Two Ears are Better than One
When diagnosed with a hearing loss many patients ask whether they must wear one hearing aid or two.
The answer: if you have a hearing loss in both ears you need to wear two hearing aids.
There are a number of reasons any reputable audiologist would recommend wearing two hearing aids:
- We have two ears for a reason, to assist us in balance and most importantly localization of sound. Localization refers to the ability to identify where sounds are coming from. It is important to localize sounds in order to orientate ourselves. A real life ex-ample would be hearing emergency vehicles when driving. When we hear a siren we need to be able to localize the sound and determine where the vehicle is approaching from.
- When a hearing loss is left untreated it causes auditory deprivation. When we have a hearing loss the auditory nerve is not adequately stimulated and be-comes lazy over time. The point of a hearing aid is to stimulate and exercise the auditory nerve ensuring it remains active and responsive to sounds. Wearing a hearing aid in one ear will ensure the auditory nerve for that ear remains active whilst the other ears nerve will continue to weaken without amplification.
- Research shows us that one hearing aid is effective in improving hearing abilities in quiet listening situations, however it falls short in noisy environments. This is because both ears are important when listening in challenging and noisy environments. There are two processes occurring in our brain that assist us in being able to hear in background noise: binaural redundancy and binaural squelch:
Binaural redundancy allows our brain two chances to get the message right. The signal from the right and left ears are processed, and if two very similar signals are available (the desired speech signal), there is a greater probability that the signal will be heard correctly. Moreover when part of the signal isn’t heard or lost by one ear the redundancy allows us to “fill in the gaps” with the signal heard from the other ear.
Binaural squelch allows the auditory centres of the brain-stem to compare the signals from the two ears, and give greater emphasis to the meaningful (speech) signal. This is referred to as binaural “squelch,” as the unwanted signal (e.g., noise) is not given the same attention and processing, and is therefore somewhat diminished.
These two processes are only effective when the two ears are both able to “hear” or process an auditory signal. When wearing a hearing aid in only one ear we prevent our brain from making use of binaural redundancy and squelch to improve our abilities to hear in background noise. There-fore one hearing aid will not assist these individuals to hear better in noisy and challenging listening situations as illustrated by the picture below:
To book a hearing test, contact CVH Audiology on 011 615 3047.