Two Ears Are Better Than One...
As hearing healthcare professionals, we are often asked 'Do I have to wear two hearing aids?'
The answer is, if you have a hearing loss in both ears, you should wear two hearing aids. If you have a hearing loss only in one ear, then you only need one hearing aid. You have two ears for a reason...
Hearing with both ears is called binaural hearing. Wearing two instruments can improve your hearing in noise, gives you the natural stereo effect and provides better sound identification and localisation.
Your ability to localise sound (tell the direction from which sound is coming) is dependent on being able to hear the higher frequencies and on the balance in hearing between both ears.
When you have a sound, coming from one side, that sound reaches one ear a fraction of a second before it reaches the other ear and at a slightly louder level. This small delay in time and level is detected by the brain and enables it to determine from which side the sound is coming. The pinna (outer ear) also helps to focus sound into the ear. You have a natural forward facing focus due to the shape of the outer ear. Unlike animals, humans cannot vary the orientation or focus of their ears in different directions like a dog can. Simply cupping your hand over your ears gives you an added level of amplification and added focus much the same way as your outer ear does. Having only one ear negates most of this natural advantage.
Your brain continuously compares the signal from the left ear to that from the right ear. It then has the ability to focus on a particular sound source and 'switch off' other sounds that it is not interested in. To do this, the brain needs balanced hearing from both ears.
If you have a hearing loss in both ears, and you only wear one hearing aid, you will only get limited benefit from that hearing instrument - mostly in very quiet situations without any distracting sounds. The moment you are in a group or noisy situation, hearing with only one ear limits the benefit of the hearing aid tremendously and you may find it of no help at all.
Much of today's modern technology utilises directional microphones in both hearing aids which work together to give you a focusing ability when you are in a noisy environment or group situation. By only having one hearing aid, you lose much of the advantage of modern hearing aid technologies.
Wearing a hearing instrument in both ears also means not having a 'bad side'. You can hear a person next to you no matter which side of you they are on.
Wearing two instruments gives you improved sound sensitivity. Most people find it much more relaxing and natural listening with both ears because you don't have to strain to hear with the one ear. When you wear two hearing instruments, you don't have to turn the instrument as loud as when you only wear one which also reduces the potential for feedback.
Another factor to consider is keeping the auditory nerve stimulated. Just as a limb that is no longer used atrophies, so the ear that is no longer used may lose the ability to understand words making it unsuitable for amplification later. With a sensorineural hearing loss (nerve deafness), what sometimes happens is that the information that is transmitted to the brain is compromised. Even though the signal has been amplified with a hearing aid and is loud enough, some of the information transmitted to the brain goes missing. When the brain now looks at the information, it cannot interpret all the information. This then limits the benefit of a hearing aid as words may appear garbled or unclear.
