vestibular function test battery, rehabilation exercises , anatomy and physiology of vestibular system

1. Vestibular function test
Dr. Rajeev gupta
Igmc shimla
h.p.

2. Vestibular anatomy
• Inner ear (labyrinth) - Bony
Membranous
• Endolymph
• Perilymph
Bony labyrinth - vestibule
semi circular canals
cochlea

5. • Membranous laby. - cochlear duct
utricle/ saccule
semicircular ducts
endolymphatic sac / duct

11. Maculae

15. • Vestibular nerve - vestibular / scarpa’s ganglion
situated in the lateral part of IAM.
• Bipolar neurons – distal process innervate
sensory epithelium of labyrinth.
- central process aggregate to
form vestibular nerve.
• these fibers end in vesti. Nuclei and some go to
directly to cerebellum.

16. • 4 vesti. Nuclei – sup. / medial / lateral/
descending
Affrents come from to these nuclei –
peripheral vestibular receptors
cerebellum
reticular formation
spinal cord
C/L vesti. Nuclei

18. • Effrents from nuclei go to -
1- nuclei of C.N iii / iv/ vi via medial longi. Bundle , ( pathway of
vestibulo ocular reflexes) causes - nystagmus.
2- motor part of spinal cord- (vestibulo spinal reflex)- coordinates head ,
neck , body
3- cerebellum- vestibulocerebellar fibers- maintain body balance
4- ANS- explains nausea , vomiting , palpitations ,sweating
5- vestibular nuclei of C/L side
6-cerebral cortex - responsible of subjective awareness of motion.

19. Physiology
• Vestibular system- peripheral
central
• Semicircular canals - 3 canals lie at right angle
to each other , but one which lies right angle
to axis of rotation is stimulated the most .
Thus HSCC respond max. to rotation on
vertical axis.

20. • Stimulation of SCC produces nystagmus and direction of
nystagmus is determined by plane of canal being
stimulated.
• So, HSCC produces- horizontal
SSCC - rotatory
PSCC - vertical
• Stimulus to SCC is flow of endolymph which displaces
cupula. Flow may be towards cupula (ampullopetal/
utriculopetal), away to cupula(ampullofugal/ utriculofugal)

21. • Slow component of nystagmus is always towards the side of flow of
endolymph and fast component is always opposite to it.
• SCC responds to angular acceleration and deceleration.
• Utricle / saccule-
• Stimulated by linear acceleration / deceleration or gravitational pull
during head tilts.
• Saccule also responds to sound stimuli also.
• Sensory hair cells of macula stimulated by displacement of otolithic
membrane during head tilts.

22. • These information sent to CNS where
information from other system also reached
and then integrated and used to regulate
equilibrium and body posture.
• Maintenance of body equilibrium –
two sided push and pull system

23. Disorder of vestibular system
Peripheral
BPPV
Vestibular neuronitis
Labyrinthitis
Perilymphatic fistula
Acoustic neuroma
Meniere’s disease
Head trauma
Vestibulotoxic drugs
central
• Vertebrobasilar
insufficiency
• Migrane
• Cerebellar disease
• Multiple sclerosis
• Tumors of brainstem
• Epilesy
• Cervical vertigo
• Post.inf. Cerebellar artery
syndrome

24. Vestibular function tests
• History
• Examinations- neuro-otologicalexamination
special laboratory tests
• Radiological investigations
• Serological investigations

25. History
1. Nature of the sensation:
dizziness, vertigo, oscillopsia, disequilibrium, syncope.
2. timing of initial spell:
3. frequency and duration of symptoms:
Short term symptoms
Medium length symptoms
Longer spells
4. precipitating / mitigating factors:
5. associated symptoms:
6. medical conditions and family history

26. Examinations
• Neurotological Examinations:
1. otoscopy with audiometric evaluation
2. eye movements: spon. / gaze nystagmus
smooth pursuit movement
saccadic eye movements
optokinetic nystagmus
3 . vestibular ocular reflexes:
doll’s head maneuvere
dynamic visual acuity
head impulse test
vor suppression test
4. Postural test : romberg test
gait
past pointing test

27. • 5. positioning test :
• 6. positional test :
• 7. fistula test :

28. • Laboratorical test :
For VOR testing
1. caloric test
2. rotatory test
3. electronystagmography
For VSR testing
1. craniocorpography
2. posturography
3. VEMP

29. • Radiological tests
• Serological test

30. • EYE MOVEMENTS
1. spontaneous nystagmus:
• Presents in straight ahead positon of eyes.
• Should note direction and waveform.
• It enhances by convergence,by moving an object in and out along visual axis.
• Absence of convergence occurs in midbrain lesion and also present in > 60 yr age
persons.
• The cover test should be done to rule out diplopia and ocular alignment and latent
nystagmus.
• If Spon. Nyst. In primary gaze present with acute vertigo and severe nausea and
unsteadiness. May be due to central/peripheral lesion.
• But, pt .comes as a routine ambulatory patient and does not look acutely ill,
nystagmus is more likely of central origin.

32. • Smooth pursuit eye movements:
• When we track an object with our eyes ,there are a combination of fast
(saccades) and slow phase (pursuit) movements.
• Velocity of smooth pursuit movement is limited to 40-50 degree/ second.
• When pursuit is abnormal called as broken up pursuit.
• So, presence of normal pursuit rules out a central vestibular disorder or
broken up pursuit almost certainly has neurological rather than
labyrinthine disorder.
• Examination procedure include two precaution-
• Because pursuit are visually guided so subject is able to target correctly.
• Target has to be moved slowly ,4-5 seconds to travel from right to left and
vice versa.

33. • Gaze evoked nystagmus:
• Soon after the acute stage of a peripheral vestibular lesion , nystagmus is
not visible in primary gaze but only on deviation of gaze to opposite side
of lesion( in fast phase direction)
• Classification to check the severity of nystagmus
• ALEXANDER’S LAW:
• 1 degree: weak nystagmus which present only when pt.look in direction of
fast component.
• 2 degree: moderate nystagmus which present when pt. looks straightly
ahead.
• 3 degree: strong nystagmus which present when pt. looks in direction of
slow component.

34. • Saccadic eye movement:
• Saccadic are fast movements of the eyes (200-
500degree/ sec.) which allows shift gaze from one
object to another.
• Saccades does not require visible moving target, it can
be generated at will or command without a specifically
command.
• Three properities are assessed velocity, accuracy,
binocular conjugacy.

36. Optokinetic nystagmus

37. • Vestibulo- ocular reflexes:
1. Doll’s head maneuvere -

39. Dynamic visual acuity

40. Head impulse test

41. Vestibulo ocular reflex suppression
test

42. • Positioning test:
• most frequently employed test is dix-hallpike maneuver.
• 4 features:
1. it has a delayed onset.(2-20 sec.)
2. it is always transient.
3. it is always accompanied by vertigo.
4. it is usually fatigable.
• Limitation : can not be done in cervical spine disease patient.
• By these methods , we can detect BPPV easily.

43. Dix - hallpike maneuver

44. Supine roll test (pagnini- macclure
maneuver)

45. • Positional test:
• Done to determine if different head positions induce or
modify vestibular nystagmus.
• In this , pt. eye movements are monitored while the head is
in at least four positions:
• Supine , head right (rt. Ear down), head left (lt. ear down),
sitting position.
• Eye movements are noted in each positions for about 20
sec. in both visual fixatation and without visual fixatation.
• Positional nystagmus may be intermittent or persistent.

46. • FISTULA TEST:
• Producing pressure changes in EAC which stimulate labyrinth induces
nystagmus and vertigo.
• Test done by siegel’s speculum , pressure on tragus
• Normally it is negative.
• Positive in :
• Erosion in HSCC by choleasteatoma , fenestration operation.
Abnormal opening in OW / RW.
• False positive: without presence of fistula seen in congenital syphilis
meniere’s disease (hennebert’s sign)
• False negative : when choleasteatoma covers site of fistula and does not
allow pressure changes.

47. Vestibulo ocular testing
Electronystagmography:
Most commonly laboratory evaluation method.
It documents, analyze the eye movements and assesses
labyrinthine function, degree of dysfunction.
Various methods for recording eye movements-
1. Electrooculography
2. Magnetic potentials (search coils)
3. Videonystagmography
4. Infrared technology

48. Procedure

49. • The pt. is instructed to avoid alcohol and
certain drugs for at least 48 hours.
• Ear examination should be done prior.
• Electrodes applying area are cleansed with
spirit and alcohol.
• Corneoretinal potential: EOG depends upon
that there is a steady DC potential, termed as
CRP.

50. • CRP is ,between the cornea and retina .
• These potentials create an electric field at the front of head
that rotates as the eyes rotate.
• The CRP is generated by the metabolic activity of the retinal
pigment epithelium. Retina is negative charged relative to
the cornea which is measured by skin surface electrodes.
• Horizontal eye position is monitored by electrodes placed
on temples, vertical eye position is monitored by electrodes
placed above and below one eye.
• By Traditional EOG ,it is difficult to detect torsional
nystagmus because rotation of eye about the axis of the
pupil does not effect a change in the CRP.

51. • Videonystagmography :
• Method of oculography in which eye movements are recorded by a
video camera not by changes in CRP.
• So , eye blinking artifacts and artifacts due to contraction of facial
muscle which alters ENG results ,do not effect VNG result.
• VNG can record torsional movements also.
• Disadvantage that , VNG can record eye movements at a speed of
60hz ,whereas during saccadic tests and other occulomotor tests
the eye movements need to be recorded at speed of 175hz .ENG is
a superior option.
• Another that, it records when eyes are open.
• Difficult in children, and more expensive.

52. • Magnetic search coil technique:
• pt. sitting in a low strength ,alternating magnetic field by
wearing a soft contact lens in which a wire coil is
embedded.
• The contact lens fits around but does not directly contact
the cornea. motion of the coil of wire in the alternating
magnetic field induces a very small current wire and this
signal can be used to obtain measurement of eye position.
• Two major adv. are provides very precise determination of
eye position in 3 dimensions and recorded very rapidly.
• Disadv. Are that it requires a sophisticated laboratory and
trained persons.

53. • Infrared oculography:
• Based upon the differing reflectance properties of iris
compared to sclera . In this, photocells of eye remain
stationary while the edge of iris move with the eye and
light sensed by the photocells differs according to eye
positions.
• Adv. that direct estimate of eye position as a function
of time can be calculated.
• Disadv. That it include the bulk of equipments which
limit visual stimulations and interfere blink movements
and makes vertical recording difficult.

54. • All types of visual oculomotor tests including
saccades, smooth pursuit and optokinetic eye
movements and gaze evoked nystagmus are
recorded and analyzed .
• Both positional / positioning test are done
with help of ENG and interpreted.
• Two main test bithermal caloric test and
rotatory test are done with help of ENG.

55. Rotational test

56. • To maintain equilibrium , the subject has to attain a sense of spatial
stability , so that , he feels that surrounding environment is stable.
• To achieve this goal , the image of objects in the visual field have to
be retained in the same place of retina.
• When head moves or visual field moves in relation to subject the
image of visual field on the retina displaced, called as retinal slip,
which produces vertigo.
• In normal persons it is prevented by a corrective movement of the
eyes which occurs reflexly by VOR.
• In the rotatory test, the head is rotated and eye movements are
monitored to assess whether the compensatory or corrective eye
movements is occuring properly or not.
• Movement occurs in horizontal plane so stimulates HSCC.
• This test first carried out by Barany .

57. • In this test ,pt,. is made sit on a special chair
and rotated for 20 seconds and then rotation
stops abruptly.
• This sudden stop sets nystagmus due to
resultant deceleration which stimulates the
HSCC on both sides.
• Nystagmus are recorded for both clockwise
and anticlockwise rotation of chair by EOG.

58. • Indication:
1. when ENG suggest well compensated state,
despite clinically significant U/L caloric weakness
with active symptomatology.
2. when caloric test cannot be performed, results in
two ears may not be compared because of
anatomic variablity.RCT is used to define B/L
weakness of vestibular system.
3. To check B/L vestibular system at same time.

59. • The computer compares head velocity, slow phase eye
velocity and calculates phase ,gain, symmetry for each of
the test frequency.
• Gain is slow eye velocity divided by head velocity.
Reduction in gain seen in B/L vestibular disease.
• Phase angle measures the temporal relationship between
eye and head velocity and measured in degrees. It has
greatest clinical significance. increase phase implies in
peripheral vestibular system and decreased phase suggest
cerebellar lesion.
• Symmetry is ratio of rightward to leftward slow phase eye
velocity. Asymmetry seen in peripheral vestibular system
weakness.

60. • Abnormalities in RCT are classified in 4 categories:
1.vestibular habituation and asymmetry-
Abnormal low frequency phase leads and high frequency asymmetry (
always towards the side of lesion) is most often seen in acute peripheral
U/L peripheral dysfunction.
2.vestibular habituation-
Consist solely of abnormally large phase leads at the lower frequency.
Often seen in patients with a chronic ,U/L peripheral vestibular lesion.
3.vestibular deficit-
Slow harmonic acceleration test shows abnormalities in patients with B/L
loss of vestibular function.
4.vestibular asymmetry
Characterized by an asymmetry at high frequency seen in patients of
acute peripheral lesion.

61. Caloric test
• Caloric test are highly sensitive for unilateral lesion
because in this we stimulate each ear separately.
• Nystagmus produced by this is analyzed and assess the
activity of vestibular system
3 types :
1. modified kobrak test
2. bithermal caloric test
3. cold air caloric test

62. Modified kobrak test:
• Office procedure
• Pt. seated with head tilted 60 degree backwards to place
HSCC in vertical position.
• Ear irrigated by ice cool water for 60 sec. with 5/ 10/20/40
ml.
• Response seen with 5ml of water towards opposite ear –
normal
• Response seen with 5 to 40 ml water –hypoactive labyrinth
• No response seen with 40 ml –dead labyrinth

63. • Bithermal caloric test-
• Fitzgerald – hallpike test
• Pt. lies supine with head tilted 30 degree forward so
that HSCC is vertical.
• Ear is irrigated for 40 sec. with water at 30 degree and
44 degree and nystagmus are noted till its end point.
• If no nystagmus appeared from any ear ,test ia
repeated with water at 20 degree water for 4 minute
before labeling the labyrinth dead.

64. • Responses of caloric test are analyzed by
calculating the velocity of each of slow phase
nystagmus and interpreted in terms of
unilateral weakness and directional
preponderance.

65. Jongkees and colleagues formula

66. • On canal pareasis (UW) if values is greater than 20% is considered
significant.
• Less or no response from particular side indicative of depressed
function of I/L labyrinth and vestibular nerve / nuclei , seen in
meniere’s disease, acoustic neuroma , postlabyrinthectomy,
vestibular nerve section.
• On directional preponderance, duration of nystagmus to rt/left
irrespective of side of ear stimulation is considered.
• If nystagmus is 25-30% or more on one side than the other , is
called as directional preponderance to that side.
• It occurs towards the side of central lesion , away from peripheral
lesion but it does not localise the lesion in central vestibular
pathway.

67. Results found in
U/L meniere’s disease – canal paresis on one
side and diectional preponderance to opposite
side.
Acoustic neuroma – canal paresis and
directional preponderance towards same I/L
side.

68. Cold air caloric test :
• Test done in perforated TM because irrigation is
contraindicated.
• Done with DUNDAS GRANT TUBE , coiled copper tube
wrapped in cloth, air is cooled by mixing with ethyl
chloride and then blown to ear.
• Problem with this tube is that we can not control on
temperature and amount of air to be used.
• So new device “varioair” is used now a days which has
precise control over amount and temperature of air.

70. Vestibulospinal reflexes testing
1. CRANIOCORPOGRAPHY(CCG)
• Described by claussen
• Procedure and interpretation:
1. The stepping test-
• Visual and proprioceptive inputs are cut off
• Pt deviate / rotate to side of weaker hypoactive vestibule.
• Parameters evaluated in test
Displacement
Angular deviation
Angular rotation
Breadth of lateral sway

72. • Interpretation:
• Displacement : walk forwards/ backwards
• Angular deviation : normal range70 degree to rt. And 50
degree left to midline. Any deviation beyond suggest
hypoactivity of vestibular periphery on the side of
deviation.
• Angular rotation : 85 degree to rt. And 60 degree to left
from midline. Any rotation beyond this suggest hypoactivity
of vestibular on side of rotation.

73. • Breadth of lateral sway : normally 3cm to 15
cm.
• Any sway more than 15cm. Suggest of central
lesion.
• So, stepping test CCG is a very effective to
evaluate peripheral vestibular compensation,
which is not possible by ENG.

74. 2. romberg test:
• Pt. blind folded and stands erect with feet close together
for 1 minute.
• Max. breadth of sway is 10 cm .if it is more than it
considered abnormal and indicates a central lesion.
3. WOFEC test:
• Graybiel and fregly
• Pt is asked to walk on floor on a imaginary straight line with
tandem walk and eyes closed.
• In central lesion and acute peripheral lesion , pt can not
perform this test and falls repeatedly.

75. Advantage:
Quick , noninvasive , can be repeated often.
Does not require vestibular stimulation as in caloric
test.
In Large screening of vestibular system for job
persons.
For drug trials
To detect malingerers.
With perforated ear patients.

76. • POSTUROGRAPHY:
• CDP is more sophisticated and sensitive test
for vestibulospinal test.
• It check overall balance function and capacity
of body to maintain erect posture and gait
• Usually done to detect vertigo in whom ENG
are normal.

77. Methods:
• The Sensory organisation test
• The motor coordination test
• In these, pt is made to stand on a platform and in front
of his eyes a screen is placed that entire vision field is
covered.
• Whole purpose is manipulate somatosensory and
visual inputs to vestibular system.

78. • In sensory organisation test, analyse the capacity of
patient to maintain equilibrium during a variety of
changing sensory input conditions.
• 1. support fixed, eyes open, visual fixed
• 2. support fixed, eyes closed, visual fixed
• 3.support fixed,eyes open,visual sway-refrenced
• 4.support swayed, eyes open,visual fixed
• 5.support swayed,eyes closed, visual fixed
• 6support swayed,eyes open,visual sway-refrenced

79. • The pt. is subjected to each test condition 3
times, and an equilibrium score is calculated for
each condition .it was compared with theoretical
limits of antero-posterior sway.
• The results of SOT inform us whether pt. is able
to properly utilise the three main sensory inputs (
visual, somatosensory, vestibular) to CNS for
maintaining posture and equilibrium.
• A score of 100% implies little sway and lower
scores corresponds to greater amounts of sway.

80. • The motor coordination test:
• In this platform is made to undergo sudden
translations forwards and backwards and the
pt. sway is monitored and analyzed by the
computer.
• An EMG of gastrocnemius is documented and
shows that muscular contractions in responses
to destabilizing forces is adequate or not.

81. • In this somatosensory inputs to brainstem
pathway is checked.
• New version is “lucerne measuring plate”
which documents , analyze ,and provide
objective information on the functional
vestibular deficiency.

82. • VESTIBULAR EVOKED MYOGENIC POTENTIALS:
• Depends upon vestibulo- colic reflexes.
• Loud sounds - stapes movement- mechanical stimulation
of saccule - mech.energy converted into electrical
energy in saccule - impulse passes through IV N -
reaches lat. Vesti. Nucleus in brainstem - I/L SAN nucleus
- impulse passes through medial vestibulospinal tract-
reaches SAN branch to SCM – contraction of SCM.
• These are recorded and documented by the EMG.

83. • VEMP are generated by the loud sound (95 -105db) of pure
tones of 500hz with rate of 3-5 stimuli/ sec.
• For proper recording of EMG ,sternocleidomastoid should
be in contracted position.
• EMG recorded wave morphology , amplitude ,latency but
amplitude is most important.
• Decreased amplitude on one side is corelated with
peripheral vestibular dysfunction from paretic lesion such
as vesti. Neuronitis, meniere’s disease, acoustic neuroma
and intratympanic gentamycin therapy.
• An increased ampiltude is seen in irritative lesions as
meniere’s disease and sup. Canal dehiscence syndrome.

84. • So disorder of saccule are practically
impossible to diagnose other than VEMP.
• in these cases ENG will normal but VEMP are
absent or abnormally low amplitude.

85. Vestibular rehabilitation
• Apart from drugs which affect on labyrinth
,there are various vestibular exercises .
• Three targets for these regimens are
adaptation
sensory substitution
habituation

86. CAWTHRONE –COOKSEY EXERCISE

88. NORRE’S APPROACH( habituation)
• Based on concept of the error signal driven
adapatation and assumption that repetition
of same stimulus causes a decline in
responses which is stimulus specific.
• It includes 19 positional maneuvers.

89. BRANDT DAROFF EXERCISE

90. GAZE STABILIZATION EXERCISES

91. Canalith Repositioning
• Posterior Canal (85-95% success)
–Epley
–Semont
• Horizontal Canal (100% success)
–Barbecue Roll (270 degree)
– baloh 360 degree yaw rotation
–GUFONI

92. EPLEY’S MANOUVERE

93. MODIFIED EPLEY’S

94. SEMONT’S MANOUVERE

95. BARBECUE/ LEMPERT MANOUVERE

96. GUFONI’S MANOUVERE

97. 360 YAW ROTATION

98. THANK YOU