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VESTIBULAR FUNCTION TESTS PowerPoint Presentation
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VESTIBULAR FUNCTION TESTS

VESTIBULAR FUNCTION TESTS

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VESTIBULAR FUNCTION TESTS

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  1. VESTIBULAR FUNCTION TESTS H.Babar-Craig

  2. VFT • Balance maintained by : • 1. Vestibular system • 2. Eyes • 3. Proprioceptors in the muscles

  3. VFT • Investigating the vestibular system consists of the following, • 1. Testing the vestibulospinal reflexes • 2. Testing spontaneous and provoked nystagmus • 3. Tests on vestibular and optokintic systems

  4. 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.

  5. Vestibulospinal Reflexes • 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 • Only deviations of > than 30o is significant

  6. Vestibulospinal Reflexes • POSITIONAL TESTS ( cerebellar lesions) • 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

  7. Nystagmus • 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 )

  8. Spontaneous Nystagmus • 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

  9. Positional Nystagmus • 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

  10. Vestibulo-ocular reflex • 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

  11. Vestibulo-ocular Reflex • 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