Date post: | 31-Dec-2015 |
Category: |
Documents |
Upload: | shannon-hamilton |
View: | 219 times |
Download: | 1 times |
Auditory Assessment Auditory Assessment
Bastaninejad, ShahinBastaninejad, Shahin, , MD, ORL-HNSMD, ORL-HNS
Assistant Prof., TUMSAssistant Prof., TUMS
Amiralam HospitalAmiralam Hospital
Acknowledgment:Acknowledgment: I would like to I would like to appreciate Prof. Borghei, for preparing this appreciate Prof. Borghei, for preparing this presentation presentation
CHLCHL SNHLSNHL
Auditory AssessmentAuditory Assessment
Subjective testsSubjective tests1.1. Tuning fork tests (TFT)Tuning fork tests (TFT)2.2. Pure tone audiometry (PTA) Pure tone audiometry (PTA) 3.3. Speech audiometrySpeech audiometry
Objective testsObjective tests1.1. Impedance audiometry (Tym,AR)Impedance audiometry (Tym,AR)2.2. Auditory Brainstem Response (ABR)Auditory Brainstem Response (ABR)3.3. Otoacoustic Emission (OAE)Otoacoustic Emission (OAE)4.4. ... ...
Tuning Fork Tests (TFT)Tuning Fork Tests (TFT)
1.1. Rinne’s test Rinne’s test
2.2. Weber’s testWeber’s test
3.3. Absolute Bone Conduction (ABC)Absolute Bone Conduction (ABC)
Rinne’s TestRinne’s Test
Tuning Fork Tests (TFT)Tuning Fork Tests (TFT)
Rinne’s Test Rinne’s Test Principal: AC>BCPrincipal: AC>BC Rinne Rinne ++: AC>BC, normal hearing or : AC>BC, normal hearing or
sensorineural hearing losssensorineural hearing loss Rinne Rinne --: AC<BC, conductive HL: AC<BC, conductive HL False Rinne False Rinne ––: unilateral deep SNHL, : unilateral deep SNHL,
due to cross over phenomena ,this due to cross over phenomena ,this can be avoided with masking can be avoided with masking
Weber’s TestWeber’s Test
Tuning Fork Tests (TFT)Tuning Fork Tests (TFT)
Weber’s Test Weber’s Test Principal: compares the BC of the two Principal: compares the BC of the two
ears ears Normal: hears equal on both sides or Normal: hears equal on both sides or
does not hear at all does not hear at all Conductive HL: lateralized to the Conductive HL: lateralized to the
more affected sidemore affected side SNHL: lateralized to the less affected SNHL: lateralized to the less affected
side side
Tuning Fork Tests (TFT)Tuning Fork Tests (TFT)
Absolute Bone Conduction test
(Schwabach test)(Schwabach test)
Compares the BC of the examiner with Compares the BC of the examiner with
the patientthe patient
• Normal: equal to the examinerNormal: equal to the examiner
• CHL: longer than the examiner CHL: longer than the examiner
• SNHL: less than the examiner SNHL: less than the examiner
Pure Tone Audiometry (PTA)Pure Tone Audiometry (PTA)
It is the graphic record of hearing It is the graphic record of hearing Quantitatively & QualitativelyQuantitatively & Qualitatively
Pure tones are delivered by head-Pure tones are delivered by head-phone for AC & by a vibrator for BCphone for AC & by a vibrator for BC• X-Axis: Frequency range X-Axis: Frequency range 125 – 12000 125 – 12000
Htz Htz (routinely depicted from 250-8000 Htz)(routinely depicted from 250-8000 Htz)
• Y-Axis: Intensity of sound in decibels (dB)Y-Axis: Intensity of sound in decibels (dB) A decibel is the smallest change in the A decibel is the smallest change in the
intensity of sound which can be intensity of sound which can be recognized by normal human ear recognized by normal human ear
Pure Tone Audiometry (PTA)Pure Tone Audiometry (PTA)
Pure Tone Audiometry (PTA)Pure Tone Audiometry (PTA)
Normal AudiogramNormal Audiogram
Pure Tone Audiometry (PTA)Pure Tone Audiometry (PTA)
Range of hearing lossRange of hearing loss
Pure Tone Audiometry (PTA)Pure Tone Audiometry (PTA)Conductive Hearing Loss (CHL)Conductive Hearing Loss (CHL)
Pure Tone Audiometry (PTA)Pure Tone Audiometry (PTA)Sensori-Neural Hearing Loss (SNHL)Sensori-Neural Hearing Loss (SNHL)
Pure Tone Audiometry (PTA)Pure Tone Audiometry (PTA)Mixed Hearing lossMixed Hearing loss
Masking Masking
To prevent To prevent ‘crossover’ ‘crossover’ phenomena phenomena Crossover happens with Crossover happens with
• 40-60 dB 40-60 dB ACAC difference in two ears difference in two ears• 0-20 dB 0-20 dB BC BC difference in two earsdifference in two ears
Masking problemMasking problem• Masking dilemma; in bilateral CHL or Masking dilemma; in bilateral CHL or
Bilateral Mixed HLBilateral Mixed HL• Overmasking Overmasking masking noise crosses masking noise crosses
over to the other sideover to the other side
Speech AudiometrySpeech Audiometry Recorded voice is usedRecorded voice is used
Speech Detection threshold(SDT)Speech Detection threshold(SDT)
An intensity level at which a listener An intensity level at which a listener
can barely can barely discerndiscern the presence of a the presence of a
speech signal in 50% of the timespeech signal in 50% of the time
It is equal to the PTA average obtained It is equal to the PTA average obtained
at 500,1000,2000Hzat 500,1000,2000Hz
Speech Reception Threshold (SRT)Speech Reception Threshold (SRT)
Two syllabus words (Spondee)Two syllabus words (Spondee)
With different intensities With different intensities
The intensity at which 50% of the The intensity at which 50% of the
presented words can be presented words can be repeated repeated
Measured in dB (it is usually 8-9dB more than Measured in dB (it is usually 8-9dB more than
SDT) SDT)
Speech AudiometrySpeech Audiometry
Speech Discrimination Score (SDS)Speech Discrimination Score (SDS) Mono syllable words Mono syllable words At 50dB higher than SRT At 50dB higher than SRT Percentage of words Percentage of words recognized recognized
correctly is noted correctly is noted • NormalNormal: 96-100%: 96-100%• CHLCHL: 90-100%: 90-100%• SNHLSNHL: low: low• Retro cochlearRetro cochlear: very low: very low
Impedance AudiometryImpedance Audiometry
Objective test Objective test
Includes :Includes :
1.1. Tympanometry Tympanometry
2.2. Acoustic Reflex Acoustic Reflex
3.3. External Canal Volume (ECV)External Canal Volume (ECV)
TympanometryTympanometry Record of resistance of conductive Record of resistance of conductive
mechanism of ear against pressure mechanism of ear against pressure changes of external canal changes of external canal
1.1. Type A:Type A: normalnormal2.2. Type B:Type B: OME, TM perforation, unfit probe, OME, TM perforation, unfit probe,
middle ear massmiddle ear mass3.3. Type C:Type C: Eustachian tube dysfunction Eustachian tube dysfunction 4.4. Type As: Type As: otosclerosis, tympanosclerosisotosclerosis, tympanosclerosis5.5. Type Ad:Type Ad: ossicular dislocation, or Atrophic TMossicular dislocation, or Atrophic TM6.6. Type DType D:: Scarred TM, or normal hypermobile Scarred TM, or normal hypermobile
TMTM
TympanometryTympanometry
Peak between -100 to +100
TympanometryTympanometry
Peak usually in-150 to -200
TympanometryTympanometry
Peak is under -300
TympanometryTympanometry
Acoustic Reflex Acoustic Reflex Stapedial muscle contraction in response to Stapedial muscle contraction in response to
loud noise loud noise
70-100 dB70-100 dB above hearing threshold above hearing threshold
Particularly useful for DDx between Particularly useful for DDx between
Cochlear and Retrocochlear lesionsCochlear and Retrocochlear lesions
Afferent : cochlear (8Afferent : cochlear (8thth) nerve ) nerve
Efferent : facial (7Efferent : facial (7thth)nerve )nerve
Acoustic Reflex Acoustic Reflex Absent bilaterally when tested ear has CHLAbsent bilaterally when tested ear has CHL BC must be better than 60dB to elicit this BC must be better than 60dB to elicit this
reflexreflex AR negative in tested ear but + in the AR negative in tested ear but + in the
contralateral contralateral Retrocochlear lesion Retrocochlear lesion AR Positive in Ipsi., but negative in AR Positive in Ipsi., but negative in
Contra.Contra. Brain Stem lesion Brain Stem lesion It also demonstrate level of facial nerve It also demonstrate level of facial nerve
lesionlesion
ABRABR
Surface recording of the electrical Surface recording of the electrical activity of auditory pathway in activity of auditory pathway in response to sound response to sound Sensitive for Sensitive for Retro-cochlear lesion lesion
Wave 1 & 2: cochlear nerveWave 1 & 2: cochlear nerve Wave 3: cochlear nucleus complexWave 3: cochlear nucleus complex Wave 4: Superior olivery complex Wave 4: Superior olivery complex Wave 5: lateral leminiscusWave 5: lateral leminiscus
11stst and 2 and 2ndnd
33rdrd 44thth
55thth Lateral Lateral lemniscuslemniscus
Cochlear Cochlear nucleusnucleus
Sup. Olivary Sup. Olivary ComplexComplex
Middle and Middle and Long Long
Latency Latency Response Response (MLR,LLR)(MLR,LLR)
ABRABR
ABRABR
Oto-Acoustic Emission (OAE)Oto-Acoustic Emission (OAE)
Normal Normal cochleacochlea generate a sound Due generate a sound Due
to the biological activity of to the biological activity of outer hair outer hair
cells cells
They are of 2 types:They are of 2 types:
I.I. Spontaneous emission Spontaneous emission (Spont.OAE(Spont.OAE50-70% 50-70%
of people) of people)
II.II. Evoked otoacoustic emission Evoked otoacoustic emission