Transcript Detection of vestibular function

Evaluation of vestibular
function
Chunfu Dai M.D & Ph.D
Balance is a highly integrated
network
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vestibular system -rotatory stimulation and
linear acceleration Information
proprioceptive system - information input from
the feet, ankle, hip, and neck
ocular system - visual perception of spatial
orientation is supplied by the
central nervous system - integrated these
information and translated to fine motor
movements
Static balance test
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Romberg test: useful in patients with an
acute unilateral labyrinthine lesion
Mann test: the patient stands heel to toe
rather than with feet together
Static posturography:
Dynamic balance test
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Dynamic posturography
Co-ordination function test:
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Point nose test
Alternative movement
Finger point
Nystagmus
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Nystagmus
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Slow phase: hypoactivity
Quick phase: hyperactivity
Direction: quick movement of eye
Plane: horizontal, rotary, vertical
Degree:
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I: quick phase side
II: quick phase side and look forward
III: quick phase side, slow phase side
and look forward
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Ocular dysmetria test:
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Smooth purpsuit test:
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Brainstem or cerebellum lesion
Optokinetic nystagmus
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Brainstem, or cerebellum lesion
Lesion in central never system
Gaze nystagmus
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Lesion in central nerve system
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Caloric test:
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Horizontal semicircular canal
Temperature: 44 and 30
Stimuli duration: 40s
Rotation test
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Fistula sign
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Fistula was blocked by
granuloma or
cholesteatom
Dead labyrinth
Hennebert sign
Tullio phenomeno
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(1)
(2)
(3)
(4)
(5)
(6)
gaze (fixation) test,
ocular pursuit test,
optokinetic test,
static positional test,
dynamic positioning test, and
bithermal caloric test.
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The normal response as the chair is rotated is
slow compensatory eye movement in the
direction opposite the rotation with a fast
saccade to return the eye in the forward position.
The test has three parameters--phase (time for
the slow phase eye movement in relationship to
the head rotation velocity), gain (ratio of
maximum eye velocity to maximum chair
velocity), and symmetry (compares the slowphase eye velocity when rotating right versus
left).52
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the test addresses two major areas:
(1) motor control test which examines the
patient's motor system and the ability of the
CANS to adapt to changing conditions, and
(2) sensory organization test which examines
proprioceptive, visual, and vestibular systems
working as an integrated whole.
characteristic
Peripheral
Central
Spontaneous
Nystagmus
direction
intensity
Horizontal rotary
Direction fixed
Diminished by visual
fixation
Increased by gaze in
direction of fast phase
Any direction
No change with visual
fixation
Gaze has little or no
effect
2-10s
Predominantly rotary
<30s
Yes
Immediate onset
Any direction
>45 s
No
Evoked Nystagmus
Latency
Direction
Duration
fatigability