Assessing Cognitive Abilities in High-Performing Cochlear Implant Users.

Despite being considered one of the most successful neural prostheses, cochlear implants (CIs) provide recipients with a wide range of speech perception performance. While some CI users can understand speech in the absence of visual cues, other recipients exhibit more limited speech perception. Cognitive skills have been documented as a contributor to complex auditory processing, such as language understanding; however, there are no normative data for existing standardized clinical tests assessing cognitive abilities in CI users. Here, we assess the impact of modality of presentation (i.e., auditory-visual versus visual) for the administration of working memory tests in high-performing CI users in addition to measuring processing speed, cognitive efficiency and intelligence quotient (IQ). Second, we relate performance on these cognitive measures to clinical CI speech perception outcomes. Methods: Twenty one post-lingually deafened, high-performing, adult CI users [age range: 52-88 years; 3 unilateral CI, 13 bimodal (i.e., CI with contralateral hearing aid), 5 bilateral CI] with clinical speech perception scores (i.e., AzBio sentences in quiet for the first-ear CI) of ≥60% were recruited. A cognitive test battery assessing auditory-visual working memory (AVWM), visual working memory (VWM), processing speed, cognitive efficiency and IQ was administered, in addition to clinical measures of speech perception in quiet (i.e., AzBio sentences in quiet). AzBio sentences were assessed in two conditions: first-ear CI only, and best-aided everyday wearing condition. Subjects also provided self-reported measures of performance and benefit from their CI using standardized materials, including the Glasgow Benefit Inventory (GBI) and the Nijmegen Cochlear Implant questionnaire (NCIQ). Results: High-performing CI users demonstrated greater VWM than AVWM recall. VWM was positively related to AzBio scores when measured in the first-ear CI only. AVWM, processing speed, cognitive efficiency, and IQ did not relate to either measure of speech perception (i.e., first-ear CI or best-aided conditions). Subjects' self-reported benefit as measured by the GBI predicted best-aided CI speech perception performance. Conclusion: In high-performing CI recipients, visual presentation of working memory tests may improve our assessment of cognitive function.

Modification of Osseointegrated Device Parameters to Improve Speech in Noise and Localization Ability: Clinical Recommendations.

OBJECTIVE: To determine how best to modify osseointegrated (OI) devices or environmental settings to maximize hearing performance. STUDY DESIGN: Prospective cohort study. SETTING: Tertiary referral center. PATIENTS: Fourteen adults with single-sided deafness (SSD) with a minimum of 6 months OI usage and nine bilaterally normal hearing controls INTERVENTIONS: : Speech in noise (SIN) and localization ability were assessed in a multi-speaker array (R-Space) with patients repeating sentences embedded in competing noise and verbally indicating the source speaker, respectively. MAIN OUTCOME MEASURES: SIN and localization were assessed with multiple OI microphone settings-fixed-directional, omnidirectional, and adaptive-as well as an unaided (OI off) condition. Participants completed the Abbreviated Profile of Hearing Aid Benefit questionnaire. RESULTS: Localization performance remains compromised for OI users with a high number of front-back confusions, but rapid learning using the fixed-directional microphone setting improved localization of sounds on the device side despite poorer localization of sounds on the normal-hearing side. SIN performance is greatly enhanced with speech presented to the contra hearing ear rather than the OI device side. Subjective report of hearing ability is highly predictive of objective SIN measures. CONCLUSIONS: Clinicians should consider implementing a fixed-directional microphone setting for improved localization for sounds behind the OI device, but inform patients of the trade-off in performance on the normal-hearing side. For better hearing in noise, clinicians should counsel OI recipients to orient the speech signal to their normal hearing ear rather than their OI device. The background noise subscale of the abbreviated profile of hearing aid benefit (APHAB) provides a meaningful metric by which to assess SIN performance of OI device users.

Assessing candidacy for bilateral cochlear implants: a survey of practices in the United States and Canada.

OBJECTIVES: There are currently no agreed-upon criteria to establish candidacy for bilateral cochlear implants (CIs). This study categorized practice patterns for establishing bilateral CI candidacy. METHODS: A postal survey was sent to all practices performing CIs in the United States and Canada. The survey queried centers regarding candidacy criteria for bilateral implantation, testing parameters, definition of 'best aided condition', use of testing in noise, localization, and quality-of-life questionnaires. The survey was resent to non-responding centers 4 weeks after the initial mailing. RESULTS: The overall response rate was 40%. 'Best aided condition' (70%) and hearing in noise (52%) were used to establish bilateral candidacy, while 45% of centers offered bilateral implants to all candidates. The majority of respondents defined 'best aided' as hearing aids only (57% non-exclusive) or CI and hearing aid together (57%). Only 25% considered a CI alone as best aided. Nearly 5% considered no aiding to be the best aided. Sound localization was used by 8% of respondents for candidacy assessment. Reimbursement affected candidacy decision for 45%. There was variability in stimulus levels (60, 50, 45, and 55 dB), signal-to-noise ratios, and speaker orientations used. DISCUSSION: There are no consistent criteria to assess patients for bilateral CIs. This practice variation makes comparing outcomes across centers challenging and leaves open the possibility of having external standards imposed by regulators or payors. Standardization of candidacy assessment is necessary to develop best practices for bilateral cochlear implantation both to optimize patient outcomes and to ensure the continuity of coverage for these services.

Standardization of reliability reporting for cochlear implants: an interim report.

OBJECTIVE: To propose a standard definition of "out of specification" for cochlear implants and a paradigm for inclusion of category C of the ISO standard 5841-2:2000 for reporting in cumulative survival statistics. HYPOTHESIS: A standard definition of "out of specification" and consistent reporting by manufacturers of cochlear implants will create a fair and consistent representation of cumulative survival. This will allow discernment of differences between manufacturers for reliability and for detection of trends in reliability between model types from the same manufacturer. DESIGN: Three separate meetings with representatives of the three manufacturers of cochlear implants marketed in the United States were staged over a 13-mo period. Standard questions, created by the authors, were addressed by each representative to determine the current state of device reliability reporting. Results were presented to clinicians at the William House Cochlear Implant study Group and the Implantable devices sub-committee of the American Academy of Otolaryngology (2004, 2005) and at the 8th International Cochlear Implant Conference (2004) for feedback. After assimilation of feedback by all parties, the standard was written and reviewed by representatives from each manufacturer for accuracy of data. RESULTS: A complaint-driven standard was developed. A "cochlear implant" as an internal device placed and skin closed in surgery. An internal device is "out of specification" when one or more technical characteristics is outside the limits of normal function and results in explantation or non-use by the patient." Children will be reported separately from adults, each model of device will be reported on annually, a minimum of 200 devices must be in each model group for Cumulative Survival Reporting (CSR). Confidence limits are set at 95%. Explants will be determined to be "biological" or "technical." Technical explants are included in CSR reports. Devices failing to meet specifications set by the manufacturer, not in use but still in situ due to patient choice not to be re-implanted are considered category C and included in CSR reports. Implants that cannot be classified at explant are placed in an "under investigation" category while evaluation is completed. If no classification is made by 6 months, these devices will be included in the CSR report. Notification to the implant center regarding "in" or "out of specification" will be made within 60 d of the explant arriving at the manufacturer with final root cause of failure reported to centers when complete. Information will be passed on to patients by members of the implant team. A standardized form will be created to provide the manufacturers with necessary patient information to guide reliability analysis, including performance after re-implant. CONCLUSIONS: The standard for reliability reporting described in this paper improves patient care by presenting data which are understandable to clinicians delivering cochlear implant services. It fosters fair and accurate reporting without discriminating or granting perceived advantage to any manufacturer. This standard provides a basis for reporting research related to or including device reliability in the medical literature.