Vestibular System

Question 1

What are the 2 things that the vestibular system can detect?

Answer 1

Static and kinetic movement of the head

Question 2

A proprioceptive system that influences axial and proximal limb muscle tone and the oculomotor system

Answer 2

Vestibular system

Question 3

What Vestibuloocular Response (VOR) would you perform on an unconscious patient?

Answer 3

Doll’s Eye Maneuver

Question 4

What are the contraindications for Doll’s Eye Maneuver?

Answer 4

CANNOT HAVE A Cervical Injury!!!! And they must be unconscious

Question 5

Describe the Doll’s Eye maneuver and the expected response

Answer 5

Side-to-side movement of the patient’s head results in their eyes turning gaze to the opposite direction

Question 6

If you are performing the Doll’s Eye maneuver and the head is turned right, what is wrong if the left eye remains neutral and the right eye is correctly ADducted?

Answer 6

Left CN VI palsy

Question 7

If you are performing the Doll’s Eye maneuver and the head is turned right, what is wrong if the right eye remains neutral and the left eye is ABducted correctly?

Answer 7

Right CN III palsy

Question 8

If you are performing the Doll’s Eye maneuver and the gaze is neutral and forward, what is wrong?

Answer 8

Possible midbrain damage

Question 9

For Doll’s Eye maneuver, if the head is turned left where should the eyes go?

Answer 9

Right side gaze

Question 10

What Vestibuloocular Response (VOR) can you perform on a conscious patient?

Answer 10

Ice or Warm water caloric test

Question 11

Describe the Ice/Warm water caloric test

Answer 11

Injecting ice water or warm water into the patients external acoustic meatus

Question 12

What is the expected response of an ice cold water caloric test?

Answer 12

Eyes turn TOWARD the affected ear and then have nystagmus AWAY

Question 13

What is the expected response of a warm water caloric test?

Answer 13

Eyes turn AWAY from the affected ear and then have nystagmus TOWARD

Question 14

What is the pneumonic to remember the direction of the nystagmus in the water caloric test for conscious patients?

Answer 14

COWS -
Cold water = Opposite
Warm water = Same

Question 15

What are the vestibular receptors?

Answer 15

Neuroepithelial cells in the cristae ampullaris and maculae of the ear

Question 16

What is the vestibular ganglion?

Answer 16

Bipolar neurons near the membranous labyrinth

Question 17

What nuclei does the vestibular nerve terminate into after getting signal from the vestibular receptors/ganglion?

Answer 17

Vestibular nucleus, Fastigial nucleus and Flocculo-nodular lobe

Question 18

What nuclei make up the vestibulocerebellum?

Answer 18

Fastigial nucleus and Flocculo-nodular lobe

Question 19

What are the tracts/areas of the Vestibular nucleus?

Answer 19

Medial Longitudinal Fasciculus (MLF)
Medial Vestibulospinal Tract (MVST)
Lateral Vestibulospinal Tract (LVST)
Reticular formation (RF)

Question 20

Some fibers of CN VIII do not go to the vestibular nucleus; where do they go directly?

Answer 20

Vestibulocerebellum (Fastigial nucleus and Flocculo-nodular lobe)

Question 21

Medial longitudinal fasiculus

Answer 21

Eyes turn toward stimulus

Question 22

Medial Vestibulospinal tract

Answer 22

Head turns toward stimulus

Question 23

Lateral Vestibulospinal tract

Answer 23

Body turns toward stimulus

Question 24

Reticular formation

Answer 24

Nausea, vertigo, visceral disturbances

Question 25

PPRF

Answer 25

Paramedian Pontine Reticular Formation

Question 26

What is the PPRF involved in?

Answer 26

Coordination of horizontal gaze

Question 27

What pathway is involved with the Doll’s Eye maneuver and the oculocaloric testing?

Answer 27

Medial longitudinal Fasciculus (MLF) - horizontal gaze

Question 28

Where does the MVST terminate?

Answer 28

Intermediate grey matter at the cervical and upper thoracic levels ONLY in the spinal cord

Question 29

What type of pathways are the MVST and the LVST?

Answer 29

Descending

Question 30

What is the function of the MVST?

Answer 30

Controls positioning of head relative to the eye movements by influencing the muscles of the neck, upper back and proximal upper limb

Question 31

Where does the LVST terminate?

Answer 31

Intermediate grey matter at ALL levels of the spinal cord

Question 32

What does the LVST fibers descend in?

Answer 32

Lateral funiculus of the spinal cord

Question 33

What is the function of the LVST?

Answer 33

Control extensor tone and reflexes of the axial and appendicular musculature (body)

Question 34

What test would you perform to test for lesions of the vestibular system?

Answer 34

Romberg’s Test

Question 35

Describe the Romberg’s Test

Answer 35

Have patient close their eyes and stand still. If they sway or when gently touched they almost fall over, that is a positive finding.

Question 36

What is a lesion of the Median longitudinal Fasciculus (MLF) called?

Answer 36

Internuchlear Opthalmoplegia

Question 37

If there is a unilateral lesion on the right side of the MLF, what are the results?

Answer 37

Horizontal gaze to the right is normal
Horizontal gaze to the left shows the following:
- Right eye unable to ADduct
- Left eye exhibits nystagmus

Question 38

If there is a lesion on the PPRF, what will be lost?

Answer 38

Horizontal gaze to the affected side!

Question 39

If a patient is unable to look to the right, where is the likely lesion?

Answer 39

Right PPRF

Question 40

A PPRF lesion destroys fibers that are going where?

Answer 40

Ipsilateral Abducens nucleus and contralateral oculomotor nucleus