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.
Story by Margie Shetterly Photos by Diane Elliott ('00) and Tyler Mallory Design by Ann HessThese 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.
