Bilateral cochlear implants in infants: a new approach--Nucleus Hybrid S12 project

Bilateral Cochlear Implants Using Two Electrode Lengths in Infants With Profound Deafness

OBJECTIVE

The goal of this investigation was to determine if a short electrode in one ear and standard electrode in the contralateral ear could be an option for infants with congenital profound deafness to theoretically preserve the structures of the inner ear. Similarities in performance between ears and compared with a control group of infants implanted with bilateral standard electrodes was evaluated.

STUDY DESIGN

Repeated-measure, single-subject experiment.

SETTING

University of Iowa-Department of Otolaryngology.

PARTICIPANTS

Nine infants with congenital profound bilateral sensorineural hearing loss.

INTERVENTION(S)

Short and standard implants.

MAIN OUTCOME MEASURE(S)

Early speech perception test (ESP), children's vowel, phonetically balanced-kindergarten (PB-K) word test, and preschool language scales-3 (PLS-3).

RESULTS

ESP scores showed performance reaching a ceiling effect for the individual short and standard ears and bilaterally. The children's vowel and PB-K word results indicated significant (both p < 0.001) differences between the two ears. Bilateral comparisons to age-matched children with standard bilateral electrodes showed no significant differences (p = 0.321) in performance. Global language performance for six children demonstrated standard scores around 1 standard deviation (SD) of the mean. Two children showed scores below the mean, but can be attributed to inconsistent device usage. Averaged total language scores between groups showed no difference in performance (p = 0.293).

CONCLUSIONS

The combined use of a short electrode and standard electrode might provide an option for implantation with the goal of preserving the cochlear anatomy. However, further studies are needed to understand why some children have or do not have symmetric performance.

Combined Electric and Acoustic Stimulation With Hearing Preservation: Effect of Cochlear Implant Low-Frequency Cutoff on Speech Understanding and Perceived Listening Difficulty

OBJECTIVE

The primary objective of this study was to assess the effect of electric and acoustic overlap for speech understanding in typical listening conditions using semidiffuse noise.

DESIGN

This study used a within-subjects, repeated measures design including 11 experienced adult implant recipients (13 ears) with functional residual hearing in the implanted and nonimplanted ear. The aided acoustic bandwidth was fixed and the low-frequency cutoff for the cochlear implant (CI) was varied systematically. Assessments were completed in the R-SPACE sound-simulation system which includes a semidiffuse restaurant noise originating from eight loudspeakers placed circumferentially about the subject's head. AzBio sentences were presented at 67 dBA with signal to noise ratio varying between +10 and 0 dB determined individually to yield approximately 50 to 60% correct for the CI-alone condition with full CI bandwidth. Listening conditions for all subjects included CI alone, bimodal (CI + contralateral hearing aid), and bilateral-aided electric and acoustic stimulation (EAS; CI + bilateral hearing aid). Low-frequency cutoffs both below and above the original "clinical software recommendation" frequency were tested for all patients, in all conditions. Subjects estimated listening difficulty for all conditions using listener ratings based on a visual analog scale.

RESULTS

Three primary findings were that (1) there was statistically significant benefit of preserved acoustic hearing in the implanted ear for most overlap conditions, (2) the default clinical software recommendation rarely yielded the highest level of speech recognition (1 of 13 ears), and (3) greater EAS overlap than that provided by the clinical recommendation yielded significant improvements in speech understanding.

CONCLUSIONS

For standard-electrode CI recipients with preserved hearing, spectral overlap of acoustic and electric stimuli yielded significantly better speech understanding and less listening effort in a laboratory-based, restaurant-noise simulation. In conclusion, EAS patients may derive more benefit from greater acoustic and electric overlap than given in current software fitting recommendations, which are based solely on audiometric threshold. These data have larger scientific implications, as previous studies may not have assessed outcomes with optimized EAS parameters, thereby underestimating the benefit afforded by hearing preservation.

Audit of Bilateral Simultaneous Cochlear Implantation in Pediatric Population: South Indian Study

Objective

To conduct a medical audit of bilateral simultaneous cochlear implantation (CI) in patients with severe prelingual sensorineural hearing loss (SNHL).

Methods

A medical audit of a tertiary care ear, nose, and throat center in Southern India was conducted on data collected from January 2007 to December 2014. All cochlear implantees <6 years of age with severe bilateral SNHL who underwent bilateral simultaneous CI were included in the present study. The exclusion criteria were children >6 years, sequential bilateral CI, revision cases, abnormal or malformed cochlea, and children with global developmental delay in milestones. Subjective outcome scores used were Category of Auditory Performance (CAP) and Speech Intelligibility Rating (SIR).

Results

The CAP and SIR results showed that 20% of implantees achieved peak scores of 7 and 5, respectively. Mean CAP and SIR scores at 12 months were 5.4 and 3.1, respectively.

Conclusion

The present study supports the claim that bilateral CI in severe prelingual bilateral SNHL is better than unilateral and recommends that bilateral CI should be the standard of care in children.

Cochlear implantation: a biomechanical prosthesis for hearing loss

Cochlear implants are a medical prosthesis used to treat sensorineural deafness, and one of the greatest advances in modern medicine. The following article is an overview of cochlear implant technology. The history of cochlear implantation and the development of modern implant technology will be discussed, as well as current surgical techniques. Research regarding expansion of candidacy, hearing preservation cochlear implantation, and implantation for unilateral deafness are described. Lastly, innovative technology is discussed, including the hybrid cochlear implant and the totally implantable cochlear implant.

Hearing preservation in cochlear implant surgery

In the past, it was thought that hearing loss patients with residual low-frequency hearing would not be good candidates for cochlear implantation since insertion was expected to induce inner ear trauma. Recent advances in electrode design and surgical techniques have made the preservation of residual low-frequency hearing achievable and desirable. The importance of preserving residual low-frequency hearing cannot be underestimated in light of the added benefit of hearing in noisy atmospheres and in music quality. The concept of electrical and acoustic stimulation involves electrically stimulating the nonfunctional, high-frequency region of the cochlea with a cochlear implant and applying a hearing aid in the low-frequency range. The principle of preserving low-frequency hearing by a “soft surgery” cochlear implantation could also be useful to the population of children who might profit from regenerative hair cell therapy in the future. Main aspects of low-frequency hearing preservation surgery are discussed in this review: its brief history, electrode design, principles and advantages of electric-acoustic stimulation, surgical technique, and further implications of this new treatment possibility for hearing impaired patients.

Pediatric cochlear implantation: candidacy evaluation, medical and surgical considerations, and expanding criteria

Since the first cochlear implant approved by the US Food and Drug Administration in the early 1980s, great advances have occurred in cochlear implant technology. With these advances, patient selection, preoperative evaluation, and rehabilitation consideration continue to evolve. This article describes the current practice in pediatric candidacy evaluation, reviews the medical and surgical considerations in pediatric cochlear implantation, and explores the expanding criteria for cochlear implantation within the pediatric population.

New frontiers in cochlear implantation: acoustic plus electric hearing, hearing preservation, and more

As cochlear implant technology has changed, so have implantation criteria. In addition to profoundly deaf individuals, candidacy has expanded to include those with significant remaining acoustic hearing. This article describes the devices that are now in clinical trial, discusses the rationale as to why residual hearing preservation is important, details the surgical techniques for hearing preservation, and shares the clinical results of electric plus acoustic processing. That a video is available online.

Electro acoustic stimulation of the auditory system: UNICAMP's surgical approach

A new era has arrived in auditory rehabilitation with the introduction of new technologies such as electroacoustic stimulation (EAS). EAS is indicated for patients with residual hearing at low frequencies and severe or profound hearing loss at high frequencies. These patients have no indication for conventional cochlear implant and have difficulties in adapting to individual sound amplification devices. Preservation of hearing is vital in this process; the surgical technique must be based on this concept.

Objectives

To present the cochlear implant surgical technique with MED-EL Mand FlexEAS to preserve hearing in patients with hearing loss at high frequencies and to maintain low frequency hearing. We are the first institution to carry out this treatment in Brazil.

Methods

A case report of the surgical technique carried out in four patients; the procedure was carried out by the cochlear implant group of a specialized clinical hospital.

Results

The procedures were successful and uneventful.

Conclusion

We described the technique used at our institution for implants using EAS; the surgical technique is complex and includes steps for preservation of hearing.