Clinical Vestibular Disorders Flashcards
What are the components of the peripheral vestibular system?
- 3 paired semicircular canals
- otolithic (macular organs)
- utricle
- saccule
- cristae
- end organs containing hair cells w/in ampullated portion of membranous labyrinth
- cupula
- gelatinous matrix where cilia of hair cells are embedded
What are otoliths?
blanket of calcium carbonate of crystals that are present only in the otolithic organs (not in SCCs) - move, depolarize & tell your brain that your head is moving
L & R eats are complimentary, not identical
Which nerve is the afferent connection from the peripheral vestibular system to the brain stem nuclei?
vestibular nerve
Which nerve goes to the superior and horizontal SCCs & utricle?
superior vestibular nerve
Which nerve goest to the posterior SCC & urticle?
inferior vestibular nerve
What is the vestibular ocular reflex (VOR)?
nystagmus
What is the illusion of rotational, linear, or tilting movement of self (subjective) or environment (objective)?
vertigo
What is the sensation of instability?
disequilibrium
What is the inability to focus on objects during head movement?
oscillopsia
What is the sense of impending faint, presyncope?
lightheadedness
What is the difference between physiologic dizziness & multisensory dizziness?
- physiologic: motion sickness, dizziness in heights
- multisensory: deterioration/degeneration in multiple sensory systems responsible for balance often related to age, diabetes, stroke, etc.
What are questions you should as when taking the history on a patient you expects has a vestibular condition?
- duration of attack
- frequency
- effect of head movements
- inducing posture or position
- associated aural symptoms
- concomitant or prior ear disease/surgery
- family history
- head trauma
- medications
- comorbidities
What is a positive head shake test?
shake head for 15 seconds
(usually) head shake nystagmus (HSN) away from involved ear
Atypical (vertical or rotary) nystagmus requires what type diagnosis exclusion?
CNS disorder
What is the test for VOR?
halmagyi (horizontal high-frequency head thrust)
What is a positive oscillopsia test?
This suggests what diagnosis?
loss of dynamic visual acuity
loss of lines of Snellen chart with rapid horizontal head shaking - suggests bilateral vestibular loss
What is a positive VOR suppression test?
Suggests what diagnosis?
inability to visually suppress nystagmus during head rotation
suggest defect of vestibulocerebellum
What is the cardinal sign of vertigo?
nystagmus
What is nystagmus?
slow phase is direction of endolymph (vestibular origin)
the quick phase (central origin) is compensatory
What is physiologic nystagmus?
end-point nystagmus on lateral gaze greater than 30 degrees
What is spontaneous nystagmus?
nystagmus without positional or labyrinthine stimulation
What is induced nystagmus?
nystagmus induced by stimulation
caloric, rotation, positional, etc.
What is Ewald’s law?
eye & head movements occur in the plane of the canal being stimulated & in the direction of the endolymph flow
ampullopetal flow stimulates the lateral canal- ampullofugal inhibits (reverse is true in posterior & superior)
What is Alexander’s law?
- amplitude of nystagmus increases when the eyes look in the direction of the fast phase
- first degree: present only when gazing in fast component direction
- second degree: 1st degree plus straight gaze
- third degree: present in all 3 directions
What are the components of a vestibular physical examination?
- HEENTN
- audiometric evaluation
- gait/walking
- cerebellar testing
- hyperventilation test
- pneumatic otoscopy
- Dix-Hallpike Test
- Head Thrust Test/Head Shake Test
In what situations is laboratory vestibular testing indicated?
Purpose?
- Indication: site/side of lesion not identified
- ascertain benefit of vestibular rehab
- assess recovery of vestibular function
- assess contralateral function if destructive procedure is contemplated
- determine if intervention has been successful
What is electronystagmogrphy?
horizontal & vertical eye movements are recorded (ENG-electrodes or VNG-video)
What is a bithermal caloric test?
Use to identify?
evaluation of the horizontal SCC with cold & warm water in caloric test position (COWS)
can identify unilateral weakness or bilateral weakness
What is the purpose of a rotational chair test?
identify residual function in patients with no calorics
What is the Scleral Search Coil & why would you perform this test?
direct contact with the globe of the eye
gold standard measurement technique for eye movement
What is a vestibular-evoked myogenic potential & why would you perform this test?
sound stimulates saccule with reflex loop to SCM
increased in middle ear pathology
decreased in SCDS, perilymphatic fistula
What is the most common cause of vertigo?
posterior SCC
(benign paroxysmal positional vertigo)
What is the mechanism causing benign paroxysmal positional vertigo?
utricular degeneration or trauma liberates otoconia that float toward ampulla of PSCC
What are the symptoms seen in Benign Paroxysmal Positional Vertigo?
severe positional vertigo with change in head position lasting seconds
spontaneous resolution within months (most cases)
What is the diagnostic maneuver for benign Paroxysmal Positional Vertigo? Positive test?
Dix-Hallpike maneuver
- lying on back with head turned to one side (repeat for other side)
- positional rotational/torsional nystagmus toward the affected ear
- latency of onset (seconds)
- short duration (less than one minute)
- fatigue on repeated testing
What drugs may give a false negative Dix-Hallpike maneuver?
vestibular suppressants
sedating antihistamines & benzos (block VOR)
What is the treatment for Benign Paroxysmal Positional Vertigo?
Epley Maneuver / Semont Maneuver
Meniere Disease (aka?) is characterized by what features?
Symptoms?
Idiopathic Endolymphatic Hydrops
bowing & rupture of Reissner’s membrane with a mix of endolymph & perilymph
Symptoms: attacs of tinnitus, vertigo, aural fullness & hearing loss lasting minutes - hours
What are otolithic crisis of Tumarkin?
“drop attacks” with sudden falls without vertigo or LOC
What is Lermoyez variant?
progressive hearing loss & aural fullness that resolves with onset of vertigo
What is cochlear hydrops?
fluctuating hearing loss, aural fullness & tinnitus without vertigo
What type of nystagmus is seen with Meniere Disease?
direction of nystagmus varies over time with course of attack
What are the results of an audiogram performed for a patient with Meniere Disease?
low frequency SNHL that fluctuates over time
What are the results of an ENG for a patient with Meniere Disease?
unilateral weakness
What is the treatment for Meniere Disease?
- Diet:
- low salt, no caffeine/stimulants
- Diuretics
- Vestibular suppressants:
- antihistamines & benzodiazepines
- Surgery
- endolymphatic sac decompression
- gentamicin ablation
- neurectomy
- labyrinthectomy
What is Cogan Syndrome? Symptoms?
autoimmune disease:
interstitial keratitis, bilateral rapidly progressive audiovestibular dysfunction & multisystem vasculitis
bilateral progressive hearing loss → progress to complete absence of vestibular function
Treatment for Cogan Syndrome?
high-dose steroid or cyclophosphamide
What is Recurrent Vestibulopathy?
recurrent attacks of episodic vertigo similar to MD without auditory or neurological dysfunction
What are the possibilities of progression for a patient with Recurrent Vestibulopathy?
8.5 years
- 60% → remission
- 15% → Meniere’s Disease
- 10% → continued active attacks
- 10% → BPPV
- 5% → other peripheral symptoms
What is Vestibular Neuronitis?
Dramatic sudden vertigo and vegetative symptoms lasting days to weeks with gradual improvement
absence of auditory dysfunction
How do you differentiate Vestibular Neuronitis from Labyrinthitis?
Labyrinthitis also has auditory dysfunction
What type of nystagmus is seen with Vestibular Neuronitis? Response to caloric test?
fast phase nystagmus away from involved side
hypofunction in response to caloric test
What is the treatment for Vestibular Neuronitis? If no improvement?
supportive for vertigo & vegetative symptoms
failure to improve over 2-3 weeks requires a CNS lesion to be excluded (MRI w/ contrast +/- ENG)
What is Traumatic Perilymphatic Fistula? Symptoms?
abnormal communication between perilymphatic space and middle ear
varying symptoms from episodic vertigo, positional vertigo, motion intolerance ; disequilibrium following increases in CSF pressure (valsalva), nose blowing or lifting (Hennebert phenomenon) or exposure to loud noises (Tullio phenomenon)
What are the possible causes of traumatic perilymphatic fistula?
barotrauma, penetrating trauma, surgical trauma (stapes), cholesteatoma, penetrating trauma, physical exertion
What is the positive fistula sign?
nystagmus to affected ear with ear pressure
What is the treatment for traumatic perilymphatic fistula?
bedrest with elevated HOB
laxatives
consider surgical exploration & patch
What is superior canal dehiscence syndrome?
form of inner ear fistula with communication between middle cranial fossa & superior SCC
creates a third mobile window within the canal with abnormal endolymphatic flow
What are the symptoms of superior canal dehiscence syndrome? Treatment?
sound & pressure evoked vertigo, hyperacusis, gaze-evoked tinnitus, chronic disquilibruim, positive VEMP
surgical repair
Diagnosis of migraine-associated vertigo requires what sign? Treatment?
close temporal associate of both conditions
antimigraine therapy
Cervicogenic vertigo causes what
vascular compression
abnormal sensory input from neck proprioceptors
cervical cord compression stenosis
CSF leak
high cervical disease (C1-C2)
Check out / write out this diagram (if you find it helpful)
nice job!
