Tympanometry
What is a measurement in daPa and what does this tell us?
Pressure and pressure of middle ear space; This is where the TM has the most compliance/mobility
What is wave reproducibility?
This is the similarity between response waveforms A and B and helps determine if there is a response.
What happens when an acoustic reflex is elicited by a loud stimulus?
The stapedius muscle contracts stiffening the middle ear system to protect ourselves from overly loud sounds
What is threshold?
The lowest level a patient reliably responds to (detects or hears) presented stimuli
Define averaging in respect to AEPs?
Taking the amplified responses and finding the average response to filter out noise and poor runs
What is a measurement in mmHo and what does it tell us?
Admittance; The amount of mobility of the TM and how much acoustic energy can move through the system.
What is a response waveform?
The OAE that has been recorded in the ear canal from the cochlea
Define ipsilateral and contralateral (where are probes and stimulus presented)
Ipsilateral is when the probe and stimulus are in the same ear. Contralateral is when the probe and stimulus are in opposite ears.
What is air conduction testing?
The evaluation of the peripheral auditory system using pure tone stimuli through insert or supra-aural headphones.
Define and compare state and stimulus-dependent AEP recordings.
State-dependent recording is impacted by the test procedures (recording parameters and stimulus) and patient state i.e. in order to get a result the patient has to be asleep or has to be upright completing a task. Stimulus-dependent recording is impacted only by the stimulus (and recording parameters) used during the test i.e. if a patient is awake or asleep, standing or laying down a response can be recorded.
What does a Type B tympanogram say about middle ear function?
Abnormal middle ear function; Stiffened middle ear space, TM is not moving.
What is Response SNR?
This is the level of a response measured against the noise floor.
What does it mean when we have absent reflexes?
Abnormal middle ear function OR thresholds above 80dB HL OR abnormality/damage to anatomy within the pathway
What is bone conduction testing?
The evaluation of the peripheral auditory system (bypassing the outer and middle ear space) using pure tone stimuli through a bone vibrator.
Define latency-intensity function in respect to ABR.
As level decreases from a higher-level stimulus to a lower-level stimulus the latency of the waveform increases at a typical rate of 0.4ms per 10dB
What does a Type C tympanogram say about middle ear function?
There is negative middle ear pressure but the TM is moving normally
What is Band Reproducibility/SNR?
This is the wave reproducibility and the Response SNR for each frequency that is tested.
What does it mean when we have present reflexes?
Normal middle ear function, thresholds greater than 55dB HL; Functioning nerves and anatomy within the pathway
What is masking?
Masking is the presentation of noise in the non-test ear to account for crossover and confirm test ear thresholds/responses. By distracting the non-test ear stimuli presented to the test ear can no longer be perceived by the non-test ear.
What is a highly synchronous response?
A high-level click stimulus elicits this by exciting many neurons across frequencies simultaneously.
What does a Type A, As, and Ad tympanogram say about middle ear function?
Type A= Normal middle ear function with normal pressure and admittance. Type As= Stiff middle ear with reduced admittance and normal pressure. Type Ad= Hypercompliant/Hypermobile TM increased admittance and normal pressure.
What is the process of OAEs?
A probe emits a stimulus (clicks, tone bursts, or pure tones) it travels through the middle ear to the cochlea where it interacts with the OHCs on the basilar membrane where the OAE is emitted to the middle ear and travels through to the ear canal where it is read by the probe with high frequencies arriving first and low frequencies last as the basal end is closer to the middle ear than the apical end.
What does it mean when we have elevated reflexes?
Normal middle ear function. SNHL is between 55dB HL and 80dB HL. Anatomy within the pathway is functioning normally.
How is dB HL related to dB SPL?
dB HL is a normalized value of dB SPL using the minimum audible pressure curve; The minimum audible pressure curve is the average threshold in dB SPL at each frequency within our test range.
Define, compare, and list what tests are associated with higher regions of activity and lower regions of activity.
High regions involve cortical function, include millions of neurons, and responses are generated closer to the electrodes; MLR, ALR, P-300 Response. While lower regions involve nerve and brainstem function, have many fewer neurons, and are generated farther from the electrodes; ABR and Ecochg.