1. Hearing Sound travels in waves caused by vibrations.
Absolute Threshold is 0 dB
Above 85dB for prolonged periods leads to hearing loss

2. Pitch—how high or low a sound is
Hearing
Pitch—how high or low a sound is
Depends on its frequency, or the number of cycles per second—the more cycles per second, the higher the pitch

3. Measured in decibels (dB)
Loudness
Hearing
Loudness—determined by the height, or amplitude, of sound waves. The higher the amplitude of the wave, the louder the sound.
Measured in decibels (dB)
Zero dB is considered the threshold of hearing (a watch ticking 20 feet away in a very quiet room)

4. Eardrum is the gateway from the outer ear to the middle ear
The Ear
The Ear
Outer ear—shaped to capture sound waves and to transmit sound to the brain
Eardrum is the gateway from the outer ear to the middle ear

5. The Ear cont…
The Ear cont…
Middle ear—the hammer, the anvil, the stirrup (smallest bone in the body). These bones vibrate and transmit sound to the inner ear.
Inner ear—consists of the cochlea (Greek word for “snail”)—a bony tube that contains fluids as well as neurons that move in response to the vibrations of the fluids
Auditory nerve—the cranial nerve that carries sound from the cochlea of the inner ear to the brain

6. THE EAR

7. 2 TYPES SENSORINEURAL CONDUCTIVE Inner Ear Middle Ear
Neurons in the Cochlea
Disease
Noise
Middle Ear
Older
Hearing Aids

8. Deafness
*May be inherited or caused by disease, injury, or old age (approx. 2 million Americans)
*Conductive Deafness—occurs because of damage to the middle ear, prevents people from hearing sounds that are not loud enough. Hearing aids often help by providing the amplification that the middle ear does not. Often seen in older people.
*Sensorineural Deafness—caused by damage to the inner ear, prevents people from perceiving sounds of certain frequencies. Most often, the neurons in the cochlea are destroyed. Can be caused by damage to the auditory nerve, either by disease or through prolonged exposure to very loud sounds.

9. WORLD TODAY Mainstreamed Interpreters ASL Closed Captioned