Cochlear implantation for single-sided deafness and tinnitus suppression.

OBJECTIVE: To quantify the potential effectiveness of cochlear implantation for tinnitus suppression in patients with single-sided deafness using the Tinnitus Handicap Inventory. METHODS: The study included 12 patients with unilateral tinnitus who were undergoing cochlear implantation for single-sided deafness. The Tinnitus Handicap Inventory was administered at the patient's cochlear implant candidacy evaluation appointment prior to implantation and every cochlear implant follow-up appointment, except activation, following implantation. Patient demographics and speech recognition scores were also retrospectively recorded using the electronic medical record. RESULTS: A significant reduction was found when comparing Tinnitus Handicap Inventory score preoperatively (61.2±27.5) to the Tinnitus Handicap Inventory score after three months of cochlear implant use (24.6±28.2, p=0.004) and the Tinnitus Handicap Inventory score beyond 6months of CI use (13.3±18.9, p=0.008). Further, 45% of patients reported total tinnitus suppression. Mean CNC word recognition score improved from 2.9% (SD 9.4) pre-operatively to 40.8% (SD 31.7) by 6months post-activation, which was significantly improved from pre-operative scores (p=0.008). CONCLUSION: The present data is in agreement with previously published studies that have shown an improvement in tinnitus following cochlear implantation for the large majority of patients with single-sided deafness.

Clinical evaluation of an image-guided cochlear implant programming strategy.

The cochlear implant (CI) has been labeled the most successful neural prosthesis. Despite this success, a significant number of CI recipients experience poor speech understanding, and, even among the best performers, restoration to normal auditory fidelity is rare. While significant research efforts have been devoted to improving stimulation strategies, few developments have led to significant hearing improvement over the past two decades. We have recently introduced image processing techniques that open a new direction for advancement in this field by making it possible, for the first time, to determine the position of implanted CI electrodes relative to the nerves they stimulate using computed tomography images. In this article, we present results of an image-guided, patient-customized approach to stimulation that utilizes the electrode position information our image processing techniques provide. This approach allows us to identify electrodes that cause overlapping stimulation patterns and to deactivate them from a patient's map. This individualized mapping strategy yields significant improvement in speech understanding in both quiet and noise as well as improved spectral resolution in the 68 adult CI recipients studied to date. Our results indicate that image guidance can improve hearing outcomes for many existing CI recipients without requiring additional surgery or the use of 'experimental' stimulation strategies, hardware or software.

Development and validation of the pediatric AzBio sentence lists.

OBJECTIVES: The goal of this study was to create and validate a new set of sentence lists that could be used to evaluate the speech-perception abilities of listeners with hearing loss in cases where adult materials are inappropriate due to difficulty level or content. The authors aimed to generate a large number of sentence lists with an equivalent level of difficulty for the evaluation of performance over time and across conditions. DESIGN: The original Pediatric AzBio sentence corpus included 450 sentences recorded from one female talker. All sentences included in the corpus were successfully repeated by kindergarten and first-grade students with normal hearing. The mean intelligibility of each sentence was estimated by processing each sentence through a cochlear implant simulation and calculating the mean percent correct score achieved by 15 normal-hearing listeners. After sorting sentences by mean percent correct scores, 320 sentences were assigned to 16 lists of equivalent difficulty. List equivalency was then validated by presenting all sentence lists, in a novel random order, to adults and children with hearing loss. A final-validation stage examined single-list comparisons from adult and pediatric listeners tested in research or clinical settings. RESULTS: The results of the simulation study allowed for the creation of 16 lists of 20 sentences. The average intelligibility of each list ranged from 78.4 to 78.7%. List equivalency was then validated, when the results of 16 adult cochlear implant users and 9 pediatric hearing aid and cochlear implant users revealed no significant differences across lists. The binomial distribution model was used to account for the inherent variability observed in the lists. This model was also used to generate 95% confidence intervals for one and two list comparisons. A retrospective analysis of 361 instances from 78 adult cochlear implant users and 48 instances from 36 pediatric cochlear implant users revealed that the 95% confidence intervals derived from the model captured 94% of all responses (385 of 409). CONCLUSIONS: The cochlear implant simulation was shown to be an effective method for estimating the intelligibility of individual sentences for use in the evaluation of cochlear implant users. Furthermore, the method used for constructing equivalent sentence lists and estimating the inherent variability of the materials has also been validated. Thus, the AzBio Pediatric Sentence Lists are equivalent and appropriate for the assessment of speech-understanding abilities of children with hearing loss as well as adults for whom performance on AzBio sentences is near the floor.

Clinical assessment of spectral modulation detection for adult cochlear implant recipients: a non-language based measure of performance outcomes.

OBJECTIVE: Spectral modulation detection (SMD) provides a psychoacoustic estimate of spectral resolution. The SMD threshold for an implanted ear is highly correlated with speech understanding and is thus a non-linguistic, psychoacoustic index of speech understanding. This measure, however, is time and equipment intensive and thus not practical for clinical use. Thus the purpose of the current study was to investigate the efficacy of a quick SMD task with the following three study aims: (1) to investigate the correlation between the long psychoacoustic, and quick SMD tasks, (2) to determine the test/retest variability of the quick SMD task, and (3) to evaluate the relationship between the quick SMD task and speech understanding. DESIGN: This study included a within-subjects, repeated-measures design. STUDY SAMPLE: Seventy-six adult cochlear implant recipients participated. RESULTS: The results were as follows: (1) there was a significant correlation between the long psychoacoustic, and quick SMD tasks, (2) the test-retest variability of the quick SMD task was highly significant and, (3) there was a significant positive correlation between the quick SMD task and monosyllabic word recognition. CONCLUSIONS: The results of this study represent the direct clinical translation of a research-proven task of SMD into a quick, clinically feasible format.

Impedance testing on cochlear implants after electroconvulsive therapy.

OBJECTIVE: Cochlear implants (CI) are neural prostheses that restore hearing to individuals with profound sensorineural hearing loss. The surgically implanted component consists of an electrode array, which is threaded into the cochlea, and an electronic processor, which is buried under the skin behind the ear. The Food and Drug Administration and CI manufacturers contend that electroconvulsive therapy (ECT) is contraindicated in CI recipients owing to risk of damage to the implant and/or the patient. We hypothesized that ECT does no electrical damage to CIs. METHODS: Ten functional CIs were implanted in 5 fresh cadaveric human heads. Each head then received a consecutive series of 12 unilateral ECT sessions applying maximum full pulse-width energy settings. Electroconvulsive therapy was delivered contralaterally to 5 CIs and ipsilaterally to 5 CIs. Electrical integrity testing (impedance testing) of the electrode array was performed before and after CI insertion, and after the first, third, fifth, seventh, ninth, and 12th ECT sessions. Electroconvulsive therapy was performed by a staff psychiatrist experienced with the technique. Explanted CIs were sent back to the manufacturer for further integrity testing. RESULTS: No electrical damage was identified during impedance testing. Overall, there were statistically significant decreases in impedances (consistent with no electrical damage) when comparing pre-ECT impedance values to those after 12 sessions. There was no statistically significant difference (P > 0.05) in impedance values comparing ipsilateral to contralateral ECT. Manufacturer testing revealed no other electrical damage to the CIs. CONCLUSION: Electroconvulsive therapy does not seem to cause any detectable electrical injury to CIs.

Tip Fold-over in Cochlear Implantation: Case Series.

OBJECTIVE: To describe the incidence, clinical presentation, and performance of cochlear implant (CI) recipients with tip fold-over. STUDY DESIGN: Retrospective case series. SETTING: Tertiary referral center. PATIENTS: CI recipients who underwent postoperative computed tomography (CT) scanning. INTERVENTION(S): Tip fold-over was identified tomographically using previously validated software that identifies the electrode array. Electrophysiologic testing including spread of excitation or electric field imaging (EFI) was measured on those with fold-over. MAIN OUTCOME MEASURE(S): Location of the fold-over; audiological performance pre and postselective deactivation of fold-over electrodes. RESULTS: Three hundred three ears of 235 CI recipients had postoperative CTs available for review. Six (1.98%) had tip fold-over with 5/6 right-sided ears. Tip fold-over occurred predominantly at 270 degrees and was associated with precurved electrodes (5/6). Patients did not report audiological complaints during initial activation. In one patient, the electrode array remained within the scala tympani with preserved residual hearing despite the fold-over. Spread of excitation supported tip fold-over, but the predictive value was not clear. EFI predicted location of the fold-over with clear predictive value in one patient. At an average follow-up of 11 months, three subjects underwent deactivation of the overlapping electrodes with two of them showing marked audiological improvement. CONCLUSION: In a large academic center with experienced surgeons, tip fold-over occurred at a rate of 1.98% but was not immediately identifiable clinically. CT imaging definitively showed tip fold-over. Deactivating involved electrodes may improve performance possibly avoiding revision surgery. EFI may be highly predictive of tip fold-over and can be run intraoperatively, potentially obviating the need for intraop fluoroscopy.

Results of Postoperative, CT-based, Electrode Deactivation on Hearing in Prelingually Deafened Adult Cochlear Implant Recipients.

OBJECTIVE: To test the use of a novel, image-guided cochlear implant (CI) programming (IGCIP) technique on prelingually deafened, adult CI recipients. STUDY DESIGN: Prospective unblinded study. SETTING: Tertiary referral center. PATIENTS: Twenty-six prelingually deafened adult CI recipients with 29 CIs (3 bilateral). INTERVENTION(S): Temporal-bone CT scans were used as input to a series of semiautomated computer algorithms which estimate the location of electrodes in reference to the modiolus. This information was used to selectively deactivate suboptimally located electrodes, i.e., those for which the distance from the electrode to the modiolus was further than a neighboring electrode to the same site. Patients used the new IGCIP program exclusively for 3-5 weeks. MAIN OUTCOME MEASURE(S): Minimum Speech Test Battery (MSTB), quality of life (QOL), and spectral modulation detection (SMD). RESULTS: On average one-third of electrodes were deactivated. At the group level, no significant differences were noted for MSTB measures nor for QOL estimates. Average SMD significantly improved after IGCIP reprogramming, which is consistent with improved spatial selectivity. Using 95% confidence interval data for CNC, AzBio, and BKB-SIN at the individual level, 76 to 90% of subjects demonstrated equivocal or significant improvement. Ultimately 21 of 29 (72.41%) elected to keep the IGCIP map because of perceived benefit often substantiated by improvement on either MSTB, QOL, and/or SMD. CONCLUSIONS: Knowledge of the geometric relationship between CI electrodes and the modiolus appears to be useful in adjusting CI maps in prelingually deafened adults. Long-term improvements may be observed resulting from improved spatial selectivity and spectral resolution.

Initial Results With Image-guided Cochlear Implant Programming in Children.

HYPOTHESIS: Image-guided cochlear implant (CI) programming can improve hearing outcomes for pediatric CI recipients. BACKGROUND: CIs have been highly successful for children with severe-to-profound hearing loss, offering potential for mainstreamed education and auditory-oral communication. Despite this, a significant number of recipients still experience poor speech understanding, language delay, and, even among the best performers, restoration to normal auditory fidelity is rare. Although significant research efforts have been devoted to improving stimulation strategies, few developments have led to significant hearing improvement over the past two decades. Recently introduced techniques for image-guided CI programming (IGCIP) permit creating patient-customized CI programs by making it possible, for the first time, to estimate the position of implanted CI electrodes relative to the nerves they stimulate using CT images. This approach permits identification of electrodes with high levels of stimulation overlap and to deactivate them from a patient's map. Previous studies have shown that IGCIP can significantly improve hearing outcomes for adults with CIs. METHODS: The IGCIP technique was tested for 21 ears of 18 pediatric CI recipients. Participants had long-term experience with their CI (5 mo to 13 yr) and ranged in age from 5 to 17 years old. Speech understanding was assessed after approximately 4 weeks of experience with the IGCIP map. RESULTS: Using a two-tailed Wilcoxon signed-rank test, statistically significant improvement (p < 0.05) was observed for word and sentence recognition in quiet and noise, as well as pediatric self-reported quality-of-life (QOL) measures. CONCLUSION: Our results indicate that image guidance significantly improves hearing and QOL outcomes for pediatric CI recipients.

Evidence for the expansion of pediatric cochlear implant candidacy.

OBJECTIVE: To test the hypothesis that children who are non-traditional cochlear implant candidates, but are not making progress with appropriately fitted hearing aids and intervention, will demonstrate significant benefit from cochlear implantation as defined by improvement in (1) speech perception, (2) auditory skills development, and/or (3) progress on standardized measures of receptive and expressive language. STUDY DESIGN: Retrospective case series. SETTING: Two tertiary academic cochlear implant centers. PATIENTS: All pediatric patients that underwent cochlear implantation were reviewed. Only those meeting one or both of the following criteria were included: (1) less severe hearing loss than specified in the current indications and (2) open-set word and/or sentence recognition scores greater than 30% for children who are able to participate in speech perception testing. Patients with auditory neuropathy were excluded. INTERVENTION(S): Cochlear implantation. MAIN OUTCOME MEASURES: Pre- and postoperative results of age appropriate speech recognition tests, auditory questionnaires, and standardized norm-referenced estimates of speech and language development. RESULTS: A total of 51 patients met study criteria. The mean age at time of surgery was 8.3 years and 24% underwent bilateral sequential implantation. Overall, the mean speech recognition improvement was 63 percentage points in the implanted ear (p < 0.001) and 40 percentage points in the bimodal condition (p < 0.001). Results of auditory and language development measures revealed significant improvement after implantation (p < 0.05). CONCLUSION: Non-traditional pediatric implant recipients derive significant benefit from cochlear implantation. A large-scale reassessment of pediatric cochlear implant candidacy, including less severe hearing losses and higher preoperative speech recognition, is warranted to allow more children access to the benefits of cochlear implantation.

Stimulation rate reduction and auditory development in poorly performing cochlear implant users with auditory neuropathy.

OBJECTIVE: Patients with auditory neuropathy spectrum disorder (ANSD) exhibit altered neural synchrony in response to auditory stimuli. It has been hypothesized that a slower rate of electrical stimulation in programming strategies for cochlear implant (CI) users with ANSD may enhance development of neural synchrony and speech perception abilities. STUDY DESIGN: Retrospective case series. SETTING: Tertiary otologic practice. PATIENTS: Twenty-two patients with ANSD underwent CI. Patients with complete postoperative audiometric data and at least 2 years of follow-up were included in further analysis. INTERVENTION: Thirteen patients patients met inclusion criteria. Five "poorly performing" CI recipients with ANSD who had not developed closed-set speech perception abilities despite at least 2 years of implant use underwent implant programming to lower the neural stimulation rate. MAIN OUTCOME MEASURES: Speech perception abilities over time using parent questionnaire, closed-set testing, and open-set measures. RESULTS: A high incidence of comorbid conditions was present in the poor performers, including cognitive delay (n = 2), motor delay (n = 3), and autism spectrum disorder (n = 1). The median time to rate slowing in 5 poor performers was 29 months after implant activation. Three of 5 patients achieved closed-set speech perception scores higher than 60% after 6 to 16 months of implant use at the slower rates. At last follow-up (median, 42 mo), no poor performer had yet achieved open-set speech perception abilities. Of all CI recipients with ANSD included in analysis, open-set speech perception abilities developed in 46% (6/13). CONCLUSION: In CI recipients with ANSD who demonstrate limited auditory skills development despite prolonged implant use, lowering the stimulation rate may facilitate acquisition of closed-set speech perception abilities. Further efforts on the study of programming parameters in ANSD patients with CIs are necessary to maximize auditory development in this patient population.