Scientists have made a breakthrough discovery when it comes to treating noise-induced hearing loss.
Scientists used mice in their experiments to see just what happens when the inner ear is exposed to loud noise. They also used a tool they developed for taking photos of the cochlea.
The results? The USC team found that loud noise — such as the extreme blast of a roadside bomb — can cause tiny sensory hair cells inside the cochlea to die off. They also found excess liquid in the inner ear that contained a high level of potassium.
“That buildup of fluid pressure in the inner ear is something you might notice if you go to a loud concert”, says author John Oghalai, MD, chair and professor of the USC Tina and Rick Caruso Department of Otolaryngology.
“When you leave the concert, your ears might feel full and you might have ringing in your ears. We were able to see that this buildup of fluid correlates with neuron loss.”
Dr Oghalai continues, “The death of sensory hair cells leads to hearing loss. But even if some sensory hair cells remain and still work, if they’re not connected to a neuron, then the brain won’t hear the sound.”
But here’s something extraordinary: while sensory hair cell death is irreversible, scientists have found that neuron damage is actually delayed and hearing loss effects can actually be reversed if treated.
To reduce the fluid build-up and reverse the effects of potassium in the inner ear, researchers have come up with simple salt and sugar solutions that prevent 45-64 per cent of neuron loss in those with noise-induced hearing loss – if administered within three of extreme noise exposure, that is.
While the sugar/salt solution method has only been tested on mice, Oghalai hopes this is just the beginning. He envisions the solution being an aid for soldiers on the front lines and as a treatment for other ear disorders.
“I can envision soldiers carrying a small bottle of this solution with them and using it to prevent hearing damage after exposure to blast pressure from a roadside bomb,” he explains.
“It might also have potential as a treatment for other diseases of the inner ear that are associated with fluid buildup, such as Meniere’s disease.”