Hearing Subtitle. The Physics of Sound Frequency: The number of cycles a sound wave completes in a given period of time Amplitude: the Strength of

HearingSubtitle

The Physics of SoundFrequency: The number

of cycles a sound wave completes in a given period of time

Amplitude: the Strength of a wave

Anatomy of the Ear

From Sound Wave to Perception1. Pinna Tympanic Membrane (eardrum)

bones of inner ear (hammer, anvil, stirrup) COCHLEA (primary hearing organ)

2. Cochlea is filled w/ fluid, which further transmits vibrations to thin membrane- Basilar Membrane

3. BM = Transduction; tiny hairs on BM tickle the sensory nerves

4. Neural message is sent to Temporal Lobe

Copyright © Allyn and Bacon 2006

How Sound Waves Become How Sound Waves Become Auditory SensationsAuditory Sensations

Tympanic membrane –The eardrum



Cochlea –Where sound waves are transduced



Auditory nerve –Neural pathway connecting the ear and the brain

3 Psychological Sensations of Sound

1.Pitch- the way we sense frequency

2.Loudness- the way we sense amplitude

3.Timbre- the way we sense the complex mix of tone


2 Hearing Theories1. Place Theory: different places on

the BM are responsible for different pitches- explains high pitches

2. Frequency Theory: BM fires off neural messages at different rates- rate of firing accounts for differences in neural transmissions, which result in us hearing low frequencies

Conduction Deafness • An inability to hear resulting from damage to

structures of the middle or inner ear

• Conductive hearing loss is often only mild and is never worse than a moderate impairment.

• Generally, with pure conductive hearing loss, the quality of hearing (speech discrimination) is good, as long as the sound is amplified loud enough to be easily heard.

• Possible Causes• Ear wax build up• Fluid inside the inner ear, like from an inner ear

infection.• If the bones of the ear get a buildup of calcium

Sensorineural Deafness… or Nerve Deafness

• An inability to hear, linked to a deficit in the body’s ability to transmit impulses from the cochlea to the brain, usually involving the auditory nerve or higher auditory processing centers

• It can be mild, moderate, severe, or profound, to the point of total deafness.

• Possible Causes• Long-term exposure to environmental noise

• Genetic• Disease or illness

• Medications• Physical trauma

Pre-Lingual Deafness

• These are people that are born deaf

Documents

Hearing Subtitle. The Physics of Sound Frequency: The number of cycles a sound wave completes in a given period of time Amplitude: the Strength of