New imaging method links inner ear fluid level to hearing loss

by Daniel Fink, MD, Chair, The Quiet Coalition

Photo credit: Kindel Media

A report on the Medical Xpress website discusses a new imaging method that links inner ear fluid levels to hearing loss. Researchers at the University of Southern California’s Keck School of Medicine modified optical coherence tomography (OCT), used to diagnose and plan treatment for eye diseases, to collect images of the inner ear.  Until now, the best available tool for imaging the inner ear was magnetic resonance imaging but it lacked the needed resolution.

The summary and abstract of the research, published in Science Translational Medicine, note that fluid imbalance in the inner ear, or endolymphatic hydrops (ELH), can cause sudden hearing loss. The researchers used intraoperative OCT to measure fluid in the semicircular canals during mastoid bone surgery. The ELH measurements correlated with the degree of hearing loss, raising the possibility that OCT imaging of ELH could aid in the management and treatment of inner ear diseases.

My interest in this topic comes not from concern about treatment of inner ear disease, but from a longstanding question about what causes the temporary muffling of sound after exposure to loud noise, known as noise-induced temporary threshold shift or NITTS. I have long suspected that somehow loud noise causes a buildup of fluid in the inner ear, thereby affecting hearing.

Unfortunately, I don’t think new technology will help answer this question because at the moment it can only be used during an operation, but it still provides a clue to the pathophysiology of NITTS. Nonetheless, the prevention of both NITTS and permanent hearing loss is simple and inexpensive. Avoid exposure to loud noise, turn down the volume, leave the noisy environment or use hearing protection.

If it sounds loud, it’s too loud and one’s auditory health is at risk.