Vestibular & Visual System/Reflexes

Question 1

Function of Pretectum

Answer 1

Pupillary Light Reflex

Question 2

In the Midbrain-Superior Colliculus, the Edinger-Wesphal nucleus is more (ventral/dorsal) in location in comparison to the Oculomotor Nucleus

Answer 2

Dorsal

Question 3

The Edinger-Wesphal nucleus is responsible for (sympathetic/parasympathetic) control of the pupil and causes (constriction/dilation)

Answer 3

Parasympathetic; Constriction

Question 4

Horner’s Syndrome is characterized by what 4 characteristics

Answer 4

Miosis (pupils constricted)
Ptosis (eyelid droop)
Anhidrosis (no sweat)
Facial Flushing (vasodilation)

Question 5

Horner’s Syndome is usually (uni/bi)lateral and (contra/ipsi)lateral

Answer 5

unilateral; ipsilateral

Question 6

Accomodation WITHOUT responsiveness; pupil is small and can constrict with PROXIMITY of objects but not with LIGHT; usually due to tertiary SYPHILIS

Answer 6

Argyll-Robertson Pupil

Question 7

Argyll-Robertson Pupil is caused by what infectious disease

Answer 7

Syphilis

Question 8

Argyll Robertson Pupil presentation

Answer 8

Pupil accommodates but doesn’t react to light

Question 9

Relative Afferent Pupillary Defect or aka. Marcus Gunn Pupil is due to damage in what cranial nerve?

Answer 9

CN II (optic nerve)

Question 10

What happens when light is shone to HEALTHY eye in RAPD patient?

Answer 10

Constriction of healthy eye and affected eye

• Direct and consensual constriction is intact

Question 11

What happens when light is shone to affected eye in RAPD patient?

Answer 11

Both pupils dilate instead of constrict

• No CN II conduction of light information

Question 12

The (utricle/saccule) detects static head position and linear head movements in the HORIZONTAL plane.

The (utricle/saccule) detects static head position and linear head movements in the VERTICAL plane.

Answer 12

Utricle

Saccule

Question 13

Movement of the stereocilia bend TOWARD the Kinocilium, the hair cell is (de/hyper)polarized

Answer 13

Depolarized

*due to the opening of K+ channels allowing entry

Question 14

Movement of the stereocilia bend AWAY from the Kinocilium, the hair cell is (de/hyper)polarized

Answer 14

Hyperpolarized

Question 15

Filamentous bridges that connect hair bundles to kinocilium and pull open the ion channels

Answer 15

Tip links

Question 16

The Utricle and Saccule have a (macula/crista) for the sensation of movement

Answer 16

Macula

Question 17

The Semicircular Canals have a (macula/crista) within ampulla for the sensation of movement

Answer 17

Crista

Question 18

The direction of the inertia of the endolymph displaces the cupula and hair cells (towards/away from) the direction of head motion, therefore causing depolarization of the hair cells

Answer 18

AWAY FROM

Question 19

Describe the pathway for vestibular information to the CNS for balance

Answer 19

Vestibular Apparatus –> CN 8 –> Vestibular nuclei in ipsilateral medulla & Purkinje cells in ipsilateral cerebellum –> Vestibular nuclei in ipsilateral medulla –> Vestibulospinal (VST) UMN tracts –> control our posture/balance

Question 20

The vestibular nuclei project to the spinal cord via ________ tract to control head and neck movements as well as posture to compensate for changes in position

Answer 20

Vestibulospinal UMN tracts

Question 21

The vestibular nuclei project to the CN 3, 4, 6 nuclei via ____________ tract to control eye movements when we move our head

Answer 21

Medial Longitudinal Fasciculus (MLF)

Question 22

Voluntary horizontal gaze (“look to the right”) is activated by the

Answer 22

cerebral cortex

Question 23

Involuntary horizontal gaze (move head to the right) is activated by the

Answer 23

vestibular apparatus/nuclei

Question 24

brainstem gaze center

Answer 24

PPRF (paramedian pontine reticular formation)

Question 25

When asked to "look to the right", voluntary control of horizontal gaze allows both eyes to look to the (left/right)

Answer 25

RIGHT

Question 26

involuntary control of horizontal gaze is governed by

Answer 26

Vestibul-Ocular Reflex (VOR)

Question 27

When asked to "move head to the right", involuntary control of horizontal gaze allows both eyes to look to the (left/right).

Answer 27

LEFT

Question 28

Under normal conditions, when the head is turned to the RIGHT, the firing rate of CN 8 ______ on the right side and _______ on the left side; that's how the brain knows the head is turning to the right

Answer 28

increases; decreases

Question 29

Under vestibular dysfunction on the LEFT side, the firing rate of CN 8 ______ on the left, therefore, the EYES are going to reflexively move to the ______ producing a nystagmus to the ______

Answer 29

decreases; LEFT; LEFT * the brain thinks the head is moving to the right (when actually not), so eyes reflexively move the left.

Question 30

In caloric testing to test for nystagmus, cold water stimulates eye movement to ____ side and warm water stimulates eye movement to ____ side if nystagmus is present.

Answer 30

opposite; same * they are fast phase of nystagmus

Question 31

What disorders can present with vertigo as one of their symptoms?

Answer 31

1. MS 2. Migraine 3. Neoplasm (vestibular swannoma, meningioma) 4. BPPV 5. Meniere's Disease 6. Labyrinthitis 7. Vestibular Neuritis 8. Ototoxicity 9. Perilymph Fistula 10. Labyrinthine Fistula

Question 32

caused by otoconia (canaliths) dislodging and migrating into one of the semicircular canals, most commonly the POSTERIOR semicircular canal, where it disrupts the endolymph dynamics

Answer 32

BPPV

Question 33

Diagnosis of BPPV

Answer 33

1. + Dix-hallpike 2. Vertigo > 1 minute with changes in head positions 3. unaffected hearing

Question 34

Tx for BPPV

Answer 34

Epley maneuver

Question 35

a disorder of the inner ear caused by impaired endolymph resorption (increased endolymph pressure in scala media/cochlear duct); very strict diagnostic criteria

Answer 35

Meniere's disease (aka. endolymph hydrops)

Question 36

What are the diagnostic criteria of meniere's disease?

Answer 36

1. Episodic vertigo lasting at least 20 min 2. Tinnitus 3. Hearing loss (low frequency is affected first; interesting!) 4. Aural fullness (feels like something is in the ear)

Question 37

What could be a clue pointing to meniere's disease when there is a HL?

Answer 37

low frequency (where as other sensorineural HL are high-frequency first)

Question 38

Tx for Meniere's disease

Answer 38

Medical (low salt, diuretics) or Surgical

Question 39

Infection of the endolymph and perilymph caused by bacteria or virus

Answer 39

Labyrinthitis

Question 40

the idiopathic inflammation of the vestibular nerve. It is thought to be viral in origin because it commonly occurs AFTER URI.

Answer 40

Vestibular neuritis

Question 41

Only _____ is present in vestibular neuritis; no hearing loss and other symptoms

Answer 41

Vertigo

Question 42

A congenital or acquired abnormal connection between the inner ear and middle ear. Can cause sensorineural hearing loss, dizziness, and vertigo.

Answer 42

Perilymph Fistula

Question 43

An abnormal opening in the inner ear. This can result in leakage of the perilymph into the middle ear. Can cause sensorineural hearing loss and vertigo.

Answer 43

Labyrinthine Fistula

Question 44

reactivation of VZV in the geniculate ganglion, affecting the seventh (facial) and eighth (vestibulocochlear) cranial nerves; clinical features include shingles in pinna/EAM, vertigo, SNHL, and facial paralysis

Answer 44

Herpes zoster oticus * aka. Ramsay Hunt Syndrome

Question 45

The most common site of lesion leading to Bell's palsy

Answer 45

Meatal foramen of fallopian canal

Question 46

Fallopian canal is aka.

Answer 46

facial nerve canal

Question 47

Tx for Herpes zoster oticus and Bell's Palsy

Answer 47

1. Steroids | 2. Antivirals (NOT for Bell's Palsy though!)