the vestibular system

Question 1

vestibular system

Answer 1

function is to maintain equilibrium and balance

• located in the inner ear
• clinical signs and symptoms:
• • nystagmus
• -tinnitus
• -vertigo
• -hearing loss
• loss of balance and possible falls
• compensatory movements
• sweating, nausea, and vomiting

Question 2

VOR- vestibular ocular reflex

Answer 2

stabilize vision when our head moves. moves eyes to track an object while we are moving (fasting reflex we have in the body). Left to right or up and down. Inner ear sending signals to the eyeballs to track along with movement.

If ratio of eye movement to head movement is off, will lead to blurry vision and can lead to nausea and dizziness.

Question 3

VSR- vestibular spinal reflex

Answer 3

sends signals to our motor system to try and keep us upright. Gives body internal automatic feedback.

Question 4

Semicircular canals

Answer 4

Anterior- nodding head yes motion

Posterior- lateral flexion

Horizontal- shaking head no

Otolithic organs:
Saccule and Utricle: linear movements, acceleration and orientation of the head in respect to earths gravity (saccule moving up and down on elevator, Utricle moving forward and backward like in a car or side to side.

Question 5

Otolith

Answer 5

means ear stones. senses linear motion, moving forward, backward, up, and down. senses gravity, acceleration, and deceleration.

Question 6

Labyrinth

Answer 6

Bony: 3 semicircular canals, the cochlea and the vestibule. It is filled with perilymphatic fluid (similar to cerebral spinal fluid) on the outside of the membrane

Membranous: is suspended within the bony section and contains membranous portions of the canals and utricle and saccule. It is filled with endolymphatic fluid (similar to intracellular fluid)

Question 7

Ampulla

Answer 7

contain the cupula (hair cells) which convert displacement into neuro firing thru bending of hair cells to detect linear/angular motion

Question 8

Otolith Organ

Answer 8

Utricle and saccule: contain calcium carbonate crystals called otoconia. Shift in these crystals set off neuro firing detecting gravity and acceleration.

seaweed swaying in the current- motion is what tells the nerves to fire.

Question 9

Kinocilium

Answer 9

bigger hair than the rest- helps influence movement on others. Swaying forward and backward.

Question 10

VCR- vestibular colic reflex

Answer 10

stabilizes the head in space

Question 11

VSR- vestibular spinal reflex

Answer 11

generates compensatory body movement in order to maintain head and postural stability, thereby preventing falls.

Question 12

Peripheral and central systems

Answer 12

Vestibular system can be divided up into peripheral and central structures

treatment options are different for the different structures
peripheral treatments are often the go to and is common for a central problem to be overlooked.

Question 13

Peripheral functions

Answer 13

• Stabilization of visual images on the fovea of the retina during head movement to allow clear vision.
• Maintain postural stability especially during movement of the head.
• Provide information used for spatial orientation.

Question 14

Peripheral structures

Answer 14

Semicircular canals (3)

• Utricle
• Saccule
• CN VII: vestibulocochlear nerve

Question 15

central structures

Answer 15

• vestibular reflexes are controlled by processes primarily in the brainstem.
• connections between the vestibular nuclei, reticular formation, thalamus, and the cerebellum
• the vestibular nuclei- very important
• CN 3, 4, and 6 for VOR to work.
• Medial and lateral vestibulospinal tracts to maintain postural control.

Question 16

blood supply

Answer 16

the Vertebral-basilar blood system is the main supplier to both central and peripheral vestibular systems.

cerebellar strokes are often missed and have secondary symptoms of vertigo***

highly susceptible to ischemia

Question 17

peripheral disorders

Answer 17

Viruses (Ramsay Hunt)

• Meniere’s disease
• BPPV
• water in the ear
• sinus infection
• toxicity (medications, alcohol)

Question 18

Central disorders

Answer 18

-Disequilibrium of aging
-CVA
-Migraine
-Head trauma (TBI, concussion)
-Tumors
Multiple sclerosis

Question 19

Vestibular Neuritis

Answer 19

2nd most common cause of vertigo

• usually affects those 30-60
• gradual and complete recovery is expected
• characterized by an acute vestibular crisis followed by gradual improvement.

Vestibular crisis- vertigo, imbalance, nausea
-absences of associated auditory symptoms

Inflammation of the vestibular nerve

Question 20

viral endolymphatic labyrinthitis

Answer 20

• Acute vestibular crisis lasting 1-4 days with a history and recovery similar to vestibular neuritis
• Key feature is a sudden hearing loss accompanied with vertigo. Hearing loss within a few hours before or after the onset of vertigo.
• Hearing loss may recover or persist
• If no vertigo reported suspect bilateral loss
• Prognosis- Excellent for dizziness with compensation and vestibular balance rehab, need immediate steroid tx to prevent hearing loss.

-Inflamed labyrinth is near cochlea so lack of hearing

Question 21

Acoustic Neuroma

Answer 21

3rd most common intracranial tumor

• Nerve sheath benign tumors arise from schwann cells lining the axons of the cochleovestibular N.
• causes progressive unilateral hearing loss or tinnitus without vestibular symptoms. Balance issues (if present) tend to be mild and intermittent.
• Rarely cause acute vestibular crises but may produce syndromes that mimic other vestibular diagnoses.
• 3 therapeutic option: watchful waiting, radiosurgery surgical and resection.

Question 22

Meniere’s Disease

Answer 22

• A disorder of the inner ear function resulting in devastating hearing loss and vestibular symptoms.
• Cause of disease is unknown. Hereditary factors may play a role. Usual onset in the 4th and 6th decades of life, equally between the sexes.
• Key features: recurrent, spontaneous spells intense rotational vertigo lasting several hours, postural imbalance, nystagmus, nausea, vomiting, hearing loss, tinnitus and aural fullness. Vertigo will persist anywhere from 30 mins to 24 hours.
• Rotational spinning (vertigo)
• symptoms gradually abate, usually ambulatory within 3 days. normal balance returns between spells.
• hearing may return to baseline or may have residual permanent sensorineural hearing loss, most common in lower frequencies.
• vestibular exercises are not appropriate unless there is permanent loss of vestibular function.

Question 23

Benign Paroxysmal Positional Vertigo (BPPV)

Answer 23

Most common cause of vertigo

• key features: brief episodes of vertigo when head is moved in certain positions
• report of symptoms: triggered by lying down, rolling over in bed, bending over, and looking up. Women may report problems in hair salon, men while changing oil under car.

otoconia in semicircular canals.

symptoms:

• starts suddenly
• occurrence of vertigo
• no hearing loss or tinnitus

procedures: Dix-Hallpike

Question 24

Canalithiasis Theory

Answer 24

• most widely accepted theory of the pathophysiology of BPPV
• Otoliths are usually attached to the membrane inside the utricle and saccule
• Otoliths become dislodged from the utricle and enter the posterior SCC
• changing head position relative to gravity causes the free otoliths to move longitudinally through the canal.

Question 25

Ramsay Hunt Syndrome

Answer 25

Herpetic infection of the VII and VIII cn

Sudden onset of pain with open sores, loss of hearing with a vestibular crisis even, facial mm weakness

Question 26

Arnold Chiari

Answer 26

• episodic to continuous imbalance and lightheadedness exacerbated by hyperextension of neck, double vision on lateral gaze.
• down beating nystagmus in primary gaze

neurosurgery is treatments with therapy afterwards

Question 27

alcohol

Answer 27

makes blood less dense. when the blood with alcohol in it enters the inner ear, the alcohol first rapidly diffuses into the inner ear and makes them susceptible to gravity.