Objective: Intraoperative far-field auditory brainstem response (ABR) and direct cochlear nerve action potential monitoring using neural response imaging (NRI) are techniques for monitoring the cochlear nerve during vestibular schwannoma (VS) surgery. A new paradigm has developed where the cochlear nerve is anatomically preserved during tumor removal to facilitate cochlear implantation in select circumstances. This report describes the use of an unmodified commercial cochlear implant (CI) to elicit electrically-evoked direct cochlear nerve and far-field ABR monitoring to evaluate the status of the cochlear nerve during tumor resection in real time. Patients: Adult female with unilateral, sporadic VS. Intervention(s): Cochlear implantation followed by translabyrinthine resection of VS in single operation. Main Outcome Measures: During tumor resection intra-cochlear electrodes were used to deliver electrical stimulation and measure NRI or the cochlear nerve action potential. Electrically-evoked ABR (eABR) was measured using surface electrodes and wave V was monitored (far-field ABR) during surgery. Results: A 61-year-old female was evaluated for a unilateral, enlarging intracanalicular VS with asymmetric SNHL. The patient opted for microsurgery and due to her bilateral hearing loss was a candidate for CI. Cochlear implantation with an unmodified, commercially available lateral wall electrode was performed. The remainder of the approach and tumor resection was performed under continuous eABR and NRI monitoring. Gross total resection was achieved with intact eABR and NRI at the conclusion of the case. Changes in ABR and NRI consistently recovered after modifying dissection strategy. The patient reported auditory percepts with her cochlear implant postoperatively. Conclusions: This report demonstrates the feasibility of using real-time NRI and eABR with a CI to facilitate preservation of the cochlear nerve during VS microsurgery. Using this method to mitigate cochlear nerve trauma during microsurgery may preserve the option of CI for hearing rehabilitation.
Assessment of Temporal Fine Structure Processing Among Older Adults With Cochlear Implants
Objectives: The purpose of this study was to determine if older adults with cochlear implants are able to take advantage of coding schemes that preserve temporal fine structure (TFS) cues. Design: A total of 19 older adults with cochlear implants participated in a prospective, repeated measures, A to B design. Participants entered the study using TFS. The participants used strategy A (high definition continuous interleaved sampling [HDCIS]) for 3 months and strategy B (TFS) for 3 months. Endpoint testing was administered at the end of each 3-month period. Testing included consonant recognition, speech understanding in noise, temporal modulation thresholds, and self-perceived benefit. Results: Older adults were able to use TFS successfully. Speech perception performance was improved using TFS compared with HDCIS for voicing, but not manner or place of articulation. There were no differences between the two strategies for speech understanding in noise, temporal modulation detection, or self-perceived benefit. At the end of the study, 13 out of 19 (68%) of participants chose to continue using TFS processing. Conclusions: Advanced age does not prevent adults with cochlear implants from using TFS coding strategies. Performance outcomes using TFS and HDCIS were similar, with the exception of voicing which was improved when using TFS. The data support the idea of using various sound processing strategies with older adults.
Application of Kaizen Principles to a Large Cochlear Implant Practice: A Continuous Quality Improvement Initiative at Mayo Clinic
Objective: To remove barriers and improve access for patients seeking cochlear implantation. Study Design: Prospective quality improvement study at a large tertiary academic care center. Methods: A Kaizen quality improvement model was applied over the course of a year. Four weeklong meetings were used to identify areas for improvement and remediation. Data were collected at baseline, 90-days, and 1-year postcompletion of the project. Outcome measures included lead times, defined as the wait time between first contact with the clinic and the first appointment, and the wait time between surgery and activation, and cycle times defined as the total test time needed to determine cochlear implant candidacy, and total time needed to complete initial activation. The total inventory kept as clinic stock was also calculated Results: Kaizen team members collected data for each outcome measure. After the Kaizen principles were applied, the following outcomes were observed: median lead times between first contact with the clinic to candidacy testing, candidacy testing to surgery, and surgery to activation of the implant remained stable from baseline to 1-year follow-up. Median cycle time for candidacy testing decreased from 7.3 hours at baseline to 3.0 hours at 1-year follow-up. Cycle times for initial activation of the device did not change over time. The total inventory of clinic stock was reduced by 31%. Conclusions: Though outcomes for lead and cycle times varied, implementation of Kaizen principles was found to be an effective method for completing this quality improvement project at a large cochlear implant program overall. Level of Evidence: 3a
Cochlear Implantation in Charcot-Marie-Tooth Disease: Case Report and Review of the Literature
Introduction. Charcot-Marie-Tooth (CMT) disease is a peripheral hereditary neuropathy associated with motor and sensory impairment and can result in profound sensorineural hearing loss (SNHL). Currently, the role of cochlear implantation in the setting of CMT and other progressive peripheral neurodegenerative disorders is not well established. Methods. Case report and review of the English literature. Results. A 70-year-old male with CMT was referred for evaluation of progressive asymmetric SNHL and reported a 15-year duration of deafness involving the left ear. Audiometric testing confirmed profound SNHL in the left ear, while the right ear exhibited moderate-to-severe SNHL. Left-sided cochlear implantation was performed using a conventional length lateral wall electrode. Intraoperative device testing found normal impedance levels throughout the array; however, electrically evoked auditory potentials were absent on all electrodes. Upon initial activation 3 weeks after surgery, the patient reported excellent access to sound in the cochlear implant-only condition. He has made good progress at each subsequent visit; speech perception testing after seven months showed improvement from 0% to 32% on AzBio sentence and 53% on CNC phoneme testing in the cochlear implant-only condition. Conclusion. We report the third case of cochlear implantation in a patient with CMT. SNHL in CMT is hypothesized to result from disruption of synchronous activity of the cochlear nerve. In patients with CMT, cochlear implantation may reconstitute synchronous neural activity by way of supraphysiological electrical stimulation. Our results corroborate two earlier reports that cochlear implantation is a viable option for rehabilitation of SNHL in this unique subset of patients.
Health-related quality of life outcomes following adult cochlear implantation: A prospective cohort study
Objectives/HypothesisThis study was designed to examine speech recognition and self‐perceived health‐related quality of life (HRQoL) received from cochlear implantation among a cohort of adults and children with a short duration of unilateral hearing loss greater than 6 months, but less than 2 years.Study DesignSingle‐subject repeated measures prospective study.MethodsThis study assessed changes in speech recognition and self‐perceived quality of life by prospectively analyzing data at the preoperative evaluation and at the 3‐month and 6‐month postactivation intervals. Measurement tools included Medical Outcomes Study Questionnaire Short Form 36, Nijmegen Cochlear Implant Questionnaire, Speech Spatial and Qualities of Hearing–Comparative, and speech recognition measures in quiet and in noise.ResultsResults indicated significant improvement in speech recognition, both in quiet and noise. Quality‐of‐life measures showed a significant increase in self‐perceived benefit with disease‐specific instruments, but remained constant with a generic HRQoL instrument.ConclusionsCochlear implantation was a successful intervention for improved hearing in quiet and noise, and a self‐perceived benefit for this group of adults and children with a short duration of unilateral hearing loss.Level of Evidence4 Laryngoscope, 127:1683–1688, 2017