When many newborns suffer from colds, throat and nasal infections, they often develop a hard, yellow coat in the inner ear. This kind of coating—called a hoof-feet—is even more common among deaf children. In the literature, it is called a hard crotal coating (HCR), or The Coat.
But in a study published Friday in the journal PNAS, researchers at Georgetown University Medical Center say they have found a link between a herniation of ear mucous and hearing loss.
Researchers followed a group of children for 11 months, and found that the eardrum, a structure located on the side of the inner ear, was particularly susceptible to erosion. To study the herniation, they used a device called a polypodoscope. This device lies on the teeth of the eardrum and uses ultrasound to insert a capillary through a small slit at the end of the device, allowing for fluid to flow through. The researchers examined the mucus surrounding the eardrum, and found that it contained abnormalities.
In some cases, the mucus lay within the eardrum, while in others it contained the ear canal, an opening between the eardrum and the outer ear. It also was irregularly folded, and lacked sufficient gas holding capacity.
The research suggested that the mucus may be promoting hearing loss, which has nothing to do with excessive noise or strong irritants.
“The ear belongs to the very bottom layer of the mucous membrane, and to activate this mucous wall to promote eardrum erosion, you need to target it on the weakest spot: the eardrum,” says Igor Nozizhin, a postdoctoral fellow at Georgetown and lead author of the study. Nozizhin says this may explain why eardrums are typically damaged during general medical procedures.
The next step is to conduct a clinical trial to test this hypothesis.