Juliet Reyes-
What are the first steps in communication?
•Someone wants to speak and verbally express information in an oral format.
•A listener picks up the acoustic information provided by the talker.
•The listener takes that information and transfers it to a neural signal, which is processed by their brain.
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For accurate decoding of the message, two important factors come into play:
1) effective language use by the speaker: proper grammar, vocabulary, and sentence structure
2) speech detection capability by the listener: ability to detect and perceive speech sounds. They should have intact auditory perception and processing.
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What is the common denominator in communication process from a speech or audiology standpoint?
sound
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What is the speech standpoint?
For a message to be discriminated and understood, the language used by the speaker needs to be comprehensible to the listener. They need to use the same language, grammar, syntax, and shared vocabulary.
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What is the audiology standpoint?
Even if the language used by the speaker and listener is the same, a hearing impaired person can impede the listener's ability to understand the message.
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It is crucial for equipment used by audiologists to meet the standards of who?
American National Standards Institute (ANSI)
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What is ANSI?
private, nonprofit organization that develops and accredits standards across various industries. They calibrate the equipment to ensure accurate measurements and consistent results.
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What is sound?
Sound is energy that is transmitted through pressure waves that are a byproduct of force applied to sound.
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How is sound represented and analyzed as?
waveform and spectrograms
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What axis is amplitude on?
vertical axis
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What axis is time on?
horizontal axis
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The waveforms and spectrograms show what?
frequency, time, intensity
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What is intensity?
physical measurement of sound energy and it is objective.
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How is sound measured?
in decibels (dB). It is a logarithmic scale.
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Does 0db mean no sound?
No. It represents the reference level or threshold of human hearing.
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What is loudness?
the subjective perception of sound intensity by an individual
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What do audiologists look for when completing audiograms?
frequency or pitch
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What is frequency?
The objective measurement predetermined according to the audiometer dial
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What is pitch?
the psychological correlate to frequency. It is subjective of how high or low a sound is. It is affected by the individual's sensation, intensity, and patient's annoyance to the sound.
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250 Hz frequency is associated with which sounds?
vowels, /m/, /n/
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500 Hz frequency is associated with which sounds?
/l/, /r/, /w/, /j/
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100 Hz frequency is associated with which sounds?
/sh/, /f/, /th/
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What is the common thread between the sender of the spoken message and the intended receiver?
the speech signal
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Which components of the ear help with detecting speech signals?
the outer ear, the middle ear, the inner ear
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What are the two main structures of the outer ear?
the pinna and the ear canal (EAM)
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What is the pinna?
the visible, external part of the outer ear.
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What is the ear canal (EAM)?
tube-like structure that extends from the opening of the outer ear to the eardrum (TM)
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Why should you not put cotton swabs in your ear?
1) Risk perforating the eardrum (TM)
2) Wax prevents bugs from entering the canal
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What role does the outer ear play?
sound detection
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What is the resonant frequency of the ear canal?
2500 Hz
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What is the resonant frequency of the concha?
5000 Hz
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sounds at the frequency of the canal and concha are...
enhanced by the structures
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Resonant frequencies can be influenced by
the direction from which the sound is coming
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What is the head shadow effect?
sounds coming from one side of the head are partially blocked by the head itself, resulting in difference of sound intensity between the two ears
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What is the role of the pinna?
finding the sound
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How does placing a hand in a cup position over the pinna help?
it helps them determine if the sound is in front or behind them
it can also aid in detecting the angle of origin in reference to the ear
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What are the two portions of the EAM?
cartilaginous portion, which is a continuation of the pinna
the bony part which leads to the skull
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What is the role of the EAM?
direct sound towards the eardrum and protection of the ear drum
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What is the shape of the EAM?
S shape to protect against sand, bugs, etc.
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What does the EAM help maintain?
a controlled temperature within the ear. It is an effective tool for identifying illness.
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What does the ear canal produce?
wax
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What is the function of the ear canal?
repels foreign bodies
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Why is the tympanic membrane important?
It is part of the chain of sound transmission
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What does the TM look like?
thin, semitransparent membrane
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How many layers is the TM composed of?
three layers
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The TM vibrates in response to
sound pressure
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What is an otoscopy?
helps examine the ear canal and ear drum. The cone of light is light that can be seen on the eardrum's surface.
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Where are the ossicles?
In the middle ear
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What are the three bones of the middle ear?
malleus, incus, stapes
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What is the malleus?
attached to the eardrum and it vibrates in response to sound waves then transfers sound to the incus and stapes
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What is the middle ear space typically filled with?
air
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In young children, the middle ear space can be filled with?
fluid
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The Eustachian tube is normally...
closed
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When does the Eustachian tube open?
to chew, yawn, or swallow or to maintain pressure on either side of TM
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When pressure is not equal on either side, you can feel...
stuffy
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if stuffiness builds up to a fluid filled space, it can..
rupture the eardrum and alter the perception of sound
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What are the two main parts of the inner ear?
the bony labyrinth and the membranous labyrinth
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what does the perilymph do?
keeps the membranous labyrinth from bumping into the bony labyrinth
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What is endolymph?
it is within the membranous labyrinth
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What are the three sections of the labyrinth?
semicircular canals, vestibule, cochlea
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What are the semicircular canals?
they are involved in balance
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What are the three orientations of the semicircular canals?
superior, lateral, and posterior
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What is the cochlea?
the sensory organ of hearing
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What is the shape of the cochlea?
snail-shape
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What are the three chambers of the cochlea?
scala vestibuli, scala media and scala tympani
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The cochlea is home to?
the round and oval windows
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How is the cochlea organized?
tonotopically, which means that some regions are sensitive to different frequencies of sound. low frequencies on the inside and high frequencies on the outside.
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What is the chain of sound?
Sound enters the ear canal, then reaches the tympanic membrane. The sound waves cause the TM to vibrate which causes the ossicular movement of the incus, malleus, and stapes. The stapes bone hits the oval window, which is connected to the cochlea. Inside the cochlea is the organ of corti which has hair cells which turn the vibration of sound into electrical impulses. The electrical impulses are sent to the brain to be discriminated.
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What is the passage of air conduction?
1) sound waves enter the pinna
2) They travel down the ear canal
3) They reach the tympanic membrane/ ear drum
4) They reach the ossicles and vibrate
5) They reach the cochlea
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What is the purpose of the bone conduction pathway?
- it bypasses the outer and middle ear and sends sounds directly to the outer ear
- it does not go through the ear canal or vibrate the TM
- it directly stimulates the cochlea
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If someone has middle ear fluid, they can hear by
directly stimulating the temporal bone
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If someone has noise exposure, the cochlea is damaged so
hearing through bone conduction would be affected
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What is the peripheral hearing system?
anatomical structures involved in the transmission of sounds from the outer ear to the cochlea. Outer, middle, inner ear.
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When an individual has difficulty discriminating or understanding sounds despite normal peripheral hearing, it suggests the possibility of
a central auditory processing deficit
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a disruption along the pathway of the auditory nerve or a lesion in the auditory cortex can indicate a
central hearing loss
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What is a central hearing loss?
the sound is being transmitted through the outer and middle ears effectively, but once it leaves the cochlea, the message gets disrupted
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Why is central hearing loss difficult to diagnose?
a variety of tests need to be completed
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Why are people with central hearing loss difficult to fit with hearing aids?
Hearing aids primarily amplify sound and enhance the audibility of speech and environmental sounds. However, individuals with central hearing loss may have challenges in processing and interpreting the amplified sounds effectively.
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What is a peripheral hearing impairment?
•These are individuals who have something structurally wrong.
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What are examples of a peripheral hearing impairment?
•Cracked temporal bone
•Stapes fixation – stuck in place, no vibration
•Ossicular discontinuity – one bone isn’t working
•Hair cells – died off
•Wax
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What are the levels of peripheral hearing impairment?
conductive, sensorineural, mixed
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What is conductive hearing loss??
when there is an issue with the middle ear
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Examples of conductive hearing loss
•Fluid
•Wax
•Foreign body
•Perforation
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Are conductive hearing losses treatable?
yes they are often treatable
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What is a sensorineural hearing loss?
a type of hearing loss that occurs due to problems in the cochlea, the neural pathways, or the sensory systems within the auditory system.
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Sensorineural hearing loss involves sensory receptors (hair cells) in
the cochlea, or the neural pathway from the cochlea to the auditory cortex, or a combination of both.
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Is sensorineural hearing loss curable?
no it is typically untreatable and therefore permanent
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for snhl, If the pathology is cochlear in origin,
the damage typically begins with the sensory receptors within the cochlea, which are the hair cells
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for snhl, what happens inside the organ of Corti?
•the hair cells (many many hair cells) are destroyed
•This is the first step- eventually, the destruction will continue along afferent nerve fibers, eventually rising up the pathway of the auditory system
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Can you see damage with SNHL?
no If the damage went from the organ of Corti, up the ascending pathways towards the auditory cortex, these individuals now have RETROCOCHLEAR pathology
•BEYOND the cochlea
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People with retrocochlear pathology with more damage than inside the cochlea will complain about:
•Dizziness
•Tinnitus
•Gait issues
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what 3 cranial nerves are important to hearing?
VIII Auditory
IX Glossopharyngeal
XII Hypoglossal
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What are the roles of the auditory nerve?
1) carrying auditory information from the cochlea to the auditory cortex for sound discrimination and understanding.
2) transmitting information related to balance and equilibrium from the vestibular system to the brain
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What other testing would need to be performed to determine if the pathology extends beyond the cochlea?
•VNG – balance test
•MRI
ABR - Auditory Brainstem Response
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High-frequency loss in the cochlea means
basal damage (outside of the cochlea)
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Low-frequency loss in the cochlea means
•apex damage (the inner portion of the cochlea)
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Individuals with a hearing loss restricted (for the time being) to the cochlea may also experience
an abnormal sense of loudness growth and altered production of speech sounds
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what is conductive hearing loss?
there is a problem in the transmission of sound through the outer and/or middle ear. In this case, the cochlea itself is functioning normally, but the sound waves are not reaching it effectively.
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What factors contribute to conductive hearing loss?
•Infection
•Wax
•Perforation of TM
- Ossiculardysfunction
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What is a mixed hearing loss?
a combination of both conductive and sensorineural hearing loss. It means that there is damage or dysfunction in both the middle ear and the inner ear (cochlea) or auditory nerve pathway.
