Vestibular Anatomy and Function Flashcards by Meg Heil

What are the 3 Roles of the Vestibular System?

Stabilize visual image during head movement
Provide sensory info for spatial orientation
Maintain postural stability when stationary and during movement

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Controls the body position in space for stability and orientation between body segments and the environment, appropriate for a task

Postural control

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Maintenance of the COM within the BOS

Postural Stability

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Ability to maintain a relationship between body segments and between body and environment for a task

postural orientation

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_____ System
-recognizes motion

Visual

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Children <7.5 rely on what system for balance?

Vision

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What 3 things make up the vestibular system?

Gaze stabilization
Spatial orientation
Postural stability

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____ System
-recognizes relative body movements and position
base of support, joint proprioception, pressure, cervical proprioception and kinesthesia

Somatosensory

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Explain central processing

adaptive strategies that change with the demands of a task

anticipatory strategies “pretune” sensory and motor systems based on prior learning

Ex: Cognitive override due to consideration of motivation intent and attention

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Give an example of central processing

a volley baller going to dive for the ball the central portion of the brain overrides the body going outside of its BOS.

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What arteries supply blood to the vesibular peripheral organ?

Posterior blood supply
1. Basilar Artery
2. Anterior Inferior Cerebellar Artery

Labyrinethine artery
-anterio-vestibular artery
-common cochlear

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What are the two otoliths?

utricle and saccule

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What motion is recognized by the utricle

horizontal plane motion

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What motion is recognized by the saccule

vertical plane motion

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Explain what otoconia do?

provide shear forces for hair cell deflection

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Are otoconia gravity dependent and what does that mean?

Yes Otoconia are gravity dependent
if you tip your head Otoconia shift deflecting hair cells sending signals to the brain.

these otoconia should not fall off the otolithic membrane but if they do thats what causes vertigo

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What motion do the otoliths regonize

forward/backward
up/down
tilting

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What does tonic discharge mean?

both ears have discharge even at rest

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Explain the push pull relationship between the otolith organs

if you tilt head left discharge increases while the right discharge decreases

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What motion is recognized by the semicircular canals?

angular motion-rotation

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What do the hair cells do?

tell your brain that you have moved

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How many semicircular canals are there?

3
anterior
posterior
horizontal

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Describe what happens if you move down and to the right what canal stimulates and what decreases?

stimulates right anterior and decrease left posterior

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Where does Cranial nerve VIII have its cell bodies?

scarpas ganglion
has bipolar ends

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Describe cranial never VII and VIII course of action?

travel together through the internal auditory meatus enter the pontomedullary junction of the brain

Explain where the CN VII VIII enter the brainstem in terms of nuclei

1. superior vestibular nuclei 2. inferior vestibular nuclei 3. lateral vestibular nuclei 4. medial vestibular nuclei

Do the vestibulospinal mechanisms for postural control continue to develop beyond 15 years of age?

true

The vestibulo cerebellum is

Flocculonodular lobe

What do the vestibular nuclei do to the cerebellum

can fine tune communicate info from the nuclei to the cerebellum for input and output

What is responsible for the discrimination between self movement and environment movement?

thalamus

Explain what the reticular formation does?

interprets info from all vestibular nuclei can determine if motion from a rollercoaster causes vomiting can determine that rocking a baby is safe and soothing

Why is our vestibular cortex so small?

we aren't that conscious of the motion that occurs around us

What is the blood supply for the inferior vestibular nucleus

posterior inferior cerebellar nucleus

What blood supplies the pons and more superior vestibular nuclei

basilar artery

Explain the Vestibular ocular reflex

Stabilizes gaze during head movements ex: if you turn your head your extra ocular eye muscles will go the other way

When is the VOR intact and mature

by one year

Describe the flow of input for VOR

inner ear--vestibular nuclei--- MLF--- extra ocular eye muscles

Describe the vestibulo-spinal reflex

coordinates head and body movements to maintain head in upright position

Explain the path of VSR

info from inner ear--> vestibular nuclei--> descends to the cervical spinal cord--> to extension response to catch our balance

What tracts does the VSR utilize?

LVST- Lateral vestibulo-spinal tract MVST- Medial vesibulospinal tract

Describe what the Vestibulo-colic reflex does?

head righting stabilizes head/neck produces coordinated movements to track a moving target think of the chicken video

Describe ATNR (asymmetric tonic neck reflex)

neck rotation excites ipsilateral extensors and contralateral flexors

Describe STNR (symmetric tonic neck reflex)

neck extension excites ipsilateral UE extension LE flexion

Cervico- occular reflex

eye movements are driven by neck proprioception supplements the VOR when needed facilitated when vestibular organ is injured

Cervicospinal reflex

can supplement the VSR by alerting tone in the body

cervicocolic reflex

stabilizes the head on the body may be facilitated after vestibular loss

What are some Central Pathologies of vestibular disfunction

Traumatic Brain injury Multiple Sclerosis Stroke Brain tumor Vestibular migrane

What is the most common cause of true vertigo?

Benign Paroxysmal Positional Vertigo

What is the 2nd most common cause of true vertigo?

neuritis- CN VII becomes inflammed

A floor warping, ceiling spinning, brain churning, think you're gonna die and afraid you might not- hangover

Endolymphatic Hydrops Meniere's Disease

Describe some of the presentation of Meniere's disease

acute episodes of 30 min to 24 hours usually recovery in 72 hours

What is the treatment of meniere's disease? PT involvement

Surgery or ablation- managed medically PT can help with education

What is the presentation of Perilymph Fistula?

vertigo after very loud sounds Congenital, prior ear surgery, barotrauma

What is the treatment for Perilymph Fistula? PT involvement

PT will refer!

What is the presentation of Superior Canal Dehiscence?

Creates a window through the bone vertigo and oscilopsia induced by loud noises

What is the treatment for Superior Canal Dehiscense?

Primarily medical management PTs Refer!!

What is the common presentation of Mal de Debarquement Syndrome?

perception of motion when stationary and eyes are open Usually occurs after exposure to motion, such as a cruise Difficulty adapting back to stable environment

What is the treatment for Mal de Debarquement Syndrome? PT involvement?

Possible treatment with medication focus on somatosensory referencing to vestibular sense Know how to examine- as a pt Very common but very hard to treat

What is the presentation of Peripheral Neoplasm Acoustic Neuroma?

Tumor affecting CN VII

What is the treatment for Peripheral neoplasm acoustic neuroma? PT involvement

surgical removal or radio-surgery Commonly and appropriately referred to PT for treatment

What is persistent Postural Perceptual Dizziness?

Persistent dizziness Non-spinning Vertigo Perceived unsteadiness A result of long term maladaption

What is the treatment of persistent postural perceptual dizziness?

Commonly and appropriately referred to PT for treatment

___%. of those with whiplash dizziness can take longer than 20 weeks to return to work

20%

What is the primary symptom of wiplash?

Neck pain

What are common subjective findings with patients who have cervicogenic dizziness?

occipital or bitemporal HA Neck Pain People tell me my head is not straight

What are some common subjective findings of someone who is just having dizziness non specific?

Dizziness Sensation of falling Difficulty reading Feeling tired

What are some medical and audiologic tests commonly used to diagnose vestibular disorders?

Electronystagmography Videonystagmography Medical diagnostic testing- rotary chair testing Autiogram

Medications such as Cisplatin and gentamycin, streptomycin can cause what?

ototoxic

When should you use the vertebral artery test?

neck trauma cervical surgery and/or arthritis

Is there a high specificity or sensitivity with the vertebral artery test

Specificity if it is positive likey they have insufficient blood flow

What are the 5 Ds and 3 Ns

Dizziness Diplopia Dsyphagia Dysarthria Drop attack Numbness Nystagmus Nausea

What are test can be used to diagnosis an issue with VOR?

Head impulse test Head thrust test

How do you test gaze stability?

Dynamic Visual acuity SNELLN chart

What are 3 positional testing for BPPV

Dix- hallpike Sidelying Test Roll Test

What are some test for postural control?

Berg Balance Mini Best Test Four Square step CTSIB ROmberg FUnctional reach

How to test for head righting response?

sitting on rocker board Standing on rocker board Tandem standing

What is a normal loss of line during the VOR head motion visual acuity testing

loss of 2 lines is normal

Nystagmus is named for what

the fast phase direction

Your patient has dizziness/vertigo what is the treatment

Habituation: Exercises designed to perform several repetitions of body movements or watch visual motion that cause mild to moderate symptoms

Your patient has Visual blurring with head movements what is the treatment

Gaze stability adaptation exercise to maximize remaining vestibular function

Your patient has imbalance and/or falls what is your treatment

Balance and gait may involve changes in base of support to increase balance challenge and weight shifting to improve center of gravity control

produce an error signal and recalibrate vestibular input up-train or force use particular senses central selection, prioritization, integration

remediation=adaptation/uptraining

Repetition of provoking movement with cautious symptom provocation and settling

sensory habituation=desensitization

If sensory information is missing inherent limitaitons- may need additional compensations under certain circumstances

sensory substitution= Compensation

What should be considered with central pathologies

Consider burden and location of damage uptrain vestibular function when able compensate with vision and somatosensory when maximum adaptation has occured

If patient has dizziness when the head is moved where is a strong hypothesis this is coming from?

cervical

If patient moves body and the head doesnt move and the patient has dizziness then what is your hypothesis?

vestibular

During a smooth pursuit neck torsion test the neck is placed at ____ degrees of rotation

45 degrees

What is a negative test for the smooth pursuit neck torsion test?

saccades, increase dizziness