Ch 7 Physiological Tests of the Auditory System Flashcards
Static Acoustic Compliance
A test that measures the mobility of the tympanic membrane in response to a given value of air pressure in the external ear canal
Acoustic Immittance Measurements
1) Static Acoustic Compliance
2) Tympanometry
3) Acoustic Reflex
Tympanometry Measurement
A measurement of middle ear pressure, determined by the mobility of the membrane as a function of various amounts of positive and negative air pressure in the external ear canal
Acoustic Reflex
Contraction of the middle ear muscles in response to intense sounds, which has the effect of stiffening the middle ear system and decreasing its static acoustic compliance
Reactance
The combination of mass and stiffness
Tympanogram
A graph used to measure tympanic membrane movement during Tympanometry
Type A Tympanogram
Normal tympanogram
Type A^s Tympanogram
Similar to Type A, except compliance is lower due to stiffness of the tympanic membrane
Type A^d Tympanogram
Similar to Type A tympanogram, except compliance is much higher, indicating flaccidity of the tympanic membrane or separation of the chain of middle ear bones
Type B Tympanogram
This tympanogram flatlines for the most part due to a fluid-filled middle ear
Type C Tympanogram
Similar to Type A tympanogram, except that the peak compliance is at a lower pressure, indicating negative middle ear pressure
Acoustic reflex muscles
The tensor tympani muscle and the stapedius muscle
Reflex-activating stimulus (RAS)
The signal used t produce the acoustic reflex, which can be any kind of sound from a pure tone to a noise band
Acoustic Reflex Threshold (ART)
The lowest level at which an acoustic reflex can be obtained
Acoustic Reflex Decay
When the stapedius muscle gradually relaxes after the acoustic reflex has been triggered
Otoacoustic Emissions (OAE)
When the hair cells in the cochlea vibrate producing a small sound that can be used to detect whether the cochlea works or not
Spontaneous Otoacoustic Emissions (SOAEs)
When a normal cochlea produces sound in the absence of external stimulation
Evoked Otoacoustic Emissions (EOAEs)
When the cochlea produces sound either during or immediately following acoustic stimulation
Transient-Evoked Otoacoustic Emissions (TEOAEs)
Produced by brief acoustic stimuli, such as clicks or tone pips. This is used to test the cochlea and determine if there is a hearing loss or not. A abnormal response reveals damage to any part of the hearing system up to the cochlea, but not past it. A normal response reveals that the cochlea is functioning, but does not diagnose the hearing issue.
Electrocochleography (ECoG)
The measurement of electrical responses in the brain (Auditory Evoked Potentials (AEP)) using electrodes attached to the scalp.
Auditory Evoked Potentials (AEP)
The electrical responses in the brain from sound that are measured during an electrocochleography.
Latency
The time period that elapses between the introduction of a stimulus and the occurrence of the response
Amplitude
The strength or magnitude of the AEP
Auditory Brainstem Response (ABR)
AEPs that occur within 10-15 milliseconds after the introduction of a signal that are believed to originate in the VIIIth cranial nerve and the brain stem
Auditory Middle Latency Response (AMLR)
An AEP occurring from 15-60 milliseconds in latency
Auditory Late Response (ALR)
AEPs that occurs between 50-200 milliseconds
Auditory Event Related Potentials (ERP)
AEPs that occur between 220-600 milliseconds
Recruitment
When a person cannot hear below a certain intensity, but can hear perfectly fine over that intensity. For example, a person may not be able to hear from 60 dB and below, but once 60 dB is reached, they hear that sound at that specific intensity. Hearing aids are not a good option for these patients.
Decruitment
When intensity of sounds cannot be differentiated
Tone Decay
When a tone that is heard, even at 5 dB above threshold, the sound dies away quickly
