As of Wednesday, September 4, 2013
DEAR DOCTOR K: I am losing my hearing, and my doctor wants me to get two hearing aids. Is this really necessary?
DEAR READER: If you’re like most people with hearing loss, it’s probably taken some time to accept that you need a hearing aid at all, let alone two. If you have hearing loss in only one ear and normal, or nearly normal, hearing in the other, then one hearing aid is all you need. But most people have hearing loss in both ears, especially age-related hearing loss. In that case, research and experience suggest that you’ll be more satisfied with two hearing aids.
When you have two hearing aids, you can take better advantage of the way the brain processes sound through what’s known as “binaural” hearing. With normal hearing, most sounds that we hear enter both of our ears. (There are exceptions: If you rub two fingers together just outside your right ear, virtually all of the sound from your fingers is being processed just by that ear.)
When a sound enters both of our ears, each ear sends its version of that sound to the brain. The brain interprets the sound by processing the signals from both ears, and it does a better job of processing the sound when it’s getting signals from both. For example, the brain can pick out important signals, like voices, and interpret what those voices are saying even when there’s a lot of background noise.
If you’re wearing just one hearing aid, even though you have hearing loss in both ears, your brain may have a harder time distinguishing voices from other sounds in a noisy place. It may also be harder for the brain to identify the location of particular sounds. The brain normally does this by comparing the relative loudness and frequencies of the sound signals that are coming into both your ears, as well as how long it takes them to travel through the ears. But the brain can’t locate a sound as well if sound signals are always louder through one ear.
Another advantage of wearing two hearing aids is that you can set each of them at a lower volume than if you wear just one. And lower volume means less feedback and distortion of the sounds around you.
If you’re still not sure that you want or need two hearing aids, ask your doctor if you can use two on a trial basis. Under this arrangement, you would be fitted with two hearing aids, and then, over a period of several weeks, you would decide whether you hear better with one or two. If not two, you should be able to return one of them.
Since I graduated from medical school, hearing aids have not only become better; they also have become much smaller. Many of my patients who needed hearing aids 30 years ago wouldn’t wear them because they were unsightly. Today, almost all of my patients who need hearing aids have them.
Dr. Komaroff is a physician and professor at Harvard Medical School. To send questions, go to AskDoctorK.com, or write: Ask Doctor K, 10 Shattuck St., Second Floor, Boston, MA 02115.