By 2050, the World Health Organization estimates that more than 700 million people—or one in every 10 people around the globe—will have disabling hearing loss. In the United States alone, hearing loss affects an estimated 30 million people . Hearing loss can be frustrating, isolating, and even dangerous. It is also associated with dementia, depression, anxiety, reduced mobility, and falls.
Although hearing technologies, such as hearing aids, have improved, not everyone has equal access to these advancements. In fact, though hearing aids and other assistive devices can significantly improve quality of life, only one in four U.S. adults who could benefit from these devices has ever used one. Why? People commonly report encountering economic barriers, such as the high cost of hearing aids and limited access to hearing health care. For some, the reasons are more personal. They may not believe that hearing aids are effective, or they may worry about a perceived negative association with aging. .
As the lead federal agency supporting research initiatives to prevent, detect, and treat hearing loss, NIH’s National Institute on Deafness and Other Communication Disorders (NIDCD) conducts and funds research that identifies ways to break down barriers to hearing health care. Decades of NIDCD research informed a recent landmark announcement by the Food and Drug Administration (FDA) creating a new category of over-the-counter (OTC) hearing aids. When the regulation takes effect (expected in 2022), millions of people who have trouble hearing will be able to purchase less expensive hearing aids without a medical exam, prescription, or fitting by an audiologist.
This exciting development has been on the horizon at NIDCD for some time. Back in 2009, NIDCD’s Working Group on Accessible and Affordable Hearing Health Care for Adults with Mild to Moderate Hearing Loss created a blueprint for research priorities.
The working group’s blueprint led to NIDCD funding of more than 60 research projects spanning the landscape of accessible and affordable hearing health care issues. One study showed that people with hearing loss can independently adjust the settings  on their hearing devices in response to changing acoustic environments and, when given the ability to control their own hearing aid settings, they were generally more satisfied with the sound of the devices than with the audiologist fit .
In 2017, the first randomized, double-blind, placebo-controlled clinical trial comparing an over-the-counter delivery model  of hearing aids with traditional fitting by an audiologist also found that hearing aid users in both groups reported similar benefits. A 2019 follow-up study  confirmed these results, supporting the viability of a direct-to-consumer service delivery model. A small-business research grant funded by NIDCD led to the first FDA-approved self-fitting hearing aid.
Meanwhile, in 2016, NIDCD co-sponsored a consensus report from the National Academies of Sciences, Engineering, and Medicine (NASEM). The report, Hearing Health Care for Adults: Priorities for Improving Access and Affordability, which was developed by an independent expert panel, recommended that the FDA create and regulate a new category of over-the-counter hearing devices to improve access to affordable hearing aids for adults with perceived mild-to-moderate hearing loss. These devices will not be intended for children or for adults with more severe hearing loss.
In sum, this targeted portfolio of NIDCD-funded research—together with the research blueprint and the NASEM consensus report—provided a critical foundation for the 2021 FDA rule creating the new class of OTC hearing aids. As a result of these research and policy efforts, this FDA rule will make some types of hearing aids less expensive and easier to obtain, potentially improving the health, safety, and well-being of millions of Americans.
Transforming hearing health care for adults in the U.S. remains a public health priority. The NIH applauds the scientists who provided critical evidence leading to the new category of hearing aids, and NIDCD encourages them to redouble their efforts. Gaps in hearing health care access remain to be closed.
The NIDCD actively solicits applications for research projects to fill these gaps and continue identifying barriers to care and ways to improve access. The NIDCD will also continue to help the public understand the importance of hearing health care with resources on its website, such as Hearing: A Gateway to Our World video and the Adult Hearing Health Care webpage.
 Hearing loss prevalence in the United States. Lin F, Niparko J, Ferrucci L. Arch Intern Med. 2011 Nov 14;171(20):1851-1852.
 Research drives more accessible, affordable hearing care. Tucci DL, King K. The Hearing Journal. May 2020.
 A “Goldilocks” approach to hearing aid self-fitting: Ear-canal output and speech intelligibility index. Mackersie C, Boothroyd A, Lithgow, A. Ear and Hearing. Jan 2019.
 Self-adjusted amplification parameters produce large between-subject variability and preserve speech intelligibility. Nelson PB, Perry TT, Gregan M, VanTasell, D. Trends in Hearing. 7 Sep 2018.
 The effects of service-delivery model and purchase price on hearing-aid outcomes in older adults: A randomized double-blind placebo-controlled clinical trial. Humes LE, Rogers SE, Quigley TM, Main AK, Kinney DL, Herring C. American Journal of Audiology. 1 Mar 2017.
 A follow-up clinical trial evaluating the consumer-decides service delivery model. Humes LE, Kinney DL, Main AK, Rogers SE. American Journal of Audiology. 15 Mar 2019.
Adult Hearing Health Care (NIDCD)
[Note: Acting NIH Director Lawrence Tabak has asked the heads of NIH’s Institutes and Centers (ICs) to contribute occasional guest posts to the blog to highlight some of the interesting science that they support and conduct. This is the ninth in the series of NIH IC guest posts that will run until a new permanent NIH director is in place.]
Posted on by Lawrence Tabak, D.D.S., Ph.D.
On May 11, I was pleased to appear before the U.S. House of Representatives Subcommittee on Labor, Health and Human Services, Education, and Related Agencies to discuss NIH’s budget request for Fiscal Year 2023. Joining me (left to right) were leaders of several NIH institutes: Nora Volkow, National Institute on Drug Abuse; Tony Fauci, National Institute of Allergy and Infectious Diseases; Diana Bianchi, Eunice Kennedy Shriver National Institute of Child Health and Human Development; Doug Lowy, National Cancer Institute; and Gary Gibbons, National Heart, Lung, and Blood Institute.
Posted on by Dr. Francis Collins
Our nose does a lot more than take in oxygen, smell, and sometimes sniffle. This complex organ also helps us taste and, as many of us notice during spring allergy season when our noses get stuffy, it even provides some important anatomic features to enable us to speak clearly.
This colorful, almost psychedelic image shows the entire olfactory epithelium, or “smell center,” (green) inside the nasal cavity of a newborn mouse. The olfactory epithelium drapes over the interior walls of the nasal cavity and its curvy bony parts (red). Every cell in the nose contains DNA (blue).
The olfactory epithelium detects odorant molecules in the air, providing a sense of smell. In humans, the nose has about 400 types of scent receptors, and they can detect at least 1 trillion different odors .
But this is more than just a cool image captured by graduate student Lu Yang, who works with David Ornitz at Washington University School of Medicine, St. Louis. The two discovered a new type of progenitor cell, called a FEP cell, that has the capacity to generate the entire smell center . Progenitor cells are made by stem cells. But they are capable of multiplying and producing various cells of a particular lineage that serve as the workforce for specialized tissues, such as the olfactory epithelium.
Yang and Ornitz also discovered that the FEP cells crank out a molecule, called FGF20, that controls the growth of the bony parts in the nasal cavity. This seems to regulate the size of the olfactory system, which has fascinating implications for understanding how many mammals possess a keener sense of smell than humans.
But it turns out that FGF20 does a lot more than control smell. While working in Ornitz’s lab as a postdoc, Sung-Ho Huh, now an assistant professor at the University of Nebraska Medical Center, Omaha, discovered that FGF20 helps form the cochlea . This inner-ear region allows us to hear, and mice born without FGF20 are deaf. Other studies show that FGF20 is important for development of the kidney, teeth, mammary gland, and of specific types of hair [4-7]. Clearly, this indicates multi-tasking can be a key feature of a protein, not a trivial glitch.
The image was one of the winners in the 2018 BioArt Scientific Image & Video Competition, sponsored by the Federation of American Societies for Experimental Biology (FASEB). Its vibrant colors help to show the basics of smell, and remind us that every scientific picture tells a story.
 Humans can discriminate more than 1 trillion olfactory stimuli. Bushdid C1, Magnasco MO, Vosshall LB, Keller A. Science. 2014 Mar 21;343(6177):1370-1372.
 FGF20-Expressing, Wnt-Responsive Olfactory Epithelial Progenitors Regulate Underlying Turbinate Growth to Optimize Surface Area. Yang LM, Huh SH, Ornitz DM. Dev Cell. 2018;46(5):564-580.
 Differentiation of the lateral compartment of the cochlea requires a temporally restricted FGF20 signal. Huh SH, Jones J, Warchol ME, Ornitz DM. PLoS Biol. 2012;10(1):e1001231.
 FGF9 and FGF20 maintain the stemness of nephron progenitors in mice and man. Barak H, Huh SH, Chen S, Jeanpierre C, Martinovic J, Parisot M, Bole-Feysot C, Nitschke P, Salomon R, Antignac C, Ornitz DM, Kopan R. Dev. Cell. 2012;22(6):1191-1207
 Ectodysplasin target gene Fgf20 regulates mammary bud growth and ductal invasion and branching during puberty. Elo T, Lindfors PH, Lan Q, Voutilainen M, Trela E, Ohlsson C, Huh SH, Ornitz DM, Poutanen M, Howard BA, Mikkola ML. Sci Rep. 2017;7(1):5049
 Ectodysplasin regulates activator-inhibitor balance in murine tooth development through Fgf20 signaling. D Haara O, Harjunmaa E, Lindfors PH, Huh SH, Fliniaux I, Aberg T, Jernvall J, Ornitz DM, Mikkola ML, Thesleff I. Development. 2012;139(17):3189-3199.
 Fgf20 governs formation of primary and secondary dermal condensations in developing hair follicles. Huh SH, Närhi K, Lindfors PH, Häärä O, Yang L, Ornitz DM, Mikkola ML. Genes Dev. 2013;27(4):450-458.
Taste and Smell (National Institute on Deafness and Other Communication Disorders/NIH)
Ornitz Lab, (Washington University, St. Louis)
Huh Lab, (University of Nebraska Medical Center, Omaha)
BioArt Scientific Image & Video Competition, (Federation of American Societies for Experimental Biology, Bethesda, MD)
NIH Support: National Heart, Lung, and Blood Institute; National Institute of Neurological Disorders and Stroke; National Institute on Deafness and Other Communication Disorders
Posted on by Dr. Francis Collins
It’s a problem that parents know all too well: a child won’t eat because their oatmeal is too slimy or a slice of apple is too hard. Is the kid just being finicky? Or is there a biological basis for disliking food based on its texture? This image, showing the tongue (red) of a fruit fly (Drosophila melanogaster), provides some of the first evidence that biology could indeed play a role .
The image shows a newly discovered mechanosensory nerve cell (green), which is called md-L, short for multidendritic neuron in the labellum. When the fly extends its tongue to eat, the hair bristles (short red lines) on its surface bend in proportion to the consistency of the food. If a bristle is bent hard enough, the force is detected at its base by one of the arms of an md-L neuron. In response, the arm shoots off an electrical signal that’s relayed to the central part of the neuron and onward to the brain via the outgoing informational arm, or axon.
Posted on by Dr. Francis Collins
Foster, a research associate in Mustafa Tekin’s lab at the University of Miami’s Hussman Institute for Human Genomics, is involved in the hunt for the remaining genes responsible for congenital forms of deafness.This area of research is a good fit for Foster. Not only does he have a keen interest in genetic diseases (a close family member was born with cystic fibrosis), he’s a musician with a deep appreciation of the gift of hearing—loving to play the saxophone in his free time.