Vestibular Rehab 1 Flashcards
What are the 3 semi circular canals and what type of acceleration do they detect?
- Horizontal
- Posterior
- Anterior
- Detect angular acceleration
What are the 2 otolith organs and what do each of them detect?
- Saccule: Vertical acceleration
- Utricle: Linear acceleration & head tilt
What fluid are the semi circular canals filled with?
Endolymph
What is the ampulla?
Widened end of semicircular canal
What does the ampulla contain?
Gelatinous cupula - flexible membrane
What does the cupula contain?
Sensory hair cells: stereo cilia & kinocilia
Where do the sensory hair cells in the ampulla sit?
Crista ampullaris
What occurs when the stereocilia are deflected toward kinocilia?
Excitation (depolarization)
What occurs when the stereocilia are deflected away from the kinocilia?
Inhibition
What is the healthy vestibular system resting firing rate?
70-100 spikes/sec
What are inside the otolith organs?
Maculae and otoconia that sits on top
With head tilt or acceleration, gravity/other acceleration pull on crystal which activates what?
Hair cells
What structures contain hair cells that deflect with head movements?
Cupula and maculae
What structures contain otoconia?
Utricle or saccule
What structures sense rotational head movements?
Semicircular canals
When you turn your head to the left, what occurs in an intact vestibular system?
- Left Vestibular Apparatus is Excited and Right Inhibited
- Eye go right
What is oscillopsia?
- Stationary objects in the environment appear to be in motion when the patient is in motion
- Cause blurred vision
What is disequilibrium ?
Sensation of being off balance
What might a patient report if they have vertigo?
Room is spinning
What is the pathophysiology of BPPV?
- Otoconia is dislodged from the otolith organs (usually utricle)
- It float in the semi-circular canal disrupting the vestibular signals to the brain
What does: Benign Paroxysmal Position Vertigo mean?
- Benign: not life threatening with overall favorable prognosis
- Paroxysmal: Rapid and sudden onset, short spell
- Positional: Only occurs with certain head movements
- Vertigo: Feels like you are spinning or the world around you is spinning
What is canalithiasis?
- Otoconia are free floating in the semicircular canal
- Vertigo lasts 30-90 seconds then fatigues
What is cupulothiasis?
- Otoconia are adhered to the cupula
- Vertigo greater than 90 seconds and does not fatigue
During pathophysiology of BPPV: The particles in the canal affect the flow of endolymph as the head is turned. What series of events does this cause?
- Disruption of the cupula deflection when the head is turned
- Inaccurate signals are sent down CN VIII that are different than what the head is actually doing (some hair cells excite while others inhibit and it is not consistent with the head movement)
- Discrepancy of sensory information between ears causes vertigo and nystagmus
What symptoms are seen with BPPV?
- Nystagmus & Vertigo with change in head position (lasts <15 sec)
- Occasional nausea with or without vomiting
- Disequilibrium
What is nystagmus?
involuntary eye movement
What is normal/typical nystagmus?
- Following lots of spinning
- Optokinetic reflex
What is atypical nystagmus?
- CNS Pathology, vestibular pathology, drug toxicity
- BPPV: the movement of the cupula or crystals causes alteration in firing rate
What tests and measures test the posterior or anterior canal?
- Dix-Hallpike Test
- Sidelying Test
What test examines the horizontal canal?
Roll test
What is vertebrobasilar insufficiency?
Occlusion of the vertebral artery resulting in loss of blood flow to the brain
Dix-Hallpike Maneuver examines posterior canal of (BLANK) ear and anterior canal of (BLANK) ear
Dix-Hallpike examines posterior canal of downward ear and anterior canal of upward ear
During Dix-Hallpike maneuver if the posterior canal is involved what type of nystagmus is seen?
Torsional upbeating nystagmus
During Dix-Hallpike maneuver if the anterior canal is involved what type of nystagmus is seen?
Torsional downbeating nystagmus
During Dix-Hallpike maneuver if canalithiasis is present how long will nystagmus last?
Transient nystagmus <30-90 seconds
During Dix-Hallpike maneuver if cupulolithiasis is present how long will nystagmus last?
prolonged nystagmus >90 seconds, does not fatigue
What geotropic nystagmus?
- Fast phase is toward the earth
- Otoconia are in canal
- Side with strongest nystagmus is the affected ear
What is ageotropic nystagmus?
- Fast phase is away from the ear
- Otoconia are in cupula
- Side opposite strongest nystagmus is affected ear
