Defining Hearing Loss Severity Based on Pure-Tone Audiometry and Self-Reported Perceived Hearing Difficulty: National Health and Nutrition Examination Survey

Abstract Background There is a well-known metric to describe average/normal vision, 20/20, but the same agreed-upon standard does not exist for hearing. The pure-tone average has been advocated for such a metric. Purpose We aimed to use a data-driven approach to inform a universal metric for hearing status based on pure-tone audiometry and perceived hearing difficulty (PHD). Research Design This is a cross-sectional national representative survey of the civilian noninstitutionalized population in the United States. Study sample Data from the 2011‐2012 and 2015‐2016 cycles of the National Health and Nutrition Examination Survey (NHANES) were used in our analysis. Of 9,444 participants aged 20 to 69 years from the 2011‐2012 and 2015‐2016 cycles, we excluded those with missing self-reported hearing difficulty ( n = 8) and pure-tone audiometry data ( n = 1,361). The main analysis sample, therefore, included 8,075 participants. We completed a subanalysis limited to participants with “normal” hearing based on the World Health Organization (WHO) standard (pure-tone average, PTA of 500, 1000, 2000, 4000 Hz < 20 dBHL). Analysis Descriptive analyses to calculate means and proportions were used to describe characteristics of the analysis sample across PHD levels relative to PTA. Four PTAs were compared, low frequency (LF-PTA, 500, 1,000, 2,000 Hz), four-frequency PTA (PTA4, 500, 1,000, 2,000, 4,000 Hz), high frequency (HF-PTA, 4,000, 6,000, 8,000 Hz), and all frequency (AF-PTA, 500, 1,000, 2,000, 4,000, 6,000, 8,000 Hz). Differences between groups were tested using Rao‐Scott χ 2 tests for categorical variables and F tests for continuous variables. Logistic regression was used to plot receiver operating characteristic curves with PHD as a function of PTA. The sensitivity and specificity for each PTA and PHD were also calculated. Results We found that 19.61% of adults aged 20 to 69 years reported PHD, with only 1.41% reporting greater than moderate PHD. The prevalence of reported PHD increased with higher decibel hearing levels (dBHL) categories reaching statistical significance ( p < 0.05 with Bonferroni correction) at 6 to 10 dBHL for PTAs limited to lower frequencies (LF-PTA and PTA4) and 16 to 20 dBHL when limited to higher frequencies (HF-PTA). The prevalence of greater than moderate PHD reached statistical significance at 21 to 30 dBHL when limited to lower frequencies (LF-PTA) and 41 to 55 dBHL when limited to higher frequencies (HF-PTA). Forty percent of the sample had high-frequency loss with “normal” low-frequency hearing, representing nearly 70% of hearing loss configurations. The diagnostic accuracy of the PTAs for reported PHD was poor to sufficient (<0.70); however, the HF-PTA had the highest sensitivity (0.81). Conclusion We provide four basic recommendations based on our analysis: (1) a PTA-based metric for hearing ability should include frequencies above 4,000 Hz; (2) the data-driven dBHL cutoff for any PHD/“normal” hearing is 15 dBHL; (3) when considering greater than moderate PHD, the data-driven cutoffs were more variable but estimated at 20 to 30 dBHL for LF-PTA, 30 to 35 dBHL for PTA4, 25 to 50 dBHL for AF-PTA, and 40 to 65 dBHL for HF-PTA; and (4) clinical recommendations and legislative agendas should include consideration beyond pure-tone audiometry such as functional assessment of hearing and PHD.