In the perfect world, periodically, every adult would have their hearing measured by a licensed hearing care professional using standard pure tone audiometry. For patients this routine measurement would serve as a baseline when monitoring any changes in hearing sensitivity that results from aging, noise exposure or a medical condition. For practitioners and researchers, objective hearing threshold data would be extremely helpful for determining healthcare policy and better understanding how precious health-related resources should be allocated.
Since we do not live in this idealistic world and must contend with burdens such as cost and time, we must rely on self-reported measures of hearing to determine hearing loss prevalence data, which is used to formulate public policy.
One prime example where self-reported hearing loss data is used to make important policy decisions is the 2017 OTC Hearing Aid Act. Its proposed regulatory framework recommends that the intended users of OTC devices would be adults with perceived mild to moderate hearing loss.
There is a relatively rich vein of research indicating substantial discrepancy between self-reported hearing loss and objective measure of hearing loss using pure tone audiometry. Most of these studies, however, provide a limited amount of insight on some important details, as they have focused on older adults with normal audiograms and self-reported hearing loss. Most of these studies have not examined how various non-audiological variables such as age, socioeconomic status and other health variables effect self-reported hearing loss.
Just how many people with self-reported mild hearing loss actually have severe hearing loss, is among the critical questions to better understand when regulatory policy is made that impacts millions of people and dozens of businesses and professions.
Hearing Loss: Self Reports vs. Objective Measures
A recent study published May 1 in BMJ Open, sheds additional light on the discrepancy between self-reported hearing difficulties and hearing loss, objectively measured on the audiogram.
A group of researchers led by Ji Eun Choi at Dankook University Hospital, used data from the fifth Korea National Health and Nutrition Examination Survey (KHANES) to investigate discrepancies between self-reported hearing difficulty and audiometrically measured hearing loss. More than 14,000 adults aged 19 and older, with a mean age of 49, were included in their analysis.
Those 14,000-plus participants were asked about their perceived difficulty hearing by rating on a 1 to 4 scale their response to this question:
“Which sentence best describes your hearing status (while not using hearing aids)?”
- Don’t feel difficulty at all
- A little bit difficult
- Very difficult
- Can’t hear at all
Self-report hearing difficulty was indicated when the response with either a 2, 3, or 4.
In addition to the self-rating of hearing difficulty, participants also had their hearing thresholds measured using conventional testing techniques.
For each of the qualifying participants, the self-rating of hearing difficulty was compared to their audiometrically measured hearing loss to identify possible discrepancies and used to classify participants as either possible overestimators or underestimators of their hearing impairment. (Underestimation of hearing impairment was defined as having an audiometrically measured hearing loss without self-report hearing difficulty. Overestimation of hearing impairment was defined as having self-reported hearing difficulty without audiometrically measured hearing loss.)
The results of this study indicated that 18.2% of the more than 14,000 participants had a discrepancy between their self-reported hearing difficulties and their measured hearing thresholds, with 13.1% underestimating their hearing loss and 5.1% overestimating their hearing loss. In more optimistic terms, 81.8% of the participants in this study self-reported hearing difficulty that was in agreement with their measured hearing thresholds.
In practical terms, this study suggests that about 1 in 5 patients seen in the clinic for an assessment could be either underestimating or overestimating their hearing loss.
Who is more likely to have this discrepancy? According the researchers’ multivariable analysis, age, tinnitus, occupational noise exposure, hypertension and depression are the leading clinical indicators of who could be more likely to overestimate or underestimate their hearing loss. For example, the researchers’ found that among the 2609 participants with a discrepancy between self-report hearing difficulties and their audiometrically measured hearing loss, underestimated hearing impairment was more prevalent in older participants, than overestimated hearing impairment.
The researchers’ surmise that a higher number of underestimators in the older population might be attributed to a tendency among older individuals to consider their hearing loss “normal” for their age. For clinicians and policy makers, this KHANES analysis can assist in the interpretation of other studies that use self-reported hearing difficulties as a proxy for objective audiometric testing.