1. Evaluation of Vertigo
Dr. Vishal Sharma

2. 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

4. 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.

5. 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

6. Vascular Causes 2. Wallenberg’s lateral medullary syndrome: PICA
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 Basilar migraine

7. 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

8. Miscellaneous causes
Iatrogenic  Surgical  Cholesteatoma  Stapedectomy Drug induced  Ototoxic drugs
Cervical Vertigo  Neurovascular  Neuromuscular  Mechanical vascular Ocular Vertigo  Error of refraction  Extra-ocular muscle palsy

9. 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

10. Vertigo-like symptoms
Faintness
light-headedness
unsteadiness
motion intolerance
imbalance
floating sensation

11. Causes of Vertigo-like symptoms

12. 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

13. History Taking
Can diagnose 80% cases

14. 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

15. Associated symptoms Decreased hearing: symmetric or asymmetric
Ear discharge
Tinnitus
Aural fullness
Nausea & vomiting
Imbalance

16. 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

17. Provoking or aggravating factors

18. 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

19. 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

20. Drugs causing vertigo  Alcohol  Analgesic (opiate)
 Anti-histamine  Anti-hypertensive
 Anti-angina drug  Anti-arrhythmic
 Anti-coagulant  Aminoglycoside
 Isoniazide (INH)  Rifampicin
 Anti-malarial  Corticosteroid

21. Systemic illness for vertigo
Hypertension / Hypotension
Hypoglycemia
Epilepsy
Brain infection
Brain tumors
Parkinsonism
Multiple sclerosis

22. 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

25. Routine ENT OPD tests for vertigo evaluation

26. 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

27. 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)

28. 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

29. 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

30. 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
Variable
4. Deafness & tinnitus
Common
Rare
5. Neurological deficit

31. Nystagmus (slow component)

32. Nystagmus (fast component)

33. 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

34. 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

35. 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

36. Infra-red video goggles

37. Test for gaze-evoked nystagmus

38. 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

39. 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.

40. 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

41. 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

42. Head positions Sitting position Supine 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

43. Positioning Nystagmus
Helps to detect anomalies in otolith system
Provoked by placing head rapidly in different positions
Tests
Dix-Hallpike Test
Roll Test

44. 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

45. Fistula Test

46. Sites of labyrinthine fistula
1. Horizontal semicircular canal
 Cholesteatoma destruction
 Fenestration operation
2. Oval window
 Post-stapedectomy
3. Round window membrane rupture

47. 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

48. 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)

49. Dix – Hallpike maneuver (Nylen – Barany maneuver)

50. Step 1

51. Step 2

52. Step 3

53. Step 4

54. Steps 1 to 3

55. Step 3 to 4

56. 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

57. Frenzel glasses

58. Roll Test for lateral canal BPPV

59. 1 2 3 4 5

60. 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

61. Caloric testing

62. Methods of caloric tests

63. 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)

64. Mechanism of caloric stimulation

65. 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)

66. Anatomy of vestibulo-ocular reflex

70. 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

71. Fitzgerald-Hallpike Bithermal Caloric Test

72. Fitzgerald-Hallpike Bithermal Caloric Test

73. Normal Calorigram

74. 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

75. Right Canal Paresis

76. Left Canal Paresis

77. 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

78. Right Directional Preponderance

79. Left Directional Preponderance

80. Special cases
Same sided canal paresis + same sided directional preponderance:
Acoustic Neuroma
Same sided canal paresis + opposite sided directional preponderance:
Meniere’s disease

81. Left C.P. + Left D.P.

82. Left C.P. + Right D.P.

83. 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

86. 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

87. 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

88. Tests for dys-equilibrium
Standing test
Tandem gait test
Romberg test
Modified Romberg test
Unterberger / Fukuda stepping test
Babinski Weill test

89. 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

90. Discus thrower position

91. 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

92. Tandem gait test

93. Romberg test

94. 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.

95. 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

96. 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

97. Tests for coordination
Past pointing
Fukuda writing test
Tests for cerebellar function
Finger nose test
Heel knee test
Rapid alternating task test

98. 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

99. 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

100. 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.

101. Rapid alternating task test
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).

102. Heel shin test

103. Rapid alternating task test

104. 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

105. Olfactory

106. Optic

107. Lt oculomotor nerve palsy

108. Lt trochlear nerve palsy
Primary position showing left superior oblique palsy with lack of its depressor effect

109. Lt abducens nerve palsy
Lack of abduction of left eye

110. Trigeminal

111. Trigeminal + Facial

112. Auditory

113. Glossopharyngeal & Vagus

114. Spinal Accessory

115. Hypoglossal

116. Other Specific Investigations

117. Electro-nystagmography
Computerized dynamic posturography
Cranio-corpography
Galvanic test
Vestibular rotation tests
Vestibular evoked potential
Brain Electrical Activity Mapping (BEAM)
Dynamic visual acuity

118. Electro-nystagmography

119. 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

120. Electrode positioning
Lateral to outer canthus both sides:
horizontal movement
Above & below eye one side:
vertical movement
Glabella:
ground electrode

121. Electrode placement

122. Electro-nystagmograph
Y axis: 1 cm = 20 degree ocular movement
X axis: 1 cm = 1 sec

123. 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

124. 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

125. 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

126. 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

128. ENG smooth pursuit movement

129. Culmination Frequency
No. of nystagmus beats in 30 seconds of most prolific phase of nystagmus duration in ENG
Caloric test values:
Right warm = beats / second
Right cold = beats / second
Left warm = beats / second
Left cold = beats / second

130. 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

131. Claussen’s
Butterfly
chart

132. 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

133. 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)

134. 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

135. 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

137. 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

139. Eye Visual Base Equilibrium Inputs1
Open
Steady
Vestibular + Visual + Somatosensory 2
Close
Absent
Vestibular + Somatosensory 3
Sway
Vestibular + Somatosensory + Visual (altered) 4
Vestibular + Visual + Somatosensory (altered) 5
Vestibular + Somatosensory (altered) 6
Vestibular + Visual (altered) + Somatosensory (altered)

140. Dysfunction Pattern Abnormal Test Condition
Vestibular , 6
Visual + vestibular , 5, 6
Visual preference , 6
Visual preference + vestibular , 5, 6
Somatosensory + vestibular , 3, 5, 6
Severe dysfunction , 2, 3, 4

141. 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

142. Motor coordination test

143. 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

144. Cranio-corpography

145. Left angular deviation

146. Broad lateral sway

147. Galvanic test

148. Current of 1 mA passed through saline pad to 1 ear
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
148

149. Vestibular rotation tests
Barany’s Chair Rotation Test
Sinusoidal Acceleration Test
Slow Harmonic Acceleration Test
Vestibular Auto-rotation Test (VAT)

150. 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

151. 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
151

152. 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

153. 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

154. Vestibular autorotation test

155. 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: msec (also known as Long latency rotational evoked potential)

156. Vestibular evoked potentials

157. Vestibular Evoked Myogenic Potentials (VEMP)

158. 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.

159. VEMP with threshold of 85 dB

160. 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

161. 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

163. 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

164. 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

165. 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

166. 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

167. Thank You