Vestib Rehab Foundation Flashcards
2 Subdivisions of Vestibular System
Peripheral: inner ear / 8th CN
Central: vestibular nuclei / cerebellum / higher cortical connections
What three things contribute to Spatial Awareness?
Vestibular system
Vision
Somatosensation (proprioception)
Spatial Awareness further subdivides into ___ and ___.
balance, gaze-stability
Vestibular Rehab Definition
Using neuroplasticity to re-train the brain to interpret / utilize vestibular inputs more accurately
The Vestibular system functions to sense ___.
movement
Inner Ear senses movement of head
What are the resulting symptoms of Vestibular System malfunction?
Vertigo (sensing ANY movement that isn’t really there) - spinning / rocking / swaying
Movement-related dizziness
Motion sickness
Imbalance
Path A Sound Wave Takes to Become A Sound
Wave passes through Outer Ear (External Auditory Canal)
Passes through Ossicles to Tympanic membrane (which vibrates)
Tympanic Membrane and Ossicles transmit sound waves to Inner Ear through Endolymph
Cochlea: receptive hair cells stimulated by vibration
Endolymph within Cochlea transmits mechanical energy from sound/movement to electrical energy for NS (bending of hair cells)
Electrical signal goes through Auditory N. to the brain
Semi-Circular Canals are filled with ___.
endolymph
Alignment of Semi-Circular Canals
Anterior aligns with posterior canal on the opposite side
Posterior canal aligns with anterior canal on the opposite side
Horizontal canal aligns with horizontal canal on the other side
Cupula
Hair cells within Ampulla that bend in response to endolymph movement
What occurs within the Cupula when you rotate your head to the left?
Left cupula is depolarized (excited) / right cupula is hyperpolarized (inhibited)
Endolymph moves over the cupula and the direction in which the hair cells bend determines whether excitatory or inhibitory NT are released
Utricle / Saccule vs. Semi-Circular Canals
Utricle / Saccule receives info related to linear movement and gravity (up and down / forward and back / left and right)
SSCs only receive angular / rotational info
Otoconia
Sit on top of hair cells in Utricle / Saccule and bend them
Microscopic calcium carbonate crystals
Saccule vs. Utricle Movement Processing
Saccule - vertical / gravity bends cilia
Utricle - horizontal / endolymph bends cilia
How does the Vestibulocochlear Nerve divide regarding info being sent to the brain?
Electrical energy travels over the Vestibular Nerve for movement info to be sent to the brainstem
Electrical energy travels over the Auditory Nerve for hearing info to be sent to the brainstem
Vestibular-Ocular Reflex (VOR)
Maintains gaze stability during head motion
Controls eye-head coordination (equal and opposite movement of the eyes in relation to the head)
Directly from Inner Ear
CN III nucleus / CN IV (motor) nucleus / CN VI (motor) nucleus
Vestibulo-Spinal Reflex (VSR)
Maintains head and body equilibrium by facilitating or inhibiting skeletal muscle activity (to maintain upright position)
Controlling coordination for balance
Signal from brainstem to SC / spinal muscles
Cerebellum / Vestibulospinal Tract
Cervical-Ocular Reflex (COR)
Reflex output to motor cells
Signals head position on body / maintains gaze stability secondary to VOR
Comes from cervical proprioceptive output rather than the inner ear
Otolith-Ocular Reflex (OOR)
Input from Utricle and Saccule / output to eye muscles
Controls horizontal and vertical eye movements via linear VOR
Higher Cortical Connections to Vestibular System
Thalamus
Visual Cortex
Hippocampus
Amygdala
The Peripheral Vestibular System affects ___ and ___ of movement, while the Central Vestibular System affects ___ and ___.
sensation, perception
perception, integration
Conditions Related to Malfunction of Peripheral Vestibular System
BPPV
Neuritis / Labyrinthitis
Acoustic Neuroma
Hypofunction (Unilateral / Bilateral)
Endolymphatic Hydrops / Meniere’s
Fistula / Dehiscence
Benign Paroxysmal Positional Vertigo (BPPV) Pathophysiology
Otoconia become dislodged from Utricle / Saccule and displaced into a semi-circular canal - affects endolymph flow through the canal and cupula deflection
Benign Paroxysmal Positional Vertigo (BPPV) Causes / Risk Factors / Symptoms
Causes: Idiopathic / head trauma / inflammation / ischemia / pressure fluctuations
Risk Factors: Age / female / vitamin D deficiency / HTN / migraine / hyperlipemia
Symptoms: Brief (10 - 60 second) spells of vertigo with changes in head position against gravity
___ is the most common cause of Vertigo.
BPPV
In the case of BPPV, what contributes to the “false movement” sensations? What determines the duration of these symptoms?
Otoconia move with gravity, causing endolymph to deflect cupula and continue to mov despite being done with a change in position
Spinning lasts until Otoconia returns to proper placing
Canalithiasis (BPPV)
Otoconia free-floating in semicircular canal, causing abnormal flow of endolymph with changes in head position against gravity
Delayed onset of vertigo and nystagmus upon achieving head position (seconds)
Symptoms gradually intensify and then subside (episodic)
Lasts < 1 minute
Cupulolithiasis (BPPV)
Otoconia adhered to Cupula, causing deflection of the cupula with changes in head position against gravity
Lasts longer than Canalithiasis
More immediate onset of vertigo and nystagmus
Symptom intensity remains constant
Lasts as long as head held in provoking position
Rare
Eustachian Tube
Connection between ear and nose / throat
Neuritis / Labyrinthitis Pathophysiology
Inflammation of the inner ear (Labyrinthitis, includes hearing loss) or vestibular nerve (Neuritis, no hearing loss involved)
Causes vestibular hyperstimulation and may result in damage leading to hypofunction
Neuritis / Labyrinthitis Causes and Symptoms
Causes: Viral infection (98%) / head injury
Symptoms: Sudden onset of vertigo / n/v / lasting 3-7 days with residual balance and dizziness lasting 1-2 weeks / often follows other illness (e.g., respiratory infection)
Hypofunction Pathophysiology
Damage to inner ear or vestibular nerve that results in a diminished or weaker neurological signal
Asymmetrical signals / difficulty interpreting movement
Unilateral OR Bilateral
Hypofunction Causes
Neuritis / Labyrinthitis
Meniere’s Disease
Acoustic Neuroma
Ototoxic meds
Gentamicin (aminoglycosides)
Meningitis
Ear surgery
Hypofunction Symptoms
Affects VOR and VSR
Postural instability
Gaze - instability
Movement-related dizziness
Motion sensitivity
Foggy-headedness
Kinesiophobia
Oscillopsia
In the context of Hypofunction, ___ allows for ___ compensation.
neuroplasticity, CNS
Acoustic Neuroma Pathophysiology
Benign, slow-growing tumor of the myelin sheath (Schwann cells) that cover CN 8 therefore causing compression of the nerve
Acoustic Neuroma Causes / Symptoms
Causes: Idiopathic / genetic
Symptoms: Gradual onset of unilateral hearing loss first - followed by Tinnitus / imbalance / motion-sensitivity / facial numbness + weakness
Lack of true vertigo symptoms
Endolymphatic Hydrops Pathophysiology
Build-up of endolymphatic fluid within the inner ear, causing pressure on the inner ear membranes and hair cells
Can cause inflammation and damage over time - hyperstimulation and eventual hearing loss / hypofunction
Unilateral OR Bilateral
Endolymphatic Hydrops Causes / Symptoms
Causes: Idiopathic (Meniere’s Disease) / Na or K imbalance / middle ear congestion (milder)
Symptoms: Recurring episodes of vertigo lasting 1-3 days with gradual improvement over 1-2 weeks / low-frequency hearing loss
Fistula / Dehiscence
Structural “hole” in the inner ear, causing an inability to regulate endolymph fluid pressure and flow
Causes: trauma / head injury / Valsalva
Symptoms: recurring spells of vertigo (possibly associated with loud sounds and barometric pressure changes / hearing hypersensitivity / imbalance / motion-sensitivity
Conditions Related to Malfunction of Central Vestibular System
Stroke
Brain tumor
MS lesions
Degenerative neurological conditions
Vestibular migraine
PPPD
MDDS
Anything affecting central vestibular connections in the brain / brainstem
Vestibular Migraine
Sensory perceptual disorder affecting the vestibular system
Risk Factors: Female / magnesium deficiency / migraine history
Common Triggers: Stress / hormone fluctuations / weather changes / poor sleep / caffeine / alcohol
Symptoms: Recurring episodes of vertigo (lasting 1-5 days) / HA / photophobia / phonophobia / brain fog / anxiety / dissociative symptoms / visual issues
Persistent Postural Positional Dizziness (PPPD)
Autonomic and emotional hyper-responsiveness to vestibular stimuli (fight or flight - sympathetic NS)
Causes: Abnormal adaptation following vestib trauma (BPPV, vestibular migraine)
Symptoms: Constant visual motion-sensitivity and imbalance / anxiety / kinesiophobia / “visual vertigo” / “space motion discomfort” / persists >3 months
Mal de Debarquement (MDDS)
Mal-adaptation following disembarking a moving vehicle (boats)
Associated with anxiety and emotional responses to the dizziness
Symptoms: Persistent sensation of rocking or swaying that lasts beyond the expected period of adaptation / worse when being still
Non-Vestibular Pathology Associated w/ Vestibular Symptoms
Cardiovascular: Orthostatic hypotension / low or high BP / vertebral basilar artery insufficiency
Metabolic: Low or high blood sugar / dehydration / infection (UTI/URI) / meds
Self-Report OMs Related to Vestibular Issues
Dizziness Handicap Inventory (DHI) - how does dizziness impact function / 0 = no handicap perception, 100 = complete handicap perception
Activity-Specific Balance Confidence (ABC) Scale - pts rate their confidence level with various balance tasks / great for measuring success of treatment
Vestibular Disorders Activities of Daily Living Scale (VADL)
Vestibular Activities and Participation (VAP) Questionnaire
Movement-Related Dizziness
Could be vestibular
Vertigo: Illusion of movement (spinning / rocking / swaying / falling)
Disequilibrium: Sense of being off-balance (unsteady / wobbly / drunk / tilted)
Gaze-Instability: Foggy-headed / heavy-headed / light-headed / motion sickness
Cardiovascular Dizziness
Decreased blood flow to the brain
Light-headed / pre-syncope / tunnel vision
Anxiety- and Visual-Related Dizziness
Anxiety: Floating / swimming / rocking
Visual: Diplopia / oscillopsia (vision jumping)
“Tempo” of Symptoms
Sudden/Acute: Vestibular Neuritis or Labyrinthitis (single event) / Meniere’s or Vestibular Migraine (recurring spells) / Wallenberg infarct (single event)
Short Spells: BPPV / Orthostatic Hypotension
Constant/Chronic: Bilateral hypofunction / MDDS or PPPD
Aggravating / Easing Factors Related to Movement (Vestibular Issues)
Aggravating: Positional / head movement / challenging balance situations / busy visual environments
Easing: Holding still makes it better
Vestibular Suppressant Medications
Meclizine (motion sickness med to control n/v + dizziness)
Dramamine
Valium (anxiety med)
Which medications can contribute to Ototoxicity?
Some antibiotics
Chemotherapy
Some diuretics
Some NSAIDs
Nystagmus
Rapid / repeating eye movement
Fast phase (corrective saccade) in one direction / slow phase (caused by VOR) in the other - vestibular system
Named for fast phase (from pt’s perspective)
Nystagmus caused by CNS - smooth pursuits and saccades (cerebellum / brainstem)
Nystagmus - Peripheral Vestibular System
Slow phase (VOR) / fast phase (corrective saccade)
Direction-fixed
Usually horizontal (R or L)
Decreases in intensity with fixation
Gaze towards fast phase increases intensity and vice versa (Alexander’s Law)
BPPV is exception (transient / positional / direction depends on otolith movement through canals)
Nystagmus - CNS
Direction changing - often follows gaze
Can be vertical or pendular (R/L)
Not affected by fixation
Congenital
Trauma: stroke, BI
Physiologic Nystagmus
Normal
Optokinetics (watching a train pass - eyes saccade and reset)
Spinning
On a train
Frenzel Goggles
“Take away” fixation
Illuminate the patient’s eyes so examiner can see any spontaneous nystagmus
Can conduct testing in the dark
VNG/ENG
VNG: Infrared goggles and video recording
ENG: Electrodes over eye muscles
Quantify nystagmus / smooth pursuit / saccades / positional nystagmus and calorics
What is the gold standard for identifying Unilateral Vestibular Hypofunction?
Caloric Vestibular Test
Pressure differential introduced to endolymph via warm or cold air in ear - measure nystagmus intensity
What is the gold standard for identifying Bilateral Vestibular Hypofunction?
Rotary Chair
Other Diagnostic Tests
Audiogram - hearing test
Electrocochleography (ECoG): Measures inner ear activity in response to sound / Meniere’s
Cervical or Ocular Vestibular Evoked Myogenic Potential (cVEMP, oVEMP): neck and eye muscles response to sound / utricle and saccule function
Auditory Brainstem Response (ABR): CN 8 function
Vestibular Autorotation Test (VAT): Assesses VOR
Posturography: Balance patterns / how balance is affected
Label the following diagram:
d. External Auditory Canal
e. Tympanic Membrane
r. Inner Ear
m. Vestibular Nerve
n. Auditory Nerve
p. Outer Ear
q. Middle Ear
f. Eustachian Tube
Label the following diagram:
o. Semicircular Canals
j. Cupula
i. Otoconia
g. Utricle
h. Saccule
l. Cochlea
k. Endolymph
