At a glance: Insurance coverage for hearing loss is spotty

About 15 percent of American adults ages 18 and older report some trouble hearing, according to federal statistics. Problems worsen so steadily as people age that nearly half of those 75 and older suffer from hearing loss.

It is the third most common chronic physical disorder in the United States and is twice as prevalent as diabetes or cancer, according to the Centers for Disease Control and Prevention.

Researchers are trying to better understand how problems develop, how they can be prevented and how best to help people who are suffering from hearing loss. A major obstacle for many, however, is that insurance often doesn't cover treatments or devices that improve hearing.

- WHAT'S NOT COVERED: Hearing aids for adults are not covered by the "vast majority" of insurance plans, according to Mayo Clinic expert Dr. Colin Driscoll. This coverage is more common for children. Hearing aids can cost anywhere from $500 to about $2,000.

- WHAT'S COVERED: Tests to detect hearing loss are often covered, along with surgical or medical treatments for hearing disorders. That includes procedures to repair an ear drum hole or insert cochlear implants.