Initially preoccupied by the severe injuries suffered by victims of the Boston bombings, hospitals are now grappling with a more subtle medical consequence: widespread hearing loss among those closest to the blasts.
Acoustic trauma of this sort can rupture the delicate eardrum, and hearing experts at several hospitals in Boston said Wednesday that torn eardrums accounted for most of the hearing loss they have seen among those near the explosions.
In most of these cases, the eardrum will heal in a few weeks or months. If not, a tear can be repaired with an outpatient surgical reconstruction called a tympanoplasty, which can restore normal hearing.
But proximity to an explosion also can cause "sensorineural" hearing loss: damage to hair cells in the inner ear, which is potentially permanent, said Dr. Daniel Lee, an ear surgeon at Brigham and Women's Hospital in Boston. Hair cells cannot be regenerated.
"We're generally seeing patients who have a conductive hearing loss associated with traumatic eardrum perforation," he said. "Some of the patients may develop a progressive sensorineural hearing loss in the future."
At present, most of the patients with sensorineural damage have suffered only mild to moderate hearing loss. There is great variability in the hearing loss experienced by people exposed to acoustic trauma, based on things like which way they were facing or what was between them and the explosion.
Nick Yanni, 32, a student at Bunker Hill Community College, and his wife, Lee Ann Yanni, 31, a physical therapist, were 10 feet from the first bomb when it went off. Lee Ann Yanni said she immediately lost hearing in her left ear, but at the time was far more worried about her broken left fibula.
At the emergency room at Tufts Medical Center, she struggled to answer doctors' muffled questions about her leg.
Nick Yanni discovered at the ER that he could not hear in either ear and tried to read lips. An hour or two later, his ears became painfully sensitive to background noise, so he put in earplugs. By nightfall, his hearing had returned.
"We were standing right next to each other," Lee Ann Yanni said. "His hearing loss turned out to be temporary, and mine is lasting."
After three operations for her leg fracture in five days, she was discharged Monday. "I know I can function even if my hearing isn't perfect, but I'd like to get it back," she said.
Within 24 hours of the bombings, Beth Israel Deaconess Medical Center in Boston began auditory evaluations of bombing victims after several mentioned that voices sounded as if they were underwater or that their own voices seemed louder.
Dr. Selena E. Heman-Ackah, medical director of otology, neurotology and audiology at Beth Israel Deaconess, has evaluated roughly 20 patients with hearing loss in the wake of the bombings. All but two suffered perforations of the eardrums, she said.
Given the loudness of the explosions, Heman-Ackah said she expected to see more patients with nerve-related hearing loss. She believes that the eardrum perforations might have been protective against the more permanent neural loss.
The night of the bombings, Dr. Alicia M. Quesnel, an ear specialist at the Massachusetts Eye and Ear Infirmary, began doing consultations with some patients injured by bomb blasts, once they had been stabilized, using a tuning fork to gauge the type of auditory loss.
If patients can hear the tuning fork touching their skull, the hearing loss is probably conductive -- related to a torn eardrum or damage to the tiny bones behind it. But if they can hear a tuning fork held in front of the ear better, or cannot hear either one, Quesnel said, "you worry about inner ear hearing loss that's neural."
"Most of what we are seeing is conductive hearing loss," she said. "It will either heal on its own, or down the line they won't end up with a huge hearing loss because it can be fixed."
Dr. Jonathon Sillman, an ear specialist at Tufts Medical Center, has evaluated about 10 bombing victims for hearing injuries. All were given audiogram as soon as they could sit in a wheelchair in a soundproof booth.
"One of the most striking things about this experience is how variable the injuries were," Sillman said.
One patient was standing next to a person who lost her legs, he said, yet "her only injury is one perforated eardrum with no neural hearing loss." He suspects the person who lost her limbs must have shielded his patient from the energy of the blast.
By CATHERINE SAINT LOUIS
The New York Times