Hearing - Diagnostic Audiology Flashcards
(20 cards)
Assessment protocol
Case history
Otoscopy
Physiological measures
Behavioural measures
Functional auditory assessments
Developmental screenings
Otoscopy
Visualises the pinna, ear canal and TM. Ensures there is no contraindications of inserting probe into ear.
Otoscopies can identify:
Discharge
Swollen ear canal
Wax blockage
Foreign body
Physiological measures
Evoked responses (Auditory brainstem response, ABR)
Otoacoustic emissions (OAEs)
Immitance audiometry
ABRs
Measures brain activity in response to sound. Provides an estimate of hearing in each ear. Need to test with both air/bone conduction.
OAEs
Low intensity sounds originating from OHCs of healthy cochlea.
OAEs present indicates
Mild HL, ANSD, or normal hearing.
OAEs absent indicates
Fluid in middle ear or SNHL.
Limitations of OAEs include
Middle ear status
Noise in room
Patient noise
Debris in ear canal
Immitance audiometry
Provides information on integrity of middle ear system. Uses high frequencies to elicit middle ear muscle reflex and acoustic reflex.
Tympanometry
Measures compliance of middle ear when air pressure changes.
Tympanometry measures:
Statistic compliance - how much ear drum is moving.
ECV volume - whether volume is normal, small (indicates blockage) or large (indicates perforation).
Middle ear pressure - pressure in ME should be roughly equal to outside ear pressure (0).
Acoustic reflex threshold (ART)
Lowest possible intensity needed to elicit middle ear muscle contraction.
Measuring acoustic reflex helps to:
Differentiate between middle ear and cochlea vs auditory nerve problems.
Middle ear problem - absent or elevated acoustic reflex.
Auditory nerve pathology - elevated or absent ARTs which do not align with HL.
Pure tone audiometry
Hearing test that uses pure tones at different frequencies.
Audiogram symbol - AC
Unmasked = circle (r) and x (l)
Masked = triangle (r) and square (l)
Audiogram symbol - BC
Unmasked = < (r) and > (l)
Masked = [ (r) and ] (l)
Audiogram - no response
Circle w/ arrow (r)
Cross w/ arrow (l)
Reading an audiogram
-10 - 20 = normal hearing
20+ = HL
Air-bone gap = conductive or mixed.
No AB gap = sensorinerual
IF AB gap, BC status = normal is conductive, abnormal is mixed.
Behavioural Observation Audiometry (BOA)
Can be used from 5-6 mo.
Looks at reflexive behaviours in response to sound.
Has high variability/range of acceptable responses.
