impedance audiometry part2

Aditya Ghosh RoyPGT2

MS ENT

IMPEDANCE AUDIOMETRY

FALLACIES OF TYMPANOMETRY TEST

MIDDLE EAR PATHOLOGY TWO TYPES

STATIC COMPLIANCE REPRESENTIVE OF THE MORE LATERAL PATHOLOGY

EAC TM MEC COCHLE

A

1.STAPEDIAL FIXATION AND COMMON COLD

-- MEP WITH LOW COMPLIANCE EXPECTED

BUT -- MEP WITH LOW COMPLIANCE

OTITIS MEDIA WITH EFFUSION

CASE 1.

STAPEDIAL FIXATION AND SCARRED / HEALED TM

NORMAL MEP WITH HIGH COMPLIANCE

BUT NORMAL MEP WITH HIGHCOMPLIANCE

OSSICULAR DISCONTINUITY

CASE 2.

THICKENED TM OT TYMPANOSCLEROTIC PATCH

NORMAL MEP WITH LOW COMPLIANCE

NORMAL MEP WITH LOW COMPLIANCE

STAPEDIAL OTOSCLEROSIS

CASE 3

SMALL PERFORATION OF TM

FLAT TYPE TYMPANOGRAM WITH NORAL VOLUME

FLAT TYPE TYMPANOGRAM WITH NORAL VOLUME

ADHESIVE OTITIS MEDIA, OTITIS MEDIA WITH EFFUSION

CASE 4.

OSSICULAR DISCONTINUITY WITH THIKENED TM

NORMAL MEP WITH LOW COMPLIANCE

NORMAL MEP WITH LOW COMPLIANCE

STAPEDIAL OTOSCLEROSIS

CASE 5

FUNCTION OF EUSTACHIAN TUBE

EUSTACHIAN TUBE FUNCTION TESTMAINTAINANCE OF EQUALITY OF AIR PRESSURE BETWEEN THE MIDDLE EAR AND AMBIENT ATMOSPHERE

DRAINAGE OF MUCUS FROM EAR TO THE NASOPHARYNX

AIR IN MIDDLE EAR CAVITY CONSTANTLY BEING ABSORBED

STEADY FALL IN MIDDLE EAR PRESSURE

CONTRACTION OF TENSOR PALATINI AND LEVATOR PALTINI MUSCLE DURING SWALLOWING

INTERMITTENT OPENING OF ET

AIR PASSING THROUGH IT INTO MEC

PRESSURE IN MEC BROUGHT BACK TO NORMAL

FOR TESTING WE SEE WHETHER

VALSALVA

SWALLOWING DECREASE MEP

INCREASE MEP

TWO TYPES OF TEST ARE AVAILABLE

WILLIAMS

TOYNBEES PERFORATED TM

INTACT TM

MEP MEASURED

WILLIAMS TESTRESTING

PRESSURESWALLOING WITH NOSE MOUTH

CLOSEDVALSALV

A

NORMAL PARTIALLY IMPAIRED

GROSSLY IMPAIRED

RESTING PRESSURE

0 mm WATER

SWALLOING WITH NOSE MOUTH CLOSED

NEGATIVE NEAGATIVE

NO CHANGE

NO CHANGE

VALSALVA POSITIVE NO CHANGE

POSITIVE NO CHANGE

NORMAL

RESTING PRESSURE 0 mm WATER

SWALLOING WITH NOSE MOUTH CLOSED

NEGATIVE

VALSALVA POSITIVE

PARTIALLY IMPAIRED

SWALLOING WITH NOSE MOUTH CLOSED

NEAGATIVE NO CHANGE

VALSALVA NO CHANGE NEAGATIVE

GROSSLY IMPAIRED

SWALLOING WITH NOSE MOUTH CLOSED

NO CHANGE

VALSALVA NO CHANGE

AUDIOMETER

ARTIFICIALLY INC OR DEC MEP

RECORD CHANGE IN PRESSURE EACH TIME PT. SWALLOWS

TEST CARRIED OUT FOR FIXED DURATION40SEC TO MAX 160 SEC

TOYNBEES TEST

MEP CHANGED EITHER TO +250 OR -250

PT. ASKED TO SWALLOW

CHANGE IN MEP EITHER DEC OR INC NOTED IN A STEP

LADDER PATTERN

MEP WHEN TUBE CLOSED

SUDDEN OPENING OF TUBE

DEC IN MEP

AGAIN PASSIVE CLOSURE OF TUBE

MEP BECOMES STEADY

AGAIN PT. ASKED TO SWALOW

CHANGE IN MEP

HENCE A STEP LADDER PATTERN GRAPH OBTAINED

STEP LADDER PATTERN GRAPH

OPENING OF TUBE

DEC IN MEPPASSIVE CLOSURE OF TUBE

MEP BECOMES STEADY

NORMAL PRESSURE NEUTRALISES BY 3 TO 4 SWALLOWS

PARTIALLY IMPAIRED

SOME PRESSURE PERSISTS EVEN AFTER MORE THAN 5 SWALLOWS

GROSSLY IMPAIRED

NOT NEUTRALISED AT ALL BY EPEATED SWALLOWING

NORMAL

PRESSURE NEUTRALISES BY 3 TO 4 SWALLOWS

PARTIALLY IMPAIRED

SOME PRESSURE PERSISTS EVEN AFTER MORE THAN 5 SWALLOWS

GROSSLY IMPAIREDNOT NEUTRALISED AT ALL BY EPEATED SWALLOWING

ACOUSTIC REFLEX TESTMIDDLE EAR CAVITY

STAPEDIUS TENSOR TYMPANI

7TH NERVE 5TH NERVE

EFFECT OF CONTRACTION OF STAPEDIUS MUSCLE MORE PRONOUNCED THAN THAT

OF TENSOR TYMPANI

ACOUSTIC REFLEX TESTED BY CONTRACTION OF STAPEDIUS MUSCLE

CONTRACTION OF TENSOR TYMPANI TESTED SEPARATELY

STIMULATION OF TRIGEMINAL NERVE AND DOING AUDIOMETRY

STARTLE TYPE REFLEXFATIGUEBLE IN NATUREUNSTABLELONG LATENCY PERIOD

DONE IN PT. WITH SEVERE DEAFNESS IN WHOM ACOUSTIC REFLEX CANT BE PERFORMED BUT MIDDLE EAR STATUS HAS TO BE KNOWN

NON ACOUSTIC REFLEX

ACOUSTIC REFLEX ARC

DIAGRAMMATIC REPRESENTATION OF ACOUSTIC REFLEX

Stimulus of 85 db of 1 sec

NORMAL EAR DEAF EAR

IPSILATERAL

CONTRALATERAL

IPSILATERAL

CONTRALATERAL

PRESENT ABSENT ABSENT ABSENT

UNILATEAL MODERATE TO SEVERE CONDUCTIVE HEARING

LOSS

NORMAL EAR

DEAF EAR

NORMAL EAR

NORMAL EAR

DEAF EAR

DEAF EAR

DEAF EAR

NORMAL EAR

DEAF EAR DEAF EAR

IPSILATERAL

CONTRALATERAL

IPSILATERAL

CONTRALATERAL

ABSENT ABSENT ABSENT ABSENT

BILATEAL MODERATE TO SEVERE CONDUCTIVE HEARING LOSS

DEAF EAR

NORMAL EAR

DEAF EAR

DEAF EAR

NORMAL DEAF EAR

IPSILATERAL

CONTRALATERAL

IPSILATERAL

CONTRALATERAL

PRESENT ABSENT ABSENT PRESENT

UNILATERAL SEVERE SNHL

NORMAL EAR

DEAF EARNORMAL EAR NORMAL

EAR

DEAF EAR

NORMAL EAR

DEAF EAR DEAF EAR

IPSILATERAL

CONTRALATERAL

IPSILATERAL

CONTRALATERAL

ABSENT ABSENT ABSENT ABSENT

BILATERAL SNHL

DEAF EAR DEAF EAR

IPSILATERAL

CONTRALATERAL

IPSILATERAL

CONTRALATERAL

PRESENT PRESENT PRESENT PRESENT

SEVERE NEURAL IN NATURE

MODERATE DEGREE AND COCHLEAR IN

NATURE

DEAF EAR

NORMAL EAR

DEAF EAR

DEAF EAR

NORMAL EAR NORMAL EAR

IPSILATERAL

CONTRALATERAL

IPSILATERAL

CONTRALATERAL

PRESENT ABSENT PRESENT ABSENT

CENTRAL LESION

CENTRAL LESION