Untreated hearing loss can have a profound lifelong impact on children, causing problems with speech and language, reading, and school success and putting them at risk for developmental delays. Several global research studies are underway by Duke’s Division of Head and Neck Surgery and Communication Sciences to explore innovations in hearing loss prevention as well as improved diagnostic tools, treatments, and access to hearing care for children.
Susan Emmett, MD, MPH, is a Duke otologist who provides medical and surgical care to patients with hearing disorders. She is an assistant research professor at the Duke Global Health Institute, partnering with researchers and clinicians around the world. Emmett focuses on three broad areas to help define, understand, and address the global burden of hearing loss.
Understanding Unique Etiologies
“In order to address the problem of hearing loss, we first need to understand why it’s much more common in certain populations,” says Emmett. One of her studies took place in south Asia, examining the effects of undernutrition on hearing loss. “We’ve found some potentially influential evidence that vitamin A supplements in early childhood populations reduce the risk of adult hearing loss by over 40 percent,” she reports. “This could lead to a significant opportunity for intervention over the long term.”
In addition to the vitamin A finding, Emmett and colleagues concluded that when children are undernourished, they are at increased risk for hearing loss as young adults—independent of any other factor. “Now we know that if we can intervene to address early childhood undernutrition, we can reduce the risk of hearing loss in the adult population,” she says.
Improving Diagnostics and Expanding Access to Care
Emmett is currently leading a childhood hearing loss study in remote, rural communities in Alaska focused on improving diagnostic abilities and expanding access to care—one of the fundamental problems clinicians face in addressing global hearing loss disparities. “We’re testing improvements in hearing loss evaluation by combining new cell phone-based technology for screening in schools with telemedicine to triage referrals with specialists who are miles away,” she says.
She adds that the problem of access isn’t limited to small communities in Alaska: “There are plenty of communities in rural North Carolina and all across America where children are living with undiagnosed hearing loss and would benefit from care but don’t have access to audiologists and otolaryngologists. We’re developing a system to change that.”
Making Treatments Affordable
In a series of international studies on cochlear implant (CI) cost effectiveness in low-resource settings, Emmett is looking at hearing loss through a policy and advocacy lens. Although CI has been widely established as cost effective in North America and Europe and is considered the standard of care in those regions, cost effectiveness in other economic environments hasn’t been widely explored. Emmett says that with 80 percent of the global hearing loss burden borne by low- and middle-income countries, developing affordable management strategies in these settings is essential. “Cochlear implants are very effective in helping children with severe to profound hearing loss reach language milestones and improve school performance,” says Emmett, “but because the technology is expensive, it is often not accessible in low-income areas.”
Emmett and colleagues, including Duke ear surgeons Debara Tucci, MD, and Howard Francis, MD, along with a worldwide network of surgeons, audiologists, and speech pathologists, are working to demonstrate the cost effectiveness of CI technology and how access can be expanded in low-resource areas.
“Individually, these may seem like separate activities,” says Emmett, “but they’re all part of a new paradigm where we’re pulling innovations together to address hearing disparities globally and change the way childhood hearing loss prevention, diagnosis, and treatment are accomplished.”