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 vertigoVascular 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

Neurovascular

Neuromuscular

Mechanical vascular

Ocular Vertigo

Error of refraction

Extra-ocular muscle palsy

Iatrogenic

Surgical

Cholesteatoma

Stapedectomy

Drug induced

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

Causes

Few minutes B.P.P.V., Perilymph fistula

Up to 1 hr Central vascular causes, Perilymph fistula

Hours 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

1. Nystagmus character

a. Direction Fixed Changes

b. Duration Short (days) Long (weeks)

c. Effect of optic fixation Inhibited Unchanged

d. Latency Present Absent

2. Imbalance Mild Severe

3. Nausea & vomiting Severe Variable

4. Deafness & tinnitus Common Rare

5. Neurological deficit Rare Common

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 electro-

nystagmography 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

Head upright

Right side down

Left side down

Head extended

Head flexed

Supine position

Head straight

Right side down

Left side down

Head hanging

Head hanging with right turn

Head hanging with left turn

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 examinationI = 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

Electro-nystagmography

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

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

E.N.G. procedures

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 Sway Steady Vestibular + Somatosensory + Visual (altered)

4 Open Steady Sway Vestibular + Visual + Somatosensory (altered)

5 Close Absent Sway Vestibular + Somatosensory (altered)

6 Open Sway Sway Vestibular + Visual (altered) + Somatosensory (altered)

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 sterno-

cleidomastoid 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