In thousands of people each year, the immune system attacks the inner ear, home to the tiny, delicate structures that allow us to hear. Without warning, in days or weeks, patients lose the ability to hear in one or both ears. Some might get part or all of their hearing back if they take steroid medicines, but many are left to cope with partial or total deafness without knowing what caused it. And no one knows why it happens.
Now, new research based at the University of Michigan's Kresge Hearing Research Institute may help more patients find out quickly if steroids could help them, or if they can be spared the drugs' harsh side effects. It may also expand the definition of the condition, known as autoimmune sensorineural hearing loss or AISNHL, and help more people get a firm diagnosis of what's causing their mysterious hearing loss.
In the August issue of the Archives of Otolaryngology Head and Neck Surgery, researchers reports results from a study of 63 people with rapidly progressing hearing loss in Michigan, Pennsylvania and Indiana, and 20 people with normal hearing. The patients were suspected of having an auto-immune cause for their hearing loss, and all received steroids, but they hadn't been formally diagnosed.
The researchers found that more than half of the hearing-loss patients had antibodies against a protein found in the inner ear, called IESCA for inner-ear supporting cell antigen. This is a sign their immune systems recognized it as foreign.
"In all, 28 of the 63 patients experienced improvement in their hearing after steroid treatment, and 35 did not. But the vast majority, 89 percent, of those who improved had a positive immunofluorescence test for an antibody to IESCA that
Contact: Kara Gavin
University of Michigan Health System