Vestibular Disorders Flashcards
Vestibular system is a key _____ receptor
sensory
VS is sensitive to:
- head movement
- head position
- effect of gravity
Function of VS
- detect movement
- maintain gaze stability during motion
- maintain balance
When not functioning properly, what other systems compensate and what is the main impairment
Visual and SS compensate (body must learn this)
balance is an issue
What are the peripheral parts of VS?
Labyrinth! = 3 SC canals and otolith (saccule + utricle)
What type of movement/position does the otolith (saccule and utricle) respond to?
static positions
linear acceleration
What type of movement/position do the semicircular canals respond to?
Angular head movements
Anterior = head nod (tilt in sagital plane)
Posterior = head tilt (tilt in frontal plane)
Horizontal = head turns (tilt in transverse plane)
What is the pathway of information transmission from SC canals –> brain?
endolymph in SC canal moves –> hair cells moved in opposite direction –> sends info to cortex –> stabilizes eyes to target
Push-Pull Phenomenon
Activation of SC canal on one side inhibits SC canal on other side
*i.e. head turn to right = activation R horizontal SC canal (don’t move eyes here) + inhibition of L horizontal SC canal (turn eyes that way)
Central structures of VS
- cochlea nerve and vestibular nerve (inflammation/injury to one can cause issues with the other)
- Facial nerve (issues here can cause issues in chochlea or vestibular nerve)
- Cerebellum (inhibition or facillitation of VOR)
Lesion in central v peripheral structures (recovery time)
longer recovery time for central lesions- pt must learn compensation strategies
Corrective saccade
eyes correct themselves to reorient to center (occurs in healthy system)
Saccade
voluntary corrective movement
Smooth pursuit
slow saccades - voluntary
Nystagmus
involuntary; quick corrective movement of the eyes back to the center
Retinal Slip
image slips from person’s eyes; they are unable to process changes to a moving image (see it as more than 1 object in front of you)
Vestibulo-Occular Reflex (VOR), purpose, types/what senses it
purpose: hold images steady on retina with head movement
Angular VOR: sensed by SCC
Linear VOR: sensed by otolith
Ocular Tilt Reflex: sensed by utricle
Nystagmus- what side is the lesion on
typically the side with a quicker nystagmus is the side of the lesion (direction of the fast phase)
*evaluate during tonic and dynamic system- central lesions have nystagmus in both
Tonic System deficit
nystagmus present without movement (at rest)
Dynamic system deficit
nystagmus with movement
What is considered a “Central lesion” v “Peripheral lesion”
central = everything past internal auditory canal (disorders of the CNS) Peripheral = everything before internal auditory canal (SCC and otolith)
Peripheral lesion symptoms
- Dizziness with positional changes
- hearing loss, tinnitus
- balance problems
- symptoms with head movement during gait
- acute nystagmus
- nystagmus only present chronically if they have NOT learned to compensate
- oscillopsia- jumping of objects in visual field (can’t focus, feel like its moving up and down)
Central Lesion Symptoms
- constant dizziness
- Downbeating nystagmus (but present with anterior SCC deficit- differentiate whether it is present at rest)
- Cerebellar signs/sx (ataxia/imbalance)
- Associated head injuries/cervical injuries
- Horner’s Dyndrome
- swallowing difficulty
- Sensory changes
- babinski, clonus, changes in DTRs
- Impaired balance and gait
Symptoms common in peripheral and central lesions
- Spinning/vertigo (worsened with 3D shapes)
- Vomitting
- Nausea
- Headache
- dizziness
- impaired balance
Acoustic Neuroma (vestibular schwannoma)
will be walking more to one side than the other
benign tumor, begins on vestibular portion of acoustic n.
other symptoms: hearing and balance, tinnitus, disequilibrium, vertigo (all caused by compression of CN VIII)
if grows enough- expansion to cerebellopontine angle (near brainstem and CNVII)
Peripheral Pathologies
- Benign Paroxysmal Positional Vertigo (BPPV)
- Cervicogenic Vertigo
- Labrynthitis (inflammation of inner ear)
- Perilymph Fistula
- Meniere’s Disease (inflammation of inner ear)
Benign Paroxysmal Positional Vertigo (BPPV): Cause
Free floating otoconia
Otoconia belon in utricle; they dislodge and enter SCC
disruption of endolymph mvt –> false info sent to brain
*can occur spontaneously or following head trauma/labrynthitis
Benign Paroxysmal Positional Vertigo (BPPV): main symptom
vertigo with POSITIONAL changes
Benign Paroxysmal Positional Vertigo (BPPV): Diagnosis
onset of nystagmus and vertigo only when moved in plane of SCC
- horizontal nytagmus –> horizontal SCC
- Downwards nystagmus –> anterior SCC
- Upwards nystagmus –> posterior SCC
Benign Paroxysmal Positional Vertigo (BPPV): Evaluation
Gold standard = Dix Hallpike test
Anterior + posterior SCC = sidelying test
Horizontal SCC = horizontal roll test
Benign Paroxysmal Positional Vertigo (BPPV): Treatment
Canalith Repositioning Maneuver –> helps remove otoconia
Rotate head to affected ear –> lower into supine with head off the table
Turn head to other side , then further so parallel to floor, then rapidly further so face is almost to the floor
return to upright and head to normal
Cervicogenic Vertigo: Cause
occurs in pt with longstanding vertigo
cervical spine receptors not firing as much–> turning head in limited motion for long time
when they finally turn their head further, exposure to visual field they haven’t seen in a long time (makes them even dizzier)
Perilymph Fistula
holes in the oval or round window- endolymph enters into air-filled middle ear (not much you can do for this pt)
Central Pathologies
- CVA
- MS
- BL Vestibulopathy (inflammation of neurons by toxic substances)- hard to get better, not reversible
- head injury
Dix Hallpike Test
gold standard for BPPV (posterior canal of side tested and anterior of opposite side)
CANNOT be performed if VBI or stenosis
side of dysfunction = side head is turned to
Dynamic Visual Acuity Test
assessment of gaze stability
no reliability established in pts with TBI
Saccadic Testing
Smooth pursuits: pt scans the room, want eyes and head to have same ROM
Saccadic: pt looks back and forth from your fingers without head mvt
VOR testing
letter held at arms length from pt- maintain vision on letter with side-side head turns
looking for when they have retinal slip (trying to induce this)
VOR cancellation testing
want head and eyes to turn in same direction at same velocity
head mvt side-side while looking at pen (pen is moving with their head- movement is fast, about 2Hz)
Subjective Visual Vertigo testing (SVV)
Ability to identify whether an object is upright
with SVV- head is tilted – can’t identify verticle
*correct their head to midline! (better BL visual input)
Head Thrust Test
slowly turning their head from side-side, quickly move the head back to midline –> looks for the corrective saccade
(+) test = eyes lagging when head is thrust back to midline
Fukuda Step Test
pt marches with high knees and eyes closed (looking for sideways deviations)
involved side = side of deviation
not good interrater reliability (distance deviated not always measured), not always positive in only vestibular dysfunctions
Sidelying Test
testing anterior and posterior SCC
sitting at EOB – rotate 45 degrees AWAY from side to be tested
quickly bring head into CL sidelying (rotate to L, SL to R)
pt reports vertigo, observe for nystagmus
repeat to other side
Horizontal Roll Test
testing horizontal SCC
pt in supine – head flexed 20deg – quick head rotation
pt reports vertigo, observe for nystagmus
slow return of head to midline, quick roll to other side
Sensory Organization Test: Purpose, administration
purpose: assess effective use of visual, vestibular, and proprioceptive information (how the body organizes information between the systems)
Pt stands on moving board with visual frame (that moves) in front of them
SOT: categories/conditions
- eyes open, fixed surface, fixed visual surround
- Eyes closed, fixed surface, fixed visual surround
- Eyes open, fixed surface, sway visual surround
- Eyes open, sway surface, fixed visual surround
- eyes closed, sway surface
- eyes open, sway surface, sway visual surround
* vestibular dysfunction, usual fall in categories 5 and 6
Activities Specific Balance Confidence Scale and Dizziness Handicap Inventory (pros and cons)
pros: good psychometric properties
Cons: limited research in vestibular population
Referral back to physician
- new onset UMN s/s
- swallowing difficulties
- sensory changes
- changes in pupillary size/ptosis
- loss of consciousness
- new onset LOB
- fluctuating hearing loss
- visual field cut
- memory loss
UL v BL vestibular hypofunction (prognostic differences, inital system they rely on)
UL = better prognosis, expect recovery, initially rely on SS cues BL = poorer/longer recovery time, requires compensation, initially rely on visual cues
Acoustic Neuroma Treatment
can teach VOR to these pts- hope is for some return
a lot of rememberance issues
Central lesions: focus of treatment
balance issues
Examples of Compensation strategies
using the unaffected side to help them
avoiding putting themselves in positions of known balance compromise
Treatment: Adaptation
teaching VOR exercise- hope is that practice will help them get better
aim: reduce retinal slip, decrease symptoms, improve postural stability
Treatment: Habituation
a series of progressively more complex repeated movements designed to provoke symptoms (will make them dizzy)
Treatment: Substituation
use of alternative strategies to replace lost or compromised function (using SS and visual systems to help)
Vestibular Eval: Steps
- Check vision (glasses, distance for dbl vision, skew deviations)
- Check the cranial nerves (“H”)
- Check for visual field cut (PT and pt cover eye, introduce finger from periphery)
- Check smooth puruit
- VOR testing (horizontal and vertical)
- VOR cancellation testing
- Head thrust
- Reading test
When are skew deviations seen
with cerebellar and brainstem strokes - skew deviation present on same side
Checking for skew deviations
pt with eyes closed, ask them to open and look at your finger
when eyes open, one will be higher or lower
Reading Test
Read with head in midline, record # of lines able to read
Read while turning head side-side, record # of lines able to read
Compare the 2 numbers
(+) test = more than 2 lines of difference
Checking for visual field cut: implications of periphery loss v nasal field loss
periphery = pituitary lesion Nasal = optic chiasm
