impaired individuals (n = 4758) examined in our department, whereas 2.52% (n = 120) met the criteria for standard CI. Among the 34 EAS implant candidates, 2 individuals (5.83%) received EAS implant surgery after approval of the EAS device in Japan.ConclusionsThere was a lower prevalence of EAS implant candidates than standard CI candidates. Nevertheless, healthcare professionals should carefully examine the audiograms of patients with high frequency hearing loss with regard to meeting the indication criteria for EAS implant. This will enable patients to gain access to adequate information relating to further examinations and treatment options.     

Long-term results of hearing preservation cochlear implant surgery in patients with residual low frequency hearing

Conclusion: Differences were found between patients with stable hearing and those with progressive hearing loss in the lower frequencies with respect to the rate of progression in the contralateral ear. It is suggested that the electric acoustic stimulation (EAS) can provide improvement in hearing ability over the long-term if residual hearing might be lost to some extent.

Objective: To evaluate the long-term threshold changes in the low frequency hearing of the implanted ear as compared with the non-implanted ear, and the hearing abilities with EAS along with the extent of residual hearing.

Methods: Seventeen individuals were enrolled and received the EAS implant with a 24-mm FLEXeas electrode array. Hearing thresholds and speech perception were measured pre- and post-operatively for 1–5 years. Post-operative hearing preservation (HP) rates were calculated using the preservation numerical scale.

Results: The average linear regression coefficient for the decline in hearing preservation score was ?6.9 for the implanted ear and the patients were subsequently categorized into two groups: those with better than average, stable hearing; and those with worse than average, progressive hearing loss. EAS showed better results than electric stimulation alone, in spite of an absence of speech perception with acoustic stimulation.     

Evaluation of the Digisonic® SP cochlear implant: patient outcomes and fixation system with titanium screws

Cochlear implants have revolutionized the way patients affected by severe hearing loss experience the world. Neurelec developed a fixation system with two titanium screws that requires no skull bone drilling.ObjectiveTo describe the outcomes and procedure-related details of a series of patients implanted with the Digisonic® SP cochlear implant.MethodThis retrospective study analyzed patients submitted to cochlear implant placement within a period of 18 months. All patients had postlingual hearing impairment. Data was collected from patient charts and standard questionnaires answered by the surgeons in charge of carrying out the procedures.ResultsThe six patients offered the Digisonic® SP cochlear implants were operated by experienced surgeons. The procedures took 95 to 203 minutes (mean = 135') to be completed, which is less time than what has been described for other fixation approaches. No complications were recorded and hearing improvement was satisfactory.ConclusionThe Digisonic® SP cochlear implant developed by Neurelec offered good audiological results for adult patients, shorter surgery time, and no surgical or postoperative complications.     

Cochlear implant revision surgeries in children

IntroductionThe surgery during which the cochlear implant internal device is implanted is not entirely free of risks and may produce problems that will require revision surgeries.ObjectiveTo verify the indications for cochlear implantation revision surgery for the cochlear implant internal device, its effectiveness and its correlation with certain variables related to language and hearing.MethodsA retrospective study of patients under 18 years submitted to cochlear implant surgery from 2004 to 2015 in a public hospital in Brazil. Data collected were: age at the time of implantation, gender, etiology of the hearing loss, audiological and oral language characteristics of each patient before and after cochlear implant surgery and any need for surgical revision and the reason for it.ResultsTwo hundred and sixty-five surgeries were performed in 236 patients. Eight patients received a bilateral cochlear implant and 10 patients required revision surgery. Thirty-two surgeries were necessary for these 10 children (1 bilateral cochlear implant), of which 21 were revision surgeries. In 2 children, cochlear implant removal was necessary, without reimplantation, one with cochlear malformation due to incomplete partition type I and another due to trauma. With respect to the cause for revision surgery, of the 8 children who were successfully reimplanted, four had cochlear calcification following meningitis, one followed trauma, one exhibited a facial nerve malformation, one experienced a failure of the cochlear implant internal device and one revision surgery was necessary because the electrode was twisted.ConclusionThe incidence of the cochlear implant revision surgery was 4.23%. The period following the revision surgeries revealed an improvement in the subject's hearing and language performance, indicating that these surgeries are valid in most cases.     

Combined electric and acoustic stimulation of the auditory system: results of a clinical study

Combined electric and acoustic stimulation (EAS) of the auditory system is a new therapy for patients with severe to profound high- and mid-frequency hearing loss but remaining low-frequency hearing. In a prospective study, 13 patients with low-frequency hearing of better than 60 dB below 1 kHz were implanted with a MED-EL COMBI 40+ cochlear implant. Pure tone thresholds as well as monosyllabic word scores and Hochmair-Schulz-Moser sentences in quiet and in noise were measured with hearing aids, cochlear implant alone and in the combined stimulation mode (EAS) in the same ear. Hearing could be partially preserved in 11 out of the 13 patients. All patients scored significantly higher with cochlear implant alone than with hearing aids. Seven patients scored higher in the EAS mode than with cochlear implant alone for sentences in noise, 4 remained unchanged, and 2 could not use EAS. Synergistic effects of EAS were most prominent for hearing in noise with increases of up to 72% as compared to cochlear implant alone.     

The outcome of our modified double-flap technique for cochlear implantation: A case series of 342 consecutive patients

Abstract

Objectives

A lazy S-shaped postauricular incision with a modified double-flap technique has been used for cochlear implant surgery at our institution for the past 10 years. The postoperative surgical complications, morbidity, and outcome of this technique were evaluated.

Methods

A retrospective case review was conducted in a tertiary referral teaching center. A total of 342 patients with profound sensory hearing loss (173 female and 169 male subjects; age range, 11 months to 52 years) who underwent cochlear implantation using the double-flap postauricular transmastoid surgical approach during a 5-year period (2005 through 2009) with at least 5 years' follow-up were retrospectively evaluated. Postoperative wound complications were identified. Major complications included flap necrosis, wound infection requiring surgical intervention, and wound dehiscence with or without implant exposure. Swelling over the implant and superficial wound infections treated medically were considered minor complications. Other non-wound-related complications, surgical time, and number of electrodes inserted were also recorded.

Results

The surgical approach was accomplished in all the patients with four minor wound complications. The mean surgical time was 1.4 hours, and the mean time between surgery and the programming process was 2 weeks.

Conclusion

This modified double-flap technique was easy to perform and appeared to reduce the incidence of wound complications in cochlear implant surgery. It allowed programming of the implant after a shorter period of time.     

Post-lingual deafness: benefits of cochlear implants vs. conventional hearing aids

The technological advances in cochlear implants and processing strategies have enabled subjects affected by severe to profound hearing loss to hear sounds and recognize speech in various different degrees. The variability of hearing outcomes in subjects with post-lingual deafness has been significant and cochlear implant indications have been extended to include an ever larger population.ObjectiveThis paper aims to look into the groups of post-lingual deafness patients to find where cochlear implants have yielded better outcomes than conventional hearing aids.Materials and MethodsReview the literature available on databases SciELO, Cochrane, MEDLINE, and LILACS-BIREME. The publications selected for review were rated as A or B on evidence strength on the day of the review. Their authors analyzed and compared hearing aids and cochlear implants in populations of post-lingually deaf patients. Study Design: Systematic review.ResultsEleven out of the 2,169 papers searched were found to be pertinent to the topic and were rated B for evidence strength. Six studies were prospective cohort trials, four were cross-sectional studies and one was a clinical trial.ConclusionThe assessment done on the benefits yielded by post-lingually deaf subjects from cochlear implants showed that they are effective and provide for better results than conventional hearing aids.     

The clinical features and prognosis of mumps-associated hearing loss: a retrospective,multi-institutional investigation in Japan

Abstract

Conclusions: The majority of hearing loss due to mumps presents as unilateral profound sensorineural hearing loss, which is refractory to treatment. In rare cases of bilateral total deafness, cochlear implants were beneficial for speech perception. Vaccination against mumps is recommended to prevent mumps-associated hearing loss.

Objective: The objective of this study is to investigate the clinical characteristics of hearing loss due to mumps and to evaluate hearing outcomes.

Subjects and methods: The clinical parameters were analyzed under a retrospective multi-institutional study design in patients diagnosed with hearing loss due to mumps at the Otolaryngology departments of 19 hospitals between 1987 and 2016.

Results: Sixty-seven patients with hearing loss due to mumps were enrolled. The study population consisted of 35 males and 32 females, ranging in age from 1 to 54, with a median age of 9.5 years. Sixty-three patients presented with unilateral, and 4 with bilateral hearing loss. Profound hearing loss was observed in 65 ears. Only one ear with severe hearing loss showed complete recovery. Four patients with bilateral hearing loss received cochlear implant surgery. Most of the patients with hearing loss due to mumps had no history of vaccination.     

Preservation of residual hearing after cochlear implant surgery: an exploration of residual hearing function in a group of recipients at cochlear implant units

IntroductionThe preservation of residual hearing is becoming increasingly important in cochlear implant surgery. Conserving residual hearing is a positive prognostic indicator for improved hearing abilities.ObjectiveThe primary aim of the study was to explore the preservation of residual hearing following cochlear implantation in a group of recipients at two major cochlear implant centers.MethodsA quantitative paradigm was adopted and exploratory research conducted within a retrospective data review design. The sample consisted of 50 surgical records and 53 audiological records from 60 observations (53 patients, seven of whom were implanted bilaterally). The records were selected using purposive sampling and consisted of records from participants ranging from six to 59 years of age. The average time of when the postoperative audiograms were performed in the current study was 24.7 months (s.d. = ±9.0). Data were analyzed through both qualitative and inferential statistics and a comparative analysis of unaided pre- and postoperative audiological test results was conducted.ResultsResults indicated a high success rate of 92% preservation of residual hearing with half of the sample exhibiting complete preservation in cochlear implant recipients across all frequencies postoperatively. A total postoperative hearing loss was found in only 8% of cochlear implantees across all frequencies. There was no relationship between preoperative hearing thresholds and preservation of hearing postoperatively. The two main surgical techniques used in the current study were the contour on stylet and the advance off-stylet techniques, with the majority of surgeons utilizing a cochleostomy approach. From the findings, it became apparent that the majority of cases did not have any reported intraoperative complications. This is a positive prognostic indicator for the preservation of residual hearing.ConclusionFindings suggest improved cochlear implant surgical outcomes when compared to previous studies implying progress in surgical techniques. The surgical skill and experience of the surgeon are evidenced by the minimal intraoperative complications and the high success rate of hearing preservation. This is a positive prognostic indicator for individuals with preoperative residual hearing as the preserved residual hearing allows for the potential of electro-acoustic stimulation, which in turn has its own hearing benefits.     

Combined electro‐acoustic stimulation: a beneficial union?

Background: The most pressing problem facing cochlear implant research is no longer making artificial hearing a reality. Instead, it is to develop devices that can more clearly reflect the capabilities of the human auditory system. Current cochlear implants rarely provide adequate pitch perception. As hearing loss commonly affects higher, more than lower frequencies, a possible solution is to preserve acoustic hearing at low frequencies by inserting a short electrode array and thus deliver combined electro‐acoustic stimulation (EAS). Objective of review: To determine whether individuals with severe‐to‐profound high‐frequency hearing loss have realised this predicted benefit of combined EAS, over conventional cochlear implants, with respect to pitch. Type of review: A systematic review of publications pertaining to the benefits of combined EAS over conventional cochlear implantation, with specific reference to pitch perception. Search strategy: A systematic literature search was conducted across multiple databases and supplemented by searching the reference lists of relevant trials and identified reviews. Results: The included studies suggest an overall benefit of combined EAS, over conventional cochlear implants, with respect to pitch. In addition, (i) 13% sustained a total loss of low‐frequency hearing post‐implantation of the short electrode array and, (ii) 24% had >20 dB hearing loss across all frequencies and/or total hearing loss. Conclusions: For patients with severe‐to‐profound high‐frequency hearing loss combined EAS appears to offer a significant, everyday, long‐term benefit. However, further clinical trials with larger numbers of candidates are necessary to confirm this finding. The risks involved cannot be ignored, but there is potential for a variety of strategies to improve the safety margin.     

The hearing benefit of cochlear implantation for individuals with unilateral hearing loss,but no tinnitus

Conclusion: Cochlear implants improve the hearing abilities of individuals with unilateral hearing loss and no tinnitus. The benefit is no different from that seen in patients with unilateral hearing loss and incapacitating tinnitus.

Objective: To evaluate hearing outcomes after cochlear implantation in individuals with unilateral hearing loss and no tinnitus and compare them to those obtained in a similar group who had incapacitating tinnitus.

Methods: Six cases who did not experience tinnitus before operation and 15 subjects with pre-operative tinnitus were evaluated with a structured interview, a monosyllabic word test under difficult listening situations, a sound localization test, and an APHAB (abbreviated profile of hearing aid benefit) questionnaire.

Results: All subjects used their cochlear implant more than 8?hours a day, 7 days a week. In ‘no tinnitus’ patients, mean benefit of cochlear implantation was 19% for quiet speech, 15% for speech in noise (with the same signal-to-noise ratio in the implanted and non-implanted ear), and 16% for a more favourable signal-to-noise ratio at the implanted ear. Sound localization error improved by an average of 19°. The global score of APHAB improved by 16%. The benefits across all evaluations did not differ significantly between the ‘no tinnitus’ and ‘tinnitus’ groups.     

Electric acoustic stimulation of the auditory system: results of a multi-centre investigation

Conclusion. A high rate of hearing preservation during cochlear implantation for electric acoustic stimulation (EAS) is possible, even when surgery is conducted by a number of different surgeons. Objectives. This study aimed to determine the degree of hearing preservation using surgery for EAS in a European multi-centre clinical investigation. It also aimed to demonstrate the effect of EAS in individuals with residual low frequency hearing, both on speech perception and on subjective quality of life measures. Patients and methods. Eighteen patients with profound high frequency hearing loss were recruited in five participating European centres. Subjects were assessed based on an audiologic test battery, as well as on a subjective hearing aid benefit questionnaire. Each subject underwent attempted hearing preservation cochlear implantation using the MED-EL C40+ device with a Medium electrode. Residual ipsilateral hearing and speech discrimination abilities were assessed at defined intervals up to 12 months after the combined electric-acoustic mode was introduced. Results. Results showed that some degree of hearing preservation was possible in 15718 patients. All subjects showed statistically significant benefit on all three speech perception tests over time. These significant benefits were also reflected in the subjective benefit outcomes.     

The advantages of sound localization and speech perception of bilateral electric acoustic stimulation

Conclusion: Bilateral electric acoustic stimulation (EAS) effectively improved speech perception in noise and sound localization in patients with high-frequency hearing loss. Objective: To evaluate bilateral EAS efficacy of sound localization detection and speech perception in noise in two cases of high-frequency hearing loss. Methods: Two female patients, aged 38 and 45 years, respectively, received bilateral EAS sequentially. Pure-tone audiometry was performed preoperatively and postoperatively to evaluate the hearing preservation in the lower frequencies. Speech perception outcomes in quiet and noise and sound localization were assessed with unilateral and bilateral EAS. Results: Residual hearing in the lower frequencies was well preserved after insertion of a FLEX²⁴ electrode (24 mm) using the round window approach. After bilateral EAS, speech perception improved in quiet and even more so in noise. In addition, the sound localization ability of both cases with bilateral EAS improved remarkably.     

Conservation of low-frequency hearing in cochlear implantation

Objective As results with cochlear implants have continued to improve, patients with some remaining cochlear function have become eligible for cochlear implantation. Thus, preservation of acoustic hearing after implantation has gained importance. Hearing preservation can be considered a benchmark for atraumatic implantation preventing neural degeneration from loss of residual hair cells or subsequent to local trauma. In this prospective study, the possibility of preserving low-frequency hearing in cochlear implantation using a modified surgical technique has been explored.

Materials and Methods In a prospective study design, 14 subjects with considerable low-frequency hearing of 2–60 dB in the frequency range 125–500 Hz but with unsatisfactory speech understanding with hearing aids of < 35% monosyllabic word understanding were implanted with a MED-EL COMBI-40+ cochlear implant. The insertion depth was intentionally limited to 19–24 mm to prevent damage to low-frequency regions of the cochlea. Pre- and postoperative pure-tone thresholds were measured.

Results Hearing was conserved within 0-10 dB in 9/14 subjects and within 11–20 dB in 3/14; in 2/14 subjects hearing was completely lost in the implanted ear. Thus hearing could at least partially be conserved in 12/14 subjects (86%). Median threshold values decreased by 10, 15, 17.5 and 5 dB at 125, 250, 500 and 1000 Hz, respectively. Even high levels of hearing, e.g. 30 dB at 500 Hz, could be maintained after implantation in some subjects.

Conclusions This study reports successful conservation of hearing after cochlear implantation using a modified surgical technique. Even high levels of hearing could be maintained, showing that implantation of an intracochlear electrode can be performed atraumatically with preservation of functional structures.     

Bilateral sensorineural hearing loss and labyrinthitis ossificans secondary to neurosarcoidosis

Abstract

Objective

To report a case of cochlear ossification as a result of neurosarcoidosis in a patient with bilateral profound sensorineural hearing loss.

Study design

Case report.

Setting

University teaching hospital, tertiary referral center.

Patient

Forty-year-old man with neurosarcoidosis and bilateral profound sensorineural hearing loss.

Intervention

Unilateral cochlear implantation.

Outcome measure

Aided thresholds speech perception tests.

Results

Marked improvement in hearing following implant.

Conclusion

Patients with neurosarcoidosis are at risk of labyrinthitis ossificans. Early imaging of these patients is recommended and if early cochlear ossification is identified they should be offered rapid access to rehabilitation with a cochlear implant.