auditory assessment bastaninejad, shahin, md, orl-hns assistant prof., tums amiralam hospital...

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