The World Health Organization's hearing-impairment grading system: an evaluation for unaided communication in age-related hearing loss.

The WHO-proposed grades were created by expert consensus rather than evidence, and this review tested them after the fact. The review focused on older adults with age-related hearing loss, so it does not show the grades work for children or for other causes of hearing loss. There were too few people in the profound grade to evaluate it, and severe grades were excluded from some analyses. The normal and slight/mild grades often did not separate clearly on speech tests, so the lower end of the scale is less useful. Many speech tests were ear-specific, so the review could not fully test whether the better-ear rule used to assign grades is valid. The data are cross-sectional and secondary, so they show that grades track communication performance, not that grading causes outcomes. Self-report measures showed smaller effect sizes than speech tests, so patient-reported difficulty may not match test scores in every case. One VA dataset did not record gender, and the NHANES analysis was limited to ages 50 to 69 years. The authors could not access all potentially relevant datasets, so the review may not represent every available source.

No potential conflict of interest was reported by the author.

Do not use the WHO-proposed grade as a clear cut-off for when older adults need help, because the normal and slight/mild grades often did not differ on communication tests. The review also did not evaluate children or all causes of hearing loss.