A MELODY, DISTINCTIVELY CANARY, BUT DEEP IN PITCH, throaty in tone, erupts from the computer and fills the tiny office. Ironically, it is a song its avian vocalist cannot fully appreciate, nor always produce, the long low sound of the Belgian Waterslager canary. The hearing of this bright yellow bird has been impaired by generations of inbreeding, explains world-renowned audiologist Brenda Ryals, who, perched on the edge of her seat, leans forward to scour a list of file names on her computer. "Ah, here it is," she says, and clicks. A photo spreads over the screen. The audiology professor taps the middle of the image, the part that looks like the rubble of a building. "There," she says. "There are the damaged cells."
These are the microscopic cells that have caused the canary's hearing problems and absorbed Ryals' attention for the last decade. Over their research trajectory, Ryals and University of Maryland colleague Robert Dooling have actually brought some positive news to the melancholic history of this beautiful songbird. Once the birds of choice to detect poisonous gases in coal mines - primarily because their song was easy to hear - the canaries' melody accompanied the clanking of hammers and din of drills in those deep underground chambers. Their demise signaled the miners that they'd better evacuate - fast. The canary population dropped to a few hundred in the early 1800s, and their hearing became damaged from inbreeding.
Ryals and Dooling have discovered some remarkable things about them, however. Hair cells in the birds' inner ear can regenerate, essentially reversing hearing loss. Birds need to hear to sing their specific song; they can't just rely on memory. Soon after hearing is restored, birds can vocalize, recognize familiar sounds and distinguish among sounds. Granted, the birds need training to recognize these sounds again, "sort of like learning speech again," Ryals says, but they do regain that ability.
In this last regard, Ryals explains, birds are much like humans. The speech of people who know how to speak, but then experience hearing loss, begins to degrade over time because they don't have the auditory signals, or sound guides, they need to let them know if the sounds they are making are actually the sounds they want to make.
But while there are similarities between birds and humans, Ryals focuses on a crucial difference. Unlike mammals, birds can regenerate hair cells in their inner ears after the cells have been damaged or destroyed. These cells are crucial to hearing because as sound vibrates, it wiggles the hair cells, which then send messages to the auditory nerve cells and fibers.
In humans, these hair cells are often damaged by overexposure to loud noise and by certain drugs and diseases.
Ryals' work, funded by the National Institutes of Health continues to draw international attention because of its possible human implications. If Ryals and Dooling can pinpoint what triggers hair cell death, what triggers the hair cells to regenerate and how
regeneration is controlled so it doesn't escalate to unrestrained cell multiplying that leads to tumors, the hope is that scientists will eventually be able to stimulate hair-cell regeneration in humans to restore or enhance hearing.
Taking a team approach to the research, Ryals, the director of the JMU Auditory Research Lab and a professor of audiology in the Department of Communication Sciences and Disorders, focuses on the anatomy of the inner ear and anatomical consequences of the regeneration of auditory hair cells, while Maryland psychology professor Dooling examines the behavioral aspects and implications of hearing loss and restoration in birds.
In most birds, hair-cell regeneration keeps pace with cell death, ensuring that birds always have an adequate number. But Ryals' studies of the Waterslager show that even though these canaries can regenerate the hair cells, the regeneration never keeps up with the death of these cells. So despite regeneration, the Waterslagers never have a full number of hair cells. Ryals has been investigating why, and like any good scientific sleuth, she's armed with an endless curiosity and driven to answer questions such as "What causes this programmed cell death?" "Is there something we can do to stop it?" and "What are the neural consequences of hearing loss?" In other words, Ryals asks, "If we could solve the problem in the ear, are there constraints in the brain we'd also have to deal with?"
Based on Ryals' and Dooling's research results, "we feel very positive that any constraints are not overwhelming - or perhaps not even there" for short-term hearing loss, she says.
Down the road, Ryals hopes field research by her and others will lead to real benefits for people. For example, perhaps instead of having to regenerate hair cells in humans, "we could find ways to prevent hair cells from dying in the first place," Ryals says. If research can identify why those hair cells in Waterslagers die, "if you knew the death molecule," it might theoretically be possible to control it both in the canary and other species. That could lead to new ways to enhance the protective defense systems in the inner ear.
That enhanced protection is especially intriguing, Ryals says, since a nagging question about regeneration of hair cells - particularly in long-term hearing loss - is "will everything else come back too?"
Hand in hand with enhanced protection is the potential ability to regenerate hair cells in mammals by identifying the triggers that cause hair-cell regeneration and targeting specific cells to regenerate without unleashing uncontrolled growth. It's a difficult matter of fine-tuning and balancing all the genetic triggers and controls, Ryals says.
Soon Ryals and Dooling will be applying for additional grants to carry their research through another five years. This next phase of study will examine brain plasticity - what brain constraints are involved in restoring hearing in birds. They know that perceptions come back after a one-month hearing loss. "But what would happen if it lasted longer?" Ryals wonders. The possible brain constraints involved in a relatively short-term hearing loss may be far less formidable than those in long-term hearing loss.
For Dooling, the continuation of his research partnership with Ryals opens up many intriguing possibilities. "Everybody knows at a simple level that when you lose your hair cells you lose your hearing. What we can do that's different is we can look at very complex auditory perceptions as well as vocalizations," Dooling says. "We've developed behavior techniques to show how birds perceive and produce complex sounds."
This two-pronged approach allows them to investigate not only whether hearing can be restored and to what degree, but also to "ask questions about the role of hearing loss or partial recovery of hearing on speech perception and production in birds, if you will," Dooling says.
"What we're learning in birds could possibly be applied to humans" to improve treatment strategies, particularly for people with partial hearing loss who have difficulty clearly pronouncing some consonants or hearing above background noise, Dooling says.
The Ryals-Dooling research partnership is attracting plenty of attention in national and international research circles. The pair have written and presented numerous papers on the subject, including Ryals' article, "Hair-cell regeneration revisited: it's not just for the birds!" published in the August 2000 issue of The Hearing Journal. Additionally, Ryals is active in numerous scientific and research organizations and served as president of the American Auditory Society in 2000-01. In April, she received the annual Research Achievement Award from the American Academy of Audiology for her "innovative contributions to audiology through her rigorous research and dedication to excellence in science."
She was also recently named head of the Virginia "Healthy Hearing" team for the Special Olympics. The team will provide hearing screenings for all Virginia Special Olympians competing in state games as part of the organization's Healthy Athletes program. Ryals envisions an active role for JMU students on that team. "It'll be terrific for students to get a chance to do these hearing screenings."
This new role is a departure from the research she's known for, but Ryals believes it is all part of a bigger picture she hopes to convey to her students. "I think it's important that my students perceive me as not just an ivory tower 'I-look-at-birds'-ears' researcher, but as someone who is interested in hearing loss in people and how to help people with hearing loss."
This combination of expertise and recognition pays handsome dividends for both JMU and its students. Nicholas Bankson, head of the Department of Communication Science and Disorders until he retired in June, notes that Ryals is an internationally recognized researcher who "provides students and faculty colleagues alike a model of commitment, productivity and scholarly performance of a top-flight research academician. Her
research publications have provided her many opportunities to speak and be a part of high-level research boards. Such professional activity has brought great visibility to CSD and JMU."
It has also given her students an extra edge in scientific research experience, Bankson says. "Her research enhances her teaching and provides the opportunity for students to experience firsthand the excitement and stimulation that is part of studying with someone who not only disseminates knowledge, but adds to the knowledge base."
Audiology Ph. D. program on track
Katie Roper, one of six members in the second class of audiology doctoral candidates at JMU, became Brenda Ryals' research protégé two years ago. On track to defend her dissertation this fall and receive her doctorate in May 2004, Roper is reeling over the fact that one of the world's top audiology researchers mentors her and reviews her research. "She spends a lot of time with me making sure I understand the material. I really couldn't ask for anything more."
Roper's research and dissertation topic, "The Relationship Between Anatomical and Chronological Maturity in the Inner Ear of Two Strains of Canary: The American Singer and the Belgian Waterslager," tracks how the ears of the two types of canaries develop over time to identify differences between the two birds and their ears as they grow and become older. In the first phase of her research, Roper measured the surface areas of different places of the inner ear of both types of canaries at established time intervals, 1-2 days, 6-8 days, 10-13 days and adult, to see if there's a difference in the growth patterns of the two types of canaries and where and when those differences occur.
During the spring 2003 semester, Roper measured the individual hair cells of each type of canary, tracking both their growth and decline. So far, Roper's research has identified significant differences between the two types of canaries at different age intervals, and may help pinpoint not only when, but also why, the Waterslagers experience significant hearing loss.
Roper is spending this summer in a residency in a hospital environment in Virginia, the next step on her way to working in a hospital otolaryngology (head and neck surgery) department, with its endless variety of challenges and work, from basic diagnostics to balance testing to cochlear implants and hearing aids.
As she participates in that residency program, she is armed with far more than classroom and lab knowledge. She has the experience of being part of an ongoing research team whose work could lead to major developments in how hearing loss in humans is treated.
"Working with Dr. Ryals is really a privilege," Roper says. "She is one of the top researchers in the field."
These are the microscopic cells that have caused the canary's hearing problems and absorbed Ryals' attention for the last decade. Over their research trajectory, Ryals and University of Maryland colleague Robert Dooling have actually brought some positive news to the melancholic history of this beautiful songbird. Once the birds of choice to detect poisonous gases in coal mines - primarily because their song was easy to hear - the canaries' melody accompanied the clanking of hammers and din of drills in those deep underground chambers. Their demise signaled the miners that they'd better evacuate - fast. The canary population dropped to a few hundred in the early 1800s, and their hearing became damaged from inbreeding.
Ryals and Dooling have discovered some remarkable things about them, however. Hair cells in the birds' inner ear can regenerate, essentially reversing hearing loss. Birds need to hear to sing their specific song; they can't just rely on memory. Soon after hearing is restored, birds can vocalize, recognize familiar sounds and distinguish among sounds. Granted, the birds need training to recognize these sounds again, "sort of like learning speech again," Ryals says, but they do regain that ability.
In this last regard, Ryals explains, birds are much like humans. The speech of people who know how to speak, but then experience hearing loss, begins to degrade over time because they don't have the auditory signals, or sound guides, they need to let them know if the sounds they are making are actually the sounds they want to make.
But while there are similarities between birds and humans, Ryals focuses on a crucial difference. Unlike mammals, birds can regenerate hair cells in their inner ears after the cells have been damaged or destroyed. These cells are crucial to hearing because as sound vibrates, it wiggles the hair cells, which then send messages to the auditory nerve cells and fibers.
In humans, these hair cells are often damaged by overexposure to loud noise and by certain drugs and diseases.
Ryals' work, funded by the National Institutes of Health continues to draw international attention because of its possible human implications. If Ryals and Dooling can pinpoint what triggers hair cell death, what triggers the hair cells to regenerate and how
regeneration is controlled so it doesn't escalate to unrestrained cell multiplying that leads to tumors, the hope is that scientists will eventually be able to stimulate hair-cell regeneration in humans to restore or enhance hearing.
Taking a team approach to the research, Ryals, the director of the JMU Auditory Research Lab and a professor of audiology in the Department of Communication Sciences and Disorders, focuses on the anatomy of the inner ear and anatomical consequences of the regeneration of auditory hair cells, while Maryland psychology professor Dooling examines the behavioral aspects and implications of hearing loss and restoration in birds.
In most birds, hair-cell regeneration keeps pace with cell death, ensuring that birds always have an adequate number. But Ryals' studies of the Waterslager show that even though these canaries can regenerate the hair cells, the regeneration never keeps up with the death of these cells. So despite regeneration, the Waterslagers never have a full number of hair cells. Ryals has been investigating why, and like any good scientific sleuth, she's armed with an endless curiosity and driven to answer questions such as "What causes this programmed cell death?" "Is there something we can do to stop it?" and "What are the neural consequences of hearing loss?" In other words, Ryals asks, "If we could solve the problem in the ear, are there constraints in the brain we'd also have to deal with?"
Based on Ryals' and Dooling's research results, "we feel very positive that any constraints are not overwhelming - or perhaps not even there" for short-term hearing loss, she says.
Down the road, Ryals hopes field research by her and others will lead to real benefits for people. For example, perhaps instead of having to regenerate hair cells in humans, "we could find ways to prevent hair cells from dying in the first place," Ryals says. If research can identify why those hair cells in Waterslagers die, "if you knew the death molecule," it might theoretically be possible to control it both in the canary and other species. That could lead to new ways to enhance the protective defense systems in the inner ear.
That enhanced protection is especially intriguing, Ryals says, since a nagging question about regeneration of hair cells - particularly in long-term hearing loss - is "will everything else come back too?"
Hand in hand with enhanced protection is the potential ability to regenerate hair cells in mammals by identifying the triggers that cause hair-cell regeneration and targeting specific cells to regenerate without unleashing uncontrolled growth. It's a difficult matter of fine-tuning and balancing all the genetic triggers and controls, Ryals says.
Soon Ryals and Dooling will be applying for additional grants to carry their research through another five years. This next phase of study will examine brain plasticity - what brain constraints are involved in restoring hearing in birds. They know that perceptions come back after a one-month hearing loss. "But what would happen if it lasted longer?" Ryals wonders. The possible brain constraints involved in a relatively short-term hearing loss may be far less formidable than those in long-term hearing loss.
For Dooling, the continuation of his research partnership with Ryals opens up many intriguing possibilities. "Everybody knows at a simple level that when you lose your hair cells you lose your hearing. What we can do that's different is we can look at very complex auditory perceptions as well as vocalizations," Dooling says. "We've developed behavior techniques to show how birds perceive and produce complex sounds."
This two-pronged approach allows them to investigate not only whether hearing can be restored and to what degree, but also to "ask questions about the role of hearing loss or partial recovery of hearing on speech perception and production in birds, if you will," Dooling says.
"What we're learning in birds could possibly be applied to humans" to improve treatment strategies, particularly for people with partial hearing loss who have difficulty clearly pronouncing some consonants or hearing above background noise, Dooling says.
The Ryals-Dooling research partnership is attracting plenty of attention in national and international research circles. The pair have written and presented numerous papers on the subject, including Ryals' article, "Hair-cell regeneration revisited: it's not just for the birds!" published in the August 2000 issue of The Hearing Journal. Additionally, Ryals is active in numerous scientific and research organizations and served as president of the American Auditory Society in 2000-01. In April, she received the annual Research Achievement Award from the American Academy of Audiology for her "innovative contributions to audiology through her rigorous research and dedication to excellence in science."
She was also recently named head of the Virginia "Healthy Hearing" team for the Special Olympics. The team will provide hearing screenings for all Virginia Special Olympians competing in state games as part of the organization's Healthy Athletes program. Ryals envisions an active role for JMU students on that team. "It'll be terrific for students to get a chance to do these hearing screenings."
This new role is a departure from the research she's known for, but Ryals believes it is all part of a bigger picture she hopes to convey to her students. "I think it's important that my students perceive me as not just an ivory tower 'I-look-at-birds'-ears' researcher, but as someone who is interested in hearing loss in people and how to help people with hearing loss."
This combination of expertise and recognition pays handsome dividends for both JMU and its students. Nicholas Bankson, head of the Department of Communication Science and Disorders until he retired in June, notes that Ryals is an internationally recognized researcher who "provides students and faculty colleagues alike a model of commitment, productivity and scholarly performance of a top-flight research academician. Her
research publications have provided her many opportunities to speak and be a part of high-level research boards. Such professional activity has brought great visibility to CSD and JMU."
It has also given her students an extra edge in scientific research experience, Bankson says. "Her research enhances her teaching and provides the opportunity for students to experience firsthand the excitement and stimulation that is part of studying with someone who not only disseminates knowledge, but adds to the knowledge base."
Audiology Ph. D. program on track
Katie Roper, one of six members in the second class of audiology doctoral candidates at JMU, became Brenda Ryals' research protégé two years ago. On track to defend her dissertation this fall and receive her doctorate in May 2004, Roper is reeling over the fact that one of the world's top audiology researchers mentors her and reviews her research. "She spends a lot of time with me making sure I understand the material. I really couldn't ask for anything more."
Roper's research and dissertation topic, "The Relationship Between Anatomical and Chronological Maturity in the Inner Ear of Two Strains of Canary: The American Singer and the Belgian Waterslager," tracks how the ears of the two types of canaries develop over time to identify differences between the two birds and their ears as they grow and become older. In the first phase of her research, Roper measured the surface areas of different places of the inner ear of both types of canaries at established time intervals, 1-2 days, 6-8 days, 10-13 days and adult, to see if there's a difference in the growth patterns of the two types of canaries and where and when those differences occur.
During the spring 2003 semester, Roper measured the individual hair cells of each type of canary, tracking both their growth and decline. So far, Roper's research has identified significant differences between the two types of canaries at different age intervals, and may help pinpoint not only when, but also why, the Waterslagers experience significant hearing loss.
Roper is spending this summer in a residency in a hospital environment in Virginia, the next step on her way to working in a hospital otolaryngology (head and neck surgery) department, with its endless variety of challenges and work, from basic diagnostics to balance testing to cochlear implants and hearing aids.
As she participates in that residency program, she is armed with far more than classroom and lab knowledge. She has the experience of being part of an ongoing research team whose work could lead to major developments in how hearing loss in humans is treated.
"Working with Dr. Ryals is really a privilege," Roper says. "She is one of the top researchers in the field."
