Vestibular function tests

VESTIBULAR
FUNCTION TESTS
Presentor: Dr Kavya Sivapuram
Moderator: Dr Bharathi M.B

HEAD ROTATION
• Yaw
• Pitch
• Roll

HEAD TRANSLATION
• Bob
• Surge
• Heave

SEMICIRCULAR CANAL PLANES
• Horizontal canal plane
• RALP
• LARP
 Head rotations - Determine by SCC

Clear and stable vision:
• Image should be held steady on the retina
• Image of object of record should be brought
close to the center of the fovea
- Best spatial resolution with 0.5 degrees from
centre of fovea
- As the image moves 2 degrees from the centre
of fovea, the acuity reduces by 50 %

Functional categories of movement:
GAZE REDIRECTION:
 Saccades
 Pursuit
 Vergence
GAZE STABILIZATION:
 Vestibular
 Optokinetic

In General terms…
• Saccade:
Object of interest is changing, but stationary
Looking in different directions, jerks.
• Pursuit:
Somebody or something is moving slowly, I am
slowly following that. I am stable, the object is
moving smoothly

• Vergence:
Different depths. I am looking at a far off object ,
and close object – Convergence, Divergence .
Gaze stabilization:
World is stationary, but I am moving
Slowly sustained – Optokinetic
Rapid perterbations - Vestibular

QUESTIONS:
o The eye movement that stabilizes vision when the
individual is moving slowly is called?
Optokinetic
o The eye movement that stabilizes vision during rapid
head pertuberations is called?
Vestibular / vestibulo ocular reflex
o The eye movement that brings an object of interest at
different depths of field is called?
Vergence

o The eye movement that stabilizes the image of
a slowly moving object is called?
Persuit
o The eye movements that brings new but
stationary objects of interest on to the fovea is
called?
Saccades

Otolith organs:
 They have otoconia on top
Use: To determine the action of line of gravity.
Saccule orientation:
Parasagital/ verticle
plane
Utricle orientation :
Horizontal

Utricle is Horizontal – so if the hair cells move
side to side , it gets deflected. But if it moves
up and down , no movement. So, utricle is not
responsive to bob . Utricle responds to roll tilt.
 Sacule is parasagital : Moves up and down –
responsible for bob movement. But side to side
– no movement – no heave

Vestibulo ocular reflex
Angualr VOR – By SCC – Bilateral uticulectomy
abolishes tilt reaction
Urticle and saccule related VOR – Linear VOR /
Translational VOR
Ocular counter rolling response.

Vestibulo ocular reflex
POINTS TO REMEMBER:
When head moves to right , inner ear fluid
moves to left, cupula deflection to left, eyes
moves to left
 When head moves in horizontal plane, inner
ear fluids moves in horizontal plane.

Vestibular system functions
Vision stability – Function of SCC
Postular stability – function of Otolith organs
by
1) Anti gravity muscles – Vestibulospinal
pathways
2) Autonomic changes – vestibuloautonomic
reflex
 Basis of body’s internal global positioning
system.

HISTORY TAKING:
 Vertigo / Presyncope/ syncope
 What happened when the first time imbalance
occurred:
 Onset of symptoms with straining - semicircular
canal dehiscence or perilymphatic fistula
A correlation of symptoms with a large salt load
should raise suspicion for Meniere disease.
Onset of symptoms after head trauma may indicate
benign paroxysmal positional vertigo (BPPV) or
traumatic brain injury.

What is the duration of symptoms?
 Is it episodic / continuous ?
Sec-
min
• BPPV
• Episodic
Hours-
days
• Migraine- Episodic
• >12 hrs – Vestibular neuritis
Contino
us
• mal de debarquement syndrome
• Psychogenic dizziness

 What triggers the symptoms?
1. Begins on rolling over the bed ot tilting head
backwards and towards affected side
BPPV OF POSTERIOR CANAL
2. Begins by lying supine and turning head to the side BPPV OF HORIZONTAL CANAL
3. During rapid head rotations as oscillopsia VESTIBULAR HYPOFUNCTION
4. Brief 5-10 sec periods of vertigo can be spontaneous
or induced by head movements
VASCULAR COMPRESSION OF
VIII NERVE
5. Travel by airplane with c/o ear popping • PERILYMPHATIC FISTULA
FROM INNER EAR
• BAROTRAUMA
6. Unevetful boat cruise f/b persistant rocking
sensation on land
MAL DE DEBARQUEMENT
SYNDROME
7. Recent recreational activity • ALTERNOBARIC VERTIGO
• PERILYMPH FISTULA
• INNER EAR
DECOMPRESSION
SICKNESS

ASSOCIATED SYMPTOMS:
 HEARING LOSS
 TINNITUS
 AURAL FULLNESS
 AURA/ HEADACHE
 VISUAL LOSS
 DIPLOPIA
 EXTREMITY
NUMBNESS
 DYSARTHRIA
 LOSS OF
COUNCIOUSNESS
 SWEATING
 DYSPNEA
 PALPITATIONS

PROVOKING FACTORS:
 POSITION CHANGES
 PRESSURE CHANGES
(LIFTING , SNEEZING,
VALSALVA)
PAST HISTORY:
 CHRONIC OTITIS MEDIA
 EAR SURGERY
 UPPER RESPIRATORY
TRACT INFECTION
 EXPOSURE TO
VESTIBULOTOXIC
MEDICATIONS
 ONCOLOGICAL DISEASE
 H/O CARDIAC
ARRYTGMIAS,
COAGULOPATHIES
 H/O ANXIETY DISORDERS,
PANIC ATTACKS,
AGOROPHOBIA
• PHOTOSENSITIVITY
• SOUND SENSITIVITY

 LIFESTYLE:
Caffeine/cheese/wine/stress – can bring about the
symptoms in vestibular migraine
 ENVIRONMENT:
Change in weather or motion stimulation like from
ceiling fans, video games, fluorescent lights – Vestibular
maigraine

EXAMINATION OF PATIENT
PRESENTING WITH GIDDINESS:
• Blood pressure (supine then standing)
• Routine Ear examination
• Tuning fork examination
• Audiometry evaluation (PTA )
• Cranial nerves examination (especially II to
VIII)
• Gross visual acuity, ocular motion

A. SPONTANEOUS NYSTAGMUS :
 Involuntary, rhythmical, oscillatory movement
of eyes.
 It may be horizontal, vertical or rotatory.
 Vestibular nystagmus has a slow and a fast
component, and by convention, the direction of
nystagmus is indicated by the direction of the
fast component.

 Intensity of nystagmus is indicated by its
degree

HOW TO ELLICIT NYSTAGMUS?
Patient is seated in front of the examiner or lies
supine on the bed.
The examiner keeps his finger about 30 cm
from the patient’s eye in the central position
and moves it to the right or left, up or down.
 At any time finger should not be moved more
than 30° from the central position to avoid
gaze nystagmus.

NYSTAGMUS
• Horizontal
• Vertical
• Torsional
Waveforms:
1)Saw tooth / jerk
2) Pendular

Presence of spontaneous nystagmus always
indicates an organic lesion.
Vestibular nystagmus is called
Peripheral - lesion of labyrinth or VIIIth nerve
Central - lesion in central neural pathways
(vestibular nuclei, brainstem, cerebellum).

• Irritative lesions of the labyrinth (serous
labyrinthitis) cause nystagmus to the side of
lesion.
• Paretic lesions (purulent labyrinthitis, trauma
to labyrinth, section of VIIIth nerve) cause
nystagmus to the healthy side

o Nystagmus of peripheral origin can be :
 Suppressed - By optic fixation by looking at a
fixed point
 Enhanced - In darkness or by the use of
Frenzel glasses (+20 dioptre glasses) both of
which abolish optic fixation.
o Nystagmus of central origin cannot be
suppressed by optic fixation.

GAZE TESTING:
• Patient is asked to fixate on the examiner's finger held
in an eccentric gaze position
• Normal – No nystagmus
• Nystagmus + at eccentric gaze at 20 degrees from
center; note -intensity, direction and persistence.
• Unidirectional nystagmus that increases while gazing
in the direction of the fast phase (Alexander law)
implies a peripheral cause
• Gaze-evoked nystagmus which beats in the direction
of gaze is indicative of floccular lesions

SMOOTH PURSUIT TESTING:
• The ability to follow accurately a slowly moving target
requires foveal vision, intact occipital cortices and
oculomotor brainstem nuclei.
• Slowly move a finger or pen 20–40 deg/s in both the
lateral and vertical planes (best corrected vision)
• Normal pursuit eye movements are smooth and accurately
track the target.
• Saccadic breakup of pursuit is significant and can
suggest visual problems (especially in the elderly),
attentional problems or central pathology of the pursuit
pathways in the brainstem, occipital cortex or cerebellum

SACCADE TESTING:
• The capability to fixate conjugately on a new
visual target is generated by the saccadic
system in the frontal motor cortex and
brainstem.
• The patient is instructed to look rapidly back
and forth between two fingers presented 15–20
degrees

• Normal: Conjugate movements of the eyes
without target overshoot or undershoot .
• Cerebellar disease may cause saccadic
overshoots or undershoots
• If the adducting eye moves slowly while the
abducting eye overshoots or exhibits
nystagmus – Evaluate for multiple sclerosis

VESTIBULO OCULAR REFLEX
TESTING:
• The VOR is a three neuron arc that stabilizes vision
during high velocity impulsive head movements
• Testing of the vestibulo-ocular reflex (VOR) is
performed using
– Head thrust
– Headshake
– Dynamic visual acuity (DVA) tests
• Most widely used bedside test of the VOR is the head
thrust

HEAD THRUST:
 The patient faces the examiner with the head tilted
down about 30 degrees
 Lateral SCC - horizontal position.
 The examiner grasps the patient's head in both hands
and asks the patient to keep their gaze on the
examiner's nose.
 The head is then slowly rotated back and forth
laterally until an unexpected high-velocity, low
amplitude thrust is made to bring the head from
lateral to midline

• Patient with weak peripheral vestibular system
cannot stabilize vision
• Eyes slide past the target and are redirected to
the examiner's nose with a compensatory
saccade immediately after the thrust
• Thrust in the direction of the weak ear in
unilateral lesions elicits saccades

HEAD SHAKING TEST
• Performed by rotating the patient's head at 2
Hz in the horizontal or vertical plane for 20–30
seconds using Frenzel lenses
• Look for post-headshake nystagmus
• Nystagmus (if +) beats in the plane of head
rotation toward the stronger ear
• In Menière disease and other acute vestibular
losses, the nystagmus may beat toward the
affected

Dynamic visual acuity (DVA) tests
• DVA is assessed by comparing the change in
visual acuity induced with a high-velocity,
low-amplitude headshake.

B.FISTULA TEST
BASIS: To induce nystagmus by producing pressure
changes in the external canal which are then transmitted
to labyrinth. Stimulation of labyrinth results in
nystagmus and vertigo.
PROCEDURE:
 The test is performed
by applying intermittent
pressure on the tragus or
by using Siegel’s speculum.

Normally - Test is negative
Because Pressure changes in the external auditory
canal cannot be transmitted to the labyrinth.
Positive :
 Erosion of horizontal semicircular canal as in cholesteatoma or
a surgically created window in the horizontal canal
(fenestration operation)
 Abnormal opening in the oval window (poststapedectomy
fistula)
 Abnormal opening in round window (rupture of round window
membrane).

False negative fistula test:
Seen when cholesteatoma covers the site of fistula
and does not allow pressure changes to be
transmitted to the labyrinth.
False positive fistula test :
congenital syphilis
25% cases of Ménière’s disease
Hennebert’s sign

C. ROMBERG TEST
Patient is asked to stand with feet together and
arms by the side with eyes first open and then
closed.

D. GAIT
The patient is asked to walk along a straight
line to a fixed point, first with eyes open and
then closed.
In case of uncompensated lesion of peripheral
vestibular system, with eyes closed, the patient
deviates to the affected side.

E. PAST-POINTING AND FALLING
The past-pointing, falling and the slow
component of nystagmus
are all in the same direction.
 If there is acute vestibular failure, say on the
right side, nystagmus is to the left but the past-
pointing and falling will be towards the right,
i.e. towards side of the slow component.

F. DIX-HALLPIKE MANOEUVRE
(POSITIONAL TEST)
 This test is particularly useful when patient complains
of vertigo in certain head positions.
 Helps to differentiate a peripheral from a central lesion.
 Method :
• Patient sits on a couch.
• Examiner holds the patient’s head, turns it 45° to the
right and then places the patient in a supine position so
that his head hangs 30° below the horizontal
• Patient’s eyes are observed for nystagmus.
• The test is repeated with head turned to left and then
again in straight head-hanging position

Four parameters of nystagmus are observed:
o Latency ,Duration, Direction ,Fatiguability
In benign paroxysmal positional vertigo:
 Nystagmus appears after a latent period of 2–20 s and
less than a minute
 Nystagmus is rotational and geotropic
 Is always in one direction, i.e. towards the ear that is
undermost
 Nystagmus is fatiguable
 Reversible with return of the head to the upright
position

G. TESTS OF CEREBELLAR DYSFUNCTION
1. Asynergia
(abnormal finger-nose test)
2.Dysmetria
(inability to control range of motion)
3.Dysdiadochokinesia(inability to
perform rapid alternating movements)
4.Rebound phenomenon (inability to
control movement of extremity
When opposing forceful restraint is
suddenly released)

• Midline disease of cerebellum causes:
1. Wide base gait
2. Falling in any direction
3. Inability to make sudden turns while walking 4.
Truncal ataxia
• Nystagmus observed in midline or hemispheral
disorders of cerebellum includes gaze evoked
nystagmus, rebound nystagmus and abnormal
optokinetic nystagmus

A. CALORIC TEST
1)Modified Kobrak test:
It is a quick office procedure.

2. Fitzgerald–Hallpike test (Bithermal
caloric test).
 Patient lies supine with head tilted 30° forward
 Ears - irrigated for 40 s alternately with water at 30 °C
and at 44 °C (i.e. 7° below and above normal body
temperature)
 Eyes observed for appearance of nystagmus
 If no nystagmus is elicited from any ear, test is repeated
with water at 20 °C for 4 min before labelling the
labyrinth dead.
 A gap of 5 min should be allowed between two ears.

• Response of labyrinth is ellicited as duration of
nystagmus
• Canal paresis: Response elicited from a particular
canal right or left after stimulation with cold or warm
water is less than opposite side.
• Less or no response indicates Depressed function of
ipsilateral labyrinth – Meniers disease , acoustic
neuroma, postlabyrinthectomy, vestibular nerve
section

• Direction preponderance: It takes into consideration
the duration of nystagmus to the right or left
irrespective of whether it is elicited from the right or
left labyrinth. If the nystagmus is 25–30% or more on
one side than the other, it is called directional
preponderance to that side
• Directional preponderance : Occurs towards the side
of central lesion and away from the side of peripheral
lesion.

3. Cold-air caloric test:
 This test is done when there is perforation of
tympanic membrane.
 The test employs Dundas Grant tube, which is a
coiled copper tube wrapped in cloth.
 The air in the tube is cooled by pouring ethyl chloride
and then blown into the ear to produce vertigo and
nystagmus
 It is only a rough qualitative test

B. ELECTRONYSTAGMOGRAPHY
 Method of detecting and recording of nystagmus
 The test depends on the presence of corneoretinal
potentials which are recorded by placing electrodes at
suitable places round the eyes.
 The test is also useful to detect nystagmus, which is
not seen with the naked eye.
 It also permits to keep a permanent record of
nystagmus.

• It allows the accurate measurement of various
nystagmus like slow phase velocity, amplitude,
frequency, duration, fast phase velocity, total numbers
of beats, latency, etc.
• ENG studies the vestibular reflex which gives
valuable information about the integrity of the brain
stem.
DRAWBACKS:
 No characteristic wave configuration or abnormalities
 ENG test does not assess the functional integrity of
the vestibulospinal reflex system

• Various tests done during ENG procedure are:
1. Calibration
2. Spontaneous nystagmus test
3. Gaze test
4. Optokinetic nystagmus test
5. Positional test
6. Paroxysmal nystagmus test
7. Caloric test

C. OPTOKINETIC TEST
 Patient is asked to follow a series of vertical stripes
on a drum moving first from right to left and then
from left to right.
 Normally it produces nystagmus with slow
component in the direction of moving stripes and fast
component in the opposite direction.
 Optokinetic abnormalities are seen in brainstem and
cerebral hemisphere lesions.
 Useful to diagnose a central lesion.

D. ROTATION TEST
 Patient is seated in Barany’s revolving chair with head
tilted 30° forward and then rotated 10 turns in 20 s
 The chair is stopped abruptly and nystagmus observed.
 Normally there is nystagmus for 25–40 s.
 Can be performed in cases of congenital abnormalities
where ear canal has failed to develop
 Disadvantage of the test is that both the labyrinths are
simultaneously stimulated
during the rotation process
and cannot be tested
individually.

E. GALVANIC TEST
 It is the only vestibular test which helps in
differentiating an end organ lesion from that of
vestibular nerve.
 Patient stands with his feet together, eyes closed and
arms outstretched and then a current of 1 mA is
passed to one ear.
 Normally, person sways
towards the side of
anodal current.
(Normal vestibular nerve)

F. POSTUROGRAPHY
To evaluate vestibular function by measuring
postural stability
Maintenance of posture depends on three
sensory inputs—visual, vestibular and
somatosensory.
Uses either a fixed or a moving platform.
VIDEO

G. VESTIBULAR EVOKED
MYOGENIC POTENTIALS (VEMP)
 To study function of otolith organs—the saccule and
utricle.
 Normally their function is linear acceleration.
 They can also be stimulated by loud sound of air or
bone conduction.
 Myogenic potentials can be picked up from either the
sternocleidomastoid (cervical) muscle or ocular
muscle (inferior oblique or superior rectus) and have
respectively been called cVEMP and oVEMP.

 Since saccule is supplied by the inferior division of
nerve and utricle by the superior division, study of
VEMP in neuroma can help us to find its origin from
the superior or inferior division.
 Reflex arc : From saccule—inferior vestibular
nerve—vestibular nuclei— ipsilateral vestibular
spinal tract—spinal accessory nerve (CN XI)—
sternocleidomastoid
 Reflex arc: From utricle—superior vestibular nerve—
vestibular nuclei—medial longitudinal fasciculus—
oculomotor (CNIII) nerve—inferior oblique muscle

 Air-conducted sounds primarily activate the saccule,
 Bone-conducted sounds activate both the saccule and
the utricle.
 VEMP is being used to find the origin of an acoustic
neurons (from superior or inferior vestibular nerve),
Ménière’s disease, superior canal dehiscence,
vestibular neuritis and localisations of lesions of
posterior cranial fossa, i.e. from the upper or lower
brainstem.
 Vestibulo-ocular reflex is mediated through upper
brainstem, while vestibulospinal arc is through the
lower brainstem

CERVICAL VEMP
 The cVEMP tests Saccule and Inferior vestibular
nerve.
 Recorded from the sternocleidomastoid muscle
(SCM).
 It is an inhibitory potential and an ipsilateral
response.
• When a muscle is flexed, there is a split second
within that flex where it releases.
• That provides the waveform or the response from the
sound

OCULAR VEMP
 The oVEMP is primarily for utricle and superior
nerve response.
 Little part of oVEMP response comes from saccule.
 This is an excitatory response that we record from
the extraocular muscles.
 Waveform is generated when the person looking up
 This a contralateral response. When we stimulate the
right, we record the left and vice versa

REFERENCES:
Scott brown 8th ed
 Ballingers 18th ed
Cummings 6th ed
Dhingra 7th ed
 Hazarika 3 rd ed

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