Disorders of the Vestibular and Visual Systems

Question 1

What is vertigo?

Answer 1

An illusion of motion

*most common symptom of vestibular system disorder

Question 2

What does vertigo arise from?

Answer 2

a disturbance of spatial orientation in the vestibular cortex

Question 3

Vestibular disorders may cause ______ nystagmus

Answer 3

pathologic

Question 4

Does pathologic nystagmus fatigue and habituate in periperhal or central disorders?

Answer 4

in most peripheral disorders, but not in central disorders

Question 5

What does a complete lesion affecting receptors or cranial nerves dedicated to that system produce?

Answer 5

a total ipsilateral loss of sensory input for the particular system

Question 6

What does a complete lesion in the retina or optic nerve cause?

Answer 6

ipsilateral blindness in the visual system

Question 7

Do peripheral or central disorders typically cause recurring periods of vertigo and more severe nausea?

Answer 7

Peripheral vestibular disorders

Question 8

What always accompanies peripheral vertigo?

Answer 8

nystagmus

Question 9

What are 2 other symptoms of vestibular disorders?

Answer 9

• diminished hearing

- tinnitus

Question 10

What are 5 common peripheral vestibular disorders?

Answer 10

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

Question 11

What benign paroxysmal positional vertigo (BPPV)?

Answer 11

An inner ear disorder that causes acute onset of vertigo and nystagmus

Question 12

BPPVs are benign meaning….?
Paroxysmal meaning…?
Positional meaning…?

Answer 12

• Benign: Is not malignant.
• Paroxysmal: Has a sudden onset of a symptom or disease.
• Positional: Denotes head position as the provoking stimulus.

Question 13

Rapid change of head position, resulting in vertigo and nystagmus, will subside in less than _ minutes, even if the provoking head position is sustained.

Answer 13

2

Question 14

What are 4 activities that frequently provoke BPPV?

Answer 14

• 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

Question 15

What causes BPPV?

Answer 15

the displacement of otoconia from the macula into a semicircular canal

Question 16

Signs and symptoms of BBPV can be provoked using the _____ maneuver.

Answer 16

Hallpike

Question 17

The displacement of otoconia may occur spontaneously or it may be the result of what?

Answer 17

trauma or infection of the vestibular apparatus

Question 18

What is Vestibular Neuritis?

Answer 18

Inflammation of the vestibular nerve

Question 19

What usually causes Vestibular Neuritis?

Answer 19

a virus

Question 20

What are the symptoms of Vestibular Neuritis?

Answer 20

• dysequilibrium
• spontaneous nystagmus
• nausea
• severe vertigo

Question 21

Is hearing affected in Vestibular Neuritis?

Answer 21

no

Question 22

What is Ménière Disease?

Answer 22

A disease that causes a sensation of fullness in the ear, tinnitus, severe acute vertigo, nausea, vomiting, and hearing loss

Question 23

What is Ménière Disease associated with?

Answer 23

Abnormal fluid pressure in the inner ear

Question 24

Traumatic injury may cause what 3 things to occur which may alter the vestibular system?

Answer 24

• concussion of the inner ear
• fractures of the bone surrounding the vestibular apparatus and nerve
• pressure changes in the inner ear

Question 25

What is perilymph?

Answer 25

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

Question 26

A perilymph fistula is the result of what?

Answer 26

An opening between the middle and inner ear which allows perilymph to leak from the inner ear into the middle ear

Question 27

What does a perilymph fistula produce?

Answer 27

- abrupt onset of hearing loss - tinnitus - vertigo

Question 28

What is oscillopsia?

Answer 28

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

Question 29

Oscillopsia tends to occur because normal reflexive adjustments for head movement are _______.

Answer 29

decreased

Question 30

Oscillopsia is the initial complaint of what?

Answer 30

Bilateral Lesionsof the Vestibular Nerve

Question 31

Central Vestibular Disorders are the result of what?

Answer 31

damage to the vestibular nuclei or to the connections within the brain

Question 32

Central Vestibular Disorders are most commonly the result of what 4 things?

Answer 32

- ischemia or tumors in the brainstem/cerebellar region (e.g., Wallenberg’s syndrome) - cerebellar degeneration - multiple sclerosis - Arnold-Chiari malformation

Question 33

What may also cause vestibular dysfunction?

Answer 33

Migraine headaches

Question 34

What does unilateral vestibular loss cause problems with?

Answer 34

- posture - eye movement control - nausea

Question 35

Peripheral lesions interfering with otolithic function on one side causes imbalance which produces a tendency to fall _____ the side of the lesion.

Answer 35

toward

Question 36

A unilateral lesion affecting the otoliths or the vestibular nuclei may produce what?

Answer 36

An ocular tilt reaction

Question 37

What does bilateral vestibular loss eliminate?

Answer 37

A person’s internal sense of gravity

Question 38

What must a person with bilateral vestibular loss relay on for spatial orientation?

Answer 38

visual and proprioceptive cues

Question 39

IS vertigo present in bilateral vestibular loss? Why or why not?

Answer 39

No, because there is no asymmetry of the vestibular information

Question 40

Bilateral loss of semicircular input causes failure of which reflex?

Answer 40

VOR

Question 41

When a person with bilateral vestibular loss walks, what happens?

Answer 41

the world appears to bounce up and down

Question 42

What is a common symptom of individuals with chronic vestibular dysfunction?

Answer 42

stiffness of the neck and shoulders, due to attempting to stabilize the head to lesson vertigo or oscillopsia.

Question 43

Visual losses are clinically described by referring to the "_______________".

Answer 43

“visual field deficit.”

Question 44

What is anposia?

Answer 44

Loss of sight in one or both eyes

Question 45

What is hemianopsia?

Answer 45

Loss of sight in one half of the visual field

Question 46

What is homonymous hemianopsia?

Answer 46

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

Question 47

A lesion of the optic nerve will cause what?

Answer 47

loss of vision from the ipsilateral eye

Question 48

A lesion of the optic chiasm will cause what?

Answer 48

bitemporal hemianopsia

Question 49

A lesion of the optic tract will cause what?

Answer 49

loss of vision from the contralateral visual field of both eyes (homonymous hemianopsia)

Question 50

Describe a person who is cortically blind

Answer 50

They have no awareness of any visual information

Question 51

What is blind sight?

Answer 51

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

Question 52

How can a person who is cortically blind orient their head position?

Answer 52

Because the ability to perceive light and dark is vaguely retained in the visual system

Question 53

The ability of a cortically blind person to orient to visual objects is contingent on what?

Answer 53

Intact function of the retina and pathways from retina to superior colliculus

Question 54

Abnormalities of eye movement occur with lesions involving what 6 things?

Answer 54

- Cranial nerves that control extraocular muscles - Strength of extraocular muscles - Medial longitudinal fasciculus - Vestibular system - Cerebellum - Eye fields in the cerebral cortex

Question 55

What are tropia and phoria?

Answer 55

deviations of the ability to align the eyes

Question 56

Define tropia

Answer 56

the deviation of one eye from a forward gaze when both eyes are open

Question 57

Define phoria

Answer 57

the deviation from a forward gaze, apparent only when the person is looking forward with one eye, while the other eye is covered.

Question 58

What is motion sickness?

Answer 58

Nausea, headache, anxiety, and vomiting experienced in moving vehicles

Question 59

What may cause motion sickness?

Answer 59

A conflict between different types of sensory information or by postural instability.

Question 60

What may cause seasickness?

Answer 60

A conflict between visual and vestibular information

Question 61

When a patient reports dizziness what 4 things must the clinician distinguish among?

Answer 61

- Vertigo: illusion of movement (vestibular disorder) - Near syncope: feeling of impending faint (cardiovascular) - Dysequilibrium: loss of balance (usually neurologic) - Light-headedness: inability to concentrate (psychological such as anxiety disorder)

Question 62

What is the most important question to answer if the patient has a vestibular disorder?

Answer 62

Whether the lesion is peripherally or centrally located

Question 63

Postural tests are classified as one of what 2 types of tests? Give an example of each

Answer 63

- Static: Romberg’s test | - Dynamic: tilt boards

Question 64

Which coordination test examines lower limb coordination?

Answer 64

Tandem walking and the heel-to-shin test

Question 65

What is sensory ataxia characterized by?

Answer 65

It is characterized by impaired vibratory and position sense, decreased or lost ankle reflexes, a lack of nystagmus, and a lack of vertigo.

Question 66

What is cerebellar ataxia characterized by?

Answer 66

The inability to stand with feet together, regardless of whether the eyes are open or closed. Vertigo and nystagmus may be associated.

Question 67

When is cerebellar ataxia evident?

Answer 67

All of the time, regardless of whether the person is standing, sitting, or lying down.

Question 68

When is vestibular ataxia evident?

Answer 68

When walking; limb movements are normal when lying down

Question 69

What is sensation testing used for?

Answer 69

to localize a lesion

Question 70

What 3 senses are tested during sensation testing?

Answer 70

Hearing, proprioception, and vibration

Question 71

What are proprioception and vibration tests used to distinguish between?

Answer 71

lesions of the conscious proprioception pathways and vestibular lesions

Question 72

When performing the Hallpike maneuver, if the left ear, rotary nystagmus is _______; if the right ear is affected, rotation is ________.

Answer 72

clockwise counterclockwise

Question 73

What are 5 ways in which Vestibulo-Ocular Reflexes are tested?

Answer 73

- Passive, rapid head thrusts - Testing dynamic visual acuity - Using a rotating chair - Caloric testing - Electronystagmography

Question 74

Describe how a caloric test is performed

Answer 74

A small amount of cold (30° C) or warm (44° C) water is instilled into the ear canal. - In a conscious patient, the mnemonic COWS summarizes the saccadic movements of the eyes: cold opposite, warm same - Nausea and vomiting may result from the vestibular action on autonomic function.

Question 75

What is Electronystagmography?

Answer 75

a recording of eye movements

Question 76

The ability to direct gaze can be tested by which 3 tests?

Answer 76

- Cover test - Cover-uncover test - Alternate cover test

Question 77

What are rehab exercises designed to promote?

Answer 77

movement retraining, habituation, or substitution to improve function