Objective findings with malpositioning of a nucleus 24RE(CA) cochlear implant.

BACKGROUND: Proper intracochlear placement of cochlear implant electrode arrays is believed to be important for optimum speech perception results. However, objective tests of cochlear implant function typically provide little or no information about the intracochlear placement of the array. We report the results for a variety of objective tests, including averaged electrode voltage (AEV) measurements, in a patient where the electrode array had folded up on itself during insertion. PURPOSE: To determine whether any of the objective measures provided evidence of incorrect electrode placement. RESEARCH DESIGN: Objective test data are reported for a patient with an incorrectly positioned electrode array, prior to and following reimplantation, and compared to data obtained in 42 patients with normal insertions. STUDY SAMPLE: One patient with an incorrectly placed electrode array, prior to and following reimplantation, and a sample of 42 implant recipients with correct insertions. INTERVENTION: The patient with the malpositioned electrode array was explanted and reimplanted. The results for the first and the second implant, with regards to objective test results, are compared. The results are also compared to the data obtained on 42 implant recipients with normal insertions. DATA COLLECTION AND ANALYSIS: The objective test data (primarily AEV data) are compared with AEV results obtained in 42 patients with normal electrode insertions. RESULTS AND CONCLUSIONS: Although the electrode array had folded up on itself during insertion, intraoperative electrode impedances and VIII nerve responses, as well as postoperative electrically evoked auditory brainstem responses, were within normal limits. However, averaged electrode voltages, obtained with the Nucleus Crystal Integrity Test system, were abnormal and consistent with a low-impedance pathway between the apical and middle portions of the electrode array.

Improved residual hearing preservation using peri-operative minocycline during cochlear implantation.

OBJECTIVE: To determine whether peri-operative minocycline improves preservation of residual hearing in adult patients undergoing cochlear implantation. STUDY DESIGN: Retrospective age, gender matched study design. SETTING: Tertiary/quaternary referral centre. PATIENTS: Nine patients undergoing cochlear implantation who received minocycline peri-operatively and a historical control group of nine matched patients who did not receive minocycline. INTERVENTION(S): Minocycline 200mg orally pre-operatively and 100mg daily post-operatively for ten days. MAIN OUTCOME MEASURE(S): Change in residual hearing thresholds at 250 and 500 Hz. RESULTS: The average loss of residual hearing at 250 Hz post-cochlear implant for those who had not received minocycline was 18.9 dB (SD 12.2) compared to 16.7 dB (SD 15.0) for those who had received peri-operative minocycline (p-value 0.77). The average loss of residual hearing at 500 Hz post-cochlear implant for those who had not received minocycline was 24.4 dB (SD 15.9) compared to 19.4 dB (SD 14.3) for those who had received minocycline (p-value 0.48). Two patients who did not receive minocycline lost all residual hearing at both 250 Hz and 500 Hz post-implantation and only one patient who had received minocycline lost all residual hearing at 500 Hz. CONCLUSIONS: The neuroprotective effect of minocycline may help to preserve residual hearing post-cochlear implant. Further studies are warranted.

Cochlear implantation results in patients with Kearns-Sayre syndrome.

OBJECTIVES: To examine the evidence for a cochlear, retrocochlear, or central site of lesion for deafness in two cochlear implant recipients with Kearns-Sayre Syndrome (KSS). DESIGN: Speech perception data and electrically evoked Auditory Brainstem (eABR) and Middle Latency Responses were obtained in two patients with KSS and compared with a group of non-KSS implant recipients. RESULTS: Speech perception data and electrophysiological responses for the patients with KSS were similar to those obtained in non-KSS patients. CONCLUSIONS: Results are consistent with an initial cochlear site of lesion for deafness in KSS, and with relative sparing of the central auditory pathway early in the disease.

Ethical considerations in resource allocation in a cochlear implant program.

OBJECTIVE: To review processes of resource allocation and the ethical considerations relevant to the fair allocation of a limited number of cochlear implants to increasing numbers of potential recipients. DESIGN: Review of relevant considerations. SETTING: Tertiary referral hospital. METHODS: Editorial discussion of the ethical issues of resource allocation. MAIN OUTCOME MEASURES: Heterogeneity of audiometric thresholds, self-reported disability of hearing loss, age of the potential cochlear implant recipient, cost-effectiveness, access to resources, compliance with follow-up, social support available to the recipient, social consequences of hearing impairment, and other recipient-related factors. RESULTS: In a publicly funded health care system, there will always be a need for decision-making processes for allocation of finite fiscal resources. All candidates for cochlear implantation deserve fair consideration. However, they are a heterogeneous group in terms of needs and expected outcomes consisting of traditional and marginal candidates, with a wide range of benefit from acoustic amplification. CONCLUSIONS: We argue that implant programs should thoughtfully prioritize treatment on the basis of need and potential benefit. We reject queuing on the basis of "first-come, first-served" or on the basis of perceived social worth.

Prevalence of new-onset vestibular symptoms following cochlear implantation.

OBJECTIVE: To identify the prevalence of new-onset balance symptoms in adult patients who have undergone cochlear implantation (CI). DESIGN: A retrospective, questionnaire-based prevalence study of 227 consecutive adults (age > 16 years) who have undergone CI. The control group comprised patients awaiting CI. SETTING: Tertiary hospital, Vancouver, British Columbia. METHODS: All patients implanted at the study centre were contacted. A questionnaire regarding their past medical history and the presence and character of pre- and post-CI dizziness was completed. Patients were divided into four groups based on the presence or absence of their symptoms in relation to the time of implantation. Patients with vestibular symptoms further completed the Dizziness Handicap Inventory (DHI). MAIN OUTCOME MEASURES: Incidence of balance symptoms pre- and post-CI and associated DHI scores. RESULTS: One hundred ten of 227 patients (48%) responded. Fifty-three (48.3%) had dizziness prior to CI and 64 patients (58.2%) postimplantation. Forty-one patients (37.3%) noted new onset of balance symptoms or a change in their symptoms post-CI. The onset was immediate (within 1 week post-CI) in the majority of this group (63.4%). DHI scores were generally low across all groups. CONCLUSIONS: Delayed- and late-onset new balance-related symptoms occur in approximately 5 and 9% of CI patients, respectively, and the self-perceived handicapping effects of these symptoms may be greater compared with patients with symptoms prior to implantation.