stats/prevalence
What ratio of people who can benefit from a hearing aid actually wear one?
1/5
what does the outer ear consist of?
auricle (pinna), external auditory canal, tympanic membrane
what is shown on the vertical axis of an audiogram?
hearing sensitivity
what are the functions of the outer ear?
protection, amplification, localization
what is elasticity?
ability of a mass to return to its natural shape after being disturbed
What percentage of Americans had a dizziness or balance problem in the past year?
15%
what are the ossicles?
malleus, incus, stapes
what is classified as a severe hearing loss?
71-90dB
what are the functions of the middle ear?
impedance matching, selective oval window stimulation, pressure equalization
what requisites must be met for sound to exist?
vibrating object, force, medium
how many people have hearing loss worldwide?
466 million
what does the inner ear consist of?
semicircular canals, vestibule, cochlea
how is masked bone conduction represented?
with brackets
what are the functions of the inner ear?
filtering distribution, transduction
what is 1Hz?
1 cycle/second
how many children have a disabling hearing loss?
34 million kids
what are fibers that ascend to the same side?
ipsilateral
what frequencies are we most sensitive to?
1000-4000 Hz
what are the transducers for the inner ear?
inner hair cells
how are period and frequency related?
inversely
how many children with acquired deafness also have some loss of balance?
2/3
what does the central auditory nervous system consist of?
auditory nerve, synaptic junctions in the brainstem, temporal auditory cortex
what is another name for the horizontal axis of an audiogram?
the abscissa
how does the middle ear make up for the loss of energy going from air to water?
areal ratio and lever action of ossicles
what is transverse propagation?
particles in the medium move perpendicular to the direction of the movement of the wave