Examining the Validity of the World Health Organization's Long-Standing Hearing Impairment Grading System for Unaided Communication in Age-Related Hearing Loss

OBJECTIVE: This review article overviews a presentation at the Hearing Across the Lifespan 2018 Conference, which examined the data from 5 data sets having pure-tone thresholds and functional measures of speech communication from relatively large groups of older adults to evaluate the validity of the long-standing World Health Organization (WHO) hearing impairment (HI) grading system. DESIGN: This was a review of studies identified from the literature having both pure-tone audiometry and functional measures of speech communication from relatively large samples of older adults. STUDY SAMPLE: Three population or population–sample data sets and 2 clinical data sets were identified and included in the review. RESULTS: As the WHO-HI grade progressed from “normal” to “severe” (insufficient data from older adults were available for the “profound” category), each step in this progression led to a significant difference in functional communication relative to all other WHO-HI grades. This was true for self-report measures of speech communication and direct measures of speech recognition in quiet and noise. Cohen's d effect sizes were moderate to very large between each successive step on the WHO-HI grading scale. CONCLUSIONS: The long-standing WHO-HI grading system, developed through expert opinion and adopted by WHO originally in 1991, is validated here with evidence from studies of functional communication in older adults. The WHO-HI grade system is compared to a proposed new WHO-HI grade system that introduces several changes to the grading system.