Vestibular System III

Question 1

What is motion sickness?

Answer 1

Response to unrecognized movement elicited by various forms of real or apprent motion

Question 2

What systems are involved in producing motion sickness?

Answer 2

Vestibular system:
-Semicircular canals:
Rotational/angular acceleration
Depends on direction and intensity

• Otolith organs:
  Static position
  Detect linear acceleration
  Detects head tilt

Visual System

Somatosensory System

Sickness results from a conflict of at least two of the three systems

Question 3

What is the Sensory Conflict Theory?

Answer 3

Discrepancy between visual, proprioceptive, and somatosensory input produce motion sickness

Question 4

What is Treisman’s Theory?

Answer 4

Poison response to toxins could effect processing of vestibular and visual input

–> elicits nausea and vomiting

–> results in the feeling of motion sickness

Question 5

What increases susceptibility to motion sickness?

Answer 5

Genetic predisposition

Female > Male

Age (rare <2 years; common in 2-12)

Anxiety

Elevated vasopressin, cortisol

Vestibular disorders (BPPV, Meniere’s)

confined space

Pregnancy

Alcohol use

Poor ventilation

Migraine history

Noxious fumes

Question 6

What are the most provocative stimuli for motion sickness?

Answer 6

• Motion with a vertical component
  2 Hz/sec oscillation
• Motion with combined angular and linear component
• Unusual motion with lack of visual reference

Question 7

What are symptoms of motion sickness?

Answer 7

Stomach discomfort

Nausea

Dizziness/vertigo

Pallor

Sweating

Headache

Warmth

Drowsiness

Question 8

What should also be considered when a person presents with motion sickness?

Answer 8

Labyrinthitis

Gastroenteritis

Central or Peripheral vertigo

Question 9

What is the differenct betweeen peripheral or central vertigo?

Answer 9

Peripheral: Common and often self-limiting
–> due to inner ear issue

Central: due to cerebellar or other CNS issue
–> much more concerning

Question 10

What medications are available for motion sickness?

Answer 10

Combined anti-cholinergic/dopaminergic/histamine pharmaceuticals:

Scopolamine (muscarinic anti-cholinergic)
Promethazine
Meclizine

Antihistamines:

Dimenhydrinate (dramamine)
Diphenhydramine (benadryl)

Alternative:
Ginger
peppermint oil
Vapors of isopropyl Alcohol