Transcript VESTIBULAR FUNCTION TESTS

VESTIBULAR
FUNCTION TESTS
H.Babar-Craig
VFT
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Balance maintained by :
1. Vestibular system
2. Eyes
3. Proprioceptors in the muscles
VFT
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Investigating the vestibular system consists of
the following,
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1. Testing the vestibulospinal reflexes
2. Testing spontaneous and provoked nystagmus
3. Tests on vestibular and optokintic systems
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Vestibulospinal Reflexes
ROMBERG’S TEST
Patient stands with feet together, arms by the side
with eyes open then closed
 Peripheral vestibular lesions- the body’s centre
of gravity is displaced to the side of the
labyrinthine lesion
 Central disturbances- pattern of unsteadiness of
gait and direction of fall are irregular.
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Vestibulospinal Reflexes
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UNTERBERGER’S Stepping Test
Stepping on the spot with the eyes closed and
arms outstretched for 30 sec
Peripheral disorders- rotation of body axis to
the side of the labyrinthine lesion
Central disorders the deviation is irregular
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Only deviations of > than 30o is significant
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Vestibulospinal Reflexes
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POSITIONAL TESTS ( cerebellar lesions)
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1.Parallel supine arms- arm on side of cerebellar
lesion sinks down as a result of loss of tone
2. Finger-nose pointing- overshooting indicates
cerebellar lesion
3. Dysdidokinesia- central cerebellar lesion
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Nystagmus
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Involuntary rhythmical oscillation of eyes away
from the direction of gaze, followed by return
of eyes to their original position.
The direction of the fast component determines
the direction of the nystagmus ( towards the
dominant vestibular centre, inhibitory impulses
are suppressed i.e the side of the lesion )
Spontaneous Nystagmus
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First Degree – nystagmus present only when the
eyes deviate to the side of the lesion
Second Degree – nystagmus present when
patient looks straight ahead
Third Degree – nystagmus present in both
directions
Positional Nystagmus
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Hallpike Manouvre
Patient sits on bed, head turned 45 degrees to
left or right.
Patient is rapidly laid back with head over edge
of bed 30 degrees below the horizontal. Eyes
open look for nystagmus.
After 30 sec return patient to upright position
Repeat with head to other side
Vestibulo-ocular reflex
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ROTATIONAL TESTS
Nystagmus Induced by accelerating and
decelerating rotating chair, tests both labyrinths
simultaneously
CALORIC TESTS
COWS- cold water opposite side, warm water
same side, direction of nystagmus
Extent of caloric response indicates function of
labyrinth
Vestibulo-ocular Reflex
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Electronystagmograghy
Positive potential between the cornea and retina
recorded as eyes move from straight ahead gaze
Test includes different head positions, eyes
open, closed and caloric tests