Clinical Interpretation of Word-Recognition Scores for Listeners with Sensorineural Hearing Loss: Confidence Intervals, Limits, and Levels

Abstract

Objectives: Confidence levels were established to determine if a word-recognition score is within the expected range for a hearing loss group (based on 3-frequency pure-tone average) or significantly below or above the expected range. Design: Two large clinical databases were mined to produce data-sets composed of word-recognition scores obtained with Q/MASS NU-6 materials and VA NU-6 materials for patients with average hearing losses ranging from 0 to 70 dB HL. Percentiles representing scores that are below (2.5%, 5%, and 10%) and above (90%, 95%, and 97.5%) the expected range (defined as the 80% confidence interval) were established. To estimate the distribution of scores and percentiles for the Auditec NU-6 materials (for which a large database is not available) Q/MASS scores were transformed to Auditec scores based on published psychometric functions. Results: The resulting confidence levels and expected ranges of word-recognition scores should be useful for interpreting the relationship between a score and the distribution of scores for the patient’s hearing loss severity. Confidence levels are described as low, moderate, and high corresponding to the statistical level of assurance that a score is lower or higher than the expected score. Conclusions: The confidence levels and expected ranges may be helpful for interpreting word-recognition scores obtained with three widely used sets of NU-6 test materials.