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.
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.
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.
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.
It is crucial for equipment used by audiologists to meet the standards of who?
American National Standards Institute (ANSI)
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.
What is sound?
Sound is energy that is transmitted through pressure waves that are a byproduct of force applied to sound.
How is sound represented and analyzed as?
waveform and spectrograms
What axis is amplitude on?
vertical axis
What axis is time on?
horizontal axis
The waveforms and spectrograms show what?
frequency, time, intensity
What is intensity?
physical measurement of sound energy and it is objective.
How is sound measured?
in decibels (dB). It is a logarithmic scale.
Does 0db mean no sound?
No. It represents the reference level or threshold of human hearing.
What is loudness?
the subjective perception of sound intensity by an individual
What do audiologists look for when completing audiograms?
frequency or pitch
What is frequency?
The objective measurement predetermined according to the audiometer dial
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.
250 Hz frequency is associated with which sounds?
vowels, /m/, /n/
500 Hz frequency is associated with which sounds?
/l/, /r/, /w/, /j/
100 Hz frequency is associated with which sounds?
/sh/, /f/, /th/
What is the common thread between the sender of the spoken message and the intended receiver?
the speech signal
What are the two parts of the outer ear?
1. Pinna (auricle)
2. Ear canal (external auditory meatus)
What is the pinna?
the visible, external part of the outer ear.
What is the ear canal (EAM)?
tube-like structure that extends from the opening of the outer ear to the eardrum (TM)
Why should you not put cotton swabs in your ear?
1) Risk perforating the eardrum (TM)
2) Wax prevents bugs from entering the canal
What role does the outer ear play?
sound detection
What is the resonant frequency of the ear canal?
2500 Hz
What is the resonant frequency of the concha?
5000 Hz
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
What is the role of the pinna?
finding the sound
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
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
What is the role of the EAM?
direct sound towards the eardrum and protection of the ear drum
What is the shape of the EAM?
S shape to protect against sand, bugs, etc.
What does the EAM help maintain?
a controlled temperature within the ear. It is an effective tool for identifying illness.
What does the ear canal produce?
wax
What are the parts of the middle ear?
1. tympanic membrane
2. ossicles
3. Eustachian tube
Why is the tympanic membrane important?
It is part of the chain of sound transmission
What does the TM look like?
thin, semitransparent membrane
How many layers is the TM composed of?
three layers
The TM vibrates in response to
sound pressure
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.
What are the three bones of the middle ear?
malleus, incus, stapes
What is the malleus?
attached to the eardrum and it vibrates in response to sound waves then transfers sound to the incus and stapes
The Eustachian tube is normally...
closed
When does the Eustachian tube open?
to chew, yawn, or swallow or to maintain pressure on either side of TM
What are the parts of the inner ear?
1. cochlea
2. vestibular system
what does the perilymph do?
keeps the membranous labyrinth from bumping into the bony labyrinth
What is endolymph?
it is within the membranous labyrinth
What are the three sections of the labyrinth?
semicircular canals, vestibule, cochlea
What are the semicircular canals?
they are involved in balance
What are the three orientations of the semicircular canals?
superior, lateral, and posterior
What is the cochlea?
the sensory organ of hearing
What is the shape of the cochlea?
snail-shape
What are the three chambers of the cochlea?
scala vestibuli, scala media and scala tympani
The cochlea is home to?
the round and oval windows
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.
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.
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
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
If someone has middle ear fluid, they can hear by
directly stimulating the temporal bone
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.
When an individual has difficulty discriminating or understanding sounds despite normal peripheral hearing, it suggests the possibility of
a central auditory processing deficit
a disruption along the pathway of the auditory nerve or a lesion in the auditory cortex can indicate a
central hearing loss
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
Why is central hearing loss difficult to diagnose?
a variety of tests need to be completed
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.
What is a peripheral hearing impairment?
hearing loss or disorders that occur in the outer, middle, or inner ear.
What are the three types of peripheral hearing impairments?
1. conductive
2. sensorineural
3. mixed
What is conductive hearing loss?
Occurs when sound is unable to pass efficiently through the outer or middle ear due to blockages, malformations, or other conditions.
Examples of conductive hearing loss
•Fluid
•Wax
•Foreign body
•Perforation
Are conductive hearing losses treatable?
yes they are often treatable
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.
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.
Is sensorineural hearing loss curable?
no it is typically untreatable and therefore permanent
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
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
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
People with retrocochlear pathology with more damage than inside the cochlea will complain about:
•Dizziness
•Tinnitus
•Gait issues
what 3 cranial nerves are important to hearing?
VIII Auditory
IX Glossopharyngeal
XII Hypoglossal
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
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
High-frequency loss in the cochlea means
basal damage (outside of the cochlea)
Low-frequency loss in the cochlea means
apex damage (the inner portion of the cochlea)
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
What factors contribute to conductive hearing loss?
•Infection
•Wax
•Perforation of TM
- Ossiculardysfunction
How can you assess a conductive hearing loss?
Pure-tone audiometry: Evaluates hearing sensitivity by measuring the softest sounds a person can hear at different frequencies.
Tympanometry: Assesses the movement of the eardrum and measures middle ear pressure.
Otoscopy: Visual examination of the ear canal and eardrum to identify blockages or abnormalities.
How do you treat a conductive hearing loss?
Medical intervention: In cases of earwax blockage or middle ear infections, appropriate medical treatment (e.g., earwax removal, antibiotics) may resolve the conductive hearing loss.
Surgical options: Some conditions, such as a perforated eardrum or ossicular chain abnormalities, may require surgical intervention (e.g., tympanoplasty, ossiculoplasty) to restore hearing.
Hearing aids: For persistent or permanent conductive hearing loss, hearing aids can amplify sound and improve auditory perception.
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.
What happens if the cochlea was independently stimulated in a mixed hearing loss?
If the cochlea is independently stimulated, for example, through direct sound presentation, it may still yield better results compared to when sound has to pass through the compromised middle ear. This is because the cochlea itself may be functioning relatively better than the middle ear in this scenario.
How would you assess mixed hearing loss?
Comprehensive audiological evaluation: Includes pure-tone audiometry to measure hearing thresholds, speech audiometry to assess speech understanding, and other tests such as tympanometry, otoacoustic emissions, or auditory brainstem response to determine the type and degree of hearing loss.
How would you treat a mixed hearing loss?
Medical intervention: In cases of conductive hearing loss components (e.g., earwax blockage, middle ear infections), appropriate medical treatment (e.g., earwax removal, antibiotics) may be necessary.
Surgical options: Some cases may require surgical intervention (e.g., tympanoplasty, ossiculoplasty, cochlear implant) to address conductive or sensorineural components.
Hearing aids or assistive listening devices: Depending on the degree of hearing loss and individual needs, amplification devices can help improve hearing and communication.
What is prelingual hearing loss?
hearing loss occurred before the development of language, may have limited or no exposure to spoken language during critical periods of language acquisition.
what is post lingual hearing loss?
knows how words should sound before losing hearing
A child born with hearing loss has a more difficult time than a post-lingual adult who loses their hearing because
it could cause them to be behind in school or cause a social and emotional boundary
Hearing loss in the elderly can lead to
•Isolation
•Depression
•Frustration
For young and middle-aged adults, hearing loss can affect
employment, family, and finance
What are audiologists?
They specialize in the study of hearing and disorders of hearing
What is the role of audiologists?
They play a crucial role in the assessment, diagnosis, and intervention of various hearing-related conditions
•Promote healthy hearing, quality of life