Chapter 16 Park 2 Flashcards Preview

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Flashcards in Chapter 16 Park 2 Deck (39):
1

Oscillopsia

Lack of visual stabilization; e.g., the world appears to bounce up and down as a result of a failure of the vestibulo-ocular reflex

2

Nystagmus

Involuntary back-and-forth movements of the eyes composed of slow component in one direction and interrupted by fast saccadic-like movements in the opposite direction.

3

Pathologic nystagmus

Abnormal oscillating eye movements that occur with or without external stimulation.

4

Physiologic nystagmus

Normal involuntary back-and-forth eye movements that can be elicited in an intact nervous system by rotational or temperature stimulation of the semicircular canals or by moving the eyes to the extreme horizontal position.

5

Fistula

an abnormal passage that leads from one hollow organ or part to another

6

Paroxysm

a sudden attack or increase of symptoms of a disease (such as pain, coughing, shaking, etc.) that often occurs again and again

7

Vertigo

Illusion of motion; is common in vestibular disorders

8

What is the most common symptom of vestibular disorder?

vertigo

9

What disorders does vertigo occur with?

peripheral and central

10

What does vertigo arise from?

arises from a disturbance of spatial orientation in the vestibular cortex.

11

What always accompanies peripheral vertigo?

nystagmus

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What does peripheral vestibular disorders typically cause?

recurring periods of vertigo and more severe nausea than central disorders

13

Common peripheral vestibular disorders:

benign paroxysmal positional vertigo (BPPV),
vestibular neuritis,
Ménière’s disease,
traumatic injury, and
perilymph fistula

14

Inner ear disorders that cause the acute onset of vertigo and nystagmus are

benign
paroxysmal
positional

15

Benign:

Is not malignant

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Paroxysmal

Has a sudden onset of a symptom or disease

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Positional

Denotes head position as the provoking stimulus

18

What are activities that provoke BPPV?

Getting into or out of bed
Bending over to look under a bed
Reaching up to retrieve something from a high shelf
Turning over in bed

19

What causes BPPV?

the displacement of otoconia from the macula into a semicircular canal

20

Vestibular Neuritis

an inflammation of the vestibular nerve 
and is usually caused by a virus

21

Symptoms of vestibular neuritis:

dysequilibrium, 
spontaneous nystagmus, nausea, and 
severe vertigo
hearing is unaffected

22

Ménière Disease

Causes a sensation of fullness in the ear, tinnitus, severe acute vertigo, nausea, vomiting, and hearing loss.
Is associated with abnormal fluid pressure in the inner ear

23

What is perilymph?

fluid in the space between the 
bone and the membranous labyrinth in the 
inner ear

24

When does a fistula occur?

an opening occurs between the middle and inner ear

25

What happens with a fistula?

perilymph to leak from the inner ear into the middle ear

26

What does a perilymph fistula cause?

the abrupt onset of hearing loss, tinnitus, and vertigo

27

Bilateral Lesions of the Vestibular Nerve

Interfere with reflexive eye movements in response to head movement

28

What is oscillopsia?

the subjective sensation of visual objects bouncing when the head is moving or the persons is walking

29

Why does oscillopsia occur?

because normal reflexive adjustments for head movement are decreased

30

Central Vestibular Disorders

Are the result of damage to the vestibular nuclei or to the connections within the brain

31

Symptoms Central Vestibular Disorders:

Typically produce milder symptoms than peripheral disorders

32

What are central vestibular disorders commonly the result of?

ischemia or tumors in the brainstem/cerebellar region cerebellar degeneration, multiple sclerosis, or Arnold-Chiari malformation

33

Unilateral Vestibular Loss

Causes problems with posture, eye movement control, and nausea because signals from the intact side are not balanced by those from the lesion side

34

Cortically blind:

have no awareness of any visual information

35

Blind sight

is the ability of an individual who is cortically blind to orient or point to visual objects

36

What is blind sight contingent upon?

intact function of retina and pathways from retina to superior colliculus

37

Anopsia

Loss of sight in one or both eyes

38

Hemianopsia

Loss of sight in one half of the visual field

39

Homonymous hemianopsia

Loss of vision in the left or right visual field of both eyes