A&P vestibular

Question 1

During a lifetime what percentage of adults experience dizziness

Answer 1

40%

Question 2

What percentage of adults experience dizziness over the age of 60

Answer 2

60%

Question 3

Vestibular rehabilitation includes specific exercises and/or

repositioning maneuvers designed to:

Answer 3

decrease dizziness
increase balance function
increase general activity levels

Question 4

Exercises are designed to

Answer 4

promote CNS compensation for vestibular system hypofunction

Question 5

repositioning maneuvers are used to

Answer 5

remove otoconia from semicircularcanals of the inner ear.

Question 6

What is Anatomical Overview process

Answer 6

input (Visual Somatosensory Vestibular) >Processing (Vestibular Nuclear Complex Cerebellum)> output (Vestibular Ocular Reflex Vestibular Spinal Reflex)

Question 7

Strong Inhibitor

Answer 7

of vestibular and somatosensory systems

Question 8

Neurological Pathways

Answer 8

medial longitudinal fasciculus ( MLF)

Dieter’s tract

Question 9

Visual Cranial Nerve Examination

Answer 9

sensory: vision test
motor: smooth pursuit test

Question 10

Fastest System compared to visual and vestibular systems

Answer 10

Neurological Pathway
spinothalamic tract
dorsal column medial lemniscal tract

Question 11

Sensory Receptor Examination

Answer 11

tactile awareness
kinesthetic awareness
proprioceptive awareness

Question 12

Vestibular System Purpose:

Answer 12

head and body orientation

Conflict Resolver: of the 3 systems

Question 13

Vestibular System Components

Answer 13

Vascular Supply: labyrinthine artery
Nerve Supply: CN VIII
Bony Labyrinth: Temporal Bone
Membranous Labyrinth:
Anterior,Posterior,and Horizontal Semicircular Canals(SCC)
Utricle and Saccule (Otoliths)

Question 14

Bony Labyrinth: contains what

Answer 14

Temporal Bone
contains perilymph (high Na:Kratio); supports the membranous labyrinth

Question 15

MembranousLabyrinth: contains what

Answer 15

SCC’s contain endolymph (high K:Na ratio);

Utricle and Saccule (Otoliths) contain endolymph and otoconia (calcium carbonate crystals)

Question 16

SCC’s have a greatest sensitivity

Answer 16

greatest sensitivity to angular motions (rotation, flexion, extension, lateral tilt);

Question 17

Why do SCC’s have a greatest sensitivity have a greatest sensitivity to angular motions

Answer 17

orthogonally positioned to one another; function in co-planar pairs (left anterior/right posterior; right anterior/left posterior; left horizontal/right horizontal)

Question 18

Otoliths have a greatest sensitivity to

Answer 18

to linear motions (up, down, forward, backward)

Question 19

Why do Otoliths have a greatest sensitivity to to linear motions

Answer 19

otoconia (calcium carbonate crystals) giving them mass

Question 20

What is meant by PUSH:

Answer 20

The resting neural firing rate of the vestibular nerves are 60-100 pulses per second. When the small steriocilia are “pushed” towards the large kinocilium, that hair cell is depolarized and the frequency of action potential increases.

Question 21

What is meant by PULL:

Answer 21

The resting neural firing rate of the vestibular nerves is 60-100 pulses per second. When the small steriocilia are “pulled” away from the large kinocilium, that hair cell is hyperpolarized and the frequency of action potential decreases.

Question 22

What is the PUSH-PULL:

Answer 22

Head moves angularly (rotation, flexion, etc…) vestibular nerves on one side of the head are “pushed” and the others are “pulled”. SCC co-planar pairs report to the VNC to determine which direction the head is moving.

Question 23

What neurologically is happening For PUSH PULL

Answer 23

Push -Depolarization

Pull -Hyperpolarization

Question 24

If head turns to the right where is the push and pull coming from

Answer 24

The RIGHT Pushes or Depolarizes

The LEFT Pulls or Hyperpolarizes

Question 25

Primary Processing: occurs in the

Answer 25

vestibular nuclear complex (VNC) which is located between the pons-medulla and cerebellum

Question 26

Adaptive Processing: occurs in the

Answer 26

cerebellum and largely has a dampening or inhibitory effect on the vestibular system

Question 27

Vestibular Ocular Reflex (VOR) role is

Answer 27

maintains gaze stability while head is moving

Question 28

What is normal VOR

Answer 28

gain is = 1; meaning there is an equal but opposite head-to-eye ratio; for every 1 degree the head moves left, the eyes move 1 degree right via the VOR; this provides clear dynamic vision

Question 29

Vestibular Spinal Reflex (VSR)

Answer 29

maintains postural stability

Question 30

VOR neural pathways.

Answer 30

facillitory (depolarization) | inhibitory (hyperpolarization).

Question 31

If the head is rotating right and the VOR is driving the eyes

Answer 31

left, Follow the pathways from the horizontal SCC’s to the extra ocular eye muscles.

Question 32

What are the 3 input systems driving postural stability and dynamic visual acuity

Answer 32

``` Visual System • strongest • sensory and motor Somatosensory System • fastest • tactile/kinesthetic/proprioceptive awareness Vestibular System • conflict resolver of the 3 systems • purpose: head and body orientation) ```

Question 33

2 primary reflexes responsible for postural stability and dynamic visual acuity?

Answer 33

Vestibular Ocular Reflex • Maintains gaze stability while head is moving for clear, dynamic vision • For every 1 degree that head moves in one direction, the eyes will move 1 degree in the opposite direction Vestibular Spinal Reflex • Communicates with muscles for stability to maintain postural stability

Question 34

How do semicircular canals differ from the otoliths

Answer 34

They differ from otoliths in that otoliths are the most sensitive to linear motions (up, down, forward, backward) while the semicircular canals are the most sensitive to angular motions (rotation, flexion, extension, lateral tilt).

Question 35

How many semicircular canals are there in the human head

Answer 35

There are 6 semicircular canals in total with three in each ear. It is these 6 SCC's that function in co-planar pairs such as left anterior/right posterior; right anterior/left posterior; left horizontal/right horizontal. They are membranous rather than bone.

Question 36

Which cranial nerves are responsible for eye movement and what are their actions?

Answer 36

Cranial nerve III (Oculomotor nerve) – Responsible for eyeball movements up, down, medially, and laterally Cranial nerve IV (Trochlear nerve) – Responsible for lateral and downward eyeball movements Cranial nerve VI (Abducens nerve) – Responsible for lateral deviation of the eyeball CN III = up, down, in CN IV = down and in (intorsion) CN VI = out