SLHS 4801 Final Exam

tinnitus

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?

1. Assess middle ear function

2. Assess auditory pathway integrity

3. Evaluate for otitis media and other middle ear abnormalities

4. 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?

1. Peak admittance and pressure

2. Ear canal volume

3. Static admittance

4. 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’s?

-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’s not present?

when hearing loss is greater than 40-50 dB HL

what structure do OAE’s 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’s generated by?

OHC

What is the purpose of OAE’s?

-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’s?

1. Spontaneous

2. Transient evoked

   1. 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’s used clinically?

no

TEOAE’s (transient evoked otoacoustic emissions)

-measured in response to a transient (very brief) stimulus such as a click

why are TEOAE’s used clinically?

-imply hearing status because they are a measure of cochlear function (cochlear function is assumed for frequencies at which TEOAE’s are present with an amplitude of 3-6 dB above the noise floor)

what are the three TEOAE measurements?

1. Stimulus (such as a click)

2. Response waveform

   1. 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’s 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’s?

cochlear function is assumed for frequencies at which DPOAE’s are present with an amplitude of 6 dB above the noise floor

what is the same about TEOAE’s and DPOAE’s? Are they used clinically?

both imply hearing status because it is an assessment of cochlear function- yes both are used clinically.

How do OAE’s relate to potential hearing status?

-TEOAE’s and DPOAE’s 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’s 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’s are measured above the noise floor

auditory evoked potentials (AEP’s)

-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’s

-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