Transcript Evaluation of vertigo - The Medical Post | Trusting Medicine

Evaluation of
Vertigo
Dr. Vishal Sharma
Definition of vertigo

A sensation of rotation or imbalance of one's self
or of one's surroundings in any plane

rotation of one's self = subjective vertigo

rotation of one's surroundings = objective vertigo
Causes for vertigo
A. Peripheral: lesions of vestibular end organs &
vestibular nerve. Account for 85% of all cases of
vertigo.
B. Central: lesions of central nervous system.
Account for 15% of all cases.
Central causes for vertigo
Vascular causes: see next slide
Epilepsy: both disease & its treatment
Road Traffic Accident: Head trauma
Tumor: of brainstem, 4th ventricle & cerebellum
Infection: Meningitis, Encephalitis
Glial diseases: Multiple sclerosis
Others: Parkinsonism, Psychogenic
Vascular Causes
1. Vertebro-Basilar Insufficiency
2. Wallenberg’s lateral medullary syndrome: PICA
 Ipsilateral ataxia + vertigo + nystagmus + diplopia
 loss of touch, pain & temperature: I/L face, C/L body
 Dysphagia, hoarseness, decreased gag reflex
 I/L Horner’s syndrome
3. Hypertension
4. Basilar migraine
Peripheral causes
 B.P.P.V. (commonest)
 Temporal bone #
 Meniere’s disease
 Barotrauma
 Vestibular neuronitis
 Cholesteatoma
 Labyrinthitis
 Cochlear otosclerosis
 Vestibulotoxic drugs
 Autoimmune disease
 Vestibular schwannoma  Presbystasis
 Perilymph fistula
 Paget’s disease
Miscellaneous causes
Cervical Vertigo
Iatrogenic
 Neurovascular
 Surgical
 Neuromuscular
 Cholesteatoma
 Mechanical vascular
 Stapedectomy
Ocular Vertigo
Drug induced
 Error of refraction
 Extra-ocular muscle palsy
 Ototoxic drugs
Psychogenic vertigo
Causes: anxiety, panic disorder, phobia
Diagnostic features:

Absence of organic causes

Presence of vague & fleeting symptoms

Dramatic presentation & attention seeking behaviour

Relation b/w emotional stress & onset of vertigo
Vertigo-like symptoms

Faintness

light-headedness

unsteadiness

motion intolerance

imbalance

floating sensation
Causes of Vertigo-like
symptoms
Hematological: anemia, polycythemia
Cardiovascular
Metabolic
 Orthostatic hypotension
 Diabetes mellitus
 Cardiac failure
 Hypoglycemia
 Obstructive cardiomyopathy
 Hypothyroidism
 Cardiac dysrhythmias
 Chronic renal failure
 Carotid sinus syndrome
 Alcohol intoxication
 Hyperventilation
History Taking
Can diagnose 80% cases
Important history questions

Confirmation of vertigo: rotatory sensation

Absence of syncope or light headedness

Onset: sudden or gradual

Episodic (isolated / recurrent) or continuous

Duration of each episode of vertigo

Associated symptoms

Provoking or aggravating factors

Systemic illness for vertigo
Associated symptoms

Decreased hearing: symmetric or asymmetric

Ear discharge

Tinnitus

Aural fullness

Nausea & vomiting

Imbalance
Associated
symptoms
Causes
Deafness + tinnitus
+ aural fullness
Meniere’s disease
Imbalance
Vestibular neuronitis, Acoustic
neuroma
Headache
Migraine, Acoustic neuroma
Focal neurological
findings
Acoustic neuroma, Central vascular
causes
Ear discharge
Labyrinthitis, perilymph fistula
Provoking or
aggravating factors
1. Specific head position
2. Sudden standing up from sitting position
3. Sudden head & neck movement
4. Recent U.R.T.I.
5. Trauma to ear or head
6. Stress
7. Change in ear pressure
8. Headache
9. Drug intake
10. Diplopia
Provoking factor
Causes
Change in head position
B.P.P.V., labyrinthitis, multiple
sclerosis
Sudden standing up from
sitting position
Orthostatic hypotension
Sudden neck movement
Cervical spondylosis, VBI
Recent URTI
Vestibular neuronitis
Stress
Psychogenic, migraine
Change in ear pressure
Perilymph fistula
Drugs causing vertigo
 Alcohol
 Analgesic (opiate)
 Anti-histamine
 Anti-hypertensive
 Anti-angina drug
 Anti-arrhythmic
 Anti-coagulant
 Aminoglycoside
 Isoniazide (INH)
 Rifampicin
 Anti-malarial
 Corticosteroid
Systemic illness for vertigo

Hypertension / Hypotension

Hypoglycemia

Epilepsy

Brain infection

Brain tumors

Parkinsonism

Multiple sclerosis
Duration of
one episode
Few minutes
Up to 1 hr
Hours
Causes
B.P.P.V., Perilymph fistula
Central vascular causes, Perilymph fistula
Meniere’s disease, Acoustic neuroma,
Perilymph fistula, Central vascular causes,
Head trauma
Days
Vestibular neuronitis, Multiple sclerosis,
Perilymph fistula, Central vascular causes
Weeks
Psychogenic
Routine ENT OPD
tests for vertigo
evaluation

Test for spontaneous & gaze-evoked nystagmus

Head shake test

Positional tests

Positioning tests (Dix-Hallpike & Roll tests)

Fistula test

Caloric tests

Tests for dysequilibrium

Tests for coordination

Cranial nerve examination
Nystagmus

Involuntary, rhythmical oscillatory movement of eye

Vestibular disorders cause jerk nystagmus with slow
& fast phases

Direction of nystagmus given by its fast phase

Vestibular nystagmus gets enhanced by looking in
direction of faster phase & diminished by looking
away from it (Alexander’s law)
Alexander’s Classification
Intensity grading of vestibular nystagmus:
1°  only present while looking towards fast phase
2°  present while looking towards fast phase &
also while looking straight
3°  present while looking towards fast phase,
looking straight & looking towards slow phase
Nystagmus

Vestibular lesion nystagmus gets suppressed
by optic fixation & gets enhanced with removal
of optic fixation (with Frenzel glasses or in dark)

Irritative vestibular labyrinthine lesion:
Ipsilateral nystagmus

Paralytic vestibular labyrinthine lesion:
Contralateral nystagmus
Features
Peripheral
Central
a. Direction
Fixed
Changes
b. Duration
Short (days)
Long (weeks)
c. Effect of optic fixation
Inhibited
Unchanged
d. Latency
Present
Absent
Mild
Severe
3. Nausea & vomiting
Severe
Variable
4. Deafness & tinnitus
Common
Rare
5. Neurological deficit
Rare
Common
1. Nystagmus character
2. Imbalance
Nystagmus (slow component)
Nystagmus (fast component)
Semicircular canal
stimulated
Nystagmus Direction (fast phase)
Right Lateral
Right horizontal
Left Lateral
Left horizontal
Right Superior
Down beating, counter-clockwise
Left Superior
Down beating, clockwise
Right Posterior
Up beating, counter-clockwise
Left Posterior
Up beating, clockwise
Other eyeball movements

Opsoclonus: non-rhythmic, bizarre eye movements.
Seen in brain stem & cerebellar pathology.

Ocular Flutter: mild form of opsoclonus lasting for few
seconds

Ocular Myoclonus: pendular movement of eyeball
with rhythmic movement of soft palate & tongue

Ocular Bobbing: irregular, abrupt downward jerks
seen in CNS lesions
Test for spontaneous nystagmus
Patient’s eyes examined with: pt’s looking straight
ahead with fixed head; no visual or vestibular
stimulus; no optic fixation
Best examined in dark room with infra-red video
goggles over open eyes or during electronystagmography with eyes closed
Spontaneous nystagmus seen in unilateral
peripheral vestibular lesion
Infra-red video goggles
Test for gaze-evoked nystagmus
Test for gaze-evoked nystagmus

Finger kept centrally 30 cm from pt's eyes &
moved in horizontal & vertical planes

Pt is asked to follow it with his / her eyes

Keep displacement from midline to maximum of
30° (avoids physiological end-point nystagmus)

Bidirectional vertigo seen in CNS lesions
Head Shake Test

Patient’s head grasped by physician & rapidly
shaken from side to side for 20 times. Repeat in
vertical plane for 20 times.

Presence of horizontal nystagmus indicates
peripheral vestibular disorder. Lt lesion  Rt
nystagmus. Vertical nystagmus indicates
brainstem or cerebellar lesion.
Head Shake Test

Starting from neutral position (A), rapid head thrust to
Rt in horizontal plane  compensatory eye movement
to left  pt's eyes remain stable on examiner (B)

On similar head movement to left (C), I/L hypoactive
labyrinth results in delayed catch up saccade (D) to
maintain gaze. Arrow shows direction of saccade
Positional Nystagmus

Placing pt’s head slowly in different positions,
detects response to changes in direction of
gravitational force

11 specific head position:
a. Sitting position: 5 head positions
b. Supine position: 6 head positions

Each position to be maintained for 30 sec
Head positions
Sitting position
Supine position

Head upright

Head straight

Right side down

Right side down

Left side down

Head hanging

Head hanging with right turn

Head hanging with left turn



Left side down
Head extended
Head flexed
Positioning Nystagmus

Helps to detect anomalies in otolith system

Provoked by placing head rapidly in different
positions
Tests

Dix-Hallpike Test

Roll Test
Fistula test

Transmission of increased air pressure in
E.A.C., via middle ear, into inner ear through a
labyrinthine fistula causes vertigo + nystagmus
towards affected ear

E.A.C. pressure is increased by intermittent
tragal pressure or Siegelization
Fistula Test
Sites of labyrinthine fistula
1. Horizontal semicircular canal
 Cholesteatoma destruction
 Fenestration operation
2. Oval window
 Post-stapedectomy
3. Round window membrane rupture
Hennebert’s sign
False positive fistula sign in absence of
labyrinthine fistula. Seen in:
1. Meniere's disease: fibrosis b/w stapes footplate
& utricle
2. Hyper mobile stapes footplate
 Congenital syphilis
 Idiopathic
False negative fistula sign
Negative fistula sign in presence of labyrinthine
fistula. Seen in:
1. Cholesteatoma matrix / granulation covering
labyrinthine fistula
2. Dead Labyrinth
3. Total E.A.C. obstruction (impacted wax)
Dix – Hallpike
maneuver
(Nylen – Barany
maneuver)
Step 1
Step 2
Step 3
Step 4
Steps 1 to 3
Step 3 to 4
Dix-Hallpike Manoeuvre
1. Pt in sitting position on a couch looking ahead
2. Pt’s head turned 45° towards diseased ear
3. Pt moved rapidly into supine position with
head hanging 30° below couch. Pt’s eyes
observed for nystagmus for 1 minute
4. Pt moved rapidly back into sitting position
5. Manoeuvre repeated for opposite ear
Frenzel glasses
Roll Test for
lateral canal BPPV
1
2
3
4
5
Roll test for lateral canal BPPV
1. Patient lies supine with nose pointing up
2. Head turned 900 right rapidly & kept for 30 sec
3. Head turned back to supine position for 30 sec
4. Head turned 900 left rapidly & kept for 30 sec
5. Head turned back to supine position for 30 sec
Watch for nystagmus after each step
Caloric testing
Methods of caloric tests
Fitzgerald-Hallpike Bithermal
Caloric Test
Contraindications:
1. E.A.C. obstruction
2. Ear infection
3. T.M. perforation
4. Bradyarrythmias
5. Labyrinthine sedatives (for 24 hrs)
Mechanism of caloric
stimulation
Convection current formation in endolymph due to
temperature gradient → ampullo-petal flow for
warm water  activation of Vestibulo-Ocular Reflex
OR ampullo-fugal flow for cold water  inhibition
of Vestibulo-Ocular Reflex  vertigo + horizontal
nystagmus (slow phase away from side of VOR
activation & toward side of VOR inhibition)
Anatomy of vestibulo-ocular reflex
Fitzgerald-Hallpike Bithermal
Caloric Test

Pt supine + 30° head elevation. Each ear
irrigated in turn for 40 sec with warm water at
44°C & then cold water at 30°C.

Duration of nystagmus is from start of irrigation
to end point of nystagmus. Normal = 90–140 sec

Direction of fast component:
Cold → Opposite ear; Warm → Same ear
Fitzgerald-Hallpike Bithermal
Caloric Test
Fitzgerald-Hallpike Bithermal Caloric
Test
Normal Calorigram
Canal Paresis
Duration of nystagmus with both 44°C &
30°C irrigations in one ear is 30 % less
than opposite ear. Seen in same sided
peripheral vestibular lesion.
C. P. (%) = (R30 + R44) – (L30 + L44) X 100
R30 + R44 + L30 + L44
Right Canal Paresis
Left Canal Paresis
Directional Preponderance
Duration of nystagmus in one direction is 30 %
more than opposite direction. Seen in same
sided central vestibular lesion & opposite
peripheral vestibular lesion.
D.P. (%) = (L30 + R44) – (R30 + L44) X 100
R30 + R44 + L30 + L44
Right Directional Preponderance
Left Directional Preponderance
Special cases
Same sided canal paresis + same sided
directional preponderance:
– Acoustic Neuroma
Same sided canal paresis + opposite sided
directional preponderance:
– Meniere’s disease
Left C.P. + Left D.P.
Left C.P. + Right D.P.
Caloric test in comatose patient

With brainstem intact: Only slow phase movements to
cool or warm irrigation. Fast corrective phase absent.

With B/L MLF damage (internuclear ophthalmoplegia)
in Multiple Sclerosis: only lateral movement of one eye
possible as B/L medial rectus muscles are denervated

With B/L low brainstem lesion at vestibular nuclei: no
nystagmus in either warm or cool water irrigation
Modified Kobrak's Test
E.A.C. irrigated for 60 sec with ice cold water in
increasing quantity (5, 10, 20 & 40 ml) till
nystagmus is noticed
If nystagmus noticed with:

5 ml = Normal vestibular labyrinth

10 / 20 / 40 ml = Hypoactive labyrinth

No nystagmus (40 ml) = Dead labyrinth
Dundas Grant Cold Air Caloric
Test

Done in T.M. perforation as water syringing is
contraindicated

Air in coiled copper tube is cooled by pouring
ethyl chloride in it

Effluent cool air is blown into E.A.C. to
produce vertigo + nystagmus
Tests for dys-equilibrium
1. Standing test
2. Tandem gait test
3. Romberg test
4. Modified Romberg test
5. Unterberger / Fukuda stepping test
6. Babinski Weill test
Standing Test
Patient stands normally, with eyes closed
In peripheral vestibular lesion, pt assumes Discus
Thrower’s position:

Head turned towards side of lesion

Trunk twisted to side of lesion

Raising of hand on healthy side & lowering on
side of lesion

Falling to side of lesion
Discus thrower position
Tandem gait test

Patient made to walk with eyes open in a straight
line in tandem position (toes of one feet right
behind heel of other feet). Stopped suddenly &
asked to walk back.

Test repeated with eyes closed

Falling towards side of peripheral vestibular lesion
Tandem gait test
Romberg test

Subject stands with feet together, eyes open & hands
by the sides for 1 minute. Observe for swaying.

Subject closes eyes in same position for 1 minute.
Observe for swaying.

Romberg test sharpened by tandem position of feet.

Positive Romberg = swaying towards side of lesion,
only when eyes are closed. Seen in sensory ataxia
(loss of proprioception).

Negative Romberg = swaying even when eyes are
open. Seen in cerebellar ataxia.
Unterberger test

Patient blindfolded, arms extended

Asked to step on same spot 90 times in 1 minute

Peripheral vestibular lesion: pt deviates / rotates
to side of lesion by > 30 degrees

Deviation if <30 degrees on either side is
considered normal
Babinski Weill test

Patient asked to walk with eyes closed 5 pace
forwards & 5 pace backwards 6 times in 30 sec

U/L vestibular lesion: patient walks in star shaped
trajectory
Tests for coordination
1. Past pointing
2. Fukuda writing test
3. Tests for cerebellar function
– Finger nose test
– Heel knee test
– Rapid alternating task test
Past pointing test

Pt. made to sit with hands up & index finger
extended

Examiner raises his index finger in front of pt

Pt asked to touch examiners finger with eyes open
& then with eyes closed

If pt cannot perform task smoothly  past
pointing
Fukuda writing test

Patient asked 8-10 capital letter vertically in a
straight line first with eyes open then with eyes
closed

In U/L vestibular lesion: Letter deviates >20 deg
towards involved side but are legible

In cerebellar lesion: Letters are illegible
Finger nose test
Pt asked to touch her nose & then touch examiner’s
index finger with her index finger.
Cerebellar lesion pt cannot do it.
Heel shin test

Pt asked to move heel of one leg over shin of other leg
in a straight line. Cerebellar lesion pt cannot do it.
Rapid alternating task test

Patient asked to alternately perform supination &
pronation of one palm over other palm at rapid rate.
Cerebellar lesion pt cannot do it (adiadochokinesia) or
has difficulty doing it (dysdiadochokinesia).
Heel shin test
Rapid alternating task test
Cranial nerve examination
I = Smell test
II = Snellen chart
III / IV / VI = Ocular movement
V = Corneal Reflex , Facial sensation
VII = Facial muscle movement
VIII = Tuning fork test
IX / X = Palatal movement & gag reflex
XI = Shrugging of shoulder & neck rotation
XII = Tongue movement
Olfactory
Optic
Lt oculomotor nerve palsy
Lt trochlear nerve palsy
Primary position showing left superior oblique palsy
with lack of its depressor effect
Lt abducens nerve palsy
Lack of abduction of left eye
Trigeminal
Trigeminal + Facial
Auditory
Glossopharyngeal & Vagus
Spinal Accessory
Hypoglossal
Other Specific
Investigations
1. Electro-nystagmography
2. Computerized dynamic posturography
3. Cranio-corpography
4. Galvanic test
5. Vestibular rotation tests
6. Vestibular evoked potential
7. Brain Electrical Activity Mapping (BEAM)
8. Dynamic visual acuity
Electronystagmography
Principle

Retina is negative charged
compared to positive cornea
resulting in corneo-retinal
potential

Movement of eyeball causes
movement of electrical field
currents & detected by
electrodes around eye
Electrode positioning
Lateral to outer canthus both sides:

horizontal movement
Above & below eye one side:

vertical movement
Glabella:

ground electrode
Electrode placement
Electro-nystagmograph
Y axis: 1 cm = 20 degree ocular movement
X axis: 1 cm = 1 sec
Identification of movement

Horizontal movement of eye:
– Right movement = upward deflection
– Left movement = downward deflection

Vertical movement of eye:
– Upward movement = upward deflection
– Downward movement = downward deflection
Nystagmus Identification

Nystagmus beat should be triangular in shape

Upward & downward deflection should have
different slopes

Gradual slope = slow component

Steep slope = fast component

Both slopes equal = perpendicular nystagmus
E.N.G. procedures
Vestibular tests
Oculomotor tests
 Spontaneous nystagmus
 Pursuit test
 Gaze nystagmus
 Saccade test
 Positional nystagmus
 Optokinetic test
 Positioning nystagmus
 Fixation test
 Fistula test
 Bi-thermal caloric tests
Fixation: holds image of stationary object on fovea
Vergence: moves eyes in opposite directions to place
images of single object on both foveas at one time
Saccade: brings images of objects of interest onto fovea
Optokinetic tracking: holds images steady on retina
during sustained head rotation
Smooth pursuit: holds image of moving target on fovea
Vestibulo-ocular reflex: holds images steady on retina
during brief head rotation
Nystagmus (quick phase): resets eyes during prolonged
rotation & directs gaze toward oncoming visual scene
ENG smooth pursuit movement
Culmination Frequency

No. of nystagmus beats in 30 seconds of most
prolific phase of nystagmus duration in ENG
Caloric test values:

Right warm = 22 - 59 beats / second

Right cold = 24 - 67 beats / second

Left warm = 23 - 63 beats / second

Left cold = 27 - 68 beats / second
Response graded as:
0 = normal response
1 = hypoactive response
2 = hyperactive response
Result given as code of 4 digits in order of:
Right warm, Right cold, Left warm, Left cold
Graphical presentation of this data called
Claussen’s Butterfly chart
Claussen’s
Butterfly
chart
0000 = Normal
1111 = B/l vestibular lesion or brain stem lesion
2222 = B/L brain stem + cerebellar lesion
1100 = Rt canal paresis in Rt vestibular lesion
0011 = Lt canal paresis in Lt vestibular lesion
0110 = Lt brain stem lesion
1001 = Rt brain stem lesion
0220 = Lt directional preponderance
2002 = Rt directional preponderance
0022 = Lt nystagmus dysinhibition in Rt cerebellar lesion
2200 = Rt nystagmus dysinhibition in Lt cerebellar lesion
Findings in central disorder

Spontaneous or positional nystagmus with normal
caloric results

Direction-changing nystagmus

Failure of nystagmus suppression by optic fixation

Bilateral reduced or absent caloric responses without
history of labyrinthine or middle ear disease

Abnormal saccade or pursuit results

Hyperactive caloric responses (cerebellar disease)
Findings in peripheral disorder

Unilateral caloric weakness

Bilateral caloric weakness with history of labyrinthine
disease or administration of ototoxic drugs

Fatiguing positional nystagmus

Nystagmus suppression by optic fixation

Direction-fixed nystagmus
Computerized dynamic
posturography

Consists of computer-controlled platform & visual
booth used to evaluate both sensory + motor
components of balance

Has 2 parts: a. Sensory organization test
b. Motor coordination / Motor control test

Posturography not a substitute for careful gait
examination & is more valuable in rehabilitation
Sensory organization test

Detects defect in subject’s ability to use vestibular,
somatosensory & visual inputs to maintain balance

These 3 systems are singly or collectively manipulated
to test subject’s ability to maintain balance under
these stressful conditions. Analyzed by computer.

Sensory test useful in peripheral lesions, vestibular
rehabilitation & medico legal cases
Eye Visual Base
Equilibrium Inputs
1 Open Steady
Steady Vestibular + Visual + Somatosensory
2 Close Absent
Steady
Vestibular + Somatosensory
3 Open
Steady
Vestibular + Somatosensory + Visual
(altered)
4 Open Steady
Sway
Vestibular + Visual + Somatosensory
(altered)
5 Close Absent
Sway
Vestibular + Somatosensory (altered)
6 Open
Sway
Vestibular + Visual (altered) +
Somatosensory (altered)
Sway
Sway
Dysfunction Pattern
Abnormal Test Condition
Vestibular ------------------------------------- 5, 6
Visual + vestibular ------------------------ 4, 5, 6
Visual preference --------------------------- 3, 6
Visual preference + vestibular -------- 3, 5, 6
Somatosensory + vestibular --------- 2, 3, 5, 6
Severe dysfunction --------------------- 1, 2, 3, 4
Motor coordination test
Evaluation of efferent motor pathway of balance
Support surface of CDP machine suddenly moved:
1. forward & backward
2. upward & downward
Lower limb muscle responds by movement of ankle
& hip joints. Motor output assessed by CDP
Motor coordination test
Cranio-corpography

Pt wears helmet with light bulbs

Photographic representation of pt's movement
patterns on performing Romberg & Unterberger tests

Wide angular deviation (> 700 away from sagittal axis)
indicates peripheral dysfunction on side of deviation

Lateral sway > 20 cm suggests central pathology
Cranio-corpography
Left angular deviation
Broad lateral sway
Galvanic test

Pt. stands with feet together, eyes closed, arms
outstretched. Saline pads placed in EAC or over
mastoid. Electrodes placed over sternum.

Current of 1 mA passed through saline pad to 1 ear

Normal person sways away from side of cathode (+ve)
current & nystagmus (fast phase) towards cathode

Current of >1mA required in vestibular neuronitis, long
standing Meniere’s disease

Response absent in vestibular schwannoma
Vestibular rotation tests
1. Barany’s Chair Rotation Test
2. Sinusoidal Acceleration Test
3. Slow Harmonic Acceleration Test
4. Vestibular Auto-rotation Test (VAT)
Barany’s chair rotation test
Subject seated in dental chair  pt’s head bent 300
forwards (lateral SSC lies in plain of rotation)  chair
rotated 10 times in 20 sec  rotation stopped abruptly 
nystagmus direction + intensity noted  both clockwise &
anti-clockwise rotations done
Sinusoidal acceleration test
Pt placed in suspended torsion swing chair  chair
rotated to one side & let go  spring action of bar helps in
sinusoidal to & fro rotation in vertical axis
Slow harmonic acceleration test
Sinusoidal rotation of chair controlled by computer &
intensity of nystagmus calculated by computer
Findings in rotation tests
Rt rotation (clockwise)  Rt beating nystagmus
Lt rotation (anti-clockwise)  Lt beating nystagmus
Intensity of nystagmus same for both rotations
Asymmetrical intensity  vestibular pathology
Intensity not ed on optic fixation  central lesion

Gain = ratio of maximum eye velocity to maximum
chair velocity

Depressed gain values usually seen in incorrect
testing conditions

Depressed gain values under good testing conditions
suggest bilateral peripheral lesions

Abnormally high gain can indicate presence of
cerebellar lesion that is decreasing vestibular
inhibition
Vestibular Autorotation Test

Head band worn by patient has microchip circuitry

Pt asked to perform head movements in synchrony
with computerized auditory clues

Records horizontal & vertical eye movements with
ENG electrodes

Records horizontal & vertical head movements with
microchip angular velocity sensors
Vestibular autorotation test
Vestibular evoked potentials

Vb.E.P study is like BERA with vestibular stimulus
(head movement) instead of auditory stimulus

Response recorded by electrode placed on pt’s vertex

Short latency response: recorded from first 10 msec

Middle latency response: 10 – 100 msec

Long latency response: 100 - 1000 msec (also known
as Long latency rotational evoked potential)
Vestibular evoked potentials
Vestibular Evoked
Myogenic Potentials
(VEMP)

VEMP = Electromyography response of I/L sternocleidomastoid muscle to loud click. Afferent reflex
limb from saccule via inferior vestibular nerve &
efferent limb via medial vestibulo-spinal tract.

Low audio thresholds (60 dB) for VEMP or Tullio
effect seen in Meniere’s disease, superior SCC
dehiscence, multiple sclerosis, acoustic neuromas &
vestibular neuronitis. Normal threshold > 75 dB.
VEMP with threshold of 85 dB
Brain Electrical Activity Mapping

Synonym: quantitative electro-encephalography

Method of plotting brain electrical activity in response
to auditory or vestibular stimuli at a given point of time

Electrical activity measured by placing 20 electrodes
on scalp, unlike Vb.E.P which places only 1 electrode
Interpretation of BEAM

Electrical activities from different part of scalp
computed into topographical map for continuous
plotting of electrical activity measurement

In colour map: Red  yellow  green  blue
indicates transformation from positive voltage to
negative voltage

In black & white map: Black = +ve & grey = -ve
Dynamic Visual Acuity

Movement of head causes significant retinal slip &
loss of visual acuity unless vestibulo-ocular reflex
produces compensatory response

Rotational velocity sensors + computer screen
evaluates vision during head movement providing
functional assessment of vestibulo-ocular reflex

Vestibular vertigo pt have greater reduction in dynamic
visual acuity compared with non-vestibular vertigo
Referral to other departments

Internal Medicine: cardiovascular & metabolic causes

Neurology: central nervous system causes

Ophthalmology: ocular pathology

Orthopedics: cervical spine problems

Psychiatry: psychogenic vertigo

Pediatric: in pediatric migraine

Radiology: anatomic & physiologic brain imaging
Imaging indications in vertigo

Unilateral or asymmetric hearing loss

Vertical nystagmus, nystagmus not suppressed with
fixation, inability to stand unassisted

Direction-changing spontaneous nystagmus

Presence of cerebellar signs

New-onset severe headache

Stroke risk (DM, HTN, smoking, h/o myocardial infarct)

Acute vertigo with neck pain
Plain X-ray indications:

Cervical spine problems
C.T. scan brain indications:

Ischemic strokes

Cerebral & cerebellar hemorrhage
M.R.I. brain indications:

Cerebellar stroke

Cerebello-pontine angle tumors

Multiple sclerosis
Thank You