June 2021 The Hearing Journal
Unilateral hearing loss (UHL) is a common condition that affects around 5% to 13% of adults in the United States. Prior studies examining UHL have found that it is associated with poorer educational outcomes in children with lower language, verbal, and performance IQ scores compared to children without hearing difficulties. Adults with UHL reported communication difficulties especially with regard to communicating in a noisy environment and with sound localisation. A few qualitative studies have shown that UHL negatively impacts adults’ confidence levels with associated embarrassment and withdrawal from social situations. Despite the known negative impact of UHL on many domains of a person's life, only about 2% of adults with UHL use any type of listening device to improve their hearing. Our study investigated the impact of UHL on communication on a population level for the first time and explored factors associated with UHL.
Figure 1: Prevalence of communication difficulties among adults with normal hearing and unilateral and bilateral hearing loss (weighted estimates). BHL, bilateral hearing loss; UHL, unilateral hearing loss. Error bars indicate 95% confidence intervals. Unilateral hearing loss is defined by a speech frequency pure-tone average of hearing thresholds at 0.5, 1, 2 and 4 kHz =25 dB hearing level (HL) in the worse hearing ear and <25 dB HL in the better hearing ear. Bilateral hearing loss is defined by a speech frequency pure-tone average of hearing thresholds at 0.5, 1, 2, and 4 kHz =25 dB HL in the better hearing ear. Mild hearing loss is defined as 25.0 to 39.9 dB HL, and moderate or worse hearing loss is defined as =40 dB HL.
We analysed data from the 2011-2012 and 2015-2016 National Health and Nutritional Examination Survey, which is a nationally representative dataset for U.S. adults collected by the Centers for Disease Control and Prevention. In the survey, adults between the ages of 20-69 completed an audiometric evaluation and answered questions regarding their communication (n=8,138). We assessed the prevalence of UHL among adults in the U.S., associated factors for UHL, and the impact of UHL on communication. UHL was defined as a pure-tone average of >25 dB hearing level in the worse ear and <25 dB hearing level in the better ear. Our results showed that the overall prevalence of UHL was 8.1% among U.S. adults. Additionally, only 4.8% of those with UHL reported having used hearing aids. In our multivariate regression analysis, we found that adults with UHL were more likely to be older, male, and white. They were also more likely to report lower levels of education and have diabetes and cardiovascular diseases compared to adults without UHL. Furthermore, participants with UHL were more likely to report a history of significant off-work noise exposure.
Additionally, we examined the impact of UHL on overall communication. Participants were asked about the degree of subjective hearing loss, ability to hear a whisper from across a quiet room, difficulty following conversation in noise, and frustration caused by hearing when talking. Our analysis showed that participants with UHL were significantly more likely to report difficulties in all of these domains even after adjusting for relevant demographic and clinical factors. Our results also revealed that adults with UHL were two times more likely to report difficulties following conversation in noise and three times more likely to report frustration when talking due to hearing loss in comparison to normal-hearing adults. Of note, higher levels of communication difficulties were observed with increasing severity of UHL.
IMPLICATIONS IN PRACTICE
The data we analysed showed that those with UHL were more likely to be older, white, and male. They were also more likely to have lower educational attainment and a history of diabetes, cardiovascular disease, and off-work noise exposure. The rates of UHL in our study were in the range of prior prevalence estimates in other studies. Although this was a cross-sectional study, it is possible that UHL from a younger age may have led to lower educational attainment due to difficulties with language and cognition tests.
We found that those with UHL are significantly more likely to report troubles with communication in multiple domains compared to those without any hearing impairment. Prior studies have shown that difficulties in communication as a result of UHL lead to social withdrawal, anxiety, and lower quality of life due to difficulties with listening and sound localisation. Many adults do not seek interventions for their UHL because they are not aware of the potential adverse effects of UHL or available rehabilitative options (i.e., FM systems, Contralateral Routing of Signal hearing aids, bone-conduction hearing aids, and cochlear implantations). We also found that the adults with UHL were more likely to report frustration when talking. Constant frustration during communication may lead to fatigue and increased cognitive load, which have been hypothesised as major factors in the association between hearing loss and dementia among older adults. There should be a multidisciplinary effort to explore ways to increase listening device use and improve communicative support for those with UHL. Diagnosing and properly managing UHL from an earlier onset can have large impacts on a person's quality of life through improving communication in social situations and potentially preventing adverse impacts of hearing loss on mental and cognitive health.