The Inner Ear Flashcards
The inner ear house structures for….
Hearing and Balance
What structures of the inner ear are important for hearing?
Cochlea & Auditory Nerve
What structures are important for balance?
Semicircular & Vestibular Portion of the 8th Nerve
To maintain balance, we rely on input from how many body systems?
Three
What are the body systems we rely input from to maintain balance?
- Visual
- Proprioceptive
- Vestibular
Define “visual” for the vestibular system
It provides vision, light, and help us adjust to our surroundings accordinly
Define “proprioceptive” for the vestibular system
It provides info from supporting structures such as our muscle/tendons
Define “vestibular” of for the vestibular system
It helps us maintain our balance by using gravity and inertia for info
The semi-circular canals provide…
Angular Acceleration
How does our semi-circular canals tell us when we’re turning?
From our otolith
How does the otolith work?
Since it’s organized in different planes, when it moves around the semi-circular canals, it gives stimulation to our brain to know when we’re turning
The utricle/saccule provides ….
Linear acceleration
How does the utricle/saccule work?
It does not involve turning but up/down and fwd/back
Where is the utricle/saccule located?
Between the portion of the semi-circular and cochlea
What are some things we should note about the Auditory Mechanism?
- As we transition from an air-filled space, we enter a fluid-filled cochlea
- Organ of corti is where the action occurs
- THREE rows of outer hair cell
- ONE row of inner hair cells
- Tectorial membrane is where the shearing movement of the stereocilia occurs
- Tonotopically Organized
For the Auditory system, where is the stereocilia located?
On the top of the 3 rows of outer hair cells and 1 row of inner hair cells
For the Auditory system, the tectorial membrane undergoes the shearing action when…
It touches the stereocilia which helps stimulate the shearing action
For the Auditory system, its tonotopically organized …
According to frequency
What does tonotopically organized mean?
Depending on the frequency, one part of the cochlea would respond
For our cochlea being tonotopically organized, how does it relate to the turns on the cochlea?
When we get to the first turn(base), the higher frequencies would respond and then it gets lower in frequencies and spirals down into the apex
What are the structures of the neurons?
Cell body, Axon, Dendrites
What’s the purpose of the neurons?
To carry information in one direction or the other
Afferent carries
Info from the brain to cochlea
Efferent carries
Info from the brain to the cochlea
The cochlea has _____ afferent neurons and ____ efferent neurons
30,000 and 1,800
For the vestibular portion of the inner ear, what are the disorders?
- Vestibular Dysfunction
2. Hearing Loss
What disorders falls under the vestibular dysfunction?
- Vertigo
2. Dizziness
Define vertigo
It’s true spinning. Where either you’re spinning, or the room is
Define Dizziness
Has a less concrete definition. It pertains to being off-balanced or light-headed
What type of hearing loss is associated w/Inner Ear Hearing loss?
SNHL
What SNHL mean?
That BC and AC are =
With a SNHL, what does the patient experience?
A loss of sensitivity and increase in distortion
Why would a patient w/a SNHL state “I can hear, I can’t understand?
They lose volume and clarity due to the broaden of the cochlea. When we a cochlear damage exist and send a 100Hz tone, we’re impacting the frequency response of the cochlea making it less specific and this adds more sounds is perceived as noise
What are prenatal causes of SNHL?
- Genetics
- Syndromes
- Rh factor incompatibility
- Hyperbilirubinemia
- Viruses
- Anoxia
Explain genetics being a factor for SNHL
Baby could be born with HL or can develop progressively due to the child getting the recessive gene
Explain Rh factor incompatibility
Is when there’s protein in the blood! The baby has a Rh factor but the mom doesn’t. So the mom’s immune system was to produce antibodies to protect against Rh factor and the baby’s RBC are damaged
What’s the function of RBC and how does it affect the baby?
RBC job is to transport oxygen to our body. Since the mom’s immune system produces antibodies to fight against Rh factor and RBC, this causes a decrease in oxygen being carried to our cochlea
What is hyperbilirubinemia?
When there’s too much production of bilirubin
How can hyperbilirubinemia become a problem for our ears?
Bilirubin can get deposited into the ears and if the child receives too much of it, they can receive gentamycin which can damage the inner ear
What is bilirubin a byproduct of?
Broken-down RBC
What are the types of virus that can occur prenatally?
- Rubelle
2. Cytomegalovirus (CMV)
How can rubella become a problem?
If it contacted during the first trimester, it could interrupt development of the cochlea by making it malformed and not have an organ of corti
What is anoxia?
It is oxygen deprivation that causes damage to the cochlea. If no oxygen gets to the cochlea, the hair cells can die off
What are some perinatal causes of SNHL?
- Anoxia
- Toxicity
- Prematurity
- Trauma
What are postnatal causes of SNHL?
- Meningitis
- Viral Infections (measles, mumps, chickenpox etc)
- Syphilis
- High Fever
What can meningitis cause and what does it impact?
Ossification of the cochlea after infection which impacts intervention for the pt getting a Cochlea Implant
For a pt w/meningitis, if treated early what intervention could they receive?
A cochlear implant since a cochlea implant puts electrodes into our cochlea to allow our ossicles to move
Which toxins could cause SNHL?
- Antibiotics
- Quinine
- Chemotherapy Agents
- Erectile Dysfunction Meds
- Hydrocodone
- Diuretics
What kind of antibiotics are considered systemic?
‘Mycins’ (gentamycin, neomycin etc)
What are the type categories of antibiotics?
- ‘Mycins’
2. Ototoxic/Vestibulotoxic
What is Ototoxic/Vestibulotoxic?
An antibiotic that could damage hair cells, utricle & saccule and other parts of the vestibular system
What is quinine and where else could it be found?
An anti-malaria drug and could be found in tonic water
How does chemotherapy cause SNHL?
Chemotherapy kills healthy cells which could damage hair cells
What does diuretics cause?
A temporary hearing loss due to the diuretics stopping the pumping of the hair cell because we’re upsetting the sodium potassium balance channels in the cochlea that makes this pumping possible
Which ototoxic meds cause High Frequency & Permanent HL?
- Antibiotics
- Quinine
- Chemotherapy Agents
- Erectile Dysfunction Meds
- Hydrocodone
Can Noise Induced Hearing Loss (NIHL) cause a significant HL
Yes
What are they two types of Noise Induced HL?
- Temporary Threshold Shift (TTS)
2. Permanent Threshold Shift (PTS)
What does noise interact with when it comes to factors and causing an increase in HL?
- Age
- Genetics
- Medication
Can NIHL be seen in more men than women and why?
Yes due to societal norms
What are some reasons why men experience a NIHL more than women?
- Occupation
- Recreation
- Men being less likely to wear ear protections
For NIHL, what would you find on the audiogram and what does it mean?
The “classic” 4kHz notch and that hearing is worse at 4kHz than any other frequency but we’ll see HL from 2-7kHz
Why would we see the 4kHz being the notch for those with NIHL?
For our ear canal, the resonance frequency is from 2-7kHz. 4kHz is the peak frequency and it’s the frequency that’s often over amplified. This portion of our cochlea is overworked so there’s more energy being pushed into the cochlea at 4kHz
Can NIHL be unilateral or bilateral?
Either or. It depends on how the exposure took place
What is OSHA
Occupational Safety and Health Adminsitration
What purpose does OSHA when it pertains to Audiology?
Federally mandates acceptable noise exposure levels in the workplace
What’s the # that’s acceptable for an 8-hr workday?
Eighty-five dBA
What does dBA mean?
It’s the weighting from the sound-level meter which mimics the human ear (gives a boost in the 2-7kHz)
For every increase in noise, what should occur?
For every increase in 5 dB, the time should be cut in half
What devices measures noise intensity?
Sound level meter/dosimeters
What is presbycusis?
It’s the aging of the auditory system
What is the typical compliant for those w/Presbycusis?
“Everyone mumbles
Which frequency does those w/Presbycusis have issues with hearing?
High frequencies, lower is better
Why are those w/Presbycusis state “Everyone mumbles?”
Because they have a HL in higher frequencies and constants in English language are made up of high frequencies. Consonants gives us clarity of speech. Since they still have residual hearing in the lower frequencies, they can easily hear the vowels since vowels are spoken in lower frequencies and only give us power of speech
What are OTHER causes of SNHL?
- Meniere’s Disease
- Sudden idiopathic SNHL
- Surgical complications
- Autoimmune Diseases
- Head trauma
What characteristics falls under Meniere’s disease?
- Fluctuates (comes, gets better, but never gets back to the first baseline)
- Typically, unilateral
- Low frequency SNHL
- Vertigo
- Roaring Tinnitus
What is Meniere’s disease?
It’s where the endolymphatic space in the cochlea gets bigger and it impacts the functioning of the inner ear
What are two of the most common complaints for SNHL?
- Tinnitus
2. Peripheral HL
What is tinnitus?
Perception of sound in the head without an external cause
Is tinnitus associated w/HL?
Yes. 70-80% of people with tinnitus have HL
Are there various descriptions of sounds?
Yes (hissing, buzzing, ringing etc)
What is the etiology of tinnitus?
Unknown hence why it’s hard to cure it
Even though the etiology is unknown, what are some probable causes?
- Noise-Induced
- Head/neck trauma
- Head/Neck illness
What the range of severity for tinnitus?
Ranges from tolerable - debilitating
For treatment for tinnitus, it’s a combination of
Physical and Psychological approaches
What are the physical and psychological approaches?
- Sound therapy
- Tinnitus retraining therapy
- Medications
- Psychotherapy
What is sound therapy for those w/tinnitus?
Making sure that they’re not in quite (ex: sound machines, white noises)
What is tinnitus retraining therapy those w/tinnitus?
Retraining patient’s reaction to tinnitus/teaching patients not to concentrate on sound
What purpose does medication holds for those w/tinnitus?
It doesn’t treat tinnitus but the reaction and condition that it might have brought on with it (sleep aid, anti-anxiety, or depression)
