Silke Helbig

Ipsilateral Electric Acoustic Stimulation of the Auditory System: Results of Long-Term Hearing Preservation

Objective: To evaluate long-term ipsilateral hearing preservation in patients who underwent cochlear implantation for the combined electric acoustic stimulation of the auditory system. Methods: This was a prospective observational study conducted at a tertiary referral center. Twenty-three subjects were implanted with the MED-EL C40+ standard or C40+ medium electrode using an atraumatic surgical protocol via an anterior-inferior cochleostomy approach. The desired insertion depth was 18–24 mm or 360°. All patients showed significant low-frequency hearing prior to surgery and monosyllabic word scores did not exceed 40% in the best aided condition. Pure-tone audiometry was performed prior to implantation and at distinct intervals after surgery. Results: Nine patients (39.1%) showed complete pure-tone audiometric hearing preservation (0–10 dB) over an average of 29 months. Seven subjects (30.4%) showed partial preservation of residual hearing (hearing loss 15–40 dB) until an average of 25 months. Delayed loss of residual hearing was observed in 5 cases (21.7%) and 2 patients (8.6%) completely lost residual hearing during or immediately after surgery. Freiburger Monosyllabic word understanding scores in a group of patients with complete hearing preservation increased from 13.1% preoperatively to 75% in the electric acoustic stimulation condition. Conclusion: This study documents that complete and partial preservation of ipsilateral hearing after cochlear implantation can be achieved in about 70% of cases over an average period of 27.25 months when using 360° electrode insertions.

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.

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.

Combined electric acoustic stimulation with the PULSARCI100 implant system using the FLEXEAS electrode array

Abstract Conclusion: This study demonstrates that electric acoustic stimulation (EAS) using the FLEXEAS electrode is a successful treatment method for preservation and stability of low frequency hearing, and results in significant improvements in speech perception. Objectives: Low frequency hearing preservation and stability following EAS surgery with the MED-EL PULSARCI100 implant using the FLEXEAS electrode and a combined processor in a multicentre setting, and the efficacy and benefits of EAS over time were evaluated. Methods: Eighteen subjects with normal to moderate hearing loss in the low frequencies and severe to profound hearing loss in the high frequencies were implanted with the FLEXEAS electrode. Implantation was performed by different surgeons at three participating centres using either the cochleostomy or the round window approach. Preoperatively, hearing was measured; a battery of speech perception tests and the subjective benefit questionnaire were administered. These tests were subsequently repeated: first at EAS fitting, which was due 3 months after surgery, and then again 3, 6 and 12 months after EAS fitting. Results: Hearing could be preserved in all subjects. Speech understanding showed significant improvement in all tests over time with the EAS condition outperforming the cochlear implant-only condition at all intervals. These considerable effects were also reflected in the subjective benefit outcome.

Impact of intrascalar blood on hearing

Objective/Hypothesis: The objective of this controlled animal study was to evaluate the effects of intrascalar blood on hearing.

Hearing preservation after complete cochlear coverage in cochlear implantation with the free-fitting FLEXSOFT electrode carrier.

Objectives: To demonstrate the possibility of atraumatic insertion with the free-fitting FLEXSOFT electrode by evaluating the degree of hearing preservation postoperatively. Design: Retrospective study. Setting: Academic tertiary care center. Participants: Twenty-two severely to profoundly hearing impaired subjects with measurable residual hearing preoperatively. Intervention: Atraumatic implantation with the 31.5-mm-long, free-fitting, and highly flexible FLEXSOFT electrode using either the round window approach or a cochleostomy technique. Main Outcome Measures: Subjects were tested preoperatively in unaided condition and at varying intervals postoperatively. Preoperative and postoperative low-frequency pure-tone average (PTA) and PTA shifts were calculated. Speech perception was measured preoperatively and postoperatively using the Freiburger monosyllabic word test in quiet. Results: Preoperative low-frequency hearing could be preserved to a certain degree in 77.3% of subjects (17/22) after insertion of the FLEXSOFT electrode up to the point of first resistance. Complete loss of residual hearing was observed in 22.7% of subjects (5/22). In 18.2% of the subjects (4/22), the preoperative PTA was preserved within 10 dB. Pure-tone average results between preoperative and most recent testing showed statistically significant differences (p < 0.001 to p = 0.031) for almost all loudness levels ranging from 125 Hz to 1.5 kHz. The maximum threshold shift was 40 dB at 250 Hz for the lower frequencies up to 1 kHz. Monosyllable testing in quiet demonstrated significant improvement over time (p < 0.001). Conclusion: This study showed that preservation of residual hearing is possible in a high number of subjects when a flexible electrode and atraumatic surgical techniques are used.

Site of cochlear stimulation and its effect on electrically evoked compound action potentials using the MED-EL standard electrode array

BackgroundThe standard electrode array for the MED-EL MAESTRO cochlear implant system is 31 mm in length which allows an insertion angle of approximately 720°. When fully inserted, this long electrode array is capable of stimulating the most apical region of the cochlea. No investigation has explored Electrically Evoked Compound Action Potential (ECAP) recordings in this region with a large number of subjects using a commercially available cochlear implant system. The aim of this study is to determine if certain properties of ECAP recordings vary, depending on the stimulation site in the cochlea.MethodsRecordings of auditory nerve responses were conducted in 67 subjects to demonstrate the feasibility of ECAP recordings using the Auditory Nerve Response Telemetry (ART™) feature of the MED-EL MAESTRO system software. These recordings were then analyzed based on the site of cochlear stimulation defined as basal, middle and apical to determine if the amplitude, threshold and slope of the amplitude growth function and the refractory time differs depending on the region of stimulation.ResultsFindings show significant differences in the ECAP recordings depending on the stimulation site. Comparing the apical with the basal region, on average higher amplitudes, lower thresholds and steeper slopes of the amplitude growth function have been observed. The refractory time shows an overall dependence on cochlear region; however post-hoc tests showed no significant effect between individual regions.ConclusionsObtaining ECAP recordings is also possible in the most apical region of the cochlea. However, differences can be observed depending on the region of the cochlea stimulated. Specifically, significant higher ECAP amplitude, lower thresholds and steeper amplitude growth function slopes have been observed in the apical region. These differences could be explained by the location of the stimulating electrode with respect to the neural tissue in the cochlea, a higher density, or an increased neural survival rate of neural tissue in the apex.Trial registrationThe Clinical Investigation has the Competent Authority registration number DE/CA126/AP4/3332/18/05.

A New Combined Speech Processor for Electric and Acoustic Stimulation -Eight Months Experience

Purpose: Electric acoustic stimulation (EAS) relies on the preservation of low-frequency hearing and adequate amplification of these frequencies. EAS has been achieved by fitting the cochlear implant (CI) speech processor together with an ipsilateral in-the-ear hearing aid. This study will evaluate the outcomes when CI/EAS users upgrade to a new combination of hearing aid and speech processor in 1 device (DUET™). Method: Nine EAS patients participated in this study. Before switchover and after 2 and 8 months of DUET device use, they were assessed using monosyllables and sentences in quiet and in noise. Additionally, a questionnaire, the Abbreviated Profile for Hearing Aid Benefit (APHAB), was used to evaluate subjective impressions. Results: All subjects performed equally well, or even better, after switchover. This was also demonstrated over time. The participants with EAS before switchover performed equally afterwards, while those who used CI only did markedly better with the new device, especially in noisy conditions. Slight preference for the new system was also demonstrated with the APHAB. Conclusion: All subjects showed benefit in noise; CI-only users before switchover particularly benefited from the new hearing system. Those who applied EAS before switchover performed equally well. The DUET allows individuals better access to EAS.

A coated electrode carrier for cochlear implantation reduces insertion forces.

To assess the insertion forces and feasibility of insertion of a prototype electrode carrier coated with a flexible and biodegradable coating developed for lubrication and drug delivery.

Evaluation of an electrode prototype for atraumatic cochlear implantation in hearing preservation candidates: preliminary results from a temporal bone study.

Objectives: This study aimed to evaluate an atraumatic prototype electrode carrier for cochlear implantation, the FLEXEAS 20 electrode. This electrode is designed to preserve hearing and to achieve a 360-degree insertion. Study Design: A cross-sectional human temporal bone study was conducted. Setting: Preliminarily, the prototype electrode was inserted in a scala tympani model to measure the insertion force. Thirteen human temporal bones were acquired postmortem and implanted with the new device using the round window approach. Three of them were implanted under radiologic control to demonstrate the insertion path. After embedding, the remaining 10 temporal bones were sectioned undecalcified and examined macroscopically and histologically. Main Outcome Measures: The insertion force was measured to determine intracochlear resistance peaks. The insertion angle was measured, and the degree of intracochlear trauma was determined. Results: The round window approach caused cochlear trauma in 1 of 10 specimens. An exact 360-degree insertion was achieved in 7 of 10 specimens (mean overall insertion angle, 360 degrees). Radiologic examination and insertion force measurements revealed the smooth and atraumatic insertion. Conclusion: The new prototype electrode carrier is suitable for clinical application. It can be handled easily and allows atraumatic 360-degree insertion of all electrode contacts. Therefore, this electrode concept allows good coverage of the cochlea for electrical and additional acoustic stimulation.