Two Ears are Better Than One
Many people with hearing loss wonder if they need two hearing aids. If hearing loss is present in both ears, the answer is yes. Binaural hearing serves as a huge advantage, not only for hearing, but for preserving the ear’s ability to properly process sounds.
We have two ears for a reason. Much like our eyes, our ears work together to create an accurate perception of the world around us. With two hearing ears, we hear sounds coming from left and right sides of our body, and our brain combines the information, which enables us to localize sound, hear sounds from all around us, and improves our ability to hear in noise.
Benefits of binaural amplification:
- Ability to localize sounds
- Better speech intelligibility (understanding of words) in noise
- Improved tinnitus relief
- Prevention of auditory deprivation (loss of speech intelligibility) for the unaided ear
Localization is our ability to correctly identify sound sources in a given space.
There are two main processes which allow us have “3D” perception of sound: Interaural Time Difference and Interaural Intensity Differences.
Interaural Time Difference: Sounds coming from a source on either sides of our body reach our ears at two different times. The ear closest to the sound will hear it first. This happens so fast that we don’t perceive it, however, this difference in timing gives our brain vital information needed for proper localization.
Interaural Intensity Difference: Sounds coming from different sides of our bodies also reach our ears at volumes. This is because our own heads get in the way of sound travel, and dampen the sound reaching our other ear. This is called the head shadow effect. The ear closest to the sound will hear it louder than the far ear. Although this isn’t usually perceived, our brains rely on this information to have a proper understanding of our environments.
Improved Speech Clarity
Localization is important for good speech clarity. The ability to properly localize sounds allow us to separate sounds coming from different directions in our environments. This is especially important for noisy environments. Without localization, sounds blend together, and we loose our ability to pick out important information, such as speech. Having localization cues allows our brains to separate noise from speech, allowing us to hear in places like busy restaurants.
Binaural Redundancy is another important factor in helping us hear to the best of our ability. Binaural redundancy refers to the combining of auditory input from our two ears, which happens when sound reaching the auditory cortex (the part of the brain that processes sound). Basically, this process allows us to get two “looks” at the sound around us. If one ear misses something, the other ear might pick it up.
Prevention of Auditory Deprivation
Auditory Deprivation refers to the brain’s inability to interpret words due to lack of auditory stimulation. The longer the brain is deprived of auditory information, the more likely auditory deprivation will take place.
Late Onset Auditory Deprivation specifically refers to auditory deprivation as a result of monaural (one ear) hearing aid fittings for bilateral hearing loss. In these cases, the ear that wears the hearing aid will remain stable, while the unaided ear will decline, sometimes more rapidly than if no hearing aid is worn at all. It is as if the brain learns to ignore the unaided ear and becomes completely reliant on the aided ear, as that ear is receiving the auditory information. Binaural hearing aid fitting are the only way to prevent late onset auditory deprivation.
As with hearing loss, tinnitus is often bilateral. When tinnitus accompanies a hearing loss, hearing aids is often the most effective treatment. Hearing aids allow us to hear sounds we would otherwise be missing, which will often cover up the sounds of tinnitus while the hearing aids are being worn. If the tinnitus is in both ears, bilateral hearing aids will be most effective.