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Friday, March 20, 2009

Labels: ENT, MCQs

30 challenging Questions in ENT

1. Which are the three most common organisms causing acute sinusitis ?2. What are Ducts of Rivinus ?

3. Whartons duct?

4. What is the most probable diagnosis when the findings are as follows : erythematous aryepiglotti c folds, grey granulation tissue in the interarytenoid region and posterior

thirds of vocal cords, ulcers in the posterior thirds of vocal cords ?

5. What is the deformity seen in post mandibulectomy patients called as ?

6. Which anti-microbial drug should not be given in Infectious mononucleosis ?

7. What is your first diagnosis is an elderly male who comes with progressively worsening stridor of 3 months duration ?

8. A 3 y r old boy comes with the complaint of foul smelling sero sanguinous discharge from one nostril. What is your first diagnosis ?

9. In which condition is steeple sign seen ?

10. Expand Gd-DTPA.

11. What is ELSA ?

12. What is Dorello's canal ?

13. What is the part of the tuning fork that we place on the mastoid called ?

14. Which is the causative organism of acute epiglottitis ?

15. Which ear drops will you prescribe for a person with right ear TM rupture due to trauma ?

16. What is the most common cause for intraoperative bleeding in adenoidectomy ?

17. Which is the most feared complication during removal of a foreign body from the nose of a child ?

18. What is the procedure of choice for severe air hunger in supine position in a man with supraglottic growth ?

19. "cobblestone" esophagus seen in?

20. What is the lateral rhinotomy incision also known as ?

21. What are the temperatures of water used in the Bithermal test for vestibular function ?

22. Romberg's test positive signifies _______ disorder or _________ disorder.

23. What is chondrodermatitis chronicus pinna also known as ?

24. Collar stud abscess seen in?

25. Cork screw esophagus seen in?

26. What is Woolnerian tip?

27. The Cody tack operation is used in the treatment of?

28. Wullsteins classification?

29. Blainville ears?

30. Submandibular space infection is known as?

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ANSWERS

1. Pneumococcus, H.influenzae, Moraxella catarrhalis

2. Minor ducts of the sublingual salivary gland.Some directly open into oral cavity& some unite to form major duct of Bartholin.

3. Submandibular gland duct

4. Laryngeal findings in pachyderma laryngis.

5. Andy Gump deformity.This anatomic defec t results from resec tion of the anterior mandibular arch without adequate recons truc tion.

6. Ampicil lin(can cause rash)

7. Laryngeal Cancer.

8. Foreign body Nose

9. Acute laryngotracheobronchitis .(check this post for all other signs in ENT)

10. Gadolinium Diethylene Triamine Pentaacetic Acid(It is a type of contrast agent.A substance used in magnetic resonance imaging (MRI) to help make clear pictures of the

brain, spine, heart, soft tissue of joints, and inside bones. )

11. Endoscopic Ligation of Sphenopalatine Artery.Endoscopic ligation of the sphenopalatine artery (ESPL) has recently become the treatment of choice for refractory epistaxis.

12. Abducent nerve canal.13. Footpiece(not base)

14. Hemophilus influenzae type B

15. Don't give any ear drops

16. Adenoid tags

17. Aspiration into airway

18. Cricothyrotomy

19. Moniliasis.In the diagnosis of Candida esophagitis, double contrast esophagography shows a sensitivity of about 90% , demonstrating discrete plaque-like filling defects

which have a finely nodular and granular, distinctive cobblestone or snakeskin-like appearance and correspond to the distinctive white plaques seen at endoscopy.
http://lessons4medicos.blogspot.com/2009/02/eponymous-signs-in-ent.html


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1 comment:

21. 30 C and 44 C

22. Vestibular or Posterior column

23. Also k nown as Winkler's disease. Chondrodermatitis nodularis chronicis helicis is an painful, inflammatory nodule of the external ear. nonwhites have been noted

occasionally to have lesions in areasother than the helix, such as the antihelix or antitragus. The lesions are believed by several researchersto relate totrauma or sun

damage. The nodules are more commonly reportedon the right ear, which is believed to be the preferred restingside during sleep.

24. TB lymphadenitis.Cervical lymphadenopathy is also termed scrofula, meaning glandular swelling in Latin. The nodes coalesce, break down and perforate the deep fascia,

resulting in the characteristic collar-studabscess, which this case resembles.

25. Diffuse esophageal spasm.

26. Darwin's tubercleis a congenital ear condition which often presents as a thickening on the helix at the junction of the upper and middle thirds.However Darwin himself

named it the Woolnerian tip, after Thomas Woolner, a British sculptor who had depicted it in one of his sculptures and had first theorised that it was an atavistic feature.

27. Menieres disease

28. Classification is

Type 1ossicular chain intact, only ear drum is

repaired.Myringoplasty is synonymous with

tympanoplastytype 1

Type 2 Graft placed on incus or remnant of malleus

Type 3 INCUS & MALLEUS absent & the grafted drum isplaced in contact with the HEAD of STAPES (

COLUMELLA EFFECT)

Type 4refers to the baffleeffectof a tympanic membrane

protecting the round window, while leaving open the

mobile stapes footplate of the oval window

Type 5fenestration of the lateral semicircular membrane in

the presence of a fixed footplate and an intact

tympanic membrane.

29. Asymmetry in size or shape of the auricles.

30. Ludwigs angina

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Tuesday, March 3, 2009

Labels: ENT

Fistula test, Hennebert sign & Tullio Phenomenon .

i l il h i fi l
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Fistula test or Perilymphatic fistula test: The fistula test is performed by applying positive and negative pressure to the intact eardrum using a pneumaticotoscope or by pressing tragus.

Used to detect Perilymph fistula.

Positive

Result(indicates

Perilymphatic Fistula)

Negative

Result(Normal)

when positive pressure is

applied with the pneumatic

otoscope

when positive pressure is applied

with the pneumatic otoscope

+

Onset of Nystagmus towardsipsilateral ear.

No changes noted.

when negative pressure is

applied with the pneumatic

otoscope

when positive pressure is applied

with the pneumatic otoscope

+

Nystagmus also reverses &

changes its direction towards

contralateral ear.

No changes noted.

The type of nystagmus seen can be deducted from the picture below.
http://lessons4medicos.blogspot.com/2009/02/nystagmus-decoded.html


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Ok first let me try to explain you the figure given above.

First lets take a normal person as an example ,in him when,

SCC which is stimulatedThis will be the direction of slow phase of

nystagmus in ear with fistula

right horizontal semicircular canal is stimulated it causes movement of both eyes towards the

opposite(left) side.

right posterior semicircular canal is stimulated it causes downward movement of both eyes as

well as intorsion of right eye& extorsion of left eye.

right anterior semicircular canal is stimulated it causes upward movement of both eyes as well

as intorsion of right eye& extorsion of left eye.

Now lets come to left vestibular system

left horizontal semicircular canal is stimulated it causes movement of both eyes towards the

opposite(right) side.

left posterior semicircular canal is stimulated it causes downward movement of both eyes as

well as intorsion of left eye& extorsion of right eye.

left anterior semicircular canal is stimulated it causes upward movement of both eyes as well

as intorsion of left eye& extorsion of right eye.

So, if there is fistula in right ear,then

if fistula on right horizontal SCC(that means

when positive pressure is applie d, the right

horizontal SCC will get stimulated)

when positive pressure applied via pneumatic

otoscope causes slow component of nystagmus

towards opposite ear .

As per convention direction of nystagmus is

towards fast component, therefore we say that

nystagmus is towards ipsilateral ear


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nystagmus is towards ipsilateral ear.

if fis tula on right pos terior SCC when pos it ive pressure is applied to right ear, then

according to the diagram we see that it will cause

nystagmus with slow component towards

downside& intorsion of eyeball.

As per convention direction of nystagmus is

towards fast component, therefore we say that the

nystagmus is upbeating& extorion type.

Perilymphatic fistula:

A perilymph fistula (PLF) is an abnormal opening between the air-filled middle ear and the fluid-filled inner ear. It may occur due to a defect in one of three locations:

Oval Window (most common site)

Stapedectomy surgery (for otosclerosis)

Head trauma or barotrauma (pressure injury)

Acoust ic t rauma

Round window -

Barotrauma -- SCUBA diving, airplane pressurization

Congenital malformations (such as Mondini dysplasia)

Otic capsule--

Another possible location for a fistula is in the bone of the ear (the otic capsule). This is a rare condition where the bone between the ear and brain area is miss ing or

thin, causing symptoms very similar to that of a round or oval window fistula. Problems in the otic capsule that may cause a perilymph fistula include:

Superior canal dehiscence syndrome(anterior SCC)

Cholesteatoma

Fenestration -Another type of bony fistula can occur after a surgical procedure called fenestration previously done for otosclerosis;

Temporal bone fracture

Micro-fissure

The most common type of otic capsule fistula is located just above the superior semicircular canal and is called the superior canal dehiscence syndrome.

False positive fistulatest(Hennebert sign)

False negative fistula test

Congenital syphilis

(here stapes footplate is hypermobile, so even

small pressure changes in ear, cause excessive

movement of stapes footplate & excessive

stimulation of utricular macule)

In Dead ear ( inner ear is damaged), there will

be NO response even if a Perilymphatic fistula

exists.

25% cases of Meneires disease .

(here in 25% cases of menieres ,fibrous bands

form connecting to utricular macule to stapes

footplate)

Also seen when cholesteatoma covers the site

of fistula& doesnt allow pressure changes to be

transmits to labyrinth.

HENNEBERT'S SIGN:
http://emedicine.medscape.com/article/857914-overviewhttp://lessons4medicos.blogspot.com/2009/02/eponymous-signs-in-ent.html


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The vulnerability of the optic nerve with or without the presence of an Onodi cell is further compounded by the thin lamina papyracea in the posterior ethmoid area .

This anatomic variation is found in 8-14% of casesaccording to studies using CT in association with recent developments in endoscopic sinus surgery.

The presence of Onodi cells increases the chance that the optic nerve and/or carotid artery would be exposed (or nearly exposed) in the pneumatized cell.

The optic nerve, and more rarely, the internal carotid artery, may be exposed within or lie immediately adjacent to such an air cell.

During endoscopic sinus surgery attempts to localise the sphenoidal sinus via instrumentation through the posterior most ethmoidal air cells can lead to

optic nerve, and even, internal carotid artery, injury.

Haller cell (infraorbital cell or infraorbital extension of ethmoid cell):

The Haller cell is usually situated below the orbit in the roof of the ma xilla ry sinus.(i.e., in the orbital floor).


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15 comments:

It occurs in 10% of people.

It is a pneumatized ethmoid cellthat projects along the medial roof of the maxillary sinus.

As it is closely related to ethmoidal infundibulum enlarged Haller cells may contribute to narrowing of the ethmoidal infundibulum and recurrent sinus

disease.

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11/41

y y

Labels: ENT

Eponymous Signs in ENT

Below are the compilation of all the eponymous signs in ENT from all over the net.Read & enjoy..

AQUINO'S SIGNis the blanching of the tympanic mass with gentle pressure on the carotid artery.Seen in Glomus tumors.

BATTLE SIGN- Bruising behind ear at mastoid region, due to petrous temporal bone fracture (middle fossa #)

BEZOLD'S SIGN / SYMPTOM

Inflammatory edema at the tip of the mastoid process in

mastoiditis

BOCCAS SIGN-Absence of post cricoid crackle(Muirs crackle) in Ca post cricoid

BROWNE'S SIGN

Refers to the blanching noted when applying positive pressure{with Siege's speculum} to the tympanic membrane of a patient with Glomus tumor.
http://lessons4medicos.blogspot.com/search/label/ENThttp://lessons4medicos.blogspot.com/2009/02/eponymous-signs-in-ent.htmlhttp://lessons4medicos.blogspot.com/2008/08/assessment-of-hearing.html


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BRYCE SIGN- If combined laryngocele & external laryngocele is presenting as a neck mass, compression will cause a hissing sound as the air escapes from it into thelarynx. This test is fraught with danger in cases of combined laryngoceles because air from the external component may get forced into the internal component causing acute

airway obstruction.

DELTA SIGN

Lateral sinus thrombosison CT or MRI with contrast shows an empty triangle appearance of the thrombosed sinussurrounded by contrast enhanced dura{since contrast may

flow around the clot to outline the periphery of the sinus}. It is also called as empty triangle sign.

DODDS SIGN/CRESCENT SIGN-X-ray finding-Crescent of air between the mass and posterior pharyngeal wall. positive in AC ployp Negative in Angiofibroma

FURSTENBERG'S SIGN-Positive in Encephaloceles.Owing to the intracranial connection, there is pulsation and expansion of the mass with crying, straining, or compression of

the jugular vein (Furstenbergtest).This is used to differentiate Nasal Encephaloceles from other congenital midline nasal masses like Nasal Gliomas.

GRIESINGER'S SIGN-Erythema and oedema posterior to the mastoid process resulting from septic thrombosis of the mastoid emissary vein. seen in lateral sinus thrombosis

HALO SIGN/ HANDKERCHIEF SIGN- A finding in CSF rhinorrhea when CSF is mixed with Blood.

In patients with head trauma, a mixture of blood and CSF may make the diagnosis difficult.

CSF separates from blood when it is placed on filter paper, and it produces a clinically detectable sign: the ring sign, double-ring sign, or halo sign.

CSF will separate from blood when the mixture is placed on filter paper resulting in a central area of blood with an outer ring or halo.

Blood alone does not produce a ring.

The best ring is obtained with a 50: 50 mix of blood and CSF.

More importantly, they found that the presence of a ring was not exclusive for CSF.

Blood mixed with tap water, saline, and rhinorrhea fluid also produced a ring.

The halo sign does occur, but clearly does not clinch the diagnosis.


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HITSELBERGERS SIGN- In Acoustic neuroma- loss of sensation in the postero-superior part of external auditory meatus supplied by Arnolds nerve( branch of Vagus nerve to

ear )

HOLMAN MILLER SIGN, ANTRAL SIGN-

The anterior bowing of the posterior wall of the antrum seen on lateral skull film .Pathognomic for juvenile na sopharyngeal angiofibroma.

HONDOUSA SIGNX-ray finding in Angiofibroma .

indicating infratemporal fossa involvement characterised by widening of gap between ramus of mandible and maxillary body


14/41

indicating infratemporal fossainvolvement characterised by widening of gap between ramus of mandible and maxillary body.

HENNEBERT'S SIGN

It is a false positive fistula testwhen there is no evidence of middle ear disease causing fistula of horizontal semicircular canal. It is seen in 25% cases of meniere's disease or

congenital syphilis.In 25% cases of Meneires ,fibrous bands form connecting utricular macule to stapes footplate. In syphilis due to hypermobile stapes footplate.[ Hennebert sign-

pressure induced nystagmus, Hennebert symptom- pressure induced dizziness]

IRWIN MOORES SIGN positive squeeze test in chronic tonsillitis.

LAUGIER'S SIGN-Blood behind the eardrum suggests basilar skull fracture.

LEUDET'S SIGN-Inflammation of the eustachian tube can produce a bright clicking sound heard by the examiner through the otoscope while the patient experiences it as

tinnitus.caused by reflex spasm of the tensor palati muscle.

LIGHT HOUSE SIGNA small pin hole perforation with a pulsatile ear discharge is seen in Acute suppurative otitis media.

LYRES SIGN- splaying of carotid vessels( at junction of External & internal carotid artery) in carotid body tumor.

MILIANS EAR SIGN- Erysipelascan spread to pinna(cuticular affection), where as cellulitis cannot.

Cellulitis and erysipelas manifest as areas of skin erythema, edema and warmth in the absence of underlying suppurative foci.

They differ in that erysipelas involves the upper dermis and superficial lymphatics, whereas cellulitis involves the deeper dermis and subcutaneous fat.

As a result, erys ipelas has more dis tinctive anatomic features than celluli tis; erysipelas les ions are raised above the level of surrounding skin, and there is a clear line of

demarcation between involved and uninvolved tissue.

Classic descriptions of erysipelas note "butterfly" involvement of the face.

Involvement of the ear (Milian's ear sign) is a distinguishing feature for erysipelas since this region does not contain deeper dermis tissue.


15/41

OMEGA SIGN-INFANTILE OMEGA SHAPED EPIGLOTTIS SEEN IN LARINGOMALACIA.

Paul Dudley White's winking ear lobe sign-Movement of the ear lobe coincident with the pulse suggests tricuspid insufficiency.

PHELPS SIGN- loss of crest of bone (as seen in CT-scan) between carotid canal and jugular canal in glomus jugulare.

RAT TAIL SIGN /Bird-beak sign-Sign inbarium swallow of achalasia. The oesophagus is dilated, and contrast material passes slowly into the stomach as the sphincter

opens intermittently. The distal oesophagus has a narrow segment and the image resembles a bird's beak.


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This is in contrast to the rat's tail appearance of carcinoma of oesophagus.Barium swallow shows characteristic rat tail appearance with irregular mucosa margins in

carcinoma e sophagus.

RISING SUN SIGN

There is red vascular hue seen behind the intact tympanic membrane. it is seen in glomus tumour, high jugular bulb and aberant carotid artery in the floor of middle ear.

RACCOON SIGN-Indicate subgaleal hemorrhage,and not necessarly base of skull .

SCHWARTZ SIGN

It is also called flamingo flush sign. it is seen because of increased vascularity in submucous layer of promontory in active phase of otosclerosis(otospongiosis).

STEEPLE SIGN-X-ray finding in Acute laryngotracheobronchitis(CROUP).The steeple signis produced by thepresence of edema in the trachea, which results in elevationof

the tracheal mucosa and loss of the normal shouldering (lateral convexities) of the air column.
http://lessons4medicos.blogspot.com/2008/10/clinical-images-raccoon-eyes.html


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STANKIEWICKS SIGN- indicate orbital injury during FESS. fat protrude in to nasal cavity on compression of eye ball from outside .

TEAR DROP SIGN

Seen in Orbital floor fracture. It is defined as tear drop shaped opacification seen hanging from the roof of the maxillary sinus on water's view. The floor of the orbit is the most

common portion of the orbit to sustain fracture. A classic radiographic finding in blow-out fractures is the presence of a polypoid mass (the tear-drop) protruding from the floor of the

orbit into the maxillary antrum The tear-drop represents the herniated orbital contents, periorbital fat and inferior rectus muscle.

THUMB SIGN

It is a thumb like impression (due to enlarged epiglottis) seen on X-ray lateral view neck in patients with acute epiglottitis.Direct visualization of the epiglottis by laryngoscope, if

attempted, reveals a beefy red, edematous epiglottis.


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1. Diminished perception of the deeper tones,

2. retarded bone conduction, and

3 negative Rinne's test


19/41

No comments:

3. negative Rinne's test,

pointing, in the absence of objective signs, to otosclerosis

2. Bezold's abscess

abscess deep in the neck parapharyngeal space associated with suppuration in the mastoid cells

3. Bezold's sign / symptom

Inflammatory edema at the tip of the mastoid process in mastoiditis

4. Bezold's ganglion

An aggregation of nerve cells in the interatrial septum

5. Bezold's mastoiditis

Mastoiditis with perforation medially into the digastric groove and forming a deep neck abscess


Wednesday, January 21, 2009

Labels: ENTDelphian node

A midline prelaryngeal (cricotyhroid) lymph node.
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No comments:

Receives lymphtic drainage from larynx & thyroid gland.

Can be enlarged in thyroid carcinoma or advanced larygeal cancer.

This node gets its name from Greek mythology. The Oracle of Delphi, called Pythria, was a Priestess who would answer questions posed to her, never concealing nor

revealing the truth. Thus, an enlarged Delphian node may, or may not, indicate the presence of thyroid cancer.


Sunday, January 11, 2009

Labels: ENT

Lines of Dolan and the elephants of Rogers

What are the lines of Dolan?

They are three anatomic contours best seen on the Waters view (occipitomental view )of the face, and they were first popularized by Dolan et al.

As y ou can see, the 3 lines of Dolan lead the eye along some facially important structures.

Lee Rogers pointed out that the 2nd and 3rd lines together form the profile of an elephant.
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ZMC fractures = Zygomaticomaxillary complex fractures or Tripod fractures


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1 comment: Recommend this on Google

Thursday, August 21, 2008

Labels: ENT

Assessment of Hearing

In this post we will deal with the techniques followed to assess auditory function

we should be able to know theses 4 things after doing the tests:
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type of hearing loss:

degree of hearing loss

Degree of hearing loss hearing loss range(dB)

Not significant 0-25dB(adults)

0-15dB(children)

Mild 26-40dB

Moderate 41-55dB

Moderately severe 56-70dB

Severe 71-90dB

Profound more than 91dB

total

site of lesion

cause

Tests for hearing:


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These 3 tests are non-specific & they don't indicate the type of deafness.they only give a rough idea about the hearing loss.

Finger friction test rubbing or snapping thumb & finger

close to patients ear

Watch test clicking watch brought near the

patients ear

Speech test patient stands with his test ear towards

examiner at distance of 6metres.

Tuning fork tests:remember these ,its very important

512Hz tuning fork is ideal(forks of lower frequency - produce sense of bone vibration forks of higher frequency- shorter decay time )

When we test air conduction,we actually check the functioning of both conductive & sensorineural(cochlea)

When we testBone conduction,we actually measure only cochlear function

Normally hearing through air conduction is louder & heard twice as long as through bone conduction route (AC better than BC)

Rinne test:

method:To perform this test, a 512Hz vibrating tuning fork is placed on the mastoid bone and then moved next to the external ear. The patient indicates at which of the two sites

the sound is louder.

principle:Sound transmitted through an external ear traverses the middle ear and is perceived by the cochlea (inner ear). Sound can

be transmitted directly to the cochlea, skipping the external and middle ear, by placing the vibrating tuning fork on the mastoid bonedirectly behind the ear. This is the basis for the Rinne hearing test.

normal conductive SN deafness


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normal conductive

deafness

SN deafness

Rinne AC>BC

(Rinne +)

BC>AC

(Rinne -)

AC>BC

note:

rinne (-)ve 256Hz fork 512Hz fork 1024Hz fork

minimum

air-bone gap

15dB 30dB 45dB

False negative Rinne :

in Severe Unilateral sensorineural he aring loss.

Patient does not perceive sound by air conduction ,but responds to bone conduction

response to bone conduction is because the patient perceives sound from opposite ear because of transcranial transmission of sound.

corrected by :masking opposite ear with Barany's noise box ,so that transcranial transmission of sound is not perceived.

note:A Barany noise box can also be used to see noise based vertigo (Tullio phenomenon). This commercially available box simply

makes a loud (100 dB) noise. When the box is slowly moved towards the patient's symptomatic ear, the vertiginous symptoms may be

re-created.

Weber test:

method:Place the tuning fork in the center of the forehead and the physician asks the patient where he or she hears it.

principle:

The occlusion effect is responsible for this phenomenon. Sound conductedthrough bone causes the

cochlea, the ossicular chain, and theair in the external auditory canal to vibrate. Some lower frequency

sound, as produced by the 512 Hz tuning fork, escapes from thecanal. When the ear is occluded, these

frequencies cannot escapeand the sound seems to becomelouder.

it is the occlusion effect, rather than elimination of environmental sound, that is responsible for the improved bone conduction

threshold when occluding a normal ear.

Middle ear effusion and ossicular chaindisruptions cause a "mass loaded" middle ear, with lowering ofthe inherent resonant frequency.

Ossicular chain fixation causes a phase shift in the sound wave. Both cause preferential transmissionof lower frequencies to the

cochlea

normal conductive

deafness

SN deafness

Weber not lateralised lateralised to

poorer ear

lateralised to

better ear

note:lateralisation of sound in Weber test with a tuning fork of 512Hz implies either

conductive loss of 15-20dB in ipsilateral ear (or)

sensorineural deafness in contralateral ear

Absolute bone conduction test(ABC) test:

method:

patients bone conduction compared to that of examiner(presuming that examiner has normal hearing)by keeping on mastoid.

External auditory meatus of both patient & examiner is occluded by pressing tragus inwards,this is to prevent external ambient noise entering through air

d ti t


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conduction route.

normal conductive

deafness

SN deafness

ABC tes t hear the fork for

same duration

as examiner

hear the fork

for same

duration as

examiner.

reduced

Schwabach test:

method:same as ABC test,but meatus is not occluded.

normal conductive

deafness

SN deafness

Schwabach equal lengthened in

patient(due to

absence of

external

ambient noise

the patient

hears it for

longer time)

reduced

Bing test::

determine whether closing of ear canal results in occlusion effect.

The Bing test can simulate unilateral (one-sided) conductive he aring lossresults by placing a finger in one ear while performing the Weber test.

method:tuning fork placed on mastoid while examiner alternately closes & opens ear canal by pressing tragus inwards.

principle:same principle as Weber test(occlusion effect)

normal conductive

deafness

SN deafness

Bing test louder(when

occluded)

no effect

(bing negative)

louder

Gelle's test:

method:A vibrating tuning fork is applied over the mastoid process; if it is heard, the air in the external auditory canal is compressed, by means of a Siegle 's

speculum.


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a test of the mobility of the ossicles.

principle:

when air pressure is increased in ear canal, it pushes tympanic membrane inside & leading to increased stiffness of the ossicular chain & thus decreaseshearing.

And when pressure is again relea sed ,i t again normalises.

normal stapes

fixation(otosclerosis)

SN deafness

Gelle's test decreased in

intensity after

increasing

pressure

does not alter decreased in

intensity after

increasing

pressure

Audiometric tests:

Pure tone audiometry:

used to measure the auditory threshold of an individual

pure tone-a single frequency sound is used while testing ,audiometer-an electronic device which produces pure tones.

Audiometer: There are two types of audiometers widely used. They are :

1. Those that require a subjective responseon the part of the patient and

2. Those that require no subjective responsefrom the patient.Examples include:

1. Pure tone a udiometer is the classic example of the first type

2. Impedence a udiometer/ BERA (Brainstem Auditory Evoked Responses audiometer) are examples of the second type.

The frequencies generated are 125, 250, 500,750, 1000, 1500, 2000, 3000, 4000, 6000 and 8000 Hz.

Intensity is the level of sound power measured in decibels; loudness is the perceptual correlate of intensity.

Frequency is cycles per unit of time. Pitch is the perceptual correlate of frequency. Frequency is measured in hertz, which are cycles per second.

Usually frequencies of 250-8000 Hz are used in testingbecause this range represents most of the speech spectrum , although the human ear can detect

frequencies from 20-20,000 Hz.

The hearing level (HL) is quantified relative to "normal" hearing in decibels (dB), with higher numbers of dB indicating worse hearing. The dB score is not really percent

loss, but neverthless 100 dB hearing loss is nearly equivalent to complete deafness for that particular frequency. A score of 0 is normal. It is possible to have scores

less than 0, which indicate better than average hearing.

note: In a normal PTA audio ram we see that both AC air conduction & BC bone conduction are at the same 0dB level.But we knowthat AC is better thanBC.So ou

may get a doubt how come they are same here.Actually In a clinic a calibrated audiometer is used to present the correct intensity for each tone such that 'normalhearing' registers as 0 dB HL (audiometric zero).This is done for the ease of reading the audiogram report.& standardisation

0 dB Hearing Level a t 1000 Hz = 7 dB SPL


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Pure tone air conduction testing:

This is a measurement of air conduction thresholds of audibility.

Pure tone air conduction threshold is tested using head phones:

method:

note:when establishing threshold ,2 choices are ascending & descending way to change intensity.

ascending(Hughson - Westlake ascending technique)- begins with stimuli that are below patient's threshold & intensity is

increased until patient responds.

descending- stimuli presented first are above patient's threshold & intensity is decreased until the patient no longer

responds.

but both have drawbacks=

in descending technique the patient might continue to respond to stimuli ,when he no longer perceives (false +

response)

in ascending technique the patient may fail to respond even when stimuli are audible.(false - response)

Modified Hughson - Westlake technique:this procedure uses an ascending technique to determine threshold .but each threshold search is preceede d by a

descending familiarization trial.

ex:"Up 5-down 10" method of threshold estimation

1. The better ear is tested first in order to determine the need for masking.

2. Start with a 1000 Hz toneat a level above the threshold to allow easy identification of the tone. This tone is selected because it is an important speech frequency, and

the patient is less apt to mistake the frequency.To ensure the subject is familiar with the task, present a tone of 1000 Hz that is clearly audible (e.g. at 40 dB

HL for a normally hearing subject or approximately 30 dBabove the estimated threshold for a subject with a hearing impairment,)

3. If the patient is suspected to be having a profound hearing loss then the testing should be started with 250Hz frequency. This is because of the fact that the individuals with

profound hearing loss often have testable hearing only in the low frequency range.

4. Next, test 2000, 4000, 8000, 500 and 250 Hz in that order

5. As the threshold levels are being reached, a check should be made for the existance of abnormal tone decay. This is done by sustaining the tone for several seconds longer

than usual. If the index finger drops before the tone is discontinued, abnormal tone decay should be suspected.

6. "Up 5-down 10" method=The starting intensity of the test tone is reduced in 10 dB steps following each positive response, until a hearing threshold level is reached at

which the subject fails to respond. Then, the tone is raised by 5 dB, if the subject hears this increment, the tone is reduced by 10 dB; if the tone is not heard then ti is raised

by another 5 dB increment. This 5 dB increment is always used if the preceding tone is not heard, and a 10 dB decrement is always used when the sound is heard. The

threshold is defined as the faintest tone that can be heard 50% or more of the time, and is established after several threshold crossings.

Testing of the second ear should begin with the last frequency used to test the first ear. There is no need to start again with a 1000 Hz tone because if one side of the

heard has learned the listening task, the other side knows it as well. The test is terminated after all desired frequencies have been examined.

Bone conduction audiometry:


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Bone conduction audiometry:

This is an important measurement of hearing threshold using a bone vibrator. This helps to differentiate conductive from sensorineural hearing loss. The equipment necessary is

just a bone vibrator connected to the audiometer. The bone vibrator is placed over the mastoid process of the side to be tested. The auditory threshold is assessed as described

for air conduction assessment. The only difference is that the better hearing ea r should be ma sked using a masking tone delivered via a head phone .

Limitations of bone vibrators

1. Bone vibrators tend to emit more sound than vibration a t frequencies above 2000 HzIf testing at 3000 and 4000 Hz it is preferable to

insert an e ar plug (eg E.A.R. plug as used for hearing protection purposes) into the test ear canal or cover the test ear with a supra-aural

earphone. This attenuates the air borne radiation from the bone vibrator to a satisfactory degree. Failure to occlude the e ar canal

at high test frequencies is likely to lead to inaccurately acute bone conduction thresholds, resulting in a false air-bone gap in the

audiometric results. The canal must not be occluded at test frequencies below 3000 Hz since this may produce the occlusion effect in which

bone conduction thresholds are improved.

2. Testing is not recommended at frequencies below 500 Hz because the subjects threshold may relate to hearing at the second or third

harmonic rather than the fundamental.

3. In bone conduction audiometry high frequencies cannot be used for testing. Frequencies above 4000 Hz cannot be used because they are beyond the

vibrating capabilities of the bone vibrator.

Masking

Masking presents a constant noise to the nontest ear to prevent crossover from the test ear. The purpose of masking is to prevent the nontest ear from detectingthe signal (line busy), so only the test ear can respond.

When a signal is presented to the test ear, the signal may also travel through the head and reach the cochlea on the other side. However the intensity of the signal from

the test to the nontest ear can be reduced by the mass of the head. This signal reduction is called interaural attenuation.(transcranial transmission loss)

Forbone conduction, the interaural attenuation may be as low a s 0 dB because the bones of the skull are very efficient at transmitting sound.Thus, any

suspected difference in bone conduction between the test and nontest ears requires masking. (ie,Masking is done in all Bone conduction studies)

Crossover occurs when sound presented to the test ear travels across the head to the nontest ear. This occurs at approximately 40 dB for circumaural earphones

across all frequencies.Interaural attenuation for air conduction can range between 40 and 80 dB.Masking should be used if the difference in air conduction in

one ea r and bone conduction in the other ear is 40 dB or greater.(ie,masking required when there is difference b/w the 2 ears of minimum 40dB in air conduction

threshold )

When the difference in the thresholds of the two ears is greater than the transcranial transmission loss, cross-hearing may occur and the apparent threshold of the

worse ear is in fact a shadow of the better ear.

Narrow band masking noise is used

Audiograms:

red indicates right ear

blue indicates left ear.


31/41

eg: high-frequency sensorineural hearing loss in the right ear.

Audiogram depicting a mild rising conductive hearing loss in the left ea r:

The 3 types of hearing loss can be differentiated as follows:

Conductive hearing losshas normal bone-conduction thresholds, but air-conduction thresholds are poorer than normal by at least 10 dB.

Sensorineural hearing losshas bone- and air-conduction thresholds within 10 dB of each other, and thresholds are higher than 25 dB HL.

Mixed hearing losshas conductive and sensorineural components.Pure-tone air-conduction thresholds are poorer than bone-conduction thresholds by more than 10dB, and bone-conduction thresholds are less than 25 dB

Speech audiometry:

test patient's ability to hear & understand speech is measured.

different parameters are measured like:

(a)spee ch recognition threshold:Speech reception threshold:or Spondee threshold


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minimum intensity at which 50% of words repeated correctlyby patient.

Spondee w ords are used.Spondees are two syllable w ords with equal a ccent (emphasis) on ea ch syllable. Baseball, northwest, oatmeal and hotdog are

examples of spondees.

The term speech recognition threshold is synonymous with speech reception threshold. Speech recognition threshold is the preferred term because it more

accurately describes the listener's task.

SRT should be within 10dB of PTA .(since SRT encompasses far more frequencies than PTA , SRT is less than PTA )

If the SRT is significantly better than the PTA, the possibili ty ofpseudohypoacusis(patient is not co-operating properly) should be considered

1. note:Pure tone average(PTA)=av erage of pure tone threshold of 3 s eparate frequencies ( 500 ,1000 ,2000Hz) as measured by pure tone audiometry.

(b)Speech detection threshold:

Speech-awa reness threshold(SAT) is also known as speech-detection threshold (SDT).

The objective of this measurement is to obtain the lowest level at which speech can be detected at least half the time . This testdoes not have patients repeat

words; it requires patients to merely indicate when speech stimuli are present.

Speech materials usually used to determine this measurement are spondees

note:SRT differs from SDT in that SDT is merely the level at which the individual becomes aware that speech is present & SRT is level at which speech is loud

enough for the individual to understand it.

(c)speech recognition score :

Speech discrimination scoreor word recognition score(when words used) or sentence recognition score(when sentences used)

the lowest intensity speech stimulus that an individual can detect at least 50% of the time.

discrimination means judging two things whether they are sam e or not ,but this is not done in this test .t herefore the term "speech disc rimination score' not used now.

here patient doesn't repeat words,just a measure of patient's ability to understand speech.

here Phonetically bala nced words(PB) used=single syllable words=pin,bus

phonetically balanced means that the distribution of phonetic elements in list of words approximates the distribution found in everyday conversations .

list of 50 words given & then the number of correctly heard words multiplied by 2 to get score.

done at supra-threshold level i.e , at 30-40dB above SRT.

innormal people & those with conductive deafness have a high score of 90-100%.

90-100% within normal range

75-90% slight difficulty

60-75% moderate difficulty

50-60% poor discrimination


33/41


34/41

Tympanograms:

A tympanogram is a graphic representation of the relationship of external auditory canal air pressure to impedance

Pressure in the external auditory canal is varied from -200 daPa(decaPascal=mmH2O) through +200daPa w hile monitoring impedance

The Jerger system is the most commonly used classification system for tympanograms

Type A. The peak compliance occurs at or near atmospheric pressure indicating normal pressure in the middle ear. There are three subgroups. Compliance peak is -

150 to +100 daPa

A - normal shapereflects a normal mechanism . immittance is 0.2-2.5 millimhos(unit of conductance)

AD - A deep curve with a tall peak indicates an abnormally compliant middle ear, as seen in ossicular dislocation or erosion, or loss of elastic fibers in

the tympanic membrane.immittance is less than 0.2 mmhos

AS - A shallow curveindicates a stiff system, as in otosclerosis.immittance is more than 2.5 mmhos

Type B- No sharp peak, with little or no variation in impedance over a wide range, usually secondary to non-compressible fluid in the middle ear (otitis media), tympanic

membrane perforation or obstructing cerumen.


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This Type B curve must always be interpreted in conjunction with the ear canal volume. Average ear canal volume in children ranges between 0.42 - 0.97 ml,

while in adults it ranges betwee n 0.63 - 1.46 ml.

1. Type B curve with normal ear canal volumesuggests otitis media.

2. Type B curve withsmall canal volumesuggests that the ea r canal could be occluded by the presence of wax, or the probe of the impeda nce

audiometer has not been properly placed.

3. Type B curve withlarge canal volumesuggests that there could be perforation of the ear drum. (so middle ear volume is added up to volume of

ear canal)

Type C- Peak compliance is significantly below zero, indicating negative pressure (sub-atmospheric) in the middle ear space. This finding is often indicative

eustachian tube dysfunction. compliance peak is less than -150 daPa

note:Testing for the presence of absence of perilymph fistula:

Testing implies presence or absence of a fistula (ie, an abnormal opening in the inner ear labyrinthine system).

This can be indirectly assessed by the presence of intense giddiness along with nystagmus when the external canal pressure in increased by increasing the probe

pressure. This sign is also known as the Hennebert's sign.This sign is manifested only in the presence of perilymph fistula.

Testing function of eustachian tube:

A negative or positive air pressure is created (-200 to +200) in middle ear & person is asked to swallow 5 times in 20 sec.

the ability to equate the pressure indicates normal tubal function.

also used to test patency of grommet placed in tympanic membrane in cases of serous otitis media.

Physical volume of ear canal:(Equivalent ear canal volume)Includes the volume between

probe tip(of impedence audiometer) & tympanic membrane , if tympanic membrane is intact. (or)

volume of ear canal & middle ear space if tympanic membrane is perforated.

method:


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it is derived from acoustic admittance of volume of a ir media l to probe.

Under reference conditions ,a given volume of air ha s a known acoustic admittance, which can be used to calculate the equivalent volume of air.

eg;when a 226Hz probe tone is used ,1cubic cm of air has admittance of 1acoustic mmho under standard atmospheric conditions.

so, if admittance of air b/w probe & tympanic membrane is 1.5 acoustic mmho ,then equivalent volume is 1.5 cubic cm.

Average ea r canal volumes for children are 0.42-0.97 mL. Average adult volumes are 0.63-1.46 mL.

Used in case of Type B tympanograms(flat) to know the cause:

Type B curve with normal ear cana l volume suggests otitis media .

Type B curve with small canal volume suggests that the ea r canal could be occluded by the

presence of wax, or the probe of the impedance audiometer has not been properly placed.

Type B curve with large canal volume suggests that there could be perforation of the e ar drum.(so middle ear volume is added up to volume of ear canal)

Static compliance:

Measure of middle ear mobility.

it is measures in equivalent volume in cc's, based on 2 volume measurements.

C1= made with tympanic membrane in position of poor compliance with +200 mmH2O in external canal.

C2= made with tympanic membrane at max compliance

C1-C2= Static compliance, which cancels out the compliance due to column of air in external canal.the remainder is compliance due to middle ear mechanisms.

static compliance is low when value is less than 0.28cc & high when more than 2.5cc

its major contribution is to differentiate b/w fixed middle e ar & middle e ar discontinuity.

Acoustic reflex:

principle:

Contraction of the stapedius muscle occurs with loud sounds, producing a measurable change in compliance.

When the stapedius muscle contracts in response to a loud sound, that contraction changes the middle ear immittance. This change in immittance can be detected as

a deflection in the recording.

A significant change in middle ear immit tance immediately after the stimulus is considered an acoustic reflex.

A stapedial muscle contraction in response to an intense signal occurs bilaterally in normal ears with either unilateral or bilateral stimulation. This reaction occurs

because the stapedial reflex pathway has both ipsilateral and contralateral projections


37/41

we should first know a few basic terminology used here,

the immittance change caused by stapedius muscle contraction is measured in the ear containing the probe tip --this is PROBE EAR.

the ear receiving the stimulus to activate the reflex is --STIMULUS EAR.

either ear can be stimulus ear --i.e, the stimulus can even originate from the probe tip a s well as from the ear phone on the opposite ear.

Absent reflexmeans even 125dB of sound doesn't elicit contralateral reflex.

Elevated reflex: the patient's threshold is compared to respective 90th percentiles that apply to his hearing threshold for the frequencies tested.If ART fallsabove the 90th percentile it is considered elevated.

Ipsilateral or uncrossed acoustic reflex: here the stimulus is presented to the probe ear ,which is the same ear in which immitance change is measured.

Contralateral or crossed acoustic reflex:here the reflex is measured in the ear with probe tip ,but stimulus is given to opposite ear.

"right contralateral acoustic reflex " means stimulus is in right ear & probe in left ear.

"left contralatera l a coustic reflex"means stimulus is in left ear & probe in right ear.

Probe ear principle:acoustic reflexes are usually absent when there is conductive pathology in probe ear.

stimulus ear principle:a conductive disorder in the stimulus ear reduces the stimulus level reaching the

cochlea by the amount of air-bone gap,As a result ART is elevated by the amount of air-bone gap.

2 basic acoustic reflex tests:

1. acoustic reflex threshold(ART)--lowest stimulus which produces reflex

2. acoustic reflex decay--measure of how long reflex lasts when stimulus is kept for a period of time

ART:

Acoust ic reflex thresholds generally are determined in response to stimuli of 500, 1000, 2000, and 4000 Hz. For sc reening purposes, or for a general check of the

pathway's integrity, usually test at 1000 Hz.


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Range of ART :loud sound 70-100dB above threshold of hearing of that particular earis used

The greater the hearing loss, the higher the acoustic reflex threshold for conductive hearing loss.

For sensorineural hearing loss, a coustic reflex thresholds may be within the normal range, particularly for mild-to-moderate hearing losses with

recruitment.

Absent(means even 125dB of sound doesn't elicit contralateral reflex) in:

1. Reflexes usually are absent or cannot be recorded if the patient has type B tympanograms; therefore, acoustic reflexes generally are not tested in these ears.

For example,

if the ear canal is occluded with cerumen, a type B tympanogram with low volume will be recorded. In this case, acoustic reflexes cannot be measured because middle

ear immittance is not being measured. (Cerumen blocks the signal.)

For a type B tympanogram with normal volume (as in otitis media) no pressure peak for immittance is obtained. The pressure between the ear canal and middle ear are

not equilibrated, and acoustic reflexes cannot be recorded.

For a type B tympanogram with high volume (as in the presence of patent pressure equalization tubes or perforated tympanic membranes), an open exchange of air

occurs between the ear canal and middle ear; thus, any contraction of the stapedius muscle cannot be measured.

2. In the presence of severe-to-profound sensorineural hearing lossin the stimulated ear, acoustic reflexes may be absent secondary to insufficient stimulation.

3. Similarly,a conductive component may a ttenuate the signal intensity, preventing sufficient stimulation in the stimulated ear or precluding a clear response in the recording

ear.

Typical patterns for the interpretation of acoustic reflex abnormalities are as follows:

With unilateral conductive deafness:

In the given image ,right contralateral reflex absent or elevated (due to probe principle)

but left ear ipsilateral absent (due to both probe e ar & stimulus ear principles)

So in ipsilateral both principles are operative (ie,stimulus is attenuated due to conductive disorder & even immitance

change cannot be measured due to conductive disorder)

Due to this double effectipsilateral acoustic reflex are so sensitive to conductive disorder.

Bilateral conductive disorder:

both contra & ipsilateral reflexe s absent in both ears.


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Acoustic refle x decay test(adaptation):

it is measure of how long the response lasts if stimulus is kept on for a period of time.

The acoustic reflex decay test is used to assess the integrity of CN VIII.Using a stimulus of either 500 or 1000 Hz, a

contralateral continuous tone is presented for 10 seconds at a stimulus level 10 dB above the acoustic reflex

threshold for that stimulus frequency in that ear.This suprathreshold acoustic reflex then is recorded over the 10-second stimulation period. If the amplitude of the

recorded deflection on the sc reen decreases by 50% or more within 10 seconds, the test is considered positive.

In some cases of muscular or neuromuscular disorder, tone decay results also may be positive secondary to muscle fatigue.

along w ith ART (absent or e levated),acoustic reflex decay is used to detect retro-cochlear disorder

useful in:

test hearing in infants & young children -since it is objective test

find mal ingers-a person who feigns total deafness & doesn't give any response on PTA ,but shows +ve stapedial reflex is malingerer.

detect cochlear pathology -presence of stapedial reflex at lower intensities like 40 -60 dB than usual 70dB indicates recruitment & thus cochlear type hearing loss

lesions of facial nerve-absence of reflex when hearing is normal indicates lesion of facial nerve proximal to nerve to stapedius.

lesion of VIIIth nerve-Acoustic reflex decay test

lesion in brain stem:ipsilateral reflex present but contralateral absent indicates lesion is in crossed pathways in brain.

Bekesy audiometry:A subject -controlled auditory threshold test ing procedure.method:

the patient has to press a button

the button controls a motor ,which in turn controls attenuator & a pen.

patient is told to hold button down when he can hear a tone & release it when he cannot.

holding the button causes the intensity to fall & releasing to rise.intensity change 2.5dB/sec

this course of events will cause the level of of tone to rise & fall around the patient's threshold.

the pen tracks the level of of tone on a paper resulting in zigzag pattern around the patient's threshold.

the width of the zigzags is EXCURSION WIDTH& thepatient's threshold is midpoint of these thresholds.

Conventional Bekesy audiometry:

Bekesy audiograms are obtained either

one frequency at a time(fixed frequency Bekesy audiome try):one frequency for a given period of time.

test frequency changes from low to high.(swee p frequency Bekesy audiometry):test tone increases smoothly from 100 to 10,000Hz at rate of 1 octave/sec

Each Bekesy audiogram is obtained twice

once with a continuous tone (CONTINUOUS TRACING)

other with a tone that pulses on & off 2.5 times/sec(PULSED TRACING)

Types of tracing:the shifting of tracing is result of tone decay.

continuous tracing -(C)

pulsed tracing-(P)


40/41

types pattern seen in illustration

I (C) &(P)

tracings

overlap

normal hearing &

conductive hearing loss.

II continuous

& pulsed

tracings

overlap up

to 1000Hz

& then (C)

tracing falls

by an

amount

that is less

than 20dB

&

excursions

of (C)decreases

up to even

3-5dB wide

cochlear loss

III (C) tracing

falls below

(P) at 100

to 500Hz

,even up to

40-50dB

separation

& even up

to

audiometer

limits

retrocochlear lesion

IV (C) fallsbelow (P)

at

frequencies

up to

1000Hz by

retrocochlear lesion


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1000Hz by

more than

25dB but

not to

audiometer

limits.

V(C) above

(P)

non -organic hearing

loss(pseudohypoacusis)

Modifications of Bekesy audiometry:

Reverse Bekesy tracings:

Here the sweep of the (C) tracing is from high to low frequency & compared with (P) tracing from low to high.

advantage is that the patients with sensorineural loss as a result of retrocochlear pathological condition in the region of brain stem had more hearing loss withthis procedure.

Bekesy comfort loudness test:

Patients are instructed to respond to suprathreshold stimuli rather than threshold stimuli .(at a comfortable loudness rather than too loud or too soft)

reason:retrocochlear disorders initially appear at suprathreshold levels.

We will discuss about the "special tests for hearing assessment" in the next post.


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