ABOUT THE EAR: There are three main parts to the human ear: outer, middle and inner ear. The outer ear is the part you can see and opens into the ear canal, which leads to the middle ear. The middle ear is a closed, air-filled chamber, separated from the outer ear by the ear drum, and ventilated by the Eustachian tube. Sometimes the pressure in the middle ear becomes higher or lower than that in the outer ear, causing hearing loss, severe pain, and the accumulation of fluid in the middle ear. The inner ear contains the nerve that sends information about sound to the brain.
ABOUT HEARING LOSS: Loud sounds stress and potentially damage the delicate hair cells in the inner ear that convert mechanical vibrations (sound) into the electrical signals that the brain interprets as sound. Over time, the hair cells can become permanently damaged and stop working, producing hearing loss. Noise-induced hearing loss can be caused by two types of noise: sudden bursts, such as firearms or fireworks, or continuous exposure to loud noise, such as motorized recreational vehicles, loud sporting events, power tools, farming equipment, or amplified music. For the latter, it depends on the level and duration of the noise exposure. It takes repeated exposures over many years to cause a gradual onset of noise-induced hearing loss in both children and adults. The type of profound hearing loss that leads to the prescription of cochlear implants is typically the result of very severe illnesses or hearing damage, and their use typically replaces any residual hearing remaining in the damaged ear.
The Acoustical Society of America, and the American Physical Society contributed to the information contained in the TV portion of this report.