The Evolution of Cochlear Implant Care

On average, it takes 17 years for medical research to transition from discovery to widespread clinical practice, a delay often termed the "research-to-practice gap." This period encompasses stages like discovery, evidence gathering, guideline development, dissemination, and eventual adoption. The healthcare sector, in particular, tends to be slow in adapting due to factors like institutional inertia, limited training, and resource constraints.

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Over the past two decades, we have seen significant evolution in cochlear implant (CI) candidacy, testing, and evaluation. Examples include adjustments in testing presentation levels (e.g., from 70dB SPL to 60dB SPL), testing materials (shifting from CID and HINT sentences to AzBio sentences), and testing conditions (moving from testing in quiet environments to conditions with +10 or +5 SNR). Additionally, the variety of patients we evaluate has expanded significantly from more traditional bilateral severe to profound patients to patients with low frequency preservable hearing, single-sided deafness (SSD) and asymmetrical hearing loss (AHL).

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The MSTB-3 shows an evolution from the previous MSTB recommendations by focusing on evaluating and optimizing each ear individually to maximize bilateral outcomes.  It changes the focus of candidacy recommendations to be based on CNC word scores, rather than AzBio sentence scores, since sentences are more significantly affected by cognition, auditory memory, and executive function.  CNC word scores, on the other hand, are a more straightforward test of discrimination. The MSTB-3 also defines the concept of “best-aided condition” as testing using a hearing aid optimized for hearing loss in the ear being implanted. This sets important framework for standardized care and comparison of patients between clinics. Testing in the “everyday listening condition” with the optimized hearing configuration the patient uses (bilateral aids, unilateral aid, CROS aid, unoccluded ears, etc.…) is recommended for pre- verses post-op comparison.

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The primary goal of the MSTB-3 is to provide a streamlined and standardized framework for evaluating speech perception in CI patients, with modifications to help evaluate the variety of patients seen by CI clinics today. Designed as an efficient clinical protocol, the MSTB-3 produces reliable, objective, and comparable data to assess CI candidacy and performance over time. This standardization helps clinicians make informed decisions, enhances patient outcomes, and ensures more consistent assessments of cochlear implant performance across various clinics. This consistency is crucial for maintaining referral patterns and gathering meaningful research data across institutions. Ultimately, the MSTB-3's purpose is to provide a standardized approach to measuring speech perception in adults with cochlear implants, across various listening configurations in order to improve patient outcomes, streamline testing processes, and expand access to cochlear implant care.