Quantification of Hearing Loss Research on Children Compared With Older Adults

Hearing loss is an often underestimated public health concern with implications for individual patient health and the operation of health care systems. In children, hearing loss can lead to delayed speech and language development and impede educational outcomes.¹ In older adults, hearing loss may be a modifiable risk factor for dementia.² Untreated hearing loss was associated with more than $22 000 additional health care costs per patient during a 10-year period.³ Understanding the current research landscape is important for informing policy in a quickly evolving legislative domain.⁴ This study aimed to quantify hearing loss research areas in children and older adults.

To quantify research on hearing loss in children and older adults in aggregate and over time, we used an advanced search in the PubMed databases. To specify literature on children, we used the terms children, pediatrics, and adolescents. To specify literature on older adults, we used the terms older adults, geriatrics, and elderly in addition to each categorical term specified. For example, to search hearing loss in children, we used the following query: hearing loss AND children AND policy OR hearing loss AND pediatrics AND policy OR hearing loss AND adolescents AND policy.

A total of 11 623 publications on hearing loss were identified from 1946 to 2017, with the number of publications remaining constant from 1946 to 1975 and increasing after 1975, most notably after 1996. Approximately 137 articles were published on children and 26 articles on older adults per year during the 71-year period, but the number of publications increased throughout the study period, with 16 published in 1987 and 147 in 2017 (Figure).

During the study period, publications were 5 times more likely to address hearing loss in children (n = 9743) than older adults (n = 1880), an absolute difference of 7863 (Table). Overall, publications primarily focused on topics related to hearing loss treatment, including cochlear implants (n = 3233) and hearing aids (n = 2445), as well as language (n = 1957), with the smallest number of publications being related to policy (n = 123). The greatest discrepancy in publications by age was for articles related to cochlear implants and language, which were 22 times more likely in children than older adults and 15 times more likely in children compared with older adults, respectively (absolute differences, 2957 for cochlear implants and 1713 for language).

Our study indicates that the volume of hearing loss literature on older adults lags behind that of children despite hearing loss being more than 3 times as prevalent in older adults. The detriments to this lack of research are recognized in the challenges faced by addressing hearing loss at patient, practitioner, and systems levels.⁵

Although hearing screening in newborns and children is routinely recommended, the US Preventive Services Task Force concluded insufficient evidence to assess the benefits and harms of hearing loss screening in asymptomatic older adults.⁶ However, recent research has demonstrated associations with worse health outcomes (increased hospitalizations, decreased cognitive function, and poorer communication with health care professionals), which could indicate potential benefits of preventive screening in older adults.⁵

A limitation of our study is the reliance on the PubMed databases alone and the scope of the search terms used. However, inclusion of research from additional databases would likely not alter the main findings given the large magnitude of difference in items on children and older adults in the medical literature, and our search does attempt to generate a comprehensive quantitative representation of all published literature.

In describing these disparities, our hope is not to disparage hearing loss research in children but to call attention to areas in which significant progress can be made in older adults. Topics on hearing loss in children could have significant implications and should be investigated. Recognizing the significant gaps in the medical literature on hearing loss in older adults is important to focus future research efforts. Additional studies on hearing loss have potentially far-reaching implications on patients, health care professionals, and health care systems. This study suggests areas with a critical need for additional research in older adults using the model of progress that has been made in children as an indicator of success.

Accepted for Publication: November 13, 2018.

Corresponding Author: Jennifer A. Deal, PhD, Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, 2024 E Monument St, Ste 2-700, Baltimore, MD 21205 (jdeal1@jhu.edu).

Published Online: January 17, 2019. doi:10.1001/jamaoto.2018.3889

Author Contributions: Mr Villavisanis had full access to all the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.

Concept and design: All authors.

Acquisition, analysis, or interpretation of data: Villavisanis.

Drafting of the manuscript: Villavisanis.

Critical revision of the manuscript for important intellectual content: Lin, Deal.

Obtained funding: Lin.

Study supervision: Deal.

Conflict of Interest Disclosures: Dr Lin reported receiving grants from the Eleanor Schwartz Charitable Foundation and the National Institutes of Health during the conduct of the study and personal fees from Amplifon, Cochlear Ltd, and Boehringer Ingelheim outside the submitted work. No other disclosures were reported.