Long-term hearing loss from loud explosions, such as blasts from roadside bombs, may not be as irreversible as previously thought, according to a new study by researchers at the Stanford University School of Medicine. loud blasts actually cause hair-cell and nerve-cell damage, rather than structural damage, to the cochlea, which is the auditory portion of the inner ear and may be treatable .This new study could be great news for the millions of soldiers and civilians who, after surviving these often devastating bombs, suffer long-term hearing damage.
According to earlier studies this damage would be irreversible.More than 60 percent of wounded-in-action service members have eardrum injuries, tinnitus or hearing loss, or some combination of these, the study says. Twenty-eight percent of all military personnel experience some degree of hearing loss post-deployment. The most devastating effect of blast injury to the ear is permanent hearing loss due to trauma to the cochlea.
The increasingly common use of improvised explosive devices, or IEDs (explosive device often used in unconventional warfare), around the world provided the momentum for the new study .Here is the important of this study this will be a great relief for soldiers and civilians who, after surviving these often devastating bombs, suffer long-term hearing damage.According to the researchers permanant hearing loss from loud noise begins at about 85 decibels typical of a hair dryer or a food blender. IEDs have noise levels approaching 170 decibels.
For finding the real cause of this permanant hearing loss Stanford researchers created a mouse model to study the effects of noise blasts on the ear.
After exposing anesthetized mice to loud blasts, researchers examined the inner workings of the mouse ear from the eardrum to the cochlea. The ears were examined from day one through three months. A micro-CT scanner was used to image the workings of the ear after dissection.
“When we looked inside the cochlea, we saw the hair-cell loss and auditory-nerve-cell loss,”
“With one loud blast, you lose a huge number of these cells. What’s nice is that the hair cells and nerve cells are not immediately gone. The theory now is that if the ear could be treated with certain medications right after the blast, that might limit the damage.” said Oghalai, a scientist and clinician who treats patients at Stanford Hospital & Clinics