Development and Implementation of the Cochlear Implant Quality of Life (CIQOL) Functional Staging System

The purpose of this study is to develop and implement a functional staging system using the Cochlear Implant Quality of Life (CIQOL) framework. The CIQOL-35 Profile was developed and validated following a rigorous research design and found to be more comprehensive and psychometrically sound than previous patient-reported outcome measures (PROMs) applied to adult CI users. However, interpreting the CIQOL-35 Profile (and all PROMs) relative to real-world functioning remains difficult for patients and clinicians, which limits the capacity of PROMs to direct clinical care. To address this limitation, a functional staging system based on PROM scores was developed to provide detailed descriptions of patients' self-reported abilities (clinical vignettes) without sacrificing the inherent value of the psychometrically derived scores. The current study (1) creates an evidence-based CIQOL functional staging system using advanced psychometric techniques, (2) confirms the clarity and meaningfulness of the staging system with patients, and (3) implements the staging system to measure CIQOL stage progression using data from a longitudinal study design.

Item response theory (IRT) analyses of CIQOL-35 Profile data from 705 experienced adult CI users and expert opinion were used to determine the cut-scores that separated adjacent stages for the six CIQOL-35 domains (communication, emotional, entertainment, environment, listening effort, and social). The research team then created clinical vignettes based on item response patterns for each stage. Semi-structured key informant interviews were conducted with 10 adult CI users to determine the clarity and meaningfulness of the CIQOL stages and associated clinical vignettes. Finally, we prospectively collected CIQOL-35 Profile scores from 42 CI users prior to cochlear implantation and then at 3- and 6-months post-CI activation to measure CIQOL stage progression.

Psychometric analyses identified five statistically distinct stages for the communication domain and three stages for all other domains. Using IRT analysis results for guidance, research team members independently identified the cut-scores that represented transitions between the functional stages for each domain with excellent agreement (κ = 0.98 [95% confidence interval 0.96-0.99]). Next, the key informant interviews revealed that CI users found the clinical vignettes to be clear and only minor changes were required. Participants also agreed that stage progression represented meaningful improvements in functional abilities. Finally, 88.1% of 42 patients in the prospective cohort (n = 37) improved from pre-CI functional stage by at least one functional stage in one or more domains. The communication domain had the greatest number of patients improve by one or more stages (59.5%) and the social domain the fewest (25.6%). There was also a trend for less improvement at 3- and 6-months post-CI activation for patients at higher pre-CI functional stages, even though higher stages were achievable.

The new CIQOL functional staging system provides an evidence-based understanding of the real-world functional abilities of adult CI users from pre-CI to 3- to 6-months post-CI activation across multiple domains. In addition, study results provide the proportion of CI users in each stage at each timepoint. Results can be used during discussions of expectations with potential CI users to provide enhanced insight regarding realistic outcomes and the anticipated timing for improvements. The use of the CIQOL functional staging system also presents an opportunity to develop individualized goal-based rehabilitation strategies that target barriers to stage advancement faced by CI users.

2 Laryngoscope, 132:S1-S13, 2022.