- Aug 30, 2018
- 129
- Tinnitus Since
- 8/2018
- Cause of Tinnitus
- noise exposure while doing work on home
I came upon this article and lost hope in a cure or treatment anytime soon.
https://www.buzzfeed.com/joycecohen/noise-kills-when-everyday-sound-becomes-torture
It's commonly assumed that the ear recovers from excessive noise, the kind that causes temporary muffling or ringing. "We now know definitively that is not true," says M. Charles Liberman, a professor of otology at Harvard Medical School, who also heads a hearing research lab at the Massachusetts Eye & Ear Infirmary. Exposure to noise — noise that was formerly considered non-damaging — causes massive degeneration of the cochlear nerve that progresses over time.
The ear is an organ of exquisite complexity, containing the three smallest bones of the body and two tiny muscles. When sound hits the eardrum, the vibration moves through the bones to the little round inner ear, or cochlea, which includes rows of delicate hair cells, called stereocilia. These hair cells send signals along the auditory nerve to the brain.
That's the nutshell version. It's impossible to actually reach inside the ear, which is encased deep within the temporal bone, the hardest bone in the body. "You can't biopsy the inner ear," Liberman says.
After loud noise exposure, "even if the hair cells recover" — the hair cells being the rows of stereocilia that respond to sound — "the nerve fibers that take the information to the brain don't," Liberman says, and the damage is insidious. "Even though the nerve fibers disconnect from the sensory cells very quickly, most of the fiber doesn't die for months to years."
H. Engström, courtesy of Aage Møller.
Hair cells in a monkey ear — one row of inner hair cells and three rows of outer hair cells — show damage after exposure to intense impulse noise from a gunshot.
The ability to recover from acoustic injury drops with increased exposure. "We don't know why, but that fact is incontrovertible," Liberman says. In other words, after the first concert, the muffling and ringing go away, and you're fine. And the same after the second. But maybe the 20th concert is the one that breaks the camel's back. "Noise risk is an incredibly complex equation."
The vast interpersonal difference in susceptibility to noise damage could be due to a gene variant. Actually, it's likely that numerous genes are involved, Liberman says. Attempts are underway to identify the susceptibility genes for noise-induced hearing loss, though it's unclear whether this could help in identifying susceptibility to tinnitus or hyperacusis.
"You can have identical exposure and get absolutely huge differences in the amount of damage," he says. "Tough" ears can withstand plenty of noise, while "tender" ears can withstand surprisingly little. The problem is that it's impossible to tell, until it's too late, who's at risk.
One hypothesis about how noise can cause pain is that there are "stretch-sensitive fibers in the eardrum." Another involves nerve fibers that run between ear and brain; most are covered in myelin, but there are also some unmyelinated sensory fibers that connect the cochlea's outer hair cells to the brain. "We don't have a clue what they do," Liberman says. "One speculation is that they are actually auditory pain fibers."
But ultimately, all these theories are just that. "We really don't understand tinnitus and hyperacusis at all," Liberman says. "We are so far from understanding that it's not productive to make anybody think there's an answer."
https://www.buzzfeed.com/joycecohen/noise-kills-when-everyday-sound-becomes-torture
It's commonly assumed that the ear recovers from excessive noise, the kind that causes temporary muffling or ringing. "We now know definitively that is not true," says M. Charles Liberman, a professor of otology at Harvard Medical School, who also heads a hearing research lab at the Massachusetts Eye & Ear Infirmary. Exposure to noise — noise that was formerly considered non-damaging — causes massive degeneration of the cochlear nerve that progresses over time.
The ear is an organ of exquisite complexity, containing the three smallest bones of the body and two tiny muscles. When sound hits the eardrum, the vibration moves through the bones to the little round inner ear, or cochlea, which includes rows of delicate hair cells, called stereocilia. These hair cells send signals along the auditory nerve to the brain.
That's the nutshell version. It's impossible to actually reach inside the ear, which is encased deep within the temporal bone, the hardest bone in the body. "You can't biopsy the inner ear," Liberman says.
After loud noise exposure, "even if the hair cells recover" — the hair cells being the rows of stereocilia that respond to sound — "the nerve fibers that take the information to the brain don't," Liberman says, and the damage is insidious. "Even though the nerve fibers disconnect from the sensory cells very quickly, most of the fiber doesn't die for months to years."
H. Engström, courtesy of Aage Møller.
Hair cells in a monkey ear — one row of inner hair cells and three rows of outer hair cells — show damage after exposure to intense impulse noise from a gunshot.
The ability to recover from acoustic injury drops with increased exposure. "We don't know why, but that fact is incontrovertible," Liberman says. In other words, after the first concert, the muffling and ringing go away, and you're fine. And the same after the second. But maybe the 20th concert is the one that breaks the camel's back. "Noise risk is an incredibly complex equation."
The vast interpersonal difference in susceptibility to noise damage could be due to a gene variant. Actually, it's likely that numerous genes are involved, Liberman says. Attempts are underway to identify the susceptibility genes for noise-induced hearing loss, though it's unclear whether this could help in identifying susceptibility to tinnitus or hyperacusis.
"You can have identical exposure and get absolutely huge differences in the amount of damage," he says. "Tough" ears can withstand plenty of noise, while "tender" ears can withstand surprisingly little. The problem is that it's impossible to tell, until it's too late, who's at risk.
One hypothesis about how noise can cause pain is that there are "stretch-sensitive fibers in the eardrum." Another involves nerve fibers that run between ear and brain; most are covered in myelin, but there are also some unmyelinated sensory fibers that connect the cochlea's outer hair cells to the brain. "We don't have a clue what they do," Liberman says. "One speculation is that they are actually auditory pain fibers."
But ultimately, all these theories are just that. "We really don't understand tinnitus and hyperacusis at all," Liberman says. "We are so far from understanding that it's not productive to make anybody think there's an answer."
Member
) nature/evolution shut this off. Our ears are like a big construction company, but nothing is being done cause there are no workers there. Frequency TX put the workers there!
