Hearing Health Dictionary || Toxic Noise
Hearing loss afflicts approximately 28 million people in the United States. Approximately 10 million of these impairments are at least partially attributable to damage from exposure to loud sounds. Humans hear via highly specialized cells in the ear called hair cells. When sound enters the ear, the eardrum transmits it through the three middle ear bones –the malleus, the incus and the staples- to the cochlea of the inner ear. The cochlea is filled with fluid and conducts vibrations into the basilar membrane, which covers the cochlea and is lined with hair cells. The hair cells transform the vibrations into electrical signals (neural signals). These signals are passed on to the auditory nerve, and conducted to the brain where they are interpreted. All the elements of the hearing mechanism are delicate, but hair cells are especially fragile. Hair cells differentiate from other cells in the body and begin to perform their special function while the fetus is still in the womb. No new hair cells are made after a child is born – the 30,000 hair cells that are created in vitro are the only ones a person will ever have. Loud noises can destroy these hair cells permanently and cause damage to the nerve of hearing.
Once it’s gone, it’s gone. Hearing aids – more like small hearing computers these days – are getting very sophisticated, but there is nothing like hearing with your ears. One of the side-effects of so many people becoming either deaf or de-sensitized to sound is that manufacturers don’t even bother to make machines quiet anymore.