Traditional Cochlear Implants Research Articles

Development of a 60/60 Guideline for Referring Adults for a Traditional Cochlear Implant Candidacy Evaluation.

To evaluate the effectiveness of a 60/60 referral guideline for identifying patients who should be referred for a cochlear implant candidacy evaluation (CICE), which states patients should be referred if they demonstrate a best ear unaided monosyllabic word score less than or equal to 60% correct and if they demonstrate an unaided pure-tone average in their better ear that is greater than or equal to 60 dB HL. Retrospective review of data from adults who participated in a CICE. A single tertiary medical facility. Five hundred twenty-nine patients who participated in a CICE. CICEs included unaided threshold assessment, unaided speech recognition, and aided word and sentence testing. Ninety-five percent of patients who met traditional indications for a cochlear implant (n = 250) had a pure-tone average that was greater than or equal to 60 dB, while 92% had a better ear unaided monosyllabic word score that was less than or equal to 60%. If used as a screening measure, the 60/60 measure resulted in a 96% detection rate and a 34% false-positive rate for identifying adults who would meet traditional indications for a cochlear implant. Hearing professionals should consider referring patients for a CICE when they meet the 60/60 guideline. It is hoped that provision of this guideline will result in greater numbers of adults being referred for CICEs, improving access to cochlear implants for patients who may benefit from this important technology.

How Does Quality of Life Relate to Auditory Abilities? A Subitem Analysis of the Nijmegen Cochlear Implant Questionnaire.

Objective speech recognition tasks are widely used to measure performance of adult cochlear implant (CI) users; however, the relationship of these measures with patient-reported quality of life (QOL) remains unclear. A comprehensive QOL measure, the Nijmegen Cochlear Implant Questionnaire (NCIQ), has historically shown a weak association with speech recognition performance, but closer examination may indicate stronger relations between QOL and objective auditory performance, particularly when examining a broad range of auditory skills. The aim of the present study was to assess the NCIQ for relations to speech and environmental sound recognition measures. Identifying associations with certain QOL domains, subdomains, and subitems would provide evidence that speech and environmental sound recognition measures are relevant to QOL. A lack of relations among QOL and various auditory abilities would suggest potential areas of patient-reported difficulty that could be better measured or targeted. A cross-sectional study was performed in adult CI users to examine relations among subjective QOL ratings on NCIQ domains, subdomains, and subitems with auditory outcome measures. Participants were 44 adult experienced CI users. All participants were postlingually deafened and had met candidacy requirements for traditional cochlear implantation. Participants completed the NCIQ as well as several speech and environmental sound recognition tasks: monosyllabic word recognition, standard and high-variability sentence recognition, audiovisual sentence recognition, and environmental sound identification. Bivariate correlation analyses were performed to investigate relations among patient-reported NCIQ scores and the functional auditory measures. The total NCIQ score was not strongly correlated with any objective auditory outcome measures. The physical domain and the advanced sound perception subdomain related to several measures, in particular monosyllabic word recognition and AzBio sentence recognition. Fourteen of the 60 subitems on the NCIQ were correlated with at least one auditory measure. Several subitems demonstrated moderate-to-strong correlations with auditory measures, indicating that these auditory measures are relevant to the QOL. A lack of relations with other subitems suggests a need for the development of objective measures that will better capture patients' hearing-related obstacles. Clinicians may use information obtained through the NCIQ to better estimate real-world performance, which may support improved counseling and development of recommendations for CI patients.

Design and In Vivo Verification of a CMOS Bone-Guided Cochlear Implant Microsystem.

To develop and verify a CMOS bone-guided cochlear implant (BGCI) microsystem with electrodes placed on the bone surface of the cochlea and the outside of round window for treating high-frequency hearing loss. The BGCI microsystem consists of an external unit and an implanted unit. The external system-on-chip is designed to process acoustic signals through an acquisition circuit and an acoustic DSP processor to generate stimulation patterns and commands that are transmitted to the implanted unit through a 13.56 MHz wireless power and bidirectional data telemetry. In the wireless power telemetry, a voltage doubler/tripler (2X/3X) active rectifier is used to enhance the power conversion efficiency and generate 2 and 3 V output voltages. In the wireless data telemetry, phase-locked loop based binary phase-shift keying and load-shift keying modulators/demodulators are adopted for the downlink and uplink data through high-Q coils, respectively. The implanted chip with four-channel high-voltage-tolerant stimulator generates biphasic stimulation currents up to 800 μA. Electrical tests on the fabricated BGCI microsystem have been performed to verify the chip functions. The in vivo animal tests in guinea pigs have shown the evoked third wave of electrically evoked auditory brainstem response waveforms. It is verified that auditory nerves can be successfully stimulated and acoustic hearing can be partially preserved. Different from traditional cochlear implants, the proposed BGCI microsystem is less invasive, preserves partially acoustic hearing, and provides an effective alternative for treating high-frequency hearing loss.

Hearing outcomes in children with meningitis at Red Cross War Memorial Children's Hospital, Cape Town, South Africa: A silent crisis.

Bacterial meningitis is one of the most common causes of hearing loss. Hearing loss develops within the first few days following the onset of meningitis, highlighting the importance of early audiology referrals. Post-meningitis hearing loss may lead to cochlear ossification, making traditional cochlear implantation impossible. To determine the duration of time from meningitis diagnosis to audiology referral. A second objective was to determine the prevalence and severity of meningitis-related sensorineural hearingloss (SNHL) at Red Cross War Memorial Children's Hospital (RCWMCH), a paediatric tertiary hospital in Cape Town, South Africa (SA). A retrospective folder review of all children diagnosed with meningitis and referred for audiological evaluation was conducted over an 18-month period between 1 January 2015 and 30 June 2016. Descriptive statistical methods were used for data analysis. The total number of inpatients diagnosed with unspecified meningitis at RCWMCH between January 2015 and June 2016 was 345. The total number diagnosed with bacterial meningitis was 68. Only 16 children with meningitis (23.5%) were referred to the Department of Audiology at RCWMCH over the 18-month period. Twelve children had confirmed bacterial meningitis. All the children had up-to-date immunisations. The mean (standard deviation) time from diagnosis to audiology referral was 17 weeks (16.9; range 1 - 60). The overall prevalence of hearing loss was 42.8%. Four children (28.5%) were diagnosed with severe to profound SNHL. Less than a quarter of all children diagnosed with bacterial meningitis at RCWMCH over the 18-month study period were referred to audiology. Frequent delays in referrals for audiological assessment following meningitis were noted. This may indicate a lack of awareness on the part of doctors. Healthcare practitioners need to be made aware of the need for prompt audiological testing for children with meningitis. In SA, local guidelines for early diagnosis and monitoring of hearing in children who have had meningitis should be developed in order to improve hearing outcomes.

Cochlear Implants 2016: Advances in Candidacy, Technology, and Outcomes, Factors That Drive the Expansion of Pediatric Cochlear Implant Candidacy

Cochlear implant candidacy and outcomes have advanced reflecting technology improvements, early identification, and better linkage between the surgical intervention and follow-up care. Children and adults with a range of hearing losses and other issues are now benefitting importantly from traditional cochlear implants as well as hybrid and auditory brainstem implants.

Young age is a positive prognostic factor for residual hearing preservation in conventional cochlear implantation.

To investigate the prognostic significance of various factors in hearing preservation after traditional cochlear implantation (CI). Retrospective case review. Academic tertiary referral center. A total of 153 implantations with mean patient age at implantation of 36 years (from 10 mo to 83 yr) and residual hearing at the frequencies 250, 500, and 1,000 Hz on the unaided preoperative pure-tone audiometry were included. CI with a conventional full-length electrode. The changes on the residual hearing 3 months after implantation were analyzed regarding patients' demographic factors, shape of the preoperative threshold curve, type of the electrode carrier, and approach of electrode insertion in the cochlea. Preservation of residual hearing was defined as measurable postoperative threshold at the frequencies 250, 500, and 1,000 Hz. Preservation of residual hearing was observed in almost half of the cases (47%). In more than half of these patients (54%), a maximal to complete hearing preservation (0-10 dB loss) was achieved. About one-third of these implantations (29%) showed a moderate preservation of residual hearing (11-20 dB loss). In the remaining 17%, the preservation of hearing was marginal (>21 dB loss). Hearing preservation and its extent were significantly better in children and adolescents compared with those in adults. The preservation of residual hearing after conventional CI is possible. Young age seems to have a positive impact on hearing preservation.

The Effects of Residual Hearing in Traditional Cochlear Implant Candidates After Implantation With a Conventional Electrode

To analyze the effects of residual hearing on postoperative speech performance in traditional cochlear implant (CI) patients implanted with a conventional electrode. Retrospective review. Academic tertiary referral center. A total of 129 adults implanted by a single surgeon at a tertiary care facility between June 2005 and November 2010 with measurable preoperative pure tone thresholds at any frequency were included. Cochlear implantation with a conventional electrode via an anterior inferior cochleostomy. Speech perception using monosyllabic word scores in quiet and sentences in quiet and noise in the electric (CI-only) condition of the implanted ear. Preservation of hearing was defined as complete for postoperative thresholds within 10 dB of preimplant values and partial if greater than 11 dB. Pure tone audiometry and speech perception testing were performed preoperatively and at regular intervals postoperatively, with the 1-year evaluation being the final outcome period. Preservation at any frequency or level was not a factor in speech perception outcome, although preservation was more common in low frequencies. Hearing preservation was correlated with younger age at implantation, but was not related to length of hearing loss, cause of deafness, device type, sex, preoperative speech performance, or low-frequency pure-tone average. Hearing can be preserved in traditional CI patients implanted with a conventional electrode. Although preservation of hearing may have implications for future technology, it is not currently correlated with speech performance in the CI-only condition.

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.

Reimplantation of Hybrid Cochlear Implant Users With a Full-Length Electrode After Loss of Residual Hearing

To assess word recognition and pitch-scaling abilities of cochlear implant users first implanted with a Nucleus 10-mm Hybrid electrode array and then reimplanted with a full length Nucleus Freedom array after loss of residual hearing. Although electroacoustic stimulation is a promising treatment for patients with residual low-frequency hearing,a small subset of them lose that residual hearing. It is not clear whether these patients would be better served by leaving in the 10-mm array and providing electric stimulation through it, or by replacing it with a standard full-length array. Word recognition and pitch-scaling abilities were measured in 2 users of hybrid cochlear implants who lost their residual hearing in the implanted ear after a few months. Tests were repeated over several months, first with a 10-mm array, and after, these patients were reimplanted with a full array. The word recognition task consisted of 2 50-word consonant nucleus consonant (CNC) lists. In the pitch-scaling task, 6 electrodes were stimulated in pseudorandom order, and patients assigned a pitch value to the sensation elicited by each electrode. Shortly after reimplantation with the full electrode array, speech understanding was much better than with the 10-mm array. Patients improved their ability to perform the pitch-scaling task over time with the full array, although their performance on that task was variable, and the improvements were often small. 1) Short electrode arrays may help preserve residual hearing but may also provide less benefit than traditional cochlear implants for some patients. 2) Pitch percepts in response to electric stimulation may be modified by experience.

Implantation of the Ossified Cochlea: Management with the Split Electrode Array

To describe indications for, the surgical technique required, and the expected functional results of split electrode array cochlear implants. Retrospective chart review. Data collected included etiology of deafness, radiographic findings, pre- and postoperative aided pure tone thresholds, and speech perception testing. Adult speech perception outcomes were measured using the Consonant Nucleus Consonant (CNC) monosyllable words and Hearing in Noise Test (HINT) in quiet/noise (+10 dB). The children were assessed using the Infants and Toddlers Meaningful Auditory Integration Scale. Five patients were implanted with a split electrode array. This included two adults and three children. Both adults had preoperative binaural aided pure tone averages worse than 50 dB and scores of 0% on both HINT quiet and CNC words. The children had undetectable preoperative aided thresholds and scored an average 4/40 on the IT-MAIS. Postimplant, the average threshold gain was 38.5 dB in the adults and 81.5 dB in the children. One adult improved to score 51%/22% on HINT quiet/noise at 6 months and 72%/30% at 12 months. The other adult continued to score 0% on HINT at 12 months but claimed substantial subjective auditory improvement after the first year of device use. The children averaged 28/40 on the IT MAIS at 6 months after implantation. Forty-two of 48 implanted electrodes were functional. The split electrode array is a useful alternative to traditional cochlear implants in treating deafened patients with cochlear ossification. Patients implanted with the split array show marked improvement in sound and speech perception.

Preservation of residual acoustic hearing in cochlear implantation

Recent results supporting the advantages of preserving residual acoustic hearing in cochlear implantation are reviewed. In addition to improving speech recognition ability beyond what a patient can obtain from amplification, the Acoustic+Electric approach offers advantages over traditional cochlear implants in terms of speech recognition in background noises as well as improved sound quality.