Studied by 7 peopleTags & Description
tinnitus
auditory perception not produced by an external stimulus
what is tinnitus commonly described as?
ringing, roaring, hissing or whooshing
Is tinnitus high pitch or low pitch?
it can range from high pitch to low pitch or even a noise like sound with no pitch type
objective tinnitus
tinnitus which can be heard by placing a stethoscope over the patient's ear
subjective tinnitus
patient perceives sound in the absence of objective sound source
is subjective or objective tinnitus more common?
subjective
what are three possible mechanisms that produce tinnitus?
-outer hair cell decoupling from the tectorial membrane
-hyperactivity of neural firing
-hypoactivity of neural firing
What are four ways tinnitus is characterized? (vary in, how often, arises, heard where)
-It can vary in pitch, loudness and tonal quality
-It may be constant, pulsed or intermittent
-it can arise slowly or suddenly
-it may be hear in the ears or the head
how does tinnitus affect someones life?
an individual can be annoyed by tinnitus
what is the structure that is the underlying cause of tinnitus?
cochlea
what is one underlying cause of tinnitus?
-aspirin
-noise exposure
-other factors
what are the two major systems involved in tinnitus?
-limbic system
-autonomic nervous system
how does the limbic system affect tinnitus?
involves motivation, mood and emotions and may result in mood swings and telling the brain that the sound is bad
how does the autonomic nervous system affect tinnitus?
it prepares the body for physical action (fight or flight) and tries to fix the sound or make it go away
what is habituation?
decreasing responsiveness with repeated stimulation
how does habituation relate to tinnitus?
when a patient is introduced to a neutral noise in gaps of silence, it allows for the patient to change their perception of tinnitus
consent
everyone has a right to know what procedures will be performed and what will be expected during the appointment
assumed consent
not a formal written consent, for certain non-invasive procedures such as when taking a case history
assent
children cannot provide legal consent but it is good to have their assent and to explain in simplified, age appropriate
what does PHI stand for?
protected health information
what is protected health information
information typically recorded in a health history, physical examination, test results and other health and hearing findings
what types of questions should be asked when taking a case history?
open ended questions
what are some other benefits that a case history provides?
helps you decide other assessment factors such as what ear to start with, masking, use of pulsed tones and the type of transducer you can use
what are the main components of a case history?
-identifying information
-previous evaluations
-medical history
-current challenges
-rehabilitation history
acoustic immittance
physiological measure to assess the function of the middle ear
impedance
total opposition to the flow of energy (how much the sound is being blocked)
admittance
ease that the sound flows through the system
The more admittance you have the ___ impedence?
less
what is the main purposes of an immittance test?
Assess middle ear function
Assess auditory pathway integrity
Evaluate for otitis media and other middle ear abnormalities
Verify open PE tubes
How is the immittance test performed?
An acoustic signal to the outer ear is sent and the sound energy is measured that remains in the outer ear to see how much passed to the middle ear
What equipment is used in an immittance test?
A loudspeaker to send the tone at 226 hz. Then the microphone picks up the SPL in the ear canal and the air pump can then change the pressure in the canal
what does tympanometry measure?
the change in middle ear admittance as ear canal pressure changes
what is the x-axis of the tympanogram?
units of air pressure daPa
what is the y axis of the tympanogram?
admittance or mmho
what are the four things we can find on a tympanogram?
Peak admittance and pressure
Ear canal volume
Static admittance
Window and gradient
Where is the peak admittance?
value at the peak
what is the static admittance?
the difference between the value at +200 daPa and the peak
what type of air pressure do you start with in a tympanometry?
positive air pressure- then the pressure pump changes pressure through ambient to negative pressure
admittance is greatest when pressure is at ___ pressure
at ambient pressure
what are the three possible shapes of the tympanogram?
peaked, rounded and flat
what is the normal range for static admittance?
0.3-1.5 mmho
normal ear canal volumes
Adults- 0.65-1.75
Children- 0.3-1.0
What does it mean if the ECV is large?
a perforation of the TM or open pressure equalization of PE tubes
what does it mean if the ECV is small?
there is a blockage
Type A
normal ranges for all (peak at ambient pressure, normal static admittance and normal ear canal volume)
What is type A associated with for ear functioning?
normal outer and middle ear function
Type Ad
Normal peak and ear canal volume but high static admittance
What is Ad associated with for the ear? What disorders?
abnormally increased middle ear mobility (admitting more than we are supposed to)
Ossicular disruption/discontinuity
Flaccid TM
Type As
Normal peak and ear canal volume but low static admittance
What is type As associated with in the ear? What disorders?
Consistent with reduced middle ear mobility (impeding more and admitting less)
Otosclerosis
Otitis media
Tympanosclerosis
Type B
No clear peak but a normal ear canal volume- shows that there is no point where the TM is mobile
Type B ear? Disorder?
no mobility with the TM
perforated TM, otitis media with effusion, clogged probe tip, foreign body
Type C
normal ear canal volume and can have normal static admittance but the peak is in negative pressure
Type C ear? Disorder?
abnormally negative or positive middle ear pressure
Emerging or resolving OME
Crying
what is the acoustic reflex?
the stapedius msucle contracts in response to loud sounds
When it contracts it pulls the TM and it becomes stiffened
what happens to the impedance and admittance for the acoustic reflexes?
the impedance increases and the admittance decreases (because not as much sound is allowed to go through)
what structures in the middle ear are involved with the acoustic reflex?
-stapedius muscle
-tensor-tympani muscle
why do we have an acoustic reflex?
-protection
-perception- reduce interference from unimportant sounds
Why does impedance increase in acoustic reflexes?
to reduce the sound going to the inner ear
what are the probe tone and stimulus tone responsible for?
probe- measures change in impedance or admittance
stimulus-elicits the reflex
what dB SL level do you start and end at for acoustic reflex testing?
start at 85 dB SL and end at 110 dB SL
what is the acoustic reflex threshold?
lowest intensity at which a change is detectable in the immittance of the middle ear system
what types of sound can ART be elicited to?
pure tones and noise
how does the set up for reflex testing work in relation to the tympanometry?
Same:
-probe assembly and tone of 226 Hz
-measure changes in the SPL in the canal
Different:
-air pressure is not varied
-measurement is made at the peak pressure point on the tymp
-use a stimulus tone in addition to a probe tone
how does peak pressure relate to acoustic reflex testing?
set it to 0 then present the sound
what is the normal range of levels for the acoustic reflex threshold in ears with no auditory dysfunction? Absent? Elevated?
normal- 80-85 dB SL
absent reflex- no reflex at 110-115 dB HL
elevated reflex- > 100 dB HL
acoustic reflex testing ipsilaterally
the probe tone and stimulus are in the same ear
acoustic reflex testing contralaterally
probe tone in one ear and stimulus tone in the other ear
acoustic reflex equipment
-stimulus
-probe
-air pressure pump
If contralateral reflexes are absent but ipsilateral reflexes are present, what are some possible explanations for the underlying pathology/site of lesion? Why?
Central brainstem problem because there is something that is affecting the ears when they are crossing over
otoacoustic emissions
sounds recorded in the ear canal that originate in the cochlea
what cellular structures are involved in generating OAE鈥檚?
-sounds are generated by the OHC
-OHC lengthen (hyperpolarization) and contract (depolarization)
-vibration of the OHC act as a cochlear amplifier
-still present when the auditory nerve is cut
when are OAE鈥檚 not present?
when hearing loss is greater than 40-50 dB HL
what structure do OAE鈥檚 come from?
the cochlea
what is motility?
prestin protein allows hair cells to lengthen and contract, it also is the movement of the hair cell
what are OAE鈥檚 generated by?
OHC
What is the purpose of OAE鈥檚?
-assess cochlear (OHC) function
-screening procedure
-predicting hearing status for difficult to test patients
-monitoring cochlear status during ototoxic drug administration
-distinguishing cochlear from retrocochlear hearing loss
what are the three types of OAE鈥檚?
Spontaneous
Transient evoked
Distortion product
SOAE (spontaneous OAE)
-sounds produced in the cochlea in the absence of any input
-found in 60-90% of normally hearing people
are SOAE鈥檚 used clinically?
no
TEOAE鈥檚 (transient evoked otoacoustic emissions)
-measured in response to a transient (very brief) stimulus such as a click
why are TEOAE鈥檚 used clinically?
-imply hearing status because they are a measure of cochlear function (cochlear function is assumed for frequencies at which TEOAE鈥檚 are present with an amplitude of 3-6 dB above the noise floor)
what are the three TEOAE measurements?
Stimulus (such as a click)
Response waveform
Response spectrum
Stimulus such as a click
-time is on the x axis and amplitude is on the y axis
-presented to the patient repeatedly
response waveform
-broadband waveform
-has high energy at many frequencies
-has a high amplitude
response spectrum
-compares the spectrum and level of the background noise to the spectrum and level of response from the patient鈥檚 cochlea
-amplitude of the response is much greater than the amplitude of the noise
DPOAE (distortion product OAE)
evoke these using 2 pure tones at a time because they interact in the cochlea. Once they interact it causes a traveling wave at the third frequency called a distortion product. The largest distortion product sends back an emission that can be measured in the ear canal
what is the clinical significance of DPOAE鈥檚?
cochlear function is assumed for frequencies at which DPOAE鈥檚 are present with an amplitude of 6 dB above the noise floor
what is the same about TEOAE鈥檚 and DPOAE鈥檚? Are they used clinically?
both imply hearing status because it is an assessment of cochlear function- yes both are used clinically.
How do OAE鈥檚 relate to potential hearing status?
-TEOAE鈥檚 and DPOAE鈥檚 are expected to be present from ears with normal middle ear function and pure tone less than or equal to 25 dB HL
-Not expected from ears with middle ear or cochlear hearing loss disorders greater than 35 dB HL
-may not be present when pure tone sensitivity is between 25 and 35 dB HL
when are TEOAE鈥檚 present (what dB)?
when the amplitude is 3-6 dB above the noise floor
when is DPOAE function assumed (what dB level)?
6 dB above noise floor
what does noise floor mean and why is it relevant?
-noise floor is all background noise and stuff that is not meant to be measured
-important because TEOAE and DPOAE鈥檚 are measured above the noise floor
auditory evoked potentials (AEP鈥檚)
-a physiologic response
-electrical activity we can measure on the surface of the head in response to sound
what are the three types of AEP鈥檚
-auditory brainstem response (ABR)
-middle latency response (MLR)
-long latency response (LLR)
what is the fastest AEP and most common AEP?
ABR
what is an ABR (auditory brainstem response)?
Electric potentials we measure on the scalp (electrodes/sensors on the skin)
Reflects early brain activity in response to short sounds (like clicks)
Used for hearing screenings and diagnosis when behavior is not possible as well as neurodiagnosis
what is latency? what is the latency for the ABR?
The ABR wave-V latency was defined as the time between stimulus onset in the ear canal and the wave-V peak.
What ABR wave do we use to determine threshold?
Wave V
Note
Flashcard