A patient whose mother is having hearing difficulties asked me to write about the best way to choose someone to fit hearing aids. I'd like to begin with some background on hearing.

It goes without saying that hearing is one of our most important senses. It is critical for our quality of life as well as for safety and social interaction. There are an estimated 30 million Americans who have some degree of hearing loss, 65 percent of whom are younger than 65 years of age. It's very concerning that 1/14 younger adults and 1/20 adolescents have measurable hearing loss. Since 1971, the number of Americans over age three with hearing disorders has doubled.

The primary cause of hearing loss is environmental noise. The louder the volume (measured in decibels or dB) and/or the longer the exposure, the more likely it is for damage to occur. Repeated exposure to noise over 85 dB like lawn mowers, truck traffic and shop tools can lead to gradual hearing loss.

Playing music at a device's maximum volume using headphones can deliver 105-120 dB, while using earbuds can add an additional 6-9 dB.

Other causes of hearing loss include drugs that are toxic to the hearing apparatus, aging, and various other medical conditions.

Warning signs of hearing loss include difficulty understanding people (especially if in a crowd), asking people to repeat themselves, trouble hearing the TV or radio (and hence turning up the volume), others complaining about one's hearing, and avoidance of social situations where hearing is important.

Treatment of hearing loss begins with a good hearing assessment. Audiologists and hearing aid specialists have different training and provide these services to varying degrees.

Audiologists are the only hearing professionals who receive university training and are licensed by the state to do comprehensive evaluation and treatment of hearing loss in all age groups. They typically do four years of additional training after college and receive the Doctor of Audiology degree.

Hearing aid specialists, on the other hand, are not required to undergo nearly as much training. Indiana requires them to have a high school diploma or GED, pass an examination, pay a $60 fee and receive supervision by a hearing aid dealer before they can sell hearing aids.

My preference is certainly to refer patients to an audiologist for diagnosis and treatment. Most cases of nerve damage are treatable by amplification using hearing aids, though simply selling a set of hearing aids should not be the end of the treatment process. Treatment also involves verifying the fit of the hearing aids, providing counseling on their use and doing follow up.

There have been huge advancements in hearing aid technology in the last decade. The available models and their complexity definitely require someone who is skilled in prescribing and managing them appropriately. Hearing aids are expensive, but the ability to hear properly is critical for safety and quality of life.

Remember that prevention is the best medicine. Be aware that loud and/or prolonged noise can cause hearing loss, evaluate your surroundings so you can avoid the noise and wear hearing protection if you can't. A note to parents with kids with iPods - use the parental maximum volume control in iTunes.