Even with technological advances in hearing aids and hearing loss treatment, scientists continue their research into trying to find out exactly how sound enters the ear, is processed and moves to the brain where its translated into something we can understand – like a train whistle or a conversation. Of course, the first step for you to ensure proper hearing is to get a hearing evaluation at Hearing Health!
The hearing signals
Scientists at Harvard Medical School have isolated a protein they are calling TMC1 which they believe converts sound and head motion into electrical signals to the brain enabling hearing and balance. This is important because each step of the hearing process needs to be totally understood to better treat hearing loss.
Think of your hearing and balance – since they are tied together – as a car engine. Everything in a car engine needs to be in proper working order and it needs to work together for you to be able to drive your car.
Sensitivity to sound is part of the evolutionary statement. The way we hear, the way other species hear has been studied, but all the individual parts and pathways have not been completely identified. We know that cells in the inner ear detect sound and movement and those tiny cells then translate that into a signal to our nerves.
Finding out exactly how “hearing” works is complicated by the fact that accessing the area where you start to “hear” – the inner ear – is difficult. It’s a small area, a really small area and, there are a very small number of auditory hearing cells relatively speaking. Each ear has about 16,000 auditory hearing cells. Compare that to the eye. The retina has more than 100 million sensory cells. Retrieving, photographing the working of an auditory cell and then analyzing what happens next is very difficult.
Proteins found before
Researchers knew before they isolated TMC1 that there were proteins on the coatings of sensory hair cells in the ear and that these proteins formed miniscule pores that would open and close in response to sound. While the pores are opening and closing, electrically charged ions such as calcium and potassium enter. This creates electrical signals that move via nerve cells to the brain. See, your ear and hearing are a marvelous apparatus.
TMC1 was discovered in 2002 and researchers knew it was part of a chain of proteins that linked together to move sound to the brain, but it wasn’t until recently that it was determined how important TMC1 was.
A protein is a chain of amino acids. Harvard researchers and neurologists found 17 amino acids form the protein chain for TMC1 . Utilizing a pain-staking process, the substituted something different for each of the 17 amino acids and then studied how that altered the function of TMC1. Each substitution altered the flow of charged ions through the pores on the hairs of the auditory cells. Out of the 17 substitutions, 11 altered the flow of ions, or changed the hearing. Of the 11 – five had a very strong effect and reduced the flow of ions by up to 80%!
While a handful of amino acids play a critical role in translating sound to something we understand, TMC1 plays a critical role. Researchers note this protein is found throughout the animal kingdom. Since this protein has survived the evolution of countless species, that underscores that it is critical to survival. Findings from the most recent survey, they conclude, shows that TMC1 is THE critical molecular sensor that translates sound and motion into electrical signals that the brain can understand.
One in 1,000 newborns are affected by hearing loss and around 50% of those cases of hearing loss have a genetic cause. The TMC1 gene is one of nearly 150 genes that have been associated with genetically linked hearing loss and multiple studies have shown that mutations in the TMC1 gene contribute to hereditary hearing loss in family groups around the world.
Exciting research will lead to advances in the treatment of hearing loss. Right now, newer models of hearing aids are discreet and give the best hearing possible for all types of loss – from slight to profound. The first step towards hearing health is getting a hearing test – and then having tests done regularly at Hearing Health.