Test 3 - Vestibular Flashcards
Function of vestibular system?
maintain equilibrium and balance
Common clinical S & S of vestibular dysfunction?
Nystagmus – abnormal beating of eyes
Torsional
Side to side
Tinnitus – abnormal sounds in ears
Vertigo
Hearing loss
Loss of balance & possible falls
Compensatory movements such as a broad-based stance (to accommodate for imbalance)
Sweating, nausea, and vomiting (due to ANS involvement)Vestibular ocular reflex
(VOR) Stabilizes Vision When Head Moves Follows objects when head moves Fastest reflex in body Inner ear sends signals
Vestibular spinal reflex
(VSR) Balance Control Reflexes Signal to motor system Try to keep person upright Protective fx with autonomic reflexes
Semicircle canals
anterior - neck flex/ext
posterior - lateral neck flexion
horizontal - neck rotation
otolithic organs
saccule and utricle
Linear movements, acceleration and orientation of the head in respect to earths gravity
saccule - moving up and down on an elevator
utricle - moving forward and backward like in a car or side to side
vertigo
Vertigo: The feeling of movement when there isn’t any. Spinning sensation, swimmy head, floating sensation, lightheadedness
otoconia
Rocks or crystals that are embedded in a gelatinous layer that covers the hair cells (sterocillium and kinocillium)
crista ampullaris
The function of thecrista ampullarisis to sense angular acceleration and deceleration.
BPPV
BPPV:Benign paroxysmal positional vertigo. Otoconia get displaced in either one of the 3 semi-circular canals (most common) or in the cupula (hair cells) located in the ampula, utricle or saccual
Labyrinth
Bony: 3 semicircular canals, the cochlea and the vestibule. It is filled with perilymphatic fluid (similar to cerebral spinal fluid) on the outside or 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)
What are the motion sensory of the inner ear?
Ampulla: contain the cupula (hair cells) which convert displacement into neuro firing thru bending of hair cells to detect linear/angular motion
Otolith Organ (Utricle and Saccule): contain calcium carbonate crystals called otoconia. Shift in these crystals set off neuro firing detecting gravity and acceleration
What are the 3 motor outputs? - reflexes
VOR (Vestibular Ocular Reflex): generates eye movements, which enables clear vision while head is in motion
VSR (Vestibular Spinal Reflex): generates compensatory body movement in order to maintain head and postural stability, thereby preventing falls
VCR (Vestibular Collic Reflex): stabilizes the head in space
Peripheral structures and function
Peripheral Functions:
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
Involves the vestibular apparatus in the inner ear: Semicircular canals (3) Utricle Saccule CN VII: Vestibulocochlear nerve
Central structure and function
Vestibular reflexes are controlled by processes primarily in the brainstem
Connections between the vestibular nuclei, reticular formation, thalamus & cerebellum
Semicircular canals (angular) & otolith (linear) input is sent to the vestibular nuclei (extremely important)
Info travels to the ocular motor nuclei (III, IV , VI) for mediation of the vestibular ocular reflex
Then to the thalamus & cortex for arousal & conscious awareness of the head & body in space
Maintenance of postural control – peripheral vestibular input is sent distally to the Medial & Lateral Vestibulo-Spinal tracts
Common peripheral dysfunction
Peripheral Disorders Vestibular Neuritis/labryinthitis Viruses (Ramsay Hunt) Acoustic Neuroma Meniere’s Disease BPPV - crystals out of wack Toxicity (medication, alcohol) Water in the ear Sinus infection
Common central dysfunction
Central Disorders Disequilibrium of Aging CVA Migraine Head Trauma (TBI/Concussion) Tumors Multiple Sclerosis
Vestibular neutritis
2nd most common cause of vertigo - inflammation of vestibular Nn
Key Features: Vestibular crisis (vertigo, imbalance, nausea) improving over 1-4 days, absence of associated auditory symptoms, left with head movement sensitivity
Gradual and complete recovery is expected
Prognosis is excellent with compensation, vestibular and balance rehab
Viral Endolymphatic Labryinthitis
inflamed labyrinth
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
Acoustic neuroma
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 options: watchful waiting, radiosurgery and surgical resection
Menieres Dx
A disorder of the inner ear function resulting in devastating hearing loss and vestibular symptoms
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.
Symptoms gradually abate, usually ambulatory within 3 days. Some sensation of unsteadiness will persist but then 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
Benign Paroxysmal Positional Vertigo (BPPV)
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.
Canalithiasis: Debris floating freely in the endolymph in the long arm of the semi circular canal ( SCC)
Cupulolithiasis: Debris, probably fragments of otoconia from the utricle, adhere to the cupula
No hearing loss
Dix-Hallpike (anterior and posterior)
Epley
Nystagmus and what they mean.
R Posterior control
Cupulolithiasis – Persistent UBN & R Torsion
Canalithiasis – Transient UBN & R Torsion
L Posterior Canal
Cupulolithiasis – Persistent UBN & L Torsion
Canalithiasis – Transient UBN & L Torsion
Vertebrobasilar Vascular insufficiency
Blockages of one or more of the following aa;
Posterior Inferior Cerebellar (PICA)
Vertebral aa.
Anterior Inferior Cerebellar (AICA)
Basilar a
Superior Cerebellar (SCA)
Can involve episodic vertigo with imbalance with other brainstem signs and symptoms, loss of coordination, ocular motor control deficits as well as postural control and gait abnormalities, speech etc
Treatment: neurology + balance and gait therapy and fall prevention, habituation if symptoms present
