Vestibular Disorders

Question 1

The 3 primary functions of the peripheral vestibular system?

Answer 1

1. stabilizing visual images during head movements (for clear vision)
2. maintaining postural stability (especially with head movements)
3. providing information for spatial orientation

Question 2

Each semicircular canal has a contralateral coplanar mate, so one side is being depolarized/excited while the opposite is being hyperpolarized/inhibited. Which pairs are working together if a person is turning their head to the left?

Answer 2

• left lateral (horizontal) canal is being depolarized/excited
• right lateral (horizontal) canal is being polarized/inhibited.

Question 3

Name the semicircular canal coplanar pair’s that work together.

Answer 3

• left and right lateral (horizontal) canal’s
• left anterior (superior) and right posterior canal’s
• right anterior (superior) and left posterior canal’s

Question 4

What are the 2 otolith organs?

Answer 4

• saccule

- utricle

Question 5

How does the brain detect the direction head movement?

Answer 5

• by comparing input from coplanar pairs

- motion of endolymph results in opening or closing of transduction channels of hair cells

Question 6

What is the ampulla?

Answer 6

• located at the enlarged end of each canal

- within the ampulla lies the cupola (gelatinous barrier that contains the sensory hair cells)

Question 7

Which otolith organ is excited during horizontal linear acceleration and/or static head tilt?

Answer 7

• utricle (vertical hair cells)

Question 8

Which otolith organ is excited during vertical acceleration?

Answer 8

• saccule (hair cells are lateral)

Question 9

What part of the central vestibular system provides primary control of many vestibular reflexes?

Answer 9

• brainstem

Question 10

Where does vestibular pathways terminate (cortical area)?

Answer 10

• junction of parietal and insular lobes

Question 11

When sitting still what does the cerebellum pay more attention to?

Answer 11

• info from somatosensory system (touch, pressure, joint position)

Question 12

When you move what does the cerebellum pay more attention to?

Answer 12

• vision and vestibular inputs

Question 13

What is VOR gain and phrase?

Answer 13

• gain is equal and opposite velocity of head and eye’s

- phase is equal and opposite head and eye relationship

Question 14

What is VOR responsible for?

Answer 14

• maintaining stability of an image on the fovea of the retina during rapid head movements (rapid compensatory eye movements in opposite direction of the head when moving/rotating)

Question 15

Peripheral vestibular pathology can be one of two types?

Answer 15

• mechanical (BPPV, most common)

- decreased receptor input (UVH or BVH)

Question 16

What most commonly causes unilateral vestibular hypofunction?

Answer 16

• virus, trauma, vascular events

Question 17

What most commonly causes bilateral vestibular hypofunction?

Answer 17

• most common is ototoxicity

- others include meningitis, autoimmune disorders, head trauma

Question 18

Define otoconia?

Answer 18

• the “crystals”
• located in the gelatinous matrix
• calcium carbonate

Question 19

What is cupulolithiasis?

Answer 19

• otoconia adhere to the cupula of one of the SCC’s

Question 20

What is canalithiasis?

Answer 20

• otoconia are floating freely in one of the SCC’s

Question 21

BPPV symptoms?

Answer 21

• NYSTAGMUS and VERTIGO with HEAD POSITIONING

- occasionally nausea, vomiting, disequilibrium

Question 22

UVH symptoms?

Answer 22

• SPONTANEOUS NYSTAGMUS (at rest)
• vertigo
• visual blurring
• oscillopsia during head movements
• postural instability
• dysequalibrium

Question 23

BVH symptoms?

Answer 23

• DYSEQUILIBRIUM (unsteadiness)
• oscilliopsia
• gait ataxia

Question 24

Red Flags that require referral to neurologist?

Answer 24

• horizontal or vertical diplopia (double vision) lasting longer than 2 weeks
• pure vertical nystagmus
• spontaneous up-beating nystagmus
• positive test for skew deviation

Question 25

Contraindications to vestibular rehab (8)?

Answer 25

- acute episode of Meniere's disease - uncontrolled migraine - PLF - unrepaired superior semicircular canal dehiscence - sudden loss of hearing - increase feeling of pressure or fullness in one of both ears that is uncomfortable - post surgical, observe for fluid in ears - acute neck injuries may not tolerate

Question 26

What % of patients sustaining mild head injury (TBI) complain of vertigo?

Answer 26

- 78% | - 20-37% still after 6 mo - 5 yrs later

Question 27

Central nervous system pathology that could cause vestibular symptoms that needs to be filtered out during the exam(6)?

Answer 27

- CVA - Vertebrobasilar insufficiency (VBI) - TBI - MS - Nystagmus - Other indicators (lateropulsion, visual perceptual difficulties, oculomotor signs, skew deviation of the eyes)

Question 28

Compare common symptoms of Central vs Peripheral vestibular pathology (7).

Answer 28

1. Central - ataxia, severe (Peripheral - mild) 2. Central - abnormal smooth pursuit and saccades (Peripheral - both normal) 3. Central - usually no hearing loss but if so is sudden/permanent (Peripheral - may be hearing loss, fullness in ears, tinnitus) 4. Central - Sx diplopia, altered consciousness, lateropulsion (Peripheral - none of those) 5. Central - acute vertigo not usually suppressed by fixation (Peripheral - acute vertigo suppressed by visual fixation) (Peripheral vertigo usually intense) 6. Central - pendular nystagmus (Peripheral - slow and fast phases of nystagmus) 7. Central - pure persistent vertical nystagmus regardless of positions (Peripheral - spontaneous horizontal nystagmus)

Question 29

What symptoms would be common in Meniere's disease (4)?

Answer 29

- low frequency hearing loss and episodic vertigo - sense of fullness in ears and tinnitus - episodes can last several hours - PT indicated for chronic meniere's

Question 30

How can a PT help motion sickness?

Answer 30

- habituation training can be effective if debilitating

Question 31

Why is it important to know if your vestibular patient has MS?

Answer 31

- can cause symptoms just like UVH (CN VIII)

Question 32

What % of patients with migraine-related dizziness had abnormal nystagmus during episode?

Answer 32

100%

Question 33

What is cervicogenic dizziness?

Answer 33

- pathology affecting c-spine and related soft tissue - upper c-spine sends proprioceptive input to contralateral vestibular nucleus - soft tissue injury or joint dysfunction might alter afferent input