Vestibular Flashcards
What are the reflexes of the eyes?
VOR
Vestibulocollic reflex (VCR)
Vestibulospinal reflex (VSR)
definition: Generates eye movements that enable clear vision while the head is in motion
primary mechanism for gaze stability during movement
VOR
definition: eye reflex
- Acts on neck musculature to stabilize the head
- Looks like ataxia
vestibulocollic reflex (VCR)
definition: Generates compensatory body movement in order to maintain head and postural stability to prevent falls
vestibulospinal reflex (VSR)
The vestibular system is a (open/closed) system
closed
Includes the:
3 semicircular canals (SCC)
Cochlea and vestibule
Perilymphatic fluid
bony labyrinth
definition: structure that is suspended within bony by perilymphatic fluid and connective tissue
contains:
- membranous portions of the 3 SCC
- otholiths
- endolymphatic fluid
membranous labyrinth
The membranous portions of the 3 SCCs have one widened end to form the ___.
ampulla
(true/false) Endolymph and perilymph do not mix under normal circumstances
true
Where is perilymphatic fluid found?
in the bony labyrinth
Where are the hair cells of the vestibular system found?
ampulla and otoliths
definition: calcium carbonate crystals that weight the otolithic membrane down
- Can fall off, move into the ampulla, and get lodged in the cupula
otoconia
What do the SCCs provide?
sensory input about the head velocity
–> enables VOR to generate eye movement that matched the velocity of the head
Each canal plane within each labyrinth is _____ to the other canal planes
perpendicular
(true/false) Angular head motion occurs in a shared plane
true
Endolymph of the coplanar pair is dislocated in ___ directions with respect to ampullae
opposite
Coplanar pairing of canals is associated with a push-pull change in the quantity of ___ output.
SCC
definition: push-pull pairing
co-planar pairing
The canals are arranged in such a way that each canal on the left side has an almost ____
counterpart on the right side.
almost parallel
Horizontal canals are ___% elevated.
30%
What do otoliths do?
- Register forces related to linear acceleration
- Respond to both linear head motion and static tilt
Otoliths respond to ___ motion and ___.
linear motion and acceleration
The vestibular nerve transmits AFFERENT signals from the labyrinths along its course through the ______.
internal auditory canal (IAC)
What structures do the internal auditory canal contain?
Vestibular nerve
cochlear nerve
facial nerve
nervus intermedius
Labyrinthine artery
definition: Afferent projection from the bipolar neurons of Scarpa’s (vestibular) ganglion
Vestibular nerve
What is the primary central processor of vestibular input? What does it do?
Vestibular nuclear complex
Implements direct, fast connections between incoming afferent information and motor output neurons
What is considered as an adaptive central processor of vestibular input? What does it do?
cerebellum
Monitors vestibular performance and readjusts vestibular central vestibular processing if needed
What are the 4 major nuclei of the vestibular nuclear complex?
Superior
Medial
Lateral
Descending
There are at least ____ minor nuclei in the vestibular nuclear complex
7
What are the components of VOR?
Angular (SCC) and linear (otoliths)
Gaze stabilization is correlated with ___ VOR.
angular
When does BPPV occur?
With changes in position
What does true vertigo include?
The sensation of spinning
What are characteristics of BPPV?
- Brief episodes of vertigo
- Uncommon in children but reported in adults of all ages
- May have both spontaneous occurrence and remission
- Reports of this happening before
- Head trauma
- Viral neuronitis
- balance issues
vague sensations/floating feeling - lightheadedness
What is the most common vestibular disorder?
BPPV
What causes BPPV?
movement of detached otoconia within the ear
OR
otoconia are adherent to the cupula
definition: otoconia are adhered to the cupula
cupulolisthasis
definition: movement of detached otoconia in the endolymph of the ear canal
canalithiasis
Debris adhere to the cupula (decreases/increases) density
increases
What are the characteristics of cupulolisthiasis?
- immediate onset of vertigo when moved into a provoking position
- nystagmus
- persistence of vertigo and nystagmus as long as the patient’s head is in a provoking position
What are the characteristics of canalithiasis?
- delay in onset of vertigo from 1-40 seconds after the patient was moved into a provoking position
- nystagmus
- fluctuation in the intensity of vertigo and nystagmus which increase and then decrease within 60 seconds
What SCC is commonly involved with BPPV?
posterior
(true/false) BPPV will not have nystagmus when returning to a sitting position
FALSE (it will be present)
What is the most common BPPV test?
dix-hallpike
What is a (+) test on Dix-hallpike for right posterior SCC involvement?
up-beating and right torsion
What is a (+) test on Dix-hallpike for right anterior SCC involvement?
down-beating and right torsion
What is a (+) test on Dix-hallpike for left anterior SCC involvement?
down-beating and left torsion
(true/false) Dix-hallpike test can trigger vertigo due to anterior canal being in a more dependent position when downward
true – will be down-beating and torsional
What test is done to rule out horizontal canal BPPV?
roll test
When do you perform a roll test?
After getting a (-) dix-hallpike test
(true/false) During a roll test, vertigo and nystagmus will occur when the head is turned to the right AND the left
true
When do you rule in horizontal canal BPPV during the roll test?
When nystagmus is present
Duration of nystagmus and patient’s complaints are believed to be worse when the head is turned toward the affected ear in ________.
canalithiasis
Duration of nystagmus and patient’s complaints are believed to be worse when the head is turned toward the less symptomatic ear in _____.
cupulolisthiasis
You will see ___ nystagmus with canalithiasis.
geotropic (quick downward beating)
Nystagmus with canalithiasis (will/will not) fatigue.
it will
Nystagmus with cupulolisthiasis (will/will not) fatigue.
will not
You will see ___ nystagmus with cupulolisthiasis.
apogeotopic (quick beats upward)
What treatment(s) are used with anterior/posterior canal BPPV?
CRP/CRT for ant/post canal BPPV (Epley)
Brandt-Daroff habituation exercises
What are post treatment instructions after performing the epley?
Stay upright for 5-20 minutes after treatment
What are the treatment(s) for posterior SCC cupulolisthiasis and canalisthiasis? Which one are they more commonly used for?
semont/liberatory maneuver
More commonly used with cupulolisthiasis
What are the treatment(s) for horizontal SCC BPPV w/ Canalisthiasis?
CRT for Horizontal SCC BPPV, canalisthiasis (270/360 degree roll)
appiana
Forced prolonged sitting
What are the treatment(s) for horizontal SCC BPPV w/ cupulolisthiasis?
semont/casini for Horizontal canal cupulolisthiasis
When performing CRP/CRT for anterior/posterior canal BPPV, the patients eyes (should/should not) be fixed.
should not… use frenzel lenses or IR goggles
Why? Horizontal and vertical nystagmus can be suppressed by visual fixation
What should you do first when treating balance problems caused by BPPV?
attempt to resolve vertigo first
Vague imbalance with BPPV tends to resolve without intervention after ___ weeks.
2 weeks
(true/false) Medication can delay vestibular adaptation.
true
What are s/s of CNS pathology?
- acoustic neuromas
- MS
- brainstem TIAs
- cerebellar disorders
- migraines
- numbness
- tingling
- weakness
- slurred speech
- tremors
- decreased coordination
- UMN s/s
- LOC
- memory loss
- visual field loss
- CN dysfunction
- spontaneous nystagmus after 2 weeks
- vertical nystagmus without torsion
Vertical nystagmus without torsional component (is/is not) BPPV
is not BPPV
Asking patient to look at a point and have them follow it while keeping their head still (keep the white of their eye in focus)
gaze-evoked nystagmus
Seeing if the nystagmus occurs at the end range of eye movement
end-point nystagmus
(true/false) End-point nystagmus is not normal
False (it is normal)
Direction-changing, gaze-evoked nystagmus is a sign of _____.
central lesion
When does spontaneous nystagmus occur?
Room light while resting
definition: Tracking a moving object- 4 seconds from one side back to other
smooth pursuit
Smooth pursuit test can asses what CNs?
III, IV, VI
definition: Look back and forth between two horizontal or vertical targets
saccadic eye movements
definition: an illusion of an unstable vision, made up of the perception of the to-and-fro movement of the environment
oscillopsia
(true/false) Skew deviations during oculomotor and VOR testing are named after the elevated side event though the side affected is the dropped eye.
true
Skew deviations should resolve within ___-___days of insult
3-7 days
definition: when the eyes are not aligned
Skewed deviation
Dynamic visual acuity test evaluates ____ function.
VOR function
What test is this? What is a (+) test?
- read the eye wall chart with head in stationary
- gently oscillate the head
Dynamic visual acuity…
(+) visual acuity degrades by 3 or 4 lines (uncompensated unilateral vestibular loss)
(true/false) Coordination is commonly affected with vestibular lesions
FALSE
What vestibular disorder is postural issues found with?
central vestibular disorders
What system does the vestibular system influence?
autonomic nervous system
–> explains why indiv. have trouble breathing, experience nausea, or have irregular heartbeat when feeling overwhelmed
What kind of lesion is peripheral vestibular hypofunction (Unilateral vestibular hypofunction (UVH))?
peripheral
BPPV makes up ___% of dizziness cases.
20%
BPPV is responsible for ___% of vertigo cases in adults over 80 y/o.
50%
What are examples of UVH?
vestibular neuritis, one-sided meniere’s disease, age-related vestibular loss
Vestibular neuritis is reponsible for __% of dizziness cases.
5%
Vestibular neuritis is responsible for ___% cases of vertigo
15%
What are s/s of acute vestibular neuritis?
- vertigo
- tilt response
- absence of tinnitus
- A-febrile
- static defect
Where are structural and functional impairments found with peripheral lesions?
VOR
VSR
sensory mismatch
physical deconditioning
VOR produces eye movements of EQUAL velocity with (same/opposite) eye direction to the head movement.
opposite
When is VOR gain reduced with unilateral labyrinthine lesions?
immediately after movement
What oculomotor tests are not affected by vestibular loss?
saccades
smooth pursuit
Under normal conditions, what works with VOR to stabilize gaze during eye movements?
saccades and smooth pursuit
(true/false) acute vestibular dysfunction asymmetry occurs with actual movement of the head
false
(true/false) chronic vestibular dysfunction asymmetry occurs with actual movement of the head
true
What reflex contributes to postural disturbances?
VSR
What do patients with unilateral peripheral deficits experience with postural instability?
- enhanced tibialis anterior responses contralaterally
- reduced tibialis anterior responses ipsilaterally
- reduced neck muscle activity
- increased angular accelerations of the head
Those with poor VOR gain have what activity limitations?
difficulty seeing during head movement
Those with poor VSR gain have what activity limitations?
- decreased confidence in balance
- reduced gait speed
- increased risk of falling
description: Vertigo, sudden onset, short duration, episodic, daily
BPPV
description: Vertigo, sudden onset, long duration, one episode followed by imbalance or oscilopsia
Vestibular neuritis
labyrinthitis
First occurrence of meniere’s or migraine attack
CVA
description: Vertigo, sudden onset, long duration, episodic not daily
meniere’s
migraine
recurrent TIA
description: Imbalance, gradual onset, continuous or wax and wane
UVH
progressive disease
schwanomma
small vessel disease
white matter degeneration
multi-lacunar infarction
Spontaneous nystagmus is observed in those with (acute/chronic) UVH
acute
–> will suppress after a few days with visual fixation
What can smooth pursuit assess?
CN III, IV, VI
What type of nystagmus is indicative of a central lesion?
direction-changing, gaze-evoked nystagmus
What is alexander’s law used for?
Screen for UVH nystagmus
If UVH nystagmus is present, what phase of eye movement has more intense nystagmus?
quick phase
What is 1st degree nystagmus according to alexander’s law?
nystagmus is present only in gaze going towards the fast phase
What is 2nd degree nystagmus according to alexander’s law?
nystagmus present in primary gaze and stronger in gaze towards the fast phase
What is 3rd degree nystagmus according to alexander’s law?
nystagmus is present in all gazes and is strongest in gaze towards the fast phase
What happens with visual acuity when a person has uncompensated UVH?
degrades 3-4 lines on a dynamic visual acuity test
–> oscillate head at 2 Hz
Why would one want to perform a loaded dix-hallpike test?
Produces longer duration and more intense symptoms –> fewer false negative results
When do asymmetrical disturbances of static vestibular function recover?
3-14 days
What is the point of a retinal slip?
Slip results in an error signal that the brain attempts to minimize by increasing the gain of the vestibular responses (Vestibular adaptation)
definition: Exercises or movements that systematically expose the individual to a provocative stimulus that over time with repeated exposure leads to a reduction in symptoms.
habituation
