Is the clinical head impulse test helpful in cochlear implantation candidacy evaluation?

Objective: Vestibular dysfunction is a known risk of cochlear implantation (CI). However, the utility of the physical exam to screen CI candidates for vestibular dysfunction is not well-studied. The objective of this study is to evaluate the preoperative role of the clinical head impulse test (cHIT) in subjects undergoing CI surgery evaluation. Study Design Setting and Subjects: We conducted a retrospective review of 64 adult CI candidacy cases between 2017 and 2020 at a tertiary health care center. Methods: All patients underwent audiometric testing and evaluation by the senior author. Patients with an abnormal catch-up saccade contralateral to their worse hearing ear during cHIT were referred for formal vestibular testing. Outcomes included clinical and formal vestibular results, operated ear with regard to audiometric and vestibular results, and postoperative vertigo. Results: Among all CI candidates, 44% (n = 28) reported preoperative disequilibrium symptoms. Overall, 62% (n = 40) of the cHITs were normal, 33% (n = 21) were abnormal, and 5% (n = 3) were inconclusive. There was one patient who presented with a false positive cHIT. Among the patients who endorsed disequilibrium, 43% had a positive preoperative cHIT. Fourteen percent of the subjects (n = 9) without disequilibrium had an abnormal cHIT. In this cohort, bilateral vestibular impairment (71%) was more common than unilateral vestibular impairment (29%). In 3% of the cases (n = 2), surgical management was revisited or altered due to cHIT findings. Conclusion: There is a high prevalence of vestibular hypofunction in the CI candidate population. Self-reported assessments of vestibular function are often not congruent with cHIT results. Clinicians should consider incorporating cHITs as part of the preoperative physical exam to potentially avoid bilateral vestibular dysfunction in a minority of patients.

GJB2 gene mutations in cochlear implant recipients: prevalence and impact on outcome.

OBJECTIVE: To determine the prevalence of GJB2 gene mutations in patients undergoing cochlear implantation (CI) and their impact on rehabilitative outcome following implantation. DESIGN: Prospective determination of GJB2 mutation by sequence analysis by denaturing high-performance liquid chromatography and its correlation with outcome following CI. SETTINGS: Two tertiary academic medical centers. PATIENTS: Subjects who have met the audiologic criteria and have undergone CI. RESULTS: Of 77 cochlear implant recipients screened, 13 (18%) harbored a detectable sequence alteration in the GJB2 gene. Only 3 of these 13 patients had hearing loss clearly attributable to a biallelic GJB2 mutation. There were 2 patients with homozygous mutations, including a 35delG and a 167delT mutation, and a third with a compound heterozygous mutation. Of the remaining 10 patients, 8 had 1 deafness allele, while 2 had a normal polymorphism that was not believed to be implicated in the hearing loss. Six patients had the common 35delG mutation: 5 patients had heterozygous mutations, which are probably not related to the underlying hearing loss (a second deafness allele cannot be ruled out in these cases because of the screening methodology used), while 1 patient had a homozygous mutation, which was clearly implicated in the patient's deafness. Rehabilitative outcome among those with detectable sequence alterations, as well as the 3 patients with biallelic mutations, varied but were similar on average when compared with outcomes seen in our entire CI population. CONCLUSIONS: A large percentage of implant candidates harbor mutations or sequence alterations in the GJB2 gene, although only a small number of these changes are biallelic and a clear cause of the hearing loss. These results demonstrate that patients with GJB2-related deafness clearly benefit from CI.

Cochlear implant outcomes in the elderly.

OBJECTIVE: This study aimed to review cochlear implantation with respect to surgical and auditory outcomes in subjects aged 70 years and older. STUDY DESIGN: Retrospective chart review. SETTING: Tertiary referral centers. PATIENTS: Sixty-five patients aged 70 years or older at the time of implantation were compared to a group of patients aged <70 years. INTERVENTION: Patients underwent multichannel cochlear implantation with either the Clarion or Nucleus device. MAIN OUTCOME MEASURE: Presence or absence of surgical complications and auditory performance with open-set word and sentence recognition testing. RESULTS: In patients implanted at age 70 or older, significant improvement in speech understanding was demonstrated in performance scores using Consonant Nucleus Consonant words, Central Institute for the Deaf sentences, and Hearing in Noise Test sentences at 3, 6, and 12 months when compared to preimplantation scores. However, their performance was slightly poorer when compared to a control group of patients <70 years of age in the same measures at 3, 6, and 12 months. CONCLUSIONS: The elderly population showed significant improvement in auditory performance tests following cochlear implantation compared to their preimplantation scores but performed less well than younger patients.

Cochlear implantation in different health-care systems: disparities between Germany and the United States.

INTRODUCTION: Cochlear implantation is a popular procedure to restore hearing in patients with severe-to-profound hearing loss. Despite the widespread acceptance of the intervention, many variables exist in the evaluation for and implementation of this technology throughout the world. The primary aim of this investigation is to analyze treatment disparities between Germany and the United States in cochlear implantation. MATERIALS AND METHODS: Cochlear implant recipients in 2 representative cochlear implant centers in the United States and Germany were retrospectively analyzed. Differences in preoperative, perioperative, and postoperative treatment paradigms as well as the disparities in the follow-up were recorded. Objective measures included demographic data, length of hospitalization, minor and major complication rates, and speech scores within the first 3 years. Moreover, a cost analysis comparison between both centers was performed. RESULTS: A number of differences in treatment were noted between the two centers. The primary difference was that in Germany the procedure was inpatient with an average 4-day hospital stay, whereas in the United States, it was an outpatient procedure. Despite these differences, only small differences were noted in the category of minor complications, and no differences were seen in the category of major complications between the 2 centers. Comparing the results of monosyllabic speech tests, no major differences could be detected. Cost analysis between the 2 centers demonstrates that, whereas in Germany, all charges are covered by the statutory health insurance, in the United States, the reimbursements are significantly lower than the charges. DISCUSSION: Despite differences in the clinical approach to cochlear implants in Germany versus the United States, no significant differences in outcomes were seen in the 2 groups, and the complication rates were nearly identical. Interestingly, although the procedure in Germany is associated with a 4-day hospital stay, the charges for the entire procedure in Germany are approximately ½ as compared with those in the United States, although the actual reimbursement for this procedure may be lower in the United States than in Germany.

External magnet displacement in cochlear implants: causes and management.

OBJECTIVE: To evaluate the complication of external magnet displacement in cochlear implant patients. STUDY DESIGN: Retrospective case review of patients at a tertiary academic medical center. PATIENTS: Eleven patients were identified with postoperative magnetic retention difficulties after cochlear implantation. INTERVENTIONS: Skin flap thickness test, hair shaving over the magnet site, elastic headband usage, and skin flap thinning or revision were the primary interventions used. MAIN OUTCOME MEASURES: Qualitative reports of magnet retention difficulty noted in patient records during audiologic and device programming follow-up visits. RESULTS: Follow-up ranged from 2 to 4 years from the date of implantation. Interventions included initial conservative measures (e.g., shaving hair, wearing headband). Four patients required flap thinning surgery; of these, 3 showed marked improvement. Almost all patients in this series were overweight or obese. CONCLUSION: Patients with external magnet retention difficulties can present a challenge to users of cochlear implants and their providers. Conservative measures will alleviate the issue in many cases. Skin flap thinning is a viable option for those patients whose magnet retention difficulties do not resolve with conservative treatments. However, extra vigilance must be given to the skin flap in all cases to monitor the effects of both conservative and nonconservative measures because overcorrection may risk skin breakdown.