Chapter 6: Physiological Tests of the Auditory System

Question 1

Immittance

Answer 1

term to describe the measurements made of the tympanic membrane impedance, compliance, or admittance

Question 2

Acoustic Immittance

Answer 2

Can indirectly determine middle ear function based on tympanic membrane measurements

Question 3

Measurements of Acoustic Immittance Meters

Answer 3

Static acoustic compliance, tympanometry, acoustic reflex

Question 4

Contributors to Impedance

Answer 4

The impedance of any object is determined by its frictional resistance, mass, and stiffness

Question 5

Resistance in the ear

Answer 5

determined primarily by the ligaments that support the three bones in the middle-ear cavity

Question 6

Mass in the ear

Answer 6

determined primarily by the weight of these three bones and the weight of the tympanic membrane

Question 7

Stiffness in the ear

Answer 7

determined primarily by the load of fluid pressure from the inner ear on the base of the stapes, the most medial bone of the middle ear

Question 8

Equipment

Answer 8

-Three rubber tubes attached to a metal ear probe
-Miniature loud-speaker: emits a pure tone (typically at 220 or 226 Hertz)
-Tiny microphone: picks up the sound in the external ear canal
-Air pump: creates either positive or negative air pressure within the canal
-A plastic or rubber cuff of an appropriate size is placed around the probe to attain an hermetic (air tight) seal

Question 9

Static Acoustic Compliance

Answer 9

Compliance is comprised of two automatic measures that can tell the equivalent volume of the external ear canal and the mobility (compliance) of the tympanic membrane (T M).

Question 10

Measure 1 of SAC

Answer 10

The immittance meter takes a first reading c1 with the TM mobility decreased due to the positive pressure (+200 daPa) introduced into the ear canal

Question 11

Measure 2 of SAC

Answer 11

The second measure (determination of c2) is attained when the pressure in the external ear canal is decreased until the T M achieves maximum compliance (equal pressure on both sides)

Question 12

High c1 readings in SAC

Answer 12

Indicative of a TM perforation or presence of a patent (open) ventilation tube.

Question 13

What does c1 represent

Answer 13

compliance of the middle ear and reflects the equivalent volume of the external ear canal in cubic centimeters

Question 14

What does C2 represent in SAC

Answer 14

The compliance of the outer ear and middle ear combined

Question 15

What does cx represent in SAC

Answer 15

Middle ear compliance

Question 16

Very low middle ear compliance

Answer 16

suggests a change in the stiffness, mass, or resistance of the middle ear system as may be seen with fluid accumulation in the middle-ear space

Question 17

Very high middle ear compliance

Answer 17

suggests abnormal elasticity of the TM or a disruption in the normal connections of the middle-ear bones

Question 18

Tympanometry

Answer 18

Measurement of middle-ear pressure, determined by the mobility (compliance) of the T M as a function of various amounts of positive and negative air pressure in the external ear canal

Question 19

Type A Tympanogram

Answer 19

normal middle-ear function
Peak pressure near 0 daPa

Question 20

Type As Tympanogram

Answer 20

Shallow peak compliance, but normal middle ear pressure
Characteristic of stiffness of the middle-ear system

Question 21

Type Ad Tympanogram

Answer 21

High amplitude of curve
Normal peak pressure
Potential separation of middle-ear bones or tympanic membrane flaccidity

Question 22

Type B Tympanogram

Answer 22

No peak pressure or compliance reading
Tympanogram looks flat
Potential fluid in middle ear space, ear wax occlusion, or hole in the TM

Question 23

Type C Tympanogram

Answer 23

Peak pressure below negative 200 daPa
Reflection of negative pressure in the middle-ear cavity

Question 24

Acoustic Reflex

Answer 24

-Stapedius muscle contracts reflexively and bilaterally in response to an intense sound presented to either ear
-Causes tympanic membrane to stiffen and decrease in compliance

Question 25

Acoustic Reflex Threshold

Answer 25

the lowest level at which an acoustic reflex can be obtained

Question 26

Acoustic reflex threshold for normal hearing

Answer 26

bilateral reflexes 85-100dB

Question 27

Acoustic Reflex Decay

Answer 27

-A test to see how well the muscles hold on to the contraction produced by the loud stimulus -Positive decay is bad

Question 28

Ipsilateral

Answer 28

Same side

Question 29

Contralateral

Answer 29

opposite side

Question 30

Otoacoustic Emissions (OAEs)

Answer 30

The normal cochlea’s production of a sound response immediately following stimulation. Reflect activity of the outer hair cells

Question 31

Spontaneous Otoacoustic Emissions (SOAEs)

Answer 31

Occur when a cochlea produces sounds in the absence of external stimulation Occur in over half of the population of normal hearing individuals

Question 32

Transient Evoked Otoacoustic Emissions (TEAOEs)

Answer 32

-More of a screening approach. -Broadband clicks -Present in individuals with hearing thresholds less than 40 dB

Question 33

Distortion-Product Otoacoustic Emissions (DPOAEs)

Answer 33

-Favored approach because it is more frequency specific. -More diagnostic in it's approach. -Tone -Present in individuals with hearing thresholds less than 40 dB to 50dB

Question 34

What does the presence of an EOAE suggest

Answer 34

-very little or no conductive hearing loss caused by middle ear abnormality -the responding frequency regions of the cochlea are normal or exhibit no more than mild hearing loss

Question 35

EOAE present in sensory/neural hearing loss suggests

Answer 35

outer hair cell function is intact and the locus of the disorder is known to be retrocochlear

Question 36

Absent EOAEs in sensory/neural hearing loss suggests

Answer 36

Confirm cochlear pathology but do not rule out the possibility of concomitant retrocochlear involvement.

Question 37

Auditory Evoked Potentials (AEPs)

Answer 37

analyze the electric activity of the brain when stimulated by acoustic stimuli

Question 38

AEP Tests

Answer 38

ECoG: Electrocochleography ABR: Auditory brain-stem response AMLR: Auditory middle latency response ALR: Auditory late response

Question 39

Electrocochleography (ECoG)

Answer 39

The procedure of measuring electrical responses from the cochlea of the inner ear

Question 40

Auditory Brain Stem Response (ABR)

Answer 40

-The procedure of analyzing the integrity of the auditory brain-stem pathway using broadband clicks, tone pips, or bursts -Analyze wave V (5). Sound is heard if wave five is present.

Question 41

Auditory Steady State Response (ASSR)

Answer 41

-AEP used for threshold determination for children. -Evokes a steady state neural response

Question 42

Auditory Middle Latency Response (AMLR)

Answer 42

-Assesses middle latency responses, which occur between 15 and 60 milliseconds after signal presentation

Question 43

Auditory Late Responses (ALRs)

Answer 43

-Assesses the late cortical auditory-evoked potential, which includes responses that appear at least 60 milliseconds after signal presentation