Lecture 1 Flashcards
Identification vs Diagnosis
-Identification: identifying that there is a problem (e.g., hearing loss, vestibular problem, problems hearing at school)
-Diagnosis: determining the nature of the condition (based on assessment). This may or may not include etiology (underlying cause of the condition)
·E.g., a moderate sloping to severe sensorineural hearing loss bilaterally
T/F: audiologists can diagnose hearing loss
TRUE (though you can’t diagnose in Ontario)
What does the Y axis represent in audiometry?
-dB HL (air and bone)
-Loudness contours and growth
-Intensity discrimination
What does the X axis represent in audiometry?
-Frequency
-Place specificity
-The basalward shift
What does the Z axis represent in audiometry?
-Time
-Temporal integration
What is the purpose of the audiogram?
-Provides information about likely communication problems
-Critical for audiologic treatment
What are some limits of audiometry? (4)
-Poor for distinguishing sensory versus neural loss
-May miss significant loss of hair cells
-Does not assess temporal processing
-It is the beginning of assessment, not the end
What is behavioural audiometry?
-Functional characterization of clinically relevant psychoacoustic details
-Goal is not description of ability, but description of different ability
Do outer ear effects play an important role in diagnostics?
Yes, we get a big enhancement from our concha, pinna and ear canal at around 2-5 kHz with minimal audible field (MAF)
T/F: shape of hearing reflects ME and OE
TRUE
T/F: the natural shape of the absolute threshold curve (i.e., the MAP) is important for diagnostics
FALSE: the natural shape is NOT relevant for diagnostic purposes
What is dB HL?
-dB HL is a flattened version of the MAP
-dB HL = dB SPL - RETSPL (reference equivalent threshold sound pressure level)
What are RETSPLs?
-Levels in dB SPL that correspond to 0 dB HL, as measured at a calibration point
·Inserts: 2cc coupler
·TDH: 6cc coupler
·Speakers: microphone in centre of head
T/F: hearing loss looks worse (higher thresholds) when you have smaller ears
FALSE: smaller ear canals lead to greater pressure reaching your eardrum, resulting in better thresholds
What is the leak problem with inserts?
Drop in hearing in the lower frequencies because the foam inserts aren’t in tight enough
With a perforation, does that impact thresholds more when using inserts or sound field?
Inserts, because the increase in pressure will cause a greater effect than in the real world (sound field)
What are the 5 mechanisms of bone conduction?
-Sound radiating into the external ear canal
·Occlusion effect when ears are plugged
-Middle ear ossicle inertia
-Inertia of the cochlear fluids
·Most important source
-Compression of the cochlear walls
-Pressure transmission from the cerebrospinal fluid
T/F: BC thresholds can be worse than AC thresholds
TRUE: really small ear canals could cause AC to be better than BC and really large ear canals could cause an air-bone gap without any conductive loss
Where does loudness grow most quickly on the equal loudness contours?
Low frequencies
Loudness ___ with a 10 dB increase (Stevens)
Doubles
According to RM Warren, doubling loudness corresponds to ___ dB
6
What is loudness recruitment?
-With cochlear hearing loss, loudness tends to grow more quickly
-When one ear is normal, recruitment can be detected with the alternate binaural loudness balance (ABLB) test
What is the SISI (short-increment sensitivity index)?
-Count the number of 1 dB changes identified (out of 20) at 20 dB SL
-If you can hear them, recruitment is diagnosed
T/F: Weber’s law does not hold for pure tones
TRUE: level discrimination improves at high levels
What is the problem with SISI?
-The SISI test always diagnoses recruitment because loudness discrimination is naturally better at high levels (the “near miss to Weber’s law”)
-It has NO clinical value for diagnosing recruitment
What causes recruitment in hearing loss?
Inability to hear soft sounds is a function of loss of mechanical amplification (OHCs) for soft sounds
T/F: place specificity is poor at low levels
FALSE: it’s poor at high levels
The primary determinants of hearing sensitivity are ____
Peripheral (structure of middle ear, basilar membrane, etc)
Thresholds are stable as long as tones are longer than ___ second
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