Hearing, like eyesight, is something that many of us take for granted. Most of us probably never think about the fact that we need two ears to hear properly. What happens when we suddenly lose the ability to hear in one ear?
Whenever sound enters the ear, it has to first pass through the outer, middle, and inner ears before it’s sent to the brain along the auditory nerve. The brain then takes the input from both ears before processing it as sound. This type of hearing, called binaural hearing or “stereo” hearing, is how we normally hear localized, 3-D sounds and determine their direction. In noisy situations, individuals with hearing in both ears are able to better distinguish voices and accurately focus on specific sounds.
But not everyone is able to hear with both ears. Many people lose hearing in one ear as they get older, while some children are born hearing-impaired.
Single-sided deafness (SSD) makes listening much harder. When sound input comes from only one ear, it becomes difficult to hear localized sound and to determine direction (which can be very dangerous when crossing the street). It’s also harder for the brain to filter out white noise and focus on important sounds, like human voices or phone alerts.
For the hearing-impaired, two hearing aids can often be better than one. Binaural amplification has been shown repeatedly in studies to increase speech understanding, enhance sound quality, and improve sound localization. Wearing only one hearing aid is often enough to achieve functional hearing, but wearing two hearing aids adjusts the sound input from both ears so that the brain can synthesize them better. Sounds usually have a fuller, richer quality and the risk of auditory fatigue is minimized. Listening becomes more comfortable and natural.
For the profoundly deaf or hard of hearing, surgically-implanted electronic implants, called cochlear implants, are often a better choice than hearing aids. Bilateral cochlear implantation in both adults and children has been shown to restore the ability to localize sounds and can give children born with profound deafness the ability to hear and experience sounds normally. Since children’s ability to learn decreases with age, it’s advisable for cochlear implants to be implanted before the age of 3 ½ in order for sound-based learning (including language acquisition) to develop normally.
As with all surgical procedures, cochlear implantation has associated risks, but bilateral cochlear implantation has not been shown to carry significantly higher risks. Binaural amplification carries no risks at all, and can be accomplished with invisible hearing aids.
If you are considering binaural amplification or bilateral cochlear implantation, you should consult your audiologist and pay a visit to the implant center in order to establish appropriate expectations and defined goals. Speaking with other individuals who already use two hearing aids or have bilateral cochlear implantation is also invaluable when it comes to determining whether these enhancements are right for you.