auditory assess 200003
TRANSCRIPT
![Page 1: Auditory assess 200003](https://reader034.vdocuments.mx/reader034/viewer/2022042700/55636f7fd8b42a4f758b4897/html5/thumbnails/1.jpg)
PERIPHERAL AND CENTRAL AUDITORY ASSESSMENT
Ravi Pachigolla, MDJeffery T. Vrabec, MD
![Page 2: Auditory assess 200003](https://reader034.vdocuments.mx/reader034/viewer/2022042700/55636f7fd8b42a4f758b4897/html5/thumbnails/2.jpg)
Introduction
Pure tone audiometryTympanometryAcoustic reflex measurementsECochGAuditory Brainstem Response (ABR)Otoacoustic Emissions
![Page 3: Auditory assess 200003](https://reader034.vdocuments.mx/reader034/viewer/2022042700/55636f7fd8b42a4f758b4897/html5/thumbnails/3.jpg)
Pure Tone Audiometry
Most common test Threshold of audibility Activation of auditory
system Energy formatted into
neural code Air conduction assesses
entire system Bone conduction assesses
cochlea onwards
![Page 4: Auditory assess 200003](https://reader034.vdocuments.mx/reader034/viewer/2022042700/55636f7fd8b42a4f758b4897/html5/thumbnails/4.jpg)
Pure Tones
Auditory acuitySpectrally specificHigh frequency tones stimulate basal
turn of the cochleaLow frequency tones stimulate apical
turn of the cochlea
![Page 5: Auditory assess 200003](https://reader034.vdocuments.mx/reader034/viewer/2022042700/55636f7fd8b42a4f758b4897/html5/thumbnails/5.jpg)
Decibel Scales
Sound Pressure Level (SPL)
Hearing Level (HL)Sensation Level
(SL)
![Page 6: Auditory assess 200003](https://reader034.vdocuments.mx/reader034/viewer/2022042700/55636f7fd8b42a4f758b4897/html5/thumbnails/6.jpg)
Assessment of thresholds
Octave frequencies testedBone conduction thresholdsMastoid or forehead usedMastoid preferred because less
intensity requiredOcclusion effectAscending series of tone presentations
![Page 7: Auditory assess 200003](https://reader034.vdocuments.mx/reader034/viewer/2022042700/55636f7fd8b42a4f758b4897/html5/thumbnails/7.jpg)
Speech Audiometry
Speech Reception Threshold using spondaic words Standardized word lists Familiarization with spondees Ascending series of presentation Excellent speech discrimination in conductive hearing loss
patients Poor speech discrimination in cochlear hearing loss
patients Poorest speech discrimination in retrocochlear hearing loss
patients
![Page 8: Auditory assess 200003](https://reader034.vdocuments.mx/reader034/viewer/2022042700/55636f7fd8b42a4f758b4897/html5/thumbnails/8.jpg)
Clinical Masking
Nontest ear can influence thresholds of test ear
Shadow curve apparent without masking
Interaural attenuation varies from 40 to 80 dB with air conduction
Interaural attenuation is about 0 dB with bone conduction
![Page 9: Auditory assess 200003](https://reader034.vdocuments.mx/reader034/viewer/2022042700/55636f7fd8b42a4f758b4897/html5/thumbnails/9.jpg)
Shadow Curve
![Page 10: Auditory assess 200003](https://reader034.vdocuments.mx/reader034/viewer/2022042700/55636f7fd8b42a4f758b4897/html5/thumbnails/10.jpg)
Clinical Masking cont.
Compare bone conduction threshold of nontest ear with air conduction threshold of test ear to determine whether masking is necessary
![Page 11: Auditory assess 200003](https://reader034.vdocuments.mx/reader034/viewer/2022042700/55636f7fd8b42a4f758b4897/html5/thumbnails/11.jpg)
Masking using narrow bands of noise
![Page 12: Auditory assess 200003](https://reader034.vdocuments.mx/reader034/viewer/2022042700/55636f7fd8b42a4f758b4897/html5/thumbnails/12.jpg)
Plateau method
Mask nontest ear with progressively greater amounts of sound until threshold does not rise.
Masking Dilemma
![Page 13: Auditory assess 200003](https://reader034.vdocuments.mx/reader034/viewer/2022042700/55636f7fd8b42a4f758b4897/html5/thumbnails/13.jpg)
Acoustic Immitance
ImpedanceReflected energyTympanometryAcoustic Reflex
![Page 14: Auditory assess 200003](https://reader034.vdocuments.mx/reader034/viewer/2022042700/55636f7fd8b42a4f758b4897/html5/thumbnails/14.jpg)
Tympanometry configurations
![Page 15: Auditory assess 200003](https://reader034.vdocuments.mx/reader034/viewer/2022042700/55636f7fd8b42a4f758b4897/html5/thumbnails/15.jpg)
Acoustic Reflex Threshold
Stapedial muscle contraction
Temporary increase in middle impedance
Bilateral Stimulation Adaptation Neural network in lower
brainstem
![Page 16: Auditory assess 200003](https://reader034.vdocuments.mx/reader034/viewer/2022042700/55636f7fd8b42a4f758b4897/html5/thumbnails/16.jpg)
Clinical application of ASR
Middle Ear DiseaseOtosclerosisCochlear hearing loss and loudness
recruitmentRetrocochlear lesions may abolish the ASRBrainstem lesions may abolish the
contralateral reflexesDetermination of site of a seventh nerve lesionAcoustic Reflex Decay
![Page 17: Auditory assess 200003](https://reader034.vdocuments.mx/reader034/viewer/2022042700/55636f7fd8b42a4f758b4897/html5/thumbnails/17.jpg)
Electrocochleography
Cochlear MicrophonicSummating PotentialCompound Action PotentialIncreased SP/AP ratio suggests
hydropsAbility to enhance wave I of the ABR
in patients with severe high frequency hearing loss
![Page 18: Auditory assess 200003](https://reader034.vdocuments.mx/reader034/viewer/2022042700/55636f7fd8b42a4f758b4897/html5/thumbnails/18.jpg)
Electrocochleography setup
![Page 19: Auditory assess 200003](https://reader034.vdocuments.mx/reader034/viewer/2022042700/55636f7fd8b42a4f758b4897/html5/thumbnails/19.jpg)
ECochG and Meniere’s
Increased SP/AP ratio
Latency not important
Ratio greater than 0.45 suggests meniere’s
Hydrops affects elasticity of the basilar membrane
![Page 20: Auditory assess 200003](https://reader034.vdocuments.mx/reader034/viewer/2022042700/55636f7fd8b42a4f758b4897/html5/thumbnails/20.jpg)
Auditory Brainstem Response
Auditory evoked potentialFarfield recordingAcoustic clicks or tonal stimuli usedRate of stimulus presentation
![Page 21: Auditory assess 200003](https://reader034.vdocuments.mx/reader034/viewer/2022042700/55636f7fd8b42a4f758b4897/html5/thumbnails/21.jpg)
ABR continued
Waves I - V Unaffected by sleep and
pharmacotherapy ABR latencies decrease
from birth until 2 years Wave V used for threshold
testing (most robust) ABR thresholds about 10
to 20 dB poorer than behavioral measures
![Page 22: Auditory assess 200003](https://reader034.vdocuments.mx/reader034/viewer/2022042700/55636f7fd8b42a4f758b4897/html5/thumbnails/22.jpg)
Latency of response
![Page 23: Auditory assess 200003](https://reader034.vdocuments.mx/reader034/viewer/2022042700/55636f7fd8b42a4f758b4897/html5/thumbnails/23.jpg)
ABR continued
Lesions of the eighth cranial nerveInterwave latencyInteraural latency differenceAbsolute latencyAmplitude ratio
![Page 24: Auditory assess 200003](https://reader034.vdocuments.mx/reader034/viewer/2022042700/55636f7fd8b42a4f758b4897/html5/thumbnails/24.jpg)
Retrocochlear lesion
![Page 25: Auditory assess 200003](https://reader034.vdocuments.mx/reader034/viewer/2022042700/55636f7fd8b42a4f758b4897/html5/thumbnails/25.jpg)
Otoacoustic Emissions
Energy leakageEvidence of a healthy, functioning
cochleaSpontaneous and evoked emissionsEvoked emission seen only in cochleae
with thresholds less than 20 to 30 dBConductive losses affect emissionsScreening tool in infants
![Page 26: Auditory assess 200003](https://reader034.vdocuments.mx/reader034/viewer/2022042700/55636f7fd8b42a4f758b4897/html5/thumbnails/26.jpg)
Central Auditory Function
ComprehensionBackground noiseBehavioral testsMonotic vs. dichoticMonaural vs. binaural
![Page 27: Auditory assess 200003](https://reader034.vdocuments.mx/reader034/viewer/2022042700/55636f7fd8b42a4f758b4897/html5/thumbnails/27.jpg)
Case Presentation
31 yo male with left sided hearing loss noticed when listening to portable radio
No other otologic complaints, no pmh or contributory family or social history
PE normal
![Page 28: Auditory assess 200003](https://reader034.vdocuments.mx/reader034/viewer/2022042700/55636f7fd8b42a4f758b4897/html5/thumbnails/28.jpg)
Audiogram
![Page 29: Auditory assess 200003](https://reader034.vdocuments.mx/reader034/viewer/2022042700/55636f7fd8b42a4f758b4897/html5/thumbnails/29.jpg)
Assessment
Mild high frequency sensorineural hearing loss
Small amount of rolloverIpsi reflexes elevated in left earContra reflexes elevated in left ear
suggesting retrocochlear pathologyMRI showed 5 mm acoustic neuroma
![Page 30: Auditory assess 200003](https://reader034.vdocuments.mx/reader034/viewer/2022042700/55636f7fd8b42a4f758b4897/html5/thumbnails/30.jpg)
Analysis
Abnormal reflex responses in left ear indicate 7th nerve affected
Elevated contralateral thresholds in right ear means that decussating pathways from left VCN to right brainstem affected