VESTIBULAR FUNCTION TESTS
380 likes | 4.89k Vues
VESTIBULAR FUNCTION TESTS. H.Babar-Craig. VFT. Balance maintained by : 1. Vestibular system 2. Eyes 3. Proprioceptors in the muscles. VFT. Investigating the vestibular system consists of the following, 1. Testing the vestibulospinal reflexes 2. Testing spontaneous and provoked nystagmus
VESTIBULAR FUNCTION TESTS
E N D
Presentation Transcript
VESTIBULAR FUNCTION TESTS H.Babar-Craig
VFT • Balance maintained by : • 1. Vestibular system • 2. Eyes • 3. Proprioceptors in the muscles
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
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.
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
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
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 )
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
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
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
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