Human communication Exam 3

What is an audiologist?

• Audiologists are healthcare professionals who identify, assess, and manage disorders of hearing, balance, and other neural systems

• They are the primary healthcare providers for hearing and balance disorders in people of all ages from newborn infants to the elderly

Those that specilaze in the ear

otolaryngologists

These are medical doctors

otologists

Hearing instrument specialists

• or hearing aid dispensers

• Specialists trained to perform hearing tests, and select, fit, program, and maintain hearing aids

• Requires a high school diploma and 3-6 month training program. Credentials will be this

• Must pass a state board exam and obtain licensure 

Hearing Scientists 

• Hearing scientists are that study all things related to ear/hearing

• Will almost always have a phd(research degree)

• Have specialized training in a specific area. Often come from a wide variety of backgrounds

Biology, engineering, physics,neuroscience, psychology,physiology, music, communication sciences audio engineering

Medical audiology

• Most common

• Full range of diagnostic____ testing for newborns up to elderly

• Works closely with physicians, slp’s and pt’s 

Industrial

• Assess noise level in the workplace  

• Make recommendations for hearing protection_____

Manufacturer 

• Product specialist for hearing aid or cochlear implant company

• Sales representative

Waveform

is a graphic representation of the shape of a wave that indicates its characteristics (like frequency and amplitude)

Periodic motion

motion that is repetitive and repeats itself on regular time intervals

Cycle of waveform

is when the motion completes one full cycle

Frequency

number of cycles per second

Frequency unit

is hertz which is cyvle per second

Period

how long it takes to complete one cycle

seconds/cycle

Pitch

the perceptual correlate of frequency

Waveform-wavelength

• is the distance in space between two adjacent identical points on a wave

What is the relationship between frequency and wavelength 

• Inverse-as frequency goes up, wavelength goes down

What about period and wavelength?

• Direct : as period goes up, wavelength goes up

The maximum magnitude is called

amplitude

The perceptual correlate of amplitude is

Loudness

The phase relationship

• describes the difference between phases of two periodic waveforms as they cycle though time

Medium

the matter that occupies space

Transverse waves

the particles in the medium move perpendicular to the direction the wave is traveling.

Longitudinal waves

the particles in the medium move parallel to the direction the wave is traveling.

Compression

spots where particles are bunched together, creating increased density.

Rarefaction

spots where particles are spread apart, creating decreased density.

Sound diffraction

• Sound waves can bend around objects- longer wavelengths can pass over objects

Doppler effect

• s a shift in the frequency___ of a sound wave resulting from the movement__ of a sound source 

Reflection

• Sound waves bounce off hard, slick surfaces like tile, concrete,hardwood

When sound bounces around in a space

reverberation

Absorption

• Sound doesn’t just travel on forever.

• Friction between the air molecules

• Or by materials in the environment

constructive interference

• occurs when you add two in-phase waves are added together and the magnitude increases_________

destructive interference

occurs when you add two out-of-phase waves together and the magnitude_decreases____________

Beats

are slow periodic amplitude fluctuations caused when two waves that are very close in frequency interfere with each other

Tuning fork

• are an example of periodic motion

• They have a_resonance________ which is the frequency that they vibrate most easily

Resonant frequency

• is how many times the tines are moving back and forth in one second

Fundamental frequency

is the lowest frequency component in a periodic waveform.

Harmonics

are frequency components that are whole number multiples of the fundamental frequency.

octave harmonics.

The special harmonics that occur each time the fundamental frequency doubles

Waveform synthesis

The process of combining multiple

sinusoid waves together to make

one complex waveform is called

Sawtooth wave

has spectral components that include all whole-

number multiples of f0 (all harmonics) with decreasing amplitude

Square wave

has spectral components that include all odd-

number harmonics of f0 with decreasing amplitude

Triangle wave

has spectral components that include all odd-number harmonics of f0 with decreasing amplitude: like a square wave but the amplitude of the harmonics decays more quickly

Musical/pitch scale

For sound, we use a scale called the

Dosimeter

measures sound levels and the duration

of those levels

Outer ear

collects soundwaves from the environment

Middle ear

transmits sounds collected from the outer ear to the inner ear

Inner ear

the sensory organ for hearing and balance

external auditory canal/ear canal

the actual opening of the ear

Spatial localization or sound localization.

Your ears help you determine where sounds are in space

Middle ear

Is an air-filled space that

starts at the tympanic membrane and ends

at the bony wall that separates the middle

ear from the inner ea

The middke ear space is located where?

is located within the

temporal bone

Temporal bone

Very thick bone

Connected to the skull and attaches to the

jaw

Many cranial nerves pass over this

The Tympanic Membrane (eardrum or TM

is a small cone-shaped membrane.

boundary to the middle ear

It converts acoustic vibrations (sound waves)

into mechanical vibrations

Pars tensa

which is stretched(taut)

Pars flaccida

which is relatively loose

What does otoscopy mean?

means examining the ear using an otoscope, a medical instrument used to visualize the ear canal and eardrum

Used to observe the ear canal and the tympanic membrane

A healthy TM is clear-ish and reflects light

Can sometimes see the bones of the middle ear behind it

Middle ear anatomy

houses the ossicles-the middle ear bones

Eustachian tube

thin tube that connects the middle ear space to the back of the throat (nasopharynx)

Equalizes pressure in the middle ear-”popping your ear”

Also helps drain any fluid that might accumulate in the middle ear space

Acoustic reflex

these muscles contract in response to loud sounds as a protective mechanism

tympanometry

• Diagnostic tool that tests the movement of the middle ear (mostly eardrum and malleus)

• Can determine normal function or a range of other issues

• Fluid in the ear

• perforation(hole in the ear drum)

• hypermobility/stiffness

Middle ear function

• Transfers acoustical energy( sound pressure fluctuations) into mechanical energy (vibrations) that are sent to the inner ear

• air-tissue/bones-fluid

• Impedance-resistance 

• acts as an impedance matcher 

• Two mechanisms to overcome the impedance mismatch

• The area ratio pressure transformer

• The ossicular lever

Area ratio pressure transformer

• Most effective mechanism of the middle ear: area ratio pressure transformer

• pressure-force/area

• Tympanic membrane pressure-force/56mm2

• Oval window pressure-force/3.2mm2

Ossicular lever

• The length of the malleus is greater than the length of the incus

• This creates and anatomical lever

• This increases the pressure by about 3dB

Outer ear-

• funnel sound in

• localize sounds in space

• projects objects from getting in

Middle ear

• convert air pressure eaves to mechanical waves

• Protection from loud sounds

• Pressure equalization

Inner ears

• is located within the temporal bone

• Within the labyrinth are three major structures

• The cochlea is the hearing part of this It contains the organ of corti(hearing organ)

• The other parts the semicircular canals and the vestibule are the balance parts of this

The cochlea

• The bony labyrinth of this coils to form a spiral tunnel this is part of the inner ear  

  that looks like a snail shell

modiolus

• is the bony central core of the cochlea

spiral lamina

• is a bony shelf that protrudes from the modiolus. It acts like a skeleton

•  for the membranous labyrinth to be built around

Organ of Corti

• is the actual sense organ for hearing-mechanical eaves get turned into 

  electrical impulses

• sits on top of the basilar membrane 

• Sits below and is connected to the tectorial membrane

• On the inside toward the modiolus is one row of inner hair cells (ICHs)out the outside, there are Three rows of outer hair cells

Hair cells

• Each hair cell has a small bundle on top of it called stereocilia(hair bundle)

• IHCs are assembled in a u shape

• OCHs are assembled in a v or w shape

basilar membrane

• is a thin membrane in the middle of the cochlea that divides scala vestibuli

  and scala tympani

• It vibrates like a ribbon

• is thin and stiff at the base (bottom) and thick and flaccid at the apex (top)

• This design is important for how it functions

Traveling wave

• The stapes connects to the cochlea at the oval window

• Below that on the cochlea is the round window-its a thin membrane that is flexible

Outer hair cells

• Three rows of about 13,000 OCHs

• They have motility meaning that they move

• Vibration causes the stereocilia to bend, which shortens the length of this

• main function amplify the vibration of the basilar membrane

• They do not send signals to the brain

Inner hair cells

• One row of about 3500 IHCs

• Vibration of the membrane (enhanced by the OCHs) causes the stereocilia of them to bend

• Once they bend, positive ions rush in

• This results in an action potential that gets fired to the auditory nerve

• The signal gets sent to the brain

• Main function: generate electrical signal that we process as sound

Vestibulocochlear nerve

• Has two components

• Vestibular portion (balance)

• Cochlear portion (hearing)

• Often referred to as auditory nerve

• Consists of many fibers that transmit signals to the brain

Afferent nerves

• carry information toward the brain

Efferent nerves

• carry signals away from the brain

Auditory pathway

• Sound follows them from the ear to the brain

• The auditory cortex is the primary region where sound is processed

• Located in the temporal lobe

Vestibular system

• Is the balance system

• Used in conjunction with the visual system ad somatosensory system

  gives us information about where our head is relative to the ground

• Also gives info about linear and rotational acceleration