Vestibular System Flashcards
Thin elastic cartilage covered by skin that collects air vibration
Auricle
Curved tube from the auricle to eardrum
External Auditory Meatus
Length of EAM
1 inch
Outer 1/3 of EAM
Elastic Cartilage
Inner 1/3 of EAM
Bony Cartilage
A narrow oblique slit-like cavity in the ear
Middle Ear
Another name of Middle Ear
Tympanic Cavity
Wall of the ear: Fenestra Vestibuli
Medial Wall
Wall of the ear: Canal of Tensor Tympani
Anterior Wall
Wall of the ear: Tympanic Membrane
Lateral Wall
Wall of the ear: Pyramid
Posterior Wall
Wall of the internal ear
Fenestra Vestibuli
Muscle located at the pyramid
Stapedius
Another name of the tympanic membrane
Eardrum
Shape of Eardrum
Concave Laterally
Innervation of outer tympanic membrane
CN 5 and 10
Innervation of the inner tympanic membrane
CN 9
Three auditory ossicles of the ear
Malleus, Incus, Stapes
Largest auditory ossicles
Malleus
Shape of Malleus
Hammer
Shape of Incus
Anvil
Shape of Stapes
Stirrup
Attachment of Malleus
Long process = ear drum; Head = incus
Attachment of Incus
Body = malleus; Long process = stapes
Attachment of Stapes
Head = incus; Base = fenestra vestibuli
Two movements of air in the ear
Medially and laterally
Movement of Eardrum + LP of the Malleus
Medially
Movement of LP of incus + Head of Stapes
Medially
Movement of Head of Malleus + Body of Stapes
Laterally
Two muscles of the ear
Tensor Tympani and Stapedius
Origin of Tensor Tympani
Own Canal
Insertion of Tensor Tympani
Handle of Malleus
Nerve of Tensor Tympani
CN 5
Action of Tensor Tympani
Dampens vibration
Origin of Stapedius
Pyramid
Insertion of Stapedius
Neck of Stapes
Nerve of Stapedius
CN 7
Action of Stapedius
Dampens vibration
“Labyrinth”
Internal Ear
Two major components of Internal Ear
Bony and Membranous Labyrinth
Series of cavities in the internal ear
Bony Labyrinth
The fluid that fills the Bony Labyrinth
Perilymph
Three parts of Bony Labyrinth
Vestibule, Semi-circular canals and Cochlea
Central part of the bony labyrinth
Vestibule
What is contained inside the Vestibule?
Otolith organs
Posterior part of the bony labyrinth
Semi-circular canals
What is contained inside the Semi-circular canals?
Semi-circular ducts
Three Semi-circular canals
Superior or Anterior, Inferior or Posterior, Lateral or Horizontal
Hollow bony tube making 2 1/2 spiral turns
Cochlea
What does cochlea resemble?
Snail shell
Orientation of the base of the cochlea
Posteromedial
Orientation of the apex of the cochlea
Anterolateral
What is contained inside the cochlea?
Duct of cochlea
What is lodged within the bony labyrinth?
Membranous Labyrinth
What surrounds the membranous labyrinth?
Perilymph
The fluid that fills the Membranous Labyrinth
Endolymph
What is the description of endolymph?
Higher density than water
Two parts of Membranous Labyrinth
Cochlear System and Vestibular System
What composes the cochlear system
Duct of Cochlea
Forms of spinal organ of corti
Duct of Cochlea
Receptor for hearing
Spinal Organ of Corti
3 canals at the cochlear system
Scala Vestibuli, Scala Media, Scala Tympani
Canals at the cochlear system: Oval Window
Scala Vestibuli
“Oval window”
Fenestra Vestibuli
Canals at the cochlear system: Round window
Scala Tympani
Canals at the cochlear system: Duct of Cochlea
Scala Media
What prevent scatter of vibration
Scala Tympani
What pitch is the anterior canals of the cochlear system?
High pitch
What pitch is the posterior canals of the cochlear system?
Low pitch
Three primary functions of the peripheral vestibular system
(1) Stabilizes visual image during head motion; (2) Maintains postural stability; (3) Provides information about spatial orientation
5 neural structures in each labyrinth
3 SCC and 2 otolith organs
Responsible for angular rotation
SCC
Responsible for linear rotation
Otolith Organs
What structure at the end of SCC?
Ampula
What is the gel-like structure contained in the ampulla?
Cupula
What is contained in the cupula?
Hair cells
Two types of hair cells in the cupula
Kinocilia and Stereocilia
Where do the hair cells sit in the cupula?
Crista ampularis
Sensory organ for angular motion
Crista ampularis
Responsible for horizontal linear acceleration
Utricle
Responsible for vertical linear acceleration
Saccule
Crystals in the otolith organs
Otoconia
The nerve that branched out in the hair cells of SCC and otolith organs
CN 8
Where does CN 8 bring the signals to the brainstem?
Vestibular Nuclei
4 places where signals from vestibular nuclei send off to
CN 346, Thalamus, SC, and Cerebellum
What is the function of the signals sent in CN 3,4,6?
For Visual Image
What is the function of the signals sent in the Cerebellum?
For Balance
What is the function of the signals sent in SC?
For Postural Stability
What is the function of the signals sent in the Thalamus to the cortex?
For Spatial Orientation
3 principles of the vestibular system
Tonic Firing Rate, Push-pull mechanism, Vestibulo-ocular reflex
“Brain detects head motion and direction through comparison of inputs between 2 vestibular system”
Push-pull mechanism
“Vestibular system can detect head motion through excitation and inhibition”
Tonic Firing Rate
“Stabilizes visual image in the retina by generating compensatory eye motions in the direction opposite to head motion”
Vestibulo-ocular reflex
Resting Firing Rate
70-100 spikes/sec
VOR when the head rotates to the right
MR of Right and LR of left
Eye movement when looking at the right
LR of Right and MR of Left
Eye movement when the head rotates right and down
Right IO and Left SR
Eye movement when the head rotates right and up
Right SO and Left IR
True or False: Head motion is C/L with eye motion
True
5 signs and symptoms saw in patients with Vestibular conditions
Vertigo, Lightheadedness, Dysequilibrium, Oscillopsia, Nystagmus
The only s/sx cannot be seen in patients with pure vestibular pathology
Lightheadedness
“Out-of-balance”
Dysequilibrium
Primary diagnostic indicator for most central and peripheral pathology
Nystagmus
Illusion of movement
Vertigo
“Fainting is about to occur”
Lightheadedness
The motion of objects that are known to be stationary
Oscillopsia
Possible causes of vertigo
BPPV, UVH, Central Lesion
Possible causes of lightheadedness
HOPA: Hypoglycemia, OH, Panic attack, Anxiety
Possible causes of dysequilibrium
BVH, UVH, Central lesion
Possible cause of oscillopsia
Vestibular Hypofunction
Nystagmus is slow and fast movement
Jerk Nystagmus
Nystagmus that are equal in movement
Pendular Nystagmus
Three peripheral vestibular pathologies
BPPV, UVH, BVH
Most common vestibular pathology
Benign Paroxysmal Postural Vertigo (BPPV)
BPPV is secondary to _______?
Biomechanical disorder
Two biomechanical disorder that causes BPPV
Canalithiasis and Cupulolithiasis
Otoconia adhered to the cupula
Cupulolithiasis
Otoconia are found in SCC
Canalithiasis
Signs and symptoms of BPPV
Vertigo and Nystagmus
Vestibula condition due to asymmetric firing rate
Unilateral Vestibular Hypofunction (UVH)
Possible causes of UVH
Viral insults, vascular events, trauma
4 signs and symptoms of UVH
Vertigo, Oscillopsia, Dysequilibrium, Nystagmus
Vestibula condition due to otoxicity
Bilateral Vestibular Hypofunction (BVH)
The antibiotic that causes ototoxicity in BVH
Aminoglycosides
Primary complaints by the patients with BVH
Dysequilibrium
Do patients experience nystagmus and vertigo in BVH?
Usually NO
When do patients experience nystagmus and vertigo in BVH?
Unless there is an asymmetry in firing rate
4 CNS injuries that may affect the vestibular system
Vertebral Artery damage, TBI, TIA, MS
What is the structure affected in Vertebral Artery damage?
Cerebellum
What is the vestibular s/sx of Vertebral Artery damage?
Mimics vestibular pathologies
What is the vestibular s/sx of TBI and TIA?
Vertigo
What is the structure affected in MS?
Cranial nerve 8
What is the vestibular s/sx of MS?
Identical to UVH
Central or Peripheral: Severe Ataxia
Central
Central or Peripheral: Nystagmus that can be suppressed by visual fixation
Peripheral
Central or Peripheral: Mild Ataxia
Peripheral
Central or Peripheral: (+) Vertigo
Both
Central or Peripheral: (+) Diplopia
Central
Central or Peripheral: (-) Hearing Loss
Central
Central or Peripheral: (+) Hearing Loss
Peripheral
Central or Peripheral: (+) Nystagmus
Both
Central or Peripheral: Nystagmus that cannot be suppressed by visual fixation
Central
Central or Peripheral: Altered Consciousness
Central
Central or Peripheral: Tinnitus
Peripheral
Central or Peripheral: Lateropulsion
Central
Central or Peripheral: Fullness of Ear
Peripheral
Nystagmus seen in Peripheral Vestibular Pathology
Horizontal and Jerky
Nystagmus seen in Central Vestibular Pathology
Vertical and Pendular
Two examinations for Eye Movements
Dix-Hallpike and Head-Shaking Induced Nystagmus
The most common cause of vertigo
BPPV
The most common positional test for BPPV
Dix-hallpike Test
What is the tested ear in the Dix-hallpike test?
The ear that is pointed to the ground or rotation of the head
5 steps in the Procedure of Dix-Hallpike Test
(1) Long Sitting (2) Rotate head any side (3) Supine (4) Extension of head or neck (5) Check for nystagmus
A positive sign of Dix-Hallpike Test
(+) Nystagmus
Condition tested in Dix-Hallpike Test
BPPV
5 steps in the Procedure of Head-Shaking Induced Nystagmus Test
(1) EC (2) Flexion of head or neck (3) Oscillate head HORIZONTALLY (20 cycles) (4) EO (5) Check for Nystagmus
A positive sign of Head-Shaking Induced Nystagmus Test
(+) Nystagmus
Condition tested in Head-Shaking Induced Nystagmus Test
UVH
Three assessments used for vestibular function
Rotation Chair Test, Caloric Test, Vestibular Evoked Myogenic Potential (VEMP)
Two test used to check of SCC function
Rotation Chair Test, Caloric Test
SCC: Administration of infusing warm/cold air or water in the auditory canal
Caloric Test
Condition tested in Caloric Test
UVH
SCC: Patient is rotated in the darkroom
Rotation Chair Test
Condition tested in Rotation Chair Test
BVH
The assessment used to check the function of otolith organs
Vestibular Evoked Myogenic Potential (VEMP)
Two subtypes of VEMP
Ocular and Cervical VEMP
The muscle tested in Ocular VEMP
Inferior Oblique
The muscle tested in cervical VEMP
SCM
How many decibels are exposed to the patient while administering the VEMP?
95 decibels
Procedure of VEMP
The patient is exposed to loud clicks
Interpretation of VEMP
If VEMP is absent = (+) UVH
Two exercises used to treat patients with UVH
Gaze Stability Exercise and Habituation Exercise
UVH exercise to improve VOR
Gaze Stability Exercise
UVH exercise to improve motion sensitivity
Habituation Exercise
What item is used in Gaze Stability Exercise?
Card
3 steps in Gaze Stability Exercise
(1) Focus on card, (2) Rotate head to 1 side (3) Move card to opposite direction
3 steps in Habituation exercise
(1) Determine provoking position, (2) Maintain provoking position (3) Repetition: 3-5x
Habituation exercise is done how many seconds per position?
30 secs per position
Four exercises used to treat patients with BVH
Tai Chi, Balance Exercise, Pool Exercise, Exercise to improve central programming movements
What item is used in Exercise to improve central programming movements?
Cards
4 step procedure of exercise to improve central programming movements using 2 cards
(1) Arrange cards horizontally, (2) focus on card A then B, (3) Arrange cards vertically, (4) focus on card A then B
5 step procedure of exercise to improve central programming movements using 1 card
(1) Focus on the card, (2) EC, (3) Rotate head to one side (imagine that you are looking at card), (4) EO, (5) Focus on the card
Three exercises used to treat patients with BPPV
Canalith Repositioning Maneuver (CRM), Brandt-Daroff Exercise, Liberatory Semont Maneuver
Position of the patient in CRM: Anterior & Posterior SCC
Sitting
Position of the patient in CRM: Horizontal SCC
Supine
6 step procedure of CRM: Anterior & Posterior SCC
(1) Sitting (2) Rotate head to affected side (3) Supine with head/neck extension (4) Rotate head to unaffected side (5) Roll to shoulder (unaffected) (6) Assist to sitting (fit with collar)
5 step procedure of CRM: Horizontal SCC
(1) Supine (2) Rotate head to affected side (3) Rotate head to the unaffected side; wait for few seconds 2x (4) Roll to prone (unaffected) (5) wait for the symptoms to stop
What SCC does Brandt-Daroff Exercise use to improve?
Posterior SCC
5 step procedure of Brandt-Daroff Exercise
(1) SItting (2) Rotate head to 1 side (3) Side-lying to opposite side (4) Sitting (5) Repeat to another side
What SCC does Liberatory Semont Maneuver use to improve?
Posterior SCC
4 step procedure of Liberatory Semont Maneuver
(1) Sitting (2) Rotate head to unaffected side (3) Sidelying on the affected side (4) from 1 side-lying to opposite side-lying (180 degrees turn to unaffected side)
2 exercise of central lesions
Balance and Gait exercises
Purpose of Central Pathology exercise
For safety
Important Patient education
Without head motion, the vestibular system will not improve maximally
