Vestibular Flashcards
what are the roles of the vestibular system
-stabilize visual image during head movement
-provide sensory info for spatial orientation
-maintain postural stability when statinoary and during movement
define postural control
-controls bodys position in space for stability and orientation between body segments and environemnt
define postural stability
maintenance of COM over BOS
define postural orientation
ability to maintain relationship between body segments and body
at what age do children have more developed somatosemsory system but vision is more dominant for balance
<7.5
what are peripheral vestibular structures
-vestibular end organ
-cranial nerve VIII
what is the peripheral vestibular blood supply
-basiliar artery
-AICA
-labrynthine artery
-anterior-vestibular artery
-common cochlear
what is in the peripiheral end organ
otoliths:
-utrticle: horz
-saccule: vertical
semicircular canals:
-ant, post, horz
hair cells convert head motion into neural firing
-bony labyrinth, membranous lab, endolymp, perilymph
what is a otolithic membrane
gelatinous macula
what does the otoconia do
provide shear forces for hair cell deflection
what do otoliths do
linear motion detection
-fwd/bckwd
-up/down
-tilt
-tonic discharge
-push/pull relationship
what do semicircular canals do
ampulla:
-cupula deflection for hair cell depolorization
-perpendicular relationship
-3 coplanar pairs
-angular motion detection
-tonic discharge
-push/pull relationship
describe how the peripheal and central meet
vestibular portion of CN VIII is a bipolar neuron with cell bodies in scarpa’s ganglion
-CN VII and VIII travel together through IAM and enter pontomedullary junction of brain
where do CN VII and CN VIII enter the brain?
cerebellopontine angle
what is the vestibulo cerebellum
flocculonodular lobe
what does the cerebellum do
interact with LVST, MVST, RST
-vestibulospinal mechanisms for postureal control continue to develop beyond 15 years old
-afferent impulses travel directly from the end organ to cerebellum
what does the thalamus do
-assists in discrimination between self movement and environmental movement
-multisensory integration for postural control
what is the vestibular cortex
-junction of parietal and insular lobe
-multisensory integration of vestibular information with somatosensation and vision
-sensory integrative capacity for postural control evolves between 7-15 years old
what do the vertebral arties do
PICA:
supplies inferior vestibular nuclei and inferior portions of cerebellum
what does basilar artery do
supplies pons and more superior vestibular nuclei
what is the VOR
vestibular ocular reflex
-stabilizes gaze during head movmenet
-VOR gain normal is 1:1
-intact and mature by age 1
what is VSR
vestibulo spinal reflexes
they coordinate head and body movements to maintain head in upright positions
what is LVST
lateral vestibulo-spinal tract
adjusts limb movement for balance
what is MVST
medial vestibulo-spinal tract
-cervical connections
-branches to extraocular muscles
what is VCR
vestibulo-colic reflex»_space; head righting
-stabilizes head and neck
-produces coordinated movements to track a moving target
what is ATNR
aysmmetric tonic neck reflex
-neck rotation excites ipsilateral extensors and contralateral flexors
what is STNR
symmetrical tonic neck reflex
-neck flexed excites bilateral UE flexors and LE extensors
what is COR
cervico-ocular reflex
-eye movemnts driven by neck proprioceptors
-supplements the VOR when needed
-facilitated when vestibular organ injured
-can be elicited in those without labrynihts so afferents are though to come from cervical proprioceptors
-Oculo-cephalic reflex seen in indivudals who are comatose
what else is oculovestibulocephalic reflex
brainstem injury
dolls eyes
what is CSR
cervicospinal reflex
-can supplement VSR by altering tone in the body
-related to tonic neck reflexes
what is CCR
cervicocolic reflex
-stabilizes head on body
-may be facilitated after vestibular loss
what are presentations of vestibular disorders
-decreased function
-complete loss
-acute, subacute, chronic
-flucutating
what are some central patholiges
-TBI
-MS
-stroke
-brain tumor
-vestibular migraine
what are some peripheral patholiges
-BPPV= most common cause true vertigo
-infection: neuritis is 2nd common cause of vertigo
-labrynthiis
-vestibular neuritis
what is endolymphatic hydrops Menieres Disease
-acute episodes 30 min- 24 hours
-recovery usually within 72 hours
-progressive hearing and vestibular impairments
-endolymph hydrops= malabsorption of endolymph in the duct or sac
-surgery or ablation possible
-primarily medically managed but PT can educate people
what is perilymph fistula
-common at round and oval windows
-inner and middle ear communicate
-congential, prior ear surgery, barotrauma, sneezing, blast
features include:
-vertigo after loud sounds
-surgery possible
medically managed and PT refer out
what is superior canal dehiscence SCD
-creates a window through the bone
-can be seen on CT scan
features:
-vertigo and oscillopsia induced by loud noises
-surgy possible
medically managed, PT refe
what is Mal de Debarquement Syndrome
-perception of motion when stationary and eyes are open
-usually occurs after prolonged exposure to motion, such as on a cruise
-difficulty adapting back to stable environment
-getting off the boat syndrome
-possible treatment w medication
-focus on somatosensory referencing to vestibular sense
-know how to examin for this
-specialized treatment beyond entry level
what is Peripheral Neoplasms Acoustic Neroma
-a schwannoma, usually small, encapsulated, slow growing
-can be seen on MRI
-surgery possible
-common and appropriate for PT treatment
what is Persistent Postural Perceptual Dizziness
-persistent dizziness
-non spinning vertigo
-perceived unsteadiness
-result of long term maladaptation
-occurs after a neuro-otologic, medical or psychological event that triggered vestibular symptoms
common and appropriate for PT treatment
what is ototoxicity
- aminoglycoside antibitoics like gentamicin
- chemotherapy drugs: cisplatin and carboplatin
what is whiplash injury
-common with flex-ext injury
-20% of those with whiplash and dizziness can take longer than 20 weeks to return to work
-primary symptom neck pain 60-100%
-20-58% with head injury or whiplash will have dizziness or dysequilibrium
what is whiplash exam
common findings:
-occitpital or bitemporal headache
-neck pain
-not straight head
nonspecific findings:
-dizzy
-sense of falling
-hard to read
-feel tired
talk about cervicogeneic dizziness and muscle spindles
-acute neck injury can cause chemical, ischemic or inflammatory events that affect spindles
-chronic neck pathology can cuase additional secondary problems with spindles= fatiguability, atrophy, altered joint mechanics,
talk about cervical vertigo
-NOT an illusory perception of rotational, linear or rocking movement
-defined as dizziness: an unpleasant and vague feeling involving spatial discomfort, unsteadiness and dullness
what kind of mechanism is whiplash
proprioceptive cervical
talk about cervicogeneic dizziness according to landel 2014
-cervical somatosensory mismach between vestibular and visual info
-decreased cervical ROM
-neck pain
-WAD: chronic form
-dysequilibirum and NOT true vertigo NOT spinning
what is some medical diagnostic testing
- ENG
- VNG
- oculomotor function
- positional tets
- caloric testing
what is rotary chair testing
-used to determine whehter or not dizzy is due to disoder of inner ear vs brain and uni vs bilateral impairment
what is the 3 part rotary chair test
- chair test: chair turned slowly, wearing goggles
- optokinetic: view moving stripes
- fixation: chair rotation and person looks at dot of light that rotate with them
what are VEMPs
vestibular evoked myogenic potential
-test otolith function
-can help diagnose superior canal dehiscence, Menieres
what is some PT testing?
-frenzel goggles
-bucket test
-dynamic posturophy AKA sensory organization testing
how do you asssess postural control
input
processing
output
what are some diagnostis specific tests
VOR and VOR cancellation
what are some oculomotor tests
quality of movement and symptom provocation
what are some head movemnet tests
quality of movement and symptom provocation
what is an otolith test
head righting
what is a semicricular canal test
BPPV
what are some chief complaints
-diziiness
-imbalance
what is the description of dizziness
-vertigo
-oscillopsia
-lighteaded
-disequilibrium
-confused or disorientated
what are some precipitating events
-fall
-MVA
-concussion
-illness
-ototoxicity
-whiplash
-diet changesr
what are some subjective questionnaires
ABC
DHI
how do you screen for vertebral artery
-neck trauma
-cervical surgery /arthritis
-sensitivity (poor)
-specificity 67-97%
-hallmark signs of vertebrobasilar insufficiency warrant extreme caution and referral
-modiifed positions if pt has vestibular complaints
-modified version is slouch test
what are the 5 D’s
-diplopia
-dysphagia
-dysarthria
-dizziness
-drop attack
what are the 3 N’s
-nausea
-nystagmus
-numbness
what are static observations during an oculomotor exam
-ocular malalignment: head tilt towards side of lesion
may be otolithic or central dysfunction
-ocular torsion: eye on involved side rotates down
-skew deviation: vertical malalignment
what is HINTS exam
Head Impulse Test
Nystagmus
Test of vertical Skew
talk about remediation = adaptation/uptraining
-produce an error signal and recalibrate vestibular input
-uptrain or force use particular senses
-central selection, prioritization, integration
talk about sensory habituation= desensitization
repetition of provoking movements with cautious symptom provocation and settling
talk about sensory subsitution=compensation
if sensory info missing
-inherent limitations: may need additional compensations under certain circumstances
what is temporary prevention
while “uncompensated”, avoid:
-swimming
-dark environments
-running on a soft surface
-driving in rain, snow, dark
