Small Business Innovation Research
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 Dr. Francis Collins
There’s so much to celebrate about our country this Fourth of July. That includes giving thanks to all those healthcare providers who have put themselves in harm’s way to staff the ERs, hospital wards, and ICUs to care for those afflicted with COVID-19, and also for everyone who worked so diligently to develop, test, and distribute COVID-19 vaccines.
These “shots of hope,” created with rigorous science and in record time, are making it possible for a great many Americans to gather safely once again with family and friends. So, if you’re vaccinated (and I really hope you are—because these vaccines have been proven safe and highly effective), fire up the grill, crank up the music, and get ready to show your true red, white, and blue colors. My wife and I—both fully vaccinated—intend to do just that!
To help get the celebration rolling, I’d like to share a couple minutes of some pretty amazing biological fireworks. While the track of a John Philip Sousa march is added just for fun, what you see in the video above is the result of some very serious neuroscience research that is scientifically, as well as visually, breath taking. Credit for this work goes to an NIH-supported team that includes Ricardo Azevedo and Sunil Gandhi, at the Center for the Neurobiology of Learning and Memory, University of California, Irvine, and their collaborator Damian Wheeler, Translucence Biosystems, Irvine, CA. Azevedo is also an NIH National Research Service Award fellow and a Medical Scientist Training Program trainee with Gandhi.
The team’s video starts off with 3D, colorized renderings of a mouse brain at cellular resolution. About 25 seconds in, the video flashes to a bundle of nerve fibers called the fornix. Thanks to the wonders of fluorescent labeling combined with “tissue-clearing” and other innovative technologies, you can clearly see the round cell bodies of individual neurons, along with the long, arm-like axons that they use to send out signals and connect with other neurons to form signaling circuits. The human brain has nearly 100 trillion of these circuits and, when activated, they process incoming sensory information and provide outputs that lead to our thoughts, words, feelings, and actions.
As shown in the video, the nerve fibers of the fornix provide a major output pathway from the hippocampus, a region of the brain involved in memory. Next, we travel to the brain’s neocortex, the outermost part of the brain that’s responsible for complex behaviors, and then move on to explore an intricate structure called the corticospinal tract, which carries motor commands to the spinal cord. The final stop is the olfactory tubercle —towards the base of the frontal lobe—a key player in odor processing and motivated behaviors.
Azevedo and his colleagues imaged the brain in this video in about 40 minutes using their imaging platform called the Translucence Biosystems’ Mesoscale Imaging System™. This process starts with a tissue-clearing method that eliminates light-scattering lipids, leaving the mouse brain transparent. From there, advanced light-sheet microscopy makes thin optical sections of the tissue, and 3D data processing algorithms reconstruct the image to high resolution.
Using this platform, researchers can take brain-wide snapshots of neuronal activity linked to a specific behavior. They can also use it to trace neural circuits that span various regions of the brain, allowing them to form new hypotheses about the brain’s connectivity and how such connectivity contributes to memory and behavior.
The video that you see here is a special, extended version of the team’s first-place video from the NIH-supported BRAIN Initiative’s 2020 “Show Us Your BRAINS!” imaging contest. Because of the great potential of this next-generation technology, Translucence Biosystems has received Small Business Innovation Research grants from NIH’s National Institute of Mental Health to disseminate its “brain-clearing” imaging technology to the neuroscience community.
As more researchers try out this innovative approach, one can only imagine how much more data will be generated to enhance our understanding of how the brain functions in health and disease. That is what will be truly spectacular for everyone working on new and better ways to help people suffering from Alzheimer’s disease, Parkinson’s disease, schizophrenia, autism, epilepsy, traumatic brain injury, depression, and so many other neurological and psychiatric disorders.
Wishing all of you a happy and healthy July Fourth!
Medical Scientist Training Program (National Institute of General Medical Sciences/NIH)
Translucence Biosystems (Irvine, CA)
Sunil Gandhi (University of California, Irvine)
Ricardo Azevedo (University of California, Irvine)
Video: iDISCO-cleared whole brain from a Thy1-GFP mouse (Translucence Biosystems)
Show Us Your BRAINs! Photo & Video Contest (Brain Initiative/NIH)
NIH Support: National Institute of Mental Health; National Eye Institute