Long-term outcomes of cochlear implantation in patients with high-frequency hearing loss.

OBJECTIVE: To demonstrate the long-term benefits of implantation in patients with high-frequency sensorineural hearing loss, this report provides 5-year follow-up on a group of implant recipients who were subjects of the Cochlear™ Nucleus® Hybrid™ L24 Implant System pivotal clinical study. METHODS: The results of three related clinical studies were compiled to provide outcome data after 1, 3, and 5 years of implant use in a group of subjects who presented with preoperative high-frequency hearing loss and were implanted with a Nucleus Hybrid L24 (Cochlear Ltd., Sydney, Australia) cochlear implant. A subset of the 50 adult subjects (N = 32) who participated in the Hybrid L24 pivotal Investigational Device Exemption (IDE) completed comprehensive evaluations at 12 months postactivation, 3 years postactivation, and then as part of a postapproval study at 5 years postactivation. Testing included audiometric, speech perception, and subjective satisfaction measures. RESULTS: Mean unilateral speech perception performance was significantly improved at all postoperative intervals compared to preoperative best-aided results and has remained stable to 5 years postactivation. Ninety-four percent of subjects had measurable hearing, and 72% continued to use electric-acoustic stimulation in the implanted ear after 5 years of implant use. Subjective satisfaction results support objective performance improvements. CONCLUSION: Results demonstrate long-term success of patients with high-frequency hearing loss following Hybrid L24 (Cochlear) cochlear implantation. Benefits include speech perception abilities significantly better than those in the preoperative best-aided condition, with additional benefit in those using electric-acoustic stimulation in the implanted ear. LEVEL OF EVIDENCE: 2b. Laryngoscope, 1939-1945, 2018.

Cochlear Implantation in Children with Postlingual Progressive Steeply Sloping High-Frequency Hearing Loss.

BACKGROUND: Children with steeply sloping sensorineural hearing loss (SNHL) lack access to critical high-frequency cues despite the use of advanced hearing aid technology. In addition, their auditory-only aided speech perception abilities often meet Food and Drug Administration criteria for cochlear implantation. PURPOSE: The objective of this study was to describe hearing preservation and speech perception outcomes in a group of young children with steeply sloping SNHL who received a cochlear implant (CI). RESEARCH DESIGN: Retrospective case series. STUDY SAMPLE: Eight children with steeply sloping postlingual progressive SNHL who received a unilateral traditional CI at Seattle Children's Hospital between 2009 and 2013 and had follow-up data available up to 24 mo postimplant were included. DATA COLLECTION AND ANALYSIS: A retrospective chart review was completed. Medical records were reviewed for demographic information, preoperative and postoperative behavioral hearing thresholds, and speech perception scores. Paired t tests were used to analyze speech perception data. Hearing preservation results are reported. RESULTS: Rapid improvement of speech perception scores was observed within the first month postimplant for all participants. Mean monosyllabic word scores were 76% and mean phoneme scores were 86.7% at 1-mo postactivation compared to mean preimplant scores of 19.5% and 31.0%, respectively. Hearing preservation was observed in five participants out to 24-mo postactivation. Two participants lost hearing in both the implanted and unimplanted ear, and received a sequential bilateral CI in the other ear after progression of the hearing loss. One participant had a total loss of hearing in only the implanted ear. Results reported in this article are from the ear implanted first. Bilateral outcomes are not reported. CONCLUSIONS: CIs provided benefit for children with steeply sloping bilateral hearing loss for whom hearing aids did not provide adequate auditory access. In our cohort, significant improvements in speech understanding occurred rapidly postactivation. Preservation of residual hearing in children with a traditional CI electrode is possible.

Patient-Reported Outcomes From the United States Clinical Trial for a Hybrid Cochlear Implant.

OBJECTIVE: To assess patient-reported outcomes (PROs) in individuals with significant residual low-frequency hearing and severe-to-profound high-frequency sensorineural hearing loss (SNHL) who received the hybrid cochlear implant (CI). STUDY DESIGN: Prospective, multicenter, nonrandomized, single-arm repeated measures, single-subject design. SETTING: Tertiary centers, ambulatory care. PATIENTS: Fifty adults with severe-to-profound high-frequency SNHL and residual low-frequency hearing with aided word recognition scores between 10 and 60% in the ear to be implanted, and in the contralateral ear greater than or equal to implant ear less than or equal to 80%. INTERVENTION: Therapeutic; hybrid CI. MAIN OUTCOME MEASURES: Speech, spatial and qualities of hearing scale (SSQ), device use questionnaire (DUQ), University of Washington Clinical Assessment of Music Perception (UW-CAMP) assessed preoperatively and after 6 and 12 (SSQ and DUQ only) months of hybrid CI use. RESULTS: Significant improvements in mean SSQ ratings were demonstrated at 6 and 12 months postactivation overall and for domains related to speech hearing, spatial hearing, and sound quality. Significant improvement was also found for overall satisfaction on the DUQ and across a number of specific listening situations in addition to aspects related to social engagement. UW-CAMP pitch discrimination and melody and timbre recognition abilities were not compromised postoperatively, allowing hybrid subjects to maintain superior music perception abilities than typically observed with standard CIs. CONCLUSIONS: Patients who received the hybrid CI demonstrated significant PRO benefits on the SSQ and the DUQ after 6 and 12 months of CI use. In addition, given the opportunity to maintain useful low-frequency acoustic hearing, patients retained music listening abilities, as assessed by the UW-CAMP.

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.

The ototronix MAXUM middle ear implant for severe high-frequency sensorineural hearing loss: Preliminary results.

OBJECTIVES/HYPOTHESIS: To report the preliminary results of the Ototronix MAXUM middle ear implant for treatment of severe high-frequency sensorineural hearing loss. STUDY DESIGN: Case series with chart review. METHODS: Six consecutive ears with severe high-frequency sensorineural hearing loss (≥75 dB HL at 2, 3, and 4 kHz) and poor aided word recognition performance (≤60% single words) underwent implantation of the MAXUM system at a single, private otologic referral center. Primary outcome measures included frequency-specific functional gain and word recognition score improvement compared to optimally fitted hearing aids. RESULTS: Six ears, in four adult patients (two female; median age 67.5 years) were included. The median unaided preoperative high-frequency pure-tone average (HFPTA) (2, 3, and 4 kHz) was 80.0 dB (range, 75.0-85.0 dB), and the median best-aided word recognition score was 48.0% (range, 24%-60%). The median HFPTA functional gain with the MAXUM system was 47.2 dB, a 25.0 dB improvement (range, 16.7-33.3 dB) (P = .03) over optimally fit hearing aids, and the median word recognition score with MAXUM was 81.5%, a 42.0% improvement (range, 20%-48%) (P = .03) with the MAXUM middle ear implant over optimally fitted hearing aids. CONCLUSIONS: These preliminary data demonstrate that the MAXUM middle ear implant provides superior functional gain and word recognition scores in quiet for patients with severe high-frequency sensorineural hearing loss compared to optimally fitted hearing aids. Future studies with greater patient numbers and patient reported outcome measures are needed to confirm these promising but preliminary results. LEVEL OF EVIDENCE: 4 Laryngoscope, 126:2124-2127, 2016.

Intraoperative Real-time Cochlear Response Telemetry Predicts Hearing Preservation in Cochlear Implantation.

AIM: To monitor cochlear function during cochlear implantation and determine correlations with postoperative acoustic hearing. BACKGROUND: Cochlear response telemetry measures cochlear function directly from cochlear implant electrodes. We have adapted this system to provide real-time cochlear response telemetry (RT-CRT) monitoring of a patient's acoustic hearing as the cochlear implant electrode array is inserted. METHODS: Eighteen subjects (1 child and 17 adults) with sloping high frequency hearing loss were implanted with Cochlear Ltd slim straight arrays (CI422/CI522). Tone bursts (500 Hz, 100-110 dB) were presented at 14 Hz continuously during the array insertion. RT-CRT amplitudes were correlated with surgical manoeuvres recorded on the video from the operating microscope and with postoperative pure tone audiograms. RESULTS: Despite an excellent overall rate of complete or partial hearing preservation (79%), RT-CRT identified that in 47% of these implantations there was transient or permanent reduction in the amplitude of the cochlear microphonic (CM). Patients with a preserved CM at the end of insertion had on average 15 dB better low-frequency hearing preservation. The CM amplitude was most vulnerable during the last few millimeters of insertion or when inadvertent movement of the array occurred after full insertion. Physical contact/elevation of the basilar membrane is hypothesized as a likely mechanism of hearing loss rather than overt physical trauma. CONCLUSION: RT-CRT can be used to predict early postoperative hearing loss and to potentially refine surgical technique. In the future, feedback of RT-CRT may prove to be a valuable tool for maximizing preservation of residual hearing or providing feedback on electrode contact with the basilar membrane.

The Audiometric and Mechanical Effects of Partial Ossicular Discontinuity.

OBJECTIVES: Ossicular discontinuity may be complete, with no contact between the disconnected ends, or partial, where normal contact at an ossicular joint or along a continuous bony segment of an ossicle is replaced by soft tissue or simply by contact of opposing bones. Complete ossicular discontinuity typically results in an audiometric pattern of a large, flat conductive hearing loss. In contrast, in cases where otomicroscopy reveals a normal external ear canal and tympanic membrane, high-frequency conductive hearing loss has been proposed as an indicator of partial ossicular discontinuity. Nevertheless, the diagnostic utility of high-frequency conductive hearing loss has been limited due to gaps in previous research on the subject, and clinicians often assume that an audiogram showing high-frequency conductive hearing loss is flawed. This study aims to improve the diagnostic utility of high-frequency conductive hearing loss in cases of partial ossicular discontinuity by (1) making use of a control population against which to compare the audiometry of partial ossicular discontinuity patients and (2) examining the correlation between high-frequency conductive hearing loss and partial ossicular discontinuity under controlled experimental conditions on fresh cadaveric temporal bones. Furthermore, ear-canal measurements of umbo velocity and wideband acoustic immittance measurements were investigated to determine the usefulness regarding diagnosis of ossicular discontinuity. DESIGN: The authors analyzed audiograms from 66 patients with either form of surgically confirmed ossicular discontinuity and no confounding pathologies. The authors also analyzed umbo velocity (n = 29) and power reflectance (n = 12) measurements from a subset of these patients. Finally, the authors performed experiments on six fresh temporal bone specimens to study the differing mechanical effects of complete and partial discontinuity. The mechanical effects of these lesions were assessed via laser Doppler measurements of stapes velocity. In a subset of the specimen (n = 4), wideband acoustic immittance measurements were also collected. RESULTS: (1) Calculations comparing the air-bone gap (ABG) at high and low frequencies show that when high-frequency ABGs are larger than low-frequency ABGs, the surgeon usually reported soft-tissue bands at the point of discontinuity. However, in cases with larger low-frequency ABGs and flat ABGs across frequencies, some partial discontinuities as well as complete discontinuities were reported. (2) Analysis of umbo velocity and power reflectance (calculated from wideband acoustic immittance) in patients reveal no significant difference across frequencies between the two types of ossicular discontinuities. (3) Temporal bone experiments reveal that partial discontinuity results in a greater loss in stapes velocity at high frequencies when compared with low frequencies, whereas with complete discontinuity, large losses in stapes velocity occur at all frequencies. CONCLUSION: The clinical and experimental findings suggest that when encountering larger ABGs at high frequencies when compared with low frequencies, partial ossicular discontinuity should be considered in the differential diagnosis.

Cochlear implantation with the nucleus slim straight electrode in subjects with residual low-frequency hearing.

OBJECTIVES: To measure benefit in terms of speech recognition in quiet and in noise, and conservation of residual hearing in three groups of subjects implanted with the Nucleus Straight Research Array cochlear implant. This device incorporates the Nucleus Slim Straight electrode carrier designed to be easier to insert into the cochlea via the round window while potentially minimizing insertion trauma. DESIGN: The study was prospective, with sequential enrolment and within-subject repeated measures; 35 subjects were 15 to 84 years of age with varying levels of bilateral high-frequency HL. Subjects were divided into three groups (A, B, and C) according to preoperative air conduction hearing thresholds in the ear to implant at 500 Hz; A ≤ 50 (n = 11), 50 < B < 80 (n = 13), and C ≥ 80 (n = 11) dB HL. Speech recognition was assessed preoperatively and at intervals up to 1 year postimplantation. Hearing thresholds were monitored over time and CT scans were used to estimate electrode positions. RESULTS: Preoperative mean word recognition score was significantly greater for group A compared with group C in quiet (diff. 26.6%pts, p < 0.05), but not so in noise (diff. 7.9%pts, p = 0.72). However, a greater proportion of subjects in group A (81%) achieved a "worthwhile" gain in speech recognition score (>20%pts) in quiet compared with group C (63%). More importantly, for speech recognition in noise, all subjects in groups A and B achieved a >20%pts gain compared with only 73% in group C. Hearing in implanted ears was well conserved for low frequencies, both initially and up to 12 months postoperatively (15 dB median increase in thresholds 250 to 500 Hz). Only 3 of 35 (9%) cases lost all residual hearing in the implanted ear by 12 months. Where characteristic frequency corresponded to a position occupied by the electrode array, threshold increase was correlated with the preoperative hearing threshold (r = 0.7; p < 0.001) and closely approximated reported estimates of residual outer hair cell gain. For characteristic frequencies at positions apical to the electrode tip, the relation between threshold increase and residual hearing decreased in amplitude at 45 to 135 degrees (r = 0.42; p < 0.05), and disappeared at >135 degrees (r = 0.05; p > 0.05). CONCLUSION: Gains in speech recognition scores for subjects with better residual low-frequency hearing were greater or equal to those obtained by subjects with poorer residual hearing. Residual hearing after cochlear implantation with the Nucleus Slim Straight electrode array was well conserved across all three groups. It appears that the gain provided by outer hair cell function may be completely suppressed when an electrode array is in close proximity to the organ of Corti.

The use of Nucleus CI422 in a ski-slope high-frequency hearing loss and chronic external ear pathology: a case study.

OBJECTIVE AND IMPORTANCE: This case report illustrates the ongoing extending criteria for cochlear implantation (CI). It reinforces the statement that patients who do not fulfill the standard criteria for CI should be carefully considered on an individual basis. CLINICAL PRESENTATION: The patient on this report presented with a ski-slope high-frequency hearing loss and chronic external ear canal infections. The latter precluded the consistent use of hearing aids with moulds. His speech discrimination in quiet and in noise was poor and his hearing loss was interfering with his ability to work. INTERVENTION: After years of frustration, this patient decided to risk losing his low-frequency residual hearing and was implanted with the new Nucleus CI422 (Cochlear Ltd). CONCLUSION: Hearing preservation was achieved and he gained a remarkable improvement in his hearing performance. It is thought that his outcomes are the result of the combination of hearing presentation surgery, electrode design, and intensive auditory training.

Profound high-frequency sensorineural hearing loss treatment with a totally implantable hearing system.

OBJECTIVE: This study seeks to assess the efficacy of the Envoy Esteem totally implantable hearing device in treating profound high-frequency sensorineural hearing loss. PATIENTS: Five patients with profound high-frequency hearing loss participating in a prospective, multi-center, nonrandomized Food and Drug Administration clinical trial. INTERVENTION: Implantation with Esteem totally implantable hearing device and comparison to baseline unaided and aided conditions. MAIN OUTCOME MEASURE: Speech reception threshold and word recognition scores (WRS) at 50 dB HL presentation level. RESULTS: Preoperative speech reception threshold improved from an unaided 65 dB and aided 48 dB average to 26 dB with the Esteem at 12 months. WRS at 50 dB scores improved from an unaided 10% and aided 23% average to 78% postoperatively. CONCLUSION: The Esteem totally implantable middle ear hearing device provides appreciable functional gain and improvement in WRS to rehabilitate hearing in patients with a profound high-frequency sensorineural hearing loss.

Functional gain and speech understanding obtained by Vibrant Soundbridge or by open-fit hearing aid.

CONCLUSION: There is no significant difference in speech recognition scores obtained with the Vibrant Soundbridge and the open-fit hearing aid. However, the Vibrant Soundbridge may be superior to open-fit hearing aids in improving hearing at high frequencies (4-8 kHz). OBJECTIVES: To assess whether an improvement in speech recognition conferred by Vibrant Soundbridge is more marked than that afforded by open-fit hearing aids in patients with sloping high frequency sensorineural hearing loss (SNHL). METHODS: This study had a self-control prospective design. Seven patients aged 21-62 years with sloping high frequency SNHL were recruited into the study. Each patient received a Vibrant Soundbridge middle ear implant (Vibrant MED-EL) and wore an open-fit hearing aid (Danavox, DOT 10). Speech recognition tests were performed according to protocols suggested by árpád Götze's speech definition test in Hungarian language. In the first session, conventional hearing thresholds (unaided pure tone thresholds) were measured. In the second session, the aided sound-field threshold, speech understanding score and functional gain obtained using middle ear implants and open-fit hearing aids were determined after programming of the devices. RESULTS: Regarding speech recognition scores, there were no significant differences between data obtained with the middle ear implant and those with the open-fit hearing aid.

Achievement of hearing preservation in the presence of an electrode covering the residual hearing region.

CONCLUSIONS: With full insertion with a long electrode, hearing preservation can be achieved even in the presence of a long electrode covering the residual hearing region. OBJECTIVES: Advances in developing new atraumatic concepts of electrode design as well as surgical technique have enabled hearing preservation after cochlear implantation surgery, and EAS (electric acoustic stimulation) accompanied with hearing preservation is a new trend for patients with residual hearing at the lower frequencies. However, full insertion with a long/medium electrode and hearing preservation is still a challenging field that calls for discussion. METHOD: In this study, round window insertion, an atraumatic electrode, and dexamethasone administration were used and atraumaticity (hearing preservation and conservation of vestibular function) was evaluated with full insertion of the electrode. RESULTS: Postoperative evaluation after full insertion of the electrodes showed that hearing at low frequencies was well preserved in all five cases. Combined postoperative imaging with the referential tonotopic map confirmed achievement of full insertion and indicated the corresponding frequencies and the depth of the electrode. Achievement of atraumaticity of round window insertion in the present cases was confirmed from the viewpoint of the minimal drilling time as well as the preserved vestibular function.

Active middle ear implant compared with open-fit hearing aid in sloping high-frequency sensorineural hearing loss.

OBJECTIVE: To compare 2 open-ear hearing solutions for sloping high-frequency sensorineural hearing loss: open-fit hearing aid (HA) and active middle ear implant (AMEI). STUDY DESIGN: Within-subjects prospective design. SETTING: Tertiary referral hospital. PATIENTS AND DEVICES: Fourteen patients with sloping, high-frequency sensorineural hearing loss were recruited from 39 patients previously implanted with an AMEI and 10 agreed to participate, ranging in age from 44 to 73 years (mean, 59 yr). Patients were selected because their hearing thresholds (500-3,000 Hz) qualified them for both AMEI and open-fit HA use. All patients received a Vibrant Soundbridge (Vibrant MED-EL) for an average of 25.1 months before data collection and used their AMEI on a daily basis. The open-fit HA used in this study was the Delta 8000 (Oticon). Both study devices have been fit with the specific fitting strategies as recommended by the manufacturer. MAIN OUTCOME MEASURES: Sound-field hearing thresholds, Freiburger monosyllabic words in quiet, speech reception thresholds for 50% correct recognition for Freiburger numbers and for Oldenburg sentences in quiet, and speech reception thresholds for 50% correct recognition for Oldenburg sentences in noise. RESULTS: Both HA and AMEI conditions showed significantly better sound-field thresholds and speech recognition on monosyllabic word and sentence tests in quiet and in noise than in the unaided condition. A comparison of aided conditions revealed that, in the AMEI-aided condition, high-frequency audibility and speech discrimination scores in quiet and in noise were significantly better than those in the open-fit HA. CONCLUSION: Both open-fit HAs and AMEIs provided audiologic benefit to patients with sloping high-frequency sensorineural hearing loss. However, despite overlapping indication criteria for the 2 devices, performance with the AMEI was significantly better for the AMEI than for the open-fit HA.

[An overview of the studies on combined electric and acoustic stimulation of auditory system].

This paper discusses the technology of combined electric and acoustic stimulation (EAS) of the auditory system, which is a new therapy for the patients suffering from severe to profound high- and mid-frequency hearing loss but still having their low-frequency hearing. EAS uses hearing aid and cochlear implant technology together in the same ear. The hearing aid acoustically amplifies at low-frequencies, while the cochlear implant electrically stimulates at mid- and high-frequencies. The inner ear processes acoustic and electric stimuli simultaneously. This technique can provide substantial benefit in speech understanding for individuals with severe high-frequency hearing loss and can maintain their residual lower-frequency acoustic hearing. The study of EAS would significantly enhance the conventional cochlear implant therapy and benefit the patients afflicted with severe to profound hearing loss.

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.

Word recognition following implantation of conventional and 10-mm hybrid electrodes.

We compared the effectiveness of 2 surgical interventions for improving word recognition ability in a quiet environment among patients who presented with: (1) bilateral, precipitously sloping, high-frequency hearing loss; (2) relatively good auditory thresholds at and below 500 Hz, and (3) poor speech recognition. In 1 intervention (n = 25), a conventional electrode array was inserted into 1 cochlea. As a consequence, hearing was lost in the implanted ear. In the other intervention (n = 22), a Nucleus Hybrid short-electrode array was inserted 10 mm into 1 cochlea with the aim of preserving hearing in that ear. Both groups of patients had similar low-frequency hearing and speech understanding in the ear contralateral to the implant. Following surgery, both groups had significantly higher word recognition scores than before surgery. Between-group comparisons indicated that the conventional electrode array group had higher word recognition scores than the 10-mm group when stimulation was presented to the operated ear and when stimulation was presented to both ears.

Integration of acoustic and electrical hearing.

For some individuals with severe high-frequency hearing loss, hearing aids cannot provide a satisfactory improvement in speech recognition. However, these same patients often have too much residual hearing to qualify as candidates for a cochlear implant. Here we describe results with the Iowa/Nucleus Hybrid cochlear implant, which is designed to preserve the patient's residual low-frequency hearing while at the same time supplementing their high-frequency hearing through electrical stimulation. The advantages of this approach are presented, including improved speech recognition in competing backgrounds as compared with traditional cochlear implants. The results with the Iowa/Nucleus Hybrid device demonstrate the ability of the auditory system to integrate acoustic and electrical stimulation, even under conditions of severe distortions to the normal cochlear place-frequency mapping.

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.

Hybrid cochlear implantation: clinical results and critical review in 13 cases.

OBJECTIVE: To substantiate the benefits of hybrid cochlear implantation (CI) in patients with residual low-frequency hearing. STUDY DESIGN: Prospective study of patients in a manufacturer-sponsored clinical trial. SETTING: Independent referral center for CI. PATIENTS: Thirteen patients who met candidacy criteria for a hybrid CI. The 10 women and 3 men had a mean age of 51 years. INTERVENTION: Preoperative evaluation, CI with a Nucleus Hybrid cochlear implant, subsequent programming, and diagnostic testing. MAIN OUTCOME MEASURES: Benefits of high-frequency electrical stimulation from the hybrid CI as measured by conventional audiometry, consonant-nucleus-consonant monosyllabic word and Bamford-Kowal-Bench sentence in noise testing at quarterly intervals per protocol. RESULTS: Follow-up ranged from 3 to 24 months. All 13 patients had preserved hearing immediately postoperative. However, one lost residual hearing 7 days postoperatively, and 2 patients had delayed hearing losses at 2 and 24 months, the latter apparently due to barotrauma; however, this was not conclusive. Another had a bilateral symmetrically progressive hearing loss. Six patients showed changes in low-frequency hearing less than 10 dB; 2 showed changes in the range 11 to 20 dB; 2, 21 to 30 dB; and 3, more than 50 dB. Eleven of 13 had improved consonant-nucleus-consonant words ranging up to 83% when tested with hearing aid + CI in the operated ear. Four subjects exhibited improvement in Bamford-Kowal-Bench sentence in noise testing, although only one subject showed a significant decline associated with bilateral progression in hearing impairment. CONCLUSION: Combined electrical and acoustical hearing can result in significant improvement in speech understanding. Only one patient lost residual hearing as a direct result of surgery. Two others had delayed losses. There are no absolute predictive factors as to success with hybrid CI, just as there are none for conventional CI. Similarly, wide variation in results may occur. Further studies may clarify factors involved in such variation.