Vestibular-Ocular System

Question 1

What is Meniere’s disease?

Answer 1

Excess endolymph usually unilaterally, causes vertigo and ipsilateral hearing loss

Question 2

What part of the inner ear processes linear movement? angular movement?

Answer 2

Linear: macula of utricle (hor) and saccule (vert)
Angular: crista in cupula

Question 3

What is benign paroxysmal positional vertigo?

Answer 3

Otoliths dislodge to semicircular ducts

Question 4

What parts of the brainstem are needed for VOR?

Answer 4

All. Med: vestibular complex
Pons: MLF, CN6 nuc
Mid: CN3, MLF

Question 5

What is cold caloric testing?

Answer 5

Cold water/air into ear causes eyes to go that direction because it decreases hair cell/nerve function

Question 6

What are the 4 types of VOR-related nystagmus? What are the 3 unrelated ones?

Answer 6

VOR: COWS, SCOW, acquired, normal (post-rotary)

Non-VOR: end-point (normal), gaze-induced (EtOH), optokinetic (normal)

Question 7

What is COWS?

Answer 7

Caloric nystagmus with cortex intact. Cold opposite - eyes slowly toward cold. Warm same - FEF snap back to center.

Question 8

What is SCOW?

Answer 8

Caloric nystagmus w/o fxl cortex. Same cold - eyes move to cold. Opposite warm - FEF do not move back to center.

Question 9

What pathology may cause acquired vestibular nystagmus?

Answer 9

CN8, FN lobe, vestibular complex in medulla

Question 10

What symptoms does unilateral lesion CN8, vestibular complex, ICP, or FN lobe cause?

Answer 10

Vertigo/nausea, wide-based gait w/ truncal ataxia, titubations, acquired nystagmus

Question 11

What is end-point nystagmus?

Answer 11

Normal, does not involve VOR. Occurs when trying to fixate in extreme position.