Are Two Hearing Aids Really Better Than One?

© November 2002 by Neil Bauman, Ph.D.

Question: I was recently diagnosed with a hearing loss in both ears. My audiologist recommends that I get two hearing aids. Isn’t one enough? Do the advantages of wearing two hearing aids really outweigh the extra expense? (Hearing aids aren’t cheap you know!)—D. B.

Answer: Good questions. I sympathize with you. I well know how expensive hearing aids can be! Furthermore, two hearing aids cost twice as much as one. Therefore, you are right to wonder if you will get your money’s worth out of the second aid. Here’s the scoop.

God designed human beings to have binaural hearing; that is, to hear with two ears. He did not give us two ears by mistake or because He had lots left over at the time of creation! Therefore, it should be no surprise that He designed our auditory systems to take advantage of a lot of good things that happen when we hear equally with both ears.

In fact, all the wonderful things He designed our ears to do are dependent on our hearing with two balanced ears. Taking away the hearing in one ear knocks this amazing system out of balance. Wearing only one hearing aid does the same thing.

Ten Reasons To Wear Two Hearing Aids

Although, you can survive with just one ear (or one arm or one leg or one eye), life is ever so much easier and pleasant when you have both functioning properly.

You gain many advantages from having two equally-functioning ears. Here are ten reasons you should wear two hearing aids if you have a hearing loss in both ears.

1. When wearing two hearing aids, you can better locate the source of sounds. This ability to locate the source of sounds in three-dimensional space is called "localization." Your brain uses three auditory factors to help you locate where sounds are coming from. These factors are: 1) the slight difference in time it takes for a given sound to reach each ear, 2) the difference in the loudness of a given sound as heard in each ear, and 3) the slight difference in the pitch of a given sound as heard in each ear.
   
   This works because your head is an obstacle to sound waves. The extra time sound needs to cross your head and reach your other ear results in a slight delay in time. At the same time, the volume and the pitch of the sound is also reduced or changed. Although you cannot consciously detect the subtle differences in these three factors, your brain can. Without your even being aware of it, your brain quickly compares these three factors, performs some quick calculations and you then consciously become aware of the direction the sound is coming from. If you only wear one hearing aid (and the other ear also has a hearing loss), your brain cannot use these factors to help you locate the sources of sounds.
   
   In fact, with only one hearing aid, you hear the sound inside your head as it were, but you fail to pinpoint the direction from which the sound is coming. Thus, in group situations you may hear a person talking, but you will have no idea who is speaking. In order to figure out who is speaking you have to twist around to look at everyone's face to see whose lips are moving. By the time you have located the person speaking so you can speechread him, you often have missed most of what was said.



2. When wearing two hearing aids you will understand speech and conversation significantly better than if you wear only one. This is especially true under noisy and difficult listening situations. When you wear two hearing aids, your brain receives two different signals arriving at slightly different times (out of phase). This gives your brain a much better chance of subtracting out the noise you don’t want to hear and picking up the speech you really want to hear. As a result, the voice you are trying to hear more clearly stands out from the background noise. This makes listening a lot easier.



3. If you wear two hearing aids, you can reduce the volume on both hearing aids by about 10 dB and still hear better and understand more than if you only wore one hearing aid. This reduces the total volume of sound assaulting your ears—especially in noisy situations. An added benefit is that you will be able to tolerate louder sounds better with the lower volume setting. Furthermore, you will find that the sound quality improves since there is less distortion and better reproduction of amplified sounds at the lower volume setting.
   
   When one of my hearing aids quit working, I realized anew just how little I really understand with only one hearing aid. I was shocked at how much louder I had to set the volume on the remaining hearing aid in order to hear, yet I understood far less. Once you have adjusted to wearing two hearing aids, you will never want to be without both of them.



4. Wearing two hearing aids eliminates the head-shadow effect that occurs when you are wearing only one hearing aid. Studies show that if a person is speaking to you from your unaided side, the high frequency consonants (that give speech its intelligibility) will be reduced about 20 dB by the time they reach the opposite side of your head. This makes understanding speech much worse than if you wore two hearing aids.
   
   Furthermore, when wearing two hearing aids, you hear from all directions—360 degrees—not just the 180 degrees you basically hear from when you wear only one hearing aid. You will really notice this effect when someone speaks to you from the side opposite your hearing aid. The difference will be even more dramatic when there are louder sounds on your hearing aid side. The speaker on your unaided side then will be almost impossible to hear and understand.



5. Wearing two hearing aids is less tiring. This makes listening more pleasant. You can relax more while you are listening as you no longer have to strain to try to hear with only one ear. Listening with only one ear is not only tiring, but it is also difficult and frustrating. Try reading for an extended time with only one eye and you will see just how much harder it is. Hearing with one ear is just the same.



6. Wearing two hearing aids gives you a more natural balance of sound and greatly improves your listening enjoyment. This is particularly noticeable when listening to music. Here is why.
   
   Your brain consists of two halves or hemispheres. The two halves of your brain have many interconnecting links so they can rapidly "talk" back and forth as they process information. The left side of your brain is the logical (or technical) side. It gives you discrete pieces of information. The right side of your brain is the aesthetic side. It gives you your appreciation of beauty and your ability to recognize images and patterns of sound. If you only wear one hearing aid, your brain only gives you part of the message.
   
   Furthermore, God wired your brain so that the sounds from your right ear go mainly to the left side of your brain. There your brain interprets what a person is saying. The sounds from your left ear go mainly to the right side of your brain. There your brain interprets how the person speaking means it. Likewise, when listening to music, you "hear" the sounds of the individual instruments of the orchestra in your right ear but "listen" to the blended beauty of the music itself with your left ear.
   
   Take the words "I love you." Just three little words but with a myriad shades of meaning. Your right ear (and your left brain) would hear and interpret the actual words and analyze the context. Your left ear (and your right brain) would determine how you understand this message—whether sincere or sarcastic or whatever. Thus you need both your ears to completely understand all sounds, speech and music. Wearing one hearing aid only gives you part of the story.



7. Wearing two hearing aids gives you better sound depth perception and thus helps you locate and hear sounds from a specific point in space. People with normal hearing can decide which sounds they want to hear and largely ignore the others (true selective hearing). To do this, your eyes and your ears work together. For example, say you focus your eyes on one member of a distant group of people. Your brain calculates the location of the person that you eyes are focused on. Next, it instructs your ears to listen for any sounds coming from that particular point in space and filter out all others. Hard-of-hearing ears can’t do this as well as normally-hearing ears can. However, if you are not wearing two hearing aids, you can’t do this at all. Both ears have to be able to hear the sounds for this to work. Furthermore, with two hearing aids, you can hear softer sounds from greater distances.



8. When you wear two hearing aids, you stimulate both ears equally. If you only wear one hearing aid, the other ear will not be stimulated. Some think that the ear with no stimulation may eventually lose its ability to hear and interpret sounds. Current research suggests that even if your ear doesn’t lose auditory acuity over time from the lack of stimulation, there are still changes in the ways your brain processes sound when it does not hear from both ears equally. As a result, wearing two hearing aids provides the stimulation your brain needs in order to preserve and maximize the hearing you still have.



9. Since you don’t need the volume as loud when you wear two hearing aids, you have a lesser chance of getting feedback in your hearing aids. Feedback is that annoying squealing or whistling that occurs when a hearing aid (or earmold) doesn’t fit properly.



10. Wearing two hearing aids helps mask tinnitus (ringing in your ears). With one hearing aid, you can mask the tinnitus on the one side, but not normally in the unaided ear.
     

Five Reasons You Should Not Wear Two Hearing Aids

Not everyone can take advantage of wearing two hearing aids. In a few cases it is just not appropriate. Here are five situations where you should only wear one hearing aid.

1. Obviously, if you have normal hearing in one ear and are hard of hearing in the other, you only need one hearing aid.



2. Just as obviously, if you are totally deaf in one ear, wearing a hearing aid in that ear will not help you at all either.



3. If the sounds you hear in one ear are so distorted that you can’t understand speech, wearing a hearing aid in that ear will be counter-productive. The hearing aid will simply amplify this garble which will, in turn, interfere with your brain processing the speech you hear in your other ear. The final result is that you will understand even less than if you wore only one hearing aid.



4. If you have constant infections in your ear canal or eardrum that just will not clear up as long as you have a hearing aid stuffed in your ear, you should not make the situation worse by trying to wear a hearing aid in that ear. You would still benefit from wearing two hearing aids, but your physical problem precludes their use.



5. A few people have tiny ear canals—much too small to properly fit/hold hearing aids/ear molds. Thus you physically can’t wear a hearing aid in that ear.

If one of these latter two cases applies to you, all is not lost. You might want to investigate having an implantable hearing aid on that side instead. The Vibrant Soundbridge, for example, has no parts in your ear canal to bother such conditions.

Conclusion

Wearing two hearing aids will never give you normal hearing. You will always have to struggle to hear, particularly under difficult listening situations. You will never have normal sound depth perception. You will never be able to locate sounds as precisely as people with normal ears. You will never have normally-balanced sound. However, wearing two hearing aids will go a long ways towards helping you in all these areas. If you only wear one hearing aid, you will be defeated in these areas before you even start.

If you have tried wearing one hearing aid and found the results terrible, don't assume that wearing two hearing aids will be just as bad. You will be pleasantly surprised at how much better the results will be.

When I was growing up, money was scarce. Thus, for more than twenty years I wore a single hearing aid and struggled with the above disadvantages. I didn’t know what I was missing. Now, for the past couple of decades I have worn two hearing aids, and the difference is like night and day! I would never go back to wearing just one hearing aid. The truth is, after wearing two hearing aids, the overwhelming majority of hard-of-hearing people never voluntarily go back to wearing just one hearing aid again.

In an email I received recently, Joseph wrote: "When I started wearing hearing aids about three months ago I immediately started wearing two. Right now I'm reduced to one [the other one is getting repaired] and I can't wait to get my right one back in my ear. Although one is better than nothing, I sorely miss my other hearing aid. I find I'm running my left hearing aid at just about the maximum possible volume and even at that it's not doing the job that two hearing aids at the lower volume were doing for me."

Like Joseph, I think you too will discover that the advantages of wearing two hearing aids far outweighs the additional cost. Try two and prove it for yourself!