Duke's new Hearing Center wants to turn up the volume for millions who suffer from hearing loss

By Jeni Baker

Rachael Ragin was 45 years old before she knew that fizzy soda bubbles make noise.

Profoundly hearing-impaired from infancy, Ragin, of Cary, North Carolina, successfully navigated the hearing world for years with the help of two powerful hearing aids, despite being able to understand only 8 percent of the words spoken in a soundproof auditory booth. But when she entered college, her hearing deficit became increasingly difficult to overcome.

“My hearing was so bad that in addition to wearing hearing aids, I learned sign language and started relying on an interpreter,” which she did for the next two and half decades, Ragin says.

The mother of two was in her early 40s when she began investigating cochlear implants, the only auditory prosthetic devices proven effective for treating severe hearing impairment and deafness.

Debara L. Tucci, MD, MS

In 2003, Ragin underwent cochlear implant surgery, performed by Duke neurotologist Debara L. Tucci, MD. Within several weeks, Ragin’s hearing comprehension had soared to 95 percent.

“The world became magical with all the sounds it made,” Ragin says. “Being able to better communicate with my family, hearing the wind in the trees, listening
to rain fall…it was thrilling.”

While Ragin says the decision to use auditory prostheses is a personal one -- and that she, like many of the two million Americans who are deaf or profoundly hard of hearing, continues to take great pride in deaf culture -- she is delighted to have opted for cochlear implantation.

“I live and work in a hearing world,” says Ragin, a doctoral-level consultant who works with deaf and hearing-impaired children for the North Carolina Department of Public Instruction. “My implants allow me to negotiate that world as well as I do the deaf world.”

A Flat Miracle

The cochlear implant is arguably the most significant advance to date in the treatment of hearing loss -- a widespread condition that the World Health Organization consistently ranks among the top 15 medical concerns in terms of human suffering and economic cost.

In the United States, about 10 percent of the population is deaf or hard of hearing, with some 28 million people -- about half of them aged 65 and older -- experiencing hearing loss significant enough to impact their quality of life.

“Thirty years ago, there were no options, simply no treatments, for someone who was deaf or had a severe hearing loss,” says Duke-trained electrical engineer Blake S. Wilson, an adjunct professor in otolaryngology who also serves as the chief strategy advisor for MED-EL GmbH of Innsbruck, Austria, a leading developer and manufacturer of cochlear implants.

Wilson has been associated with Duke otolaryngology since 1984, when he and Duke otolaryngology chief emeritus Joseph C. Farmer Jr., MD, established the Duke Cochlear Implant Program as one of the nation’s first. Tucci has led the program since coming to Duke in 1993.

“Cochlear implants have enabled us to come a very long way in a relatively short time in terms of treating profound hearing loss,” says Wilson. “Most of today’s implanted patients can understand everyday speech with hearing alone, without lip reading -- many in noisy environments, some even on the telephone. To me, that’s a flat miracle.”

While technological advances have opened a new world of sound for many, a host of challenges remains. Not everyone with hearing loss is a candidate for cochlear implants, and outcomes vary widely among recipients -- for reasons that aren’t fully understood. And for many millions of children and adults worldwide, affording or even accessing the technology remains out of the question.

Not all people with profound hearing loss consider it a disability; many people who were born deaf or severely hard of hearing -- or who became so early in life -- find deep fulfillment and great pride in deaf culture. But for many others with untreatable or undertreated hearing loss, the economic and emotional costs can be enormous.

For those who became deaf before they learned to speak, experts estimate a lifetime cost of more than $1 million per person to address hearing-related challenges. Many of these people say their hearing deficit makes them feel disconnected, socially isolated, and discriminated against.

On January 29, Duke’s efforts to help these individuals were galvanized in a new way with the official launch of the Duke Hearing Center. This major interdisciplinary initiative is designed to harness Duke’s scientific and clinical strengths to alleviate the massive global toll of hearing loss.

Synthesizing the Science

Part of the plan for the new center, says Wilson, is to take advantage of an “explosion of knowledge” that’s occurred in the fields of otology, neurotology, and engineering, particularly in the past 10 years.

“Duke has awesome resources and capabilities across the spectrum needed to develop new treatments for hearing loss, and we’re highly unusual in that respect,” Wilson says. “The combination of all these capabilities is what’s so powerful, and a large part of the rationale for the hearing center is to bring that strength to bear on such an important societal problem as hearing loss.”

Co-directed by Tucci and Wilson, both of the Department of Surgery’s Division of Otolaryngology-Head and Neck Surgery (OHNS), the center will foster collaborations among faculty within the School of Medicine, the Pratt School of Engineering, the Duke Center for Cognitive Neuroscience, the Division of Neurology, the Duke Global Health Institute, and the Duke Institute for Genome Sciences & Policy.

Nancy Andrews, MD, PhD“It’s very important for investigators at Duke to work on solving problems that have a major patient impact, and the center’s multidisciplinary approach will be critical to this effort,” says Nancy Andrews, MD, PhD, vice chancellor for academic affairs and School of Medicine dean, who granted the program “center” status in July.

Andrews herself has a personal interest in otology, and recently made a serendipitous discovery of a gene in mice that may play a role in determining how genes are expressed in developing inner-ear cells in humans.

“Hearing loss is a large problem, but it’s one for which we have real hope that modern science will lead to solutions,” she says. “Many causes of hearing impairment are preventable, and understanding those will help in the short term. In the long run, scientific investigation will eventually help people preserve their hearing.”

For example, says Wilson, “about 60 percent of congenital hearing loss is caused by genetic defects, and there’s huge potential to identify additional defects that lead to hearing loss and develop molecular repairs for them.”

Another area of investigation the center plans to pursue is cellular-regeneration therapies, which take a cue from the animal kingdom -- some aquatic animals and birds regenerate their damaged inner-ear receptor cells with the help of nearby cells that act as stem cells.

“We hope to build upon a rapidly growing body of knowledge to better understand the biology of the mammalian inner ear, with the goal of inducing hair-cell and neural regeneration and thereby restoring hearing,” Tucci says. “This field of cell biology holds great promise for the treatment of sensorineural hearing loss, for which there is no direct treatment at present.”

Improving the Implant

In addition to pursuing basic-science and translational research, center faculty will work to improve existing treatments for hearing loss, including the groundbreaking cochlear implant.

Much of this work will build upon a longtime collaboration between OHNS and the Research Triangle Institute (RTI) Center for Auditory Prosthesis Research -- which Wilson, who is internationally recognized for inventing many implant components, led from 1994 to 2002.

This partnership has produced a number of breakthroughs in cochlear implant design, as well as the signal- and speech-processing strategies used in cochlear implants, hearing aids, and other devices used to improve hearing.

More than 130,000 people worldwide have received cochlear implants since they became widely available in the early 1980s -- and thanks to constant improvements in the devices, many more people now stand to benefit from them than ever before. In fact, says Tucci, “In our state alone, many, many people are candidates and don’t know it.”

Many insurers now cover at least one implant -- including Medicare and, for children, Medicaid -- and there are no real age restrictions for getting them, she adds. Although about a third of the division’s patients are children from one to 18 years old, “we’ve implanted patients as old as 86 who have done very well,” Tucci says.

However, Wilson points out, there’s still much work to be done to help cochlear implantation reach its true potential -- and transform the lives of even more deaf and hearing-impaired people.

Unlike hearing aids, which amplify sound so it is loud enough for damaged ears to hear it, cochlear implants reroute sound around damaged parts of the ear, directly to the auditory nerve, which stimulates the area of the brain that receives and makes sense of auditory input.

At present, the best candidates for cochlear implants are young children and people whose auditory brains have received at least some ongoing stimulation -- such as those who regularly wear hearing aids. That’s because connections among neurons and auditory pathways erode as the brain is deprived of input, and it’s easier to successfully establish or re-establish ear-brain connections when they haven’t been idle for a prolonged period.

Hearing Center researchers will explore ways to overcome that obstacle, and also address the differences in outcomes among recipients, which Wilson says are still not completely understood.

“A leading theory [as to why implants work better for some people than others] is that it’s due to individual differences in auditory brain function,” which can vary widely among people who have suffered from different degrees of hearing loss for different lengths of time.

“The brain is the tail that wags the dog in determining cochlear implant outcomes,” he says, “and we need to figure out why and what we can do about it.”

Because hearing-impaired people who are not candidates for cochlear implantation can benefit significantly from other devices, Hearing Center faculty will also work to improve auditory prostheses across the board, says Wilson. These devices include hearing aids and the hearing aid-cochlear implant hybrid -- both for people with some residual hearing -- as well as the central auditory implant (CAI), a device, still in the early stages of development, that is designed to stimulate brain structures central to the auditory nerve.

Addressing a Global Crisis -- At Home and Abroad

To speed the delivery of these advances in technology and research to the people who need them, Duke Hearing Center faculty plan to grow a statewide network of sites for clinical trials and patient care.

“One of our overarching goals is to integrate clinical research with treatment,” says Tucci, who is currently working with David L. Witsell, MD, director of the Duke Voice Care Center, on an NIH grant to develop a network of clinical research sites within academic centers and community-based private practices.

“The idea is to see which interventions work best in treating patients with otologic disease -- and for the Duke Hearing Center to have a presence in most North Carolina communities in the next five to 10 years.”

But the Hearing Center’s vision extends far beyond North Carolina. Tucci explains that the center’s mission includes fighting hearing impairment globally, where it may be an even greater problem than in the United States.

Roughly 60 million people in India suffer from significant impairments in hearing, for example, many due to congenital rubella -- which is preventable by vaccination. And in China, more than seven million people are completely deaf, an incidence due largely to widespread use of ototoxic over-the-counter antibiotics administered by the “barefoot doctors” during the country’s cultural revolution.

As part of a partnership between the Department of Surgery’s Global Health Initiative and the Duke Global Health Institute, Tucci and Wilson have traveled to India to investigate opportunities for clinical outreach and research collaboration. They also are working with Samuel L. Katz, MD, internationally known chairman emeritus of the Duke Department of Pediatrics, to create an infrastructure to prevent and treat hearing loss in India.

“We’re working with [our counterparts] there to establish rubella vaccine and hearing screening programs, to facilitate the care people need, and to make low-cost cochlear implants accessible to patients who are candidates for them,” Tucci says.

Whether it affects a child in an impoverished nation, a middle-aged American professional, or Grandma, smiling as her family shares stories around the holiday dinner table, not hearing a word, “hearing loss can be isolating and tragic, and that’s the real impetus for creating the Duke Hearing Center,” Tucci adds.

“By bringing together researchers in many areas related to hearing science and hearing health care and working to broaden our clinical outreach in the community, in the U.S., and globally, we will be able to make a tremendous difference in many people’s lives.”

Rachael Ragin is living proof of that. “Sound and communication are at the core of human society, and people with profound hearing loss often struggle to be a part of that -- particularly children, who rely on effective communication to learn,” Ragin says. “I truly believe that efforts to reduce the prevalence and the impact of hearing loss are efforts to diminish a serious human-rights concern.”

To learn more about the Duke Hearing Center, visit hearing.surgery.duke.edu and dukehealth.org/hearingcenter.

To make a referral, call the Duke Consultation and Referral Center at 1-800-MED-DUKE (1-800-633-3853).

This article was first published in the Winter 2009 edition of DukeMed Magazine.