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Objective: This study reviewed outcomes of hearing preservation (HP) surgery depending on the angle of insertion (AOI) in a cochlear implant (CI) patient population who used electric stimulation (ES) or combined electric-acoustic stimulation (EAS)., Study Design: Retrospective case review., Setting: Tertiary referral university hospital., Patients: Ninety-one patients with different degrees of preoperative low-frequency residual hearing who underwent HP surgery with a free-fitting lateral-wall electrode array (MED-EL Flex) with lengths ranging from 20.0 to 31.5 mm., Intervention: Cochlear implantation using HP surgery technique and subsequent fitting with CI speech processor for ES, or combined CI and hearing aid speech processor for EAS., Main Outcome Measures: Individual AOI were estimated using modified Stenvers' projection. Freiburg monosyllable test in quiet (free-field presentation at 65 dB SPL) and pure-tone averages for low frequencies (125, 250, and 500 Hz; PTAlow) were evaluated during a follow-up period of 12 months after implantation., Results: Estimated AOIs showed bimodal distribution: shallow insertion (SI) with mean AOI of 377 degrees and deep insertion (DI) with mean AOI of 608 degrees. Speech test scores after 12 months were comparable between AOI groups, however, they were significantly different between stimulation types with better scores for EAS. Only ES showed a positive correlation (r = 0.293) between speech test score and AOI. When HP was possible, both SI and DI showed significant postoperative PTAlow shifts with mean of 17.8 and 21.6 dB, respectively. These were comparable between AOI groups and no significant shifts were observed in follow-up intervals. Audiometric indication for HP and subsequent EAS is proposed up to 65 dB HL at 500 Hz, and up to 87 dB HL for HP., Conclusions: CI candidates can benefit from HP surgery with deep insertion when only using ES due to insufficient residual hearing. Conversely, candidates with preoperative threshold up to 65 dB HL at 500 Hz could perform significantly better with EAS which requires shallow insertion.

Conclusion: This study demonstrates that electric acoustic stimulation (EAS(®)) using the FLEX(EAS) 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 PULSARCI(100) implant using the FLEX(EAS) 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 FLEX(EAS) 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.

Conclusion: This study demonstrates that electric-acoustic stimulation (EAS) significantly decreases the subjective impairment in speech perception., Objectives: To assess the subjective benefit of EAS over the first 12 months after EAS fitting using the Abbreviated Profile of Hearing Aid Benefit (APHAB)., Method: Twenty-three EAS users, implanted with either the PULSAR(CI)(100) FLEX(EAS) provided with the DUET EAS processor or the COMBI40+ Medium provided with the TEMPO+ speech processor, were included. Electric stimulation was activated about 1 month postoperatively; ipsilateral acoustic stimulation was added 2 months thereafter. EAS benefit was measured preoperatively with only a hearing aid and postoperatively at EAS fitting and then 3, 6 and 12 months after EAS fitting using the APHAB., Results: Subjects reported significant improvements in the global score with a mean decrease in impairment from 74% preoperatively to 45% after 3 months of EAS use. Furthermore, clinical relevance was demonstrated in multiple subscales between preoperative and first fitting reflecting a true benefit of EAS with a probability of 95%., (Copyright © 2011 S. Karger AG, Basel.)

Background/aims: The aim of this study was to describe audiological outcomes and surgical considerations in electric acoustic stimulation for patients with severe to profound high-frequency hearing loss., Methods: In this latest series of patients in our center, all patients were supplied with the new (atraumatic) Flex EAS MED-EL electrode. Eleven patients (age 7.62-71.32 years) with profound high-frequency hearing loss were implanted with this electrode, which was designed to preserve residual hearing despite the intracochlear insertion of an electrode array. All patients were operated on by the same surgeon (W.G.)., Results: The rate of complete or partial hearing preservation was 100% after a mean follow-up period of 7.85 months (range 0.95-15.65 months)., Conclusion: This study proves that both refined surgical techniques and atraumatic electrodes are mandatory to preserve residual hearing after cochlear implantation. Flexible, thin, and free-fitting straight electrodes, such as the MED-EL Flex EAS electrode used in this study, seem to most accurately meet the requirements for hearing preservation in electric acoustic stimulation., (Copyright 2010 S. Karger AG, Basel.)

Background/aims: Subjects with sufficient residual low-frequency hearing after cochlear implantation can benefit from electric acoustic stimulation (EAS). A combined speech processor (MED-EL DUET), which incorporates a hearing aid and a speech processor in one device, was designed especially for this group of patients. The present report evaluates the influence of postoperative pure tone audiometric results on personal acceptance of the DUET system in EAS users., Method: Fifteen subjects underwent cochlear implantation for EAS and hearing preservation was achieved at least partially. All were fitted with the DUET EAS hearing system. Personal acceptance (measured by whether or not they were using the DUET system) in combination with audiometric results were investigated over time., Results: The combined processor was accepted by the majority of the subjects. However, those who had initial or further loss of residual hearing of more than 55 dB at 125 Hz or more than 70 dB at 250 Hz and 98 dB at 500 Hz rejected the DUET device., Conclusion: The combined processor enables subjects with sufficient hearing preservation in the low-frequency range up to 500 Hz to benefit from EAS. Acceptance is dependent on the pure tone audiometric outcomes after surgery and can vary with hearing loss progression., (Copyright 2010 S. Karger AG, Basel.)

Aims: This study compared the music perception abilities of 13 electric acoustic stimulation (EAS) users with two control groups: unilateral cochlear implant (CI) users and normal-hearing (NH) listeners., Methods: Groups were matched according to age and musical experience before hearing loss (HL) and tested using the Musical Sounds in Cochlear Implants (Mu.S.I.C.) test., Results: No difference was found on rhythm perception, chord discrimination, dissonance rating, and emotion rating subtest performance between groups. Mean frequency discrimination scores were significantly better in EAS participants than in CI participants and not significantly worse than in NH participants. However, the EAS and CI groups scored similarly (significantly worse than NH participants) on both instrument detection and identification. Results for EAS participants were not significantly worse when the hearing aid component was removed. Frequency of listening to music before HL was negatively correlated with EAS participants' frequency discrimination scores, though singing and playing an instrument appeared to have no effect. EAS participants who indicated many reasons for listening to music and who listen to many genres after implantation scored higher on instrument detection and instrument identification. Better results on these two subtests were correlated with EAS participants' better postoperative auditory thresholds at 250 and 500 Hz., Conclusions: Though EAS participants performed better on music perception testing (though not timbre-based tasks) than CI participants, their scores did not reach the level of NH participants. This indicates that acoustic hearing in the low frequencies is helpful for music perception, though not the only important factor., (Copyright 2010 S. Karger AG, Basel.)

After cochlear implantation, individuals with sufficient residual hearing in the lower frequency region are able to successfully combine acoustic and electrical stimulation patterns to improve speech perception, especially in noise, and to improve music appraisal as well. These improvements occur through enhanced transmission of fine structure information by more accurate mapping of the fundamental frequency contour through acoustic hearing. In current cochlear implant systems, the transfer of frequency and melodic contour is very coarse, and the correct detection of pitch contour requires large frequency differences. It is assumed that the acoustically transferred part of the signal enables the cochlear implant recipient to better segregate between speech signals and interfering sounds. The detection and following of a speech signal emitted by a single talker in a multitalker babble situation is improved when fundamental frequencies as grouping cues are present. The preservation of hearing in the implanted ear must be considered a major surgical challenge. The development of very flexible and soft electrode carriers in combination with surgical approaches that minimally traumatize the inner ear enable hearing preservation in nearly all cases.

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., (Copyright 2008 S. Karger AG, Basel.)

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 degrees. 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 degrees electrode insertions., (Copyright (c) 2006 S. Karger AG, Basel.)