Development and validation of the effectiveness of the auditory rehabilitation scale

Objective: To develop a new scale of hearing-related function and quality of life in patients with hearing aids that addresses overlooked concerns, such as hearing-aid comfort, convenience, and cosmetic appearance, that may influence hearing-aid adherence while maintaining brevity and sensitivity to clinical change. Design: Prospective, multicenter instrument validation. Setting: Four diverse sites in Washington State, including 2 private practices, 1 university setting, and 1 Veterans Affairs hospital. Patients: Seventy-eight patients with hearing aids. Interventions: We created 2 modules in the Effectiveness of Auditory Rehabilitation (EAR) scale. The first module (Inner EAR) covers intrinsic hearing issues such as hearing in quiet and hearing in noise and is administered both before and after treatment. The second module (Outer EAR) covers extrinsic (hearing-aid related) issues such as comfort, appearance, and convenience and is administered after hearing-aid fitting. Main Outcome Measures: Both scales were developed and validated in 3 stages. Stage 1 used a qualitative approach from multiple data sources to develop preliminary instruments. Stage 2 used approaches from classic test theory to reduce the number of items and psychometrically validate the instruments. Stage 3 examined the responsiveness or sensitivity to clinical change. Results: A 10-item Inner EAR module and a 10-item Outer EAR module were created and validated. Internal consistency of individual domains (Cronbach α=0.85 and 0.72, respectively) and test-retest reliability (intraclass correlation coefficients=0.76 and 0.81, respectively) were excellent. Evidence of construct validity included concurrent validity with other hearing scales and global visual analog scales, discriminant validity with dizziness handicap, correlation with hearing-aid adherence, and confirmatory factor analyses. Both scales had strong evidence of responsiveness (sensitivity to change), with higher effect sizes and Guyatt responsiveness statistics than the 2 widely used hearing scales in this study. The scales took an average of 5 minutes to complete. Conclusions: The EAR scale is a valid and reliable measure of the effectiveness of amplification in the treatment of sensorineural hearing loss. It addresses the range of issues that are of importance to hearing-aid patients. The scales have excellent psychometric properties, are more responsive than several widely used hearing scales, and are minimally burdensome for patients to complete. The EAR may be a valuable outcome measure in future studies of both existing hearing aids and newer hearing-aid technologies, such as bone-anchored aids or middle ear implants.