Even when we sleep, part of us is alert. Our sense of hearing is on duty 24 hours a day, detecting danger, helping us communicate, and orienting us. But hearing often suffers from sensory overload and stress.
The ear is an extremely powerful tool, but it’s also a fragile one. According to the World Health Organization, more than 400 million people worldwide are affected by hearing loss, with more than one billion young people considered at risk. Yet hearing is vitally important. Without the ear’s multitude of talents, early humans would have gone unprotected from numerous dangers. Even today, those without functioning hearing face limitations of communication, and may also experience problems with balance and spatial orientation. Didier Roche, a blind French entrepreneur, “sees” with his ears. He’s been able to share his experiences with others, by having the guests in his restaurants eat in complete darkness.
For much of the world’s population, auditory stimuli have increased dramatically since the Industrial Revolution. Our sense of hearing is often overburdened. This can happen intentionally, for example when we listen to music, or unintentionally, as with noise pollution. Either way, it can lead to hearing impairment of deafness, which these days even affects those in middle age.
Researchers at Harvard Medical School and the University of Southern California aim to help millions of people suffering such problems to hear normally again. They’re working on an easy-to-take drug that would revive cells deep inside the ear. At the University of Göttingen, teams of scientists are not only undertaking foundational research into stimulus transmission, but also working to restore hearing through optogenetics. This is the attempt to use physical light stimulation to activate nerves in the inner ear that no longer respond to sound, with digital light sources stimulating light-sensitive synapses in the cochlea. Gene therapy is also being used to enable people with certain forms of deafness to hear again, or for the very first time.