Lecture 7: Vestibular Disorders Flashcards
We need different body systems for posture, or the ability to stand upright against gravity. What are they
1) Vision
2) Vestibular
3) Somatosensation
They’re intragrated through the CNS and PNS to give us the ability to maintain upright.
The role of the vestibular system:
* Maintain clear vision during hd movement
* Determine head position in space
* Determine the speed and direction of head movement
* Critical for postural control; uniquiely identifies self-motion as different from motion in the environment (I can walk around room and know body is moving but vestibular system itself isnt)
Works as part of the sensory triad, in conjunction with vision and somatosensory inputs for postural stability
* Sensory information from all 3 systems is centrally integrated to determine appropriate postural strategies
NOTE: for the vestibular system
Not life threatening (aside from aggresive forms of neoplasm) but can cause significant disability, with a devastating sense of abnormal movement, visual instability and loss of balance
Symptoms of dizziness and imbalance cannot always be assumed to be an actual loss of vestibular function as they may also reflect inadequate sensory integration appropraite for the environmental context
* so it could be a sensory issue or something in another system that promotes balance and psoture
* Think if one of those other 2 systems in our triad is off
Comobrid dysfunction can affect functional recovery from a vestibular condition, especially if it affects the visual or somaosensory inputs
* If someone has diabetes and has polyneuropathy - impacts somatosensory system (sensation) + a vestibular deficit will just make balance and posture worse
Prior trauma, either physical or psychological, can also cause maladatption, resulting in responses to intervention that are inconsistent with typical recovery patterns
there are vestibular nucli throughout the CNS that work with the cerebellum and will process information in different areas of the CNS. Will project information outwards
KNOW: The sensory role of the vestibular system is perception of motion and orientation
What is the motor role of the vestibular system (3)
1) control eye movements
2) Gaze stabilization (ability to look at a target and hold gaze)
3) Maintain posture/equailibrium
what are the two sensory roles of the vestibular system
1) Perception of motion and orientation
NOTE: Togetehr our vestbiular system is postural, motor and oculomotor contorl
Compoenents of vestibular system
PNS: 2
CNS: 2
Reflexes: 3
PNS
* vestibule (sensory organ)
* CN 8 (vestibulocochlear)
CNS:
* Vestibular nuclei (in brainstem)
* Cerebellar pathways
Reflexes - combine both CNS and PNS to create involuntary rxns
* Vestibulo-ocular (VOR)
* Vestibulospinal (VSR)
* Vestibulocollic (VCR)
Which reflex stabilizes gaze during head motion?
Vestibulo-ocular reflex
What is the fastest reflex in the body?
Vestibulo-ocular reflex (VOR)
Which reflex generates compensatory eye movements?
* what are compensatory eye movements?
Vestibulo-ocular reflex (VOR)
EX: rotation of head to the left results in rightward compensatory eye movement (makes sense that this reflex also does stabilization of gaze)
Which reflex maintains vertical alignment of trunk?
* which side wil have flexor/extensors effects
Vestibulospinal reflex
When the head tips in one direction, the SC produces extensor effects on side. ti which head is bent and flexor effects opposite
notice the head wants to be upright
Which reflex stabilizes head in space by activating neck musculature?
Vestibulocollic reflex
Neck muscle activation to stabilize head in space, compensates for head displacement during gait
dilinating between these 3 reflexes will be on quiz
not going to hold us to the definitions
Ability to hold gaze/target on something thats moving
* tested w/ H test
Smooth pursuit
looking back and forth between multiple targets and keeping your gaze
saccades
object is stationary, not moving. stabilizing gait on something
visual fixation
ability to look at something while there is rotation/movement going on
optokinetic
Oscilatory beating of the eyes (involuntary) - only normal if its at the end ranges of their gaze and their gaze is strained.
Nystagmus
knowledge check: which reflex does stabilization of gaze?
VOR
Which part of the ear is a system of fluid filled w/ tubes and sacs
* also called
Inner ear
also called the labyrinth
we have two labyryniths 1 is boney the other is fuild
The labyrynth is responsible for what two functions?
Hearing / balance
Which part of the labyrinth is specifically responsible for hearing?
Cochlea (transmits sound to the brain)
where in the ear is tinitis formed?
cochlea
Which part of the inner ear is responsible for balance
The vestibular organs
* This is semicircular canals + otoliths
Which two things make up the vestibular organs?
Semicircular canals + Otoliths
Signals travel from labyrinth –> brain via which CN?
Vestibulocochlear nerve
Brain integrates these signals
Cochlea involvement = abnormal noise/inner ear = tinnitus
we have 3 coplanar pairs that orient our semicircular canals and orient our cells in the labyrinth
R/L horizontal pair
R anterior and L posterior pair
L anterior and R posterior pair
Turning head to the right = right vestibular nerve gets more signals and the L is decraesing its signals.
Our 3 pairs are either on a R horizontal axis or are on 2 diagonal axises
are the semicircular canals affected by gravity?
* What do they sense?
* How many in each ear?
No
Sense rotation
3 in each ear 6 total (horizontal, anterior, posterior)
Fluid that fills the semicircular canals
endolymph
which part of the semicirclar canals is dilated space/opening at the end of each canal; cilia/hair cells are located within ampulla, more specifically held in endolymph in a place called the cupula
Ampulla
Which part of the semicular canals is a gel-like bud, embedded with sensory hair cells, that sits within the ampullated (dillated) portion of each canal?
Cupula
What happens w/dysfunction of the semicircular canals?
Spinning or vertigo
Which part of the ear detects forward/backward head tilts and translation of the head (so it is affected by gravity)
Otoliths
* detect gravity and position in space
Which part of the ear is affected by gravity?
Otoliths
What are the two otolithic organs? (otoliths are in here)
Utrricle and saccule
KNOW: The otoconia are IN the otolith organs - should not be in the semi sircular canals
* this is when BPPV happens
where to semicricular canals originate?
Utricle
A feeling of pulling/shifting involves what part of the ear
Utricle dysfunction
Otoconia (that can get in the SSC) are smaller than a spec of dust
age related changes - hypertrophy, variability in size, fragmentation, fissured, putted, weakening of links - can help develop BPPV
Worse with females/osteoporosis (older age; but starts worsening in middle age)
Know: Otoconia should be in the otoliths
* belong in wall of saccule and floor of utricle
Nystagmus can be physiological (eyes straining to reach end range) or pathological
Nystagmus is named for its fast phase or side it beats fastest towards (R, L, up, down, torsion)
Slow phase is the side of dysfunction
* so its beating more toward the side thats more neurally intact
PNS dusfunction: beats quickly toward more enurally active side
* EX: L hypofunction = R beating. Hypofunction side is opposite; peripheral disorder
Side of torsion: one side will be stronger or present
CNS dysfunction = pure vertical; pure torsion
* so the beating is different if its CNS vs PNS
knowledge check: cochlea transmits sound to the brain
Where does the vertebral-basilar artery supply blood?
* What other 2 arteries play a role in supplying this area?
Components of the vestibular system
Posterior and inferior cerebellar arteries also play a role in supplying this area
What does the anterior inferior cerebellar arteries supply?
* Supplies it via what 3 arteries?
Supply the peripheral mechanism via the labyrinthine, common chochlear and anterior vestibular arteries
Vertebral artery test - tests for vertebral basilar insufficiency
* This position maximally stresses the opposite vertebral artery and decreases the space in the lumen of the artery
* Extension with contralateral rotation has been shown to decrease the diameter of the artery
* Diagnostic accuracy of the test = poor, negative test does not rule out VBI
* If the have any of the 5 D’s come on than were worried
What innervates the inner ear area
* this nerve subdivides. What does it turn into and waht does each branch innervate?
* What other nerve is very close and runs through this same area?
Vestibulocochlear
Divides into the vestibular nerve to semicricular canalas and chochlear nerve to the cochlea
Facial nerve (VII) runs right through this area as well
hearing: Sound enters external auditory meatus –> ossicles move –> causes fluid to move –> triggers hair cells –> converts to electrical signals –> to auditory (cochlear nerve) –> to brain
Which portion of the ear is responsible for conductive hearing?
Which portion of the ear is responsible for sensorineural hearing?
External / middle ear = conductive
Inner ear = sensorineural
What kind of hearing loss is trouble transferring sound waves along peripheral pathway?
Conductive
What kind of hearing loss is damage in the inner ear or sensory organs or the auditory nerve?
Sensorineural
What is a major recipient of outflow from vestibular nucleus complex, major source of inout for vestibular reflexes
Cerebellum
Knowledge check: What is the major input for vestibular reflexes
cerebellum
KNOW:
Frequency of dizzines increases w/ age
Approximately 10% of people older than 45 years visit their physicians complaning of dizziness, with rates increasing further in those older than 75 y/o
Hair cell loss occurs with aging, particullary in the ampulla
Demineralization and fragmentation of the otoconia, also increase w/ age, especially in those with osteoporosis and vitamin D deficiency
Neuronal loss in the vestibular nuclei is also estimated to occur at a rate of approximately 3% per decade from the age of 40 years
aging has a significant direct effect on vestibular function
dont need to know any of the #’s above
where does ear hair cell loss occur the most w/ aging?
Ampulla
Dont think shes going to ask anything here
Treatment for vestibular
Reflects the spectrum of etiologies and depends on the nature of the underlying vesitbular disorder
When vestibular symptoms are due to a peripheral vestibular lesion, functional recovery will begin within _ days to _ weeks through adaptive mechanisms of the brain
2 days - 4 weeks
If symptoms are severe, sedatives may be give, but ideally only for the first 24 hours
Use of antivert - can cause drowsiness
Rehab should begin within the first 3 days
Surgical itnervention is considered when symptoms are unrelenting and underling condition is determined bt is unresponsive to other medical measures
Unilatearl peripheral vestibular system lesion, but the CNS is intact. Is recovery of functional mobility possible?
Yes
Complete bilatearl vestibular loss can occur as a result of use of ototoxic medications but is realtively rare. What is the prognosis like?
POOR
KNOW: Prognosis for flucuating conditions such as endolympahtic hydrops or menieres disease is highly variable
recovery rate in a central vestibualr system disorder causing dizziness or disequlimbrium depends on the nature of the lesion and concomitant neurlogic dysfunction
* whats causing the lesion (is it a tumor - maybe we can remove it)
For vestibular - in order to determine if theres a central cause of the pts symptoms, the therapist must carefully examin the CNS by testing of function associated w/ cranial nerves, cerebellum, brainstem and cortical connections
Often, noth central and peripheral lesions can be identified.
Also evaluate the MSK and neuromuscular systems becayse compensatory movements releated to deficits in these systems may mimic vestibular dysfunctions or impact recovery
Knowledge check: who would have the most favoriable prognosis
* unilatearl peripheral lesion like BPPV would have the best prognosis
Illusion of movement, false sense of rotation or linear movement
Vertigo
Sensation of being off balance, not observable
Disequilibrium
Unsteadiness, obseravble
Imabalnce
Moving objects in the environment, subjective
Oscillopsia
* this is more theres somethign wrong w/ their eyes
Fainting feeling
Presyncope/Lightheadedness
2 autonomic signs
Diaphoresis, emesis
knowledge check: sensation of being off balance but not observable
In peripheral vestibular disorders
* Unilateral hypofunction: stable vs unstable
* or
* Bilatearl hypofunction
central vestibular disorders
Non-otogenic dizziness
In peripheral vestibular disorders how long does the event last what then what occurs
event lasts days then compensations occurs
Peripheral vestibular disorders can have unilateral hypofunction that can be stable (also called fixed) and unstable
3 examples of of stable hypofunction
4 examples of unstable unilatearl hypofunction
Stable: Weak VOR. This is what we treat
1) vestibular neuritits
2) Anterior vestibular artery ischemia
3) Labyrinthits
Unstable
1) Menieres disease
2) Acoustic neuroma
3) Superior canal dehiscene
Research shows PT is not effective in unstable flucuating conidtions
Menieres disease is a peripheral vestibular disorder thats unilataeral hypofunction. Is it stable or unstable?
s/s
* differentaiting factor
right is healthy other is swollen
Unstable
differenitating factor is the auditory symptoms
Overaccumulation of endolymph and resulting compromise of the perilymphatic space
* whats a form of this disease?
* Men or women more
* age
* genetics?
Endolymphatic hydrops
Meniere syndrome is thought by many to be a form of endolymphatic hydrops
* herilymphatic space is compromised
caucasian women are most prone to meniere syndrome
The peak incidence of meniere syndrome is in the 40-60 year old age group
Whether the variability in prevalence rates is caused by differences in environment, genetics, or diagnostic criteria is unclear
Familial occurence of meniere syndrome has been reported in 10% to 20% of cases
Genetic inheritance plays a role
presentation of endolympahtic hydrops and meniere disease
clusters of attacks may be separated by periods of long remission
Balance function between attacks can be normal
Over time there is a gradual decline in the function of the vestibular system and complaints of imbalance and mild symptoms relaeated to a unilateral dysfunction become common
The hearing loss in menieres disease is flucuating, low-frequency sensorineural loss early in the clinical course
* eventually, the loss becomes irreversible, often progressing in severity with involvement of higher frequencies and loss of speech discrimination
Syndrome of vertigo and oscillopsia induced by loud noises or by stimuli that change middle ear or intracranial pressure in patients with a dehiscence of bone overlying the superior semicircular canal
* does it need surgery?
Superior semicircular canal dehiscence syndrome
Unilatearl hypofunction (unstable)
needs surgery
As seen in fistulas, Tullio phenomenon (eye movements induced by loud noises) or heenebert sign (eye movements induced by pressure in the external auditory canal) develop and often there is chronic disequilibrium
Bilatearl hypofunction - this is now both ears
* ototoxicity, meningitits, sequential vestibular neuritits, progressive disorders, autoimmune disorders, chronic inflammatory peripheral polyneuropathy, congenital loss, and neurofibromatosis
* Most common idiopathic
Treatment: challenging, compensation for lost vestibular function
When certain medications someone is on severealy damages the vestibular system - think antibiotics like amingoglycoside and streptomycin and gentaminicin
Ototoxicity
In ototoxicity where does the pathology from the antibiotics occur?
* what is one of the most debilitating early symptom
* when are they unable to stabilize vision?
* is damagege perminant?
Damage to the hear cells in the inner ear (permanet) can result in complete loss of vestibular function within 2 to 4 weeks after these drugs are given
retinal slip = early symptom
unable to stabilize vision during head movement
damage is permanent and that the recovery of function of the vestibular mechanism is limited
Viral infection is the 2nd most common vause of vertigo and usually affects what nerve unilatearlly?
Vesitbular nerve
acute unilatearl vestibulopathy = vestibular neuritits
vestibular neuritits can be a partial unilatearl vestibular lesion, and this partial lesion can affect the superior division of the vestibular nerve, which includes and afferents from the horizontatl and anterior semicricular canals
The use of antibiotics in general has decreased the incidience of bacterial infections affecting the vestibular system
KNOW: Acute unilatearl vestibular nueronitits causes sudden onset of vertigo, spontaneous horizontal and torsional nystagmus, nausea, and vomitting
The person will immediately expereince intense disequilibrium, and hist or her ability to perceive position and motion will be profoundly disturbed
whi acute unilatearl vestibular neuronitits what is it like w/ the eyes closed?
What about open?
lateralpulsion away to to the side of lesion?
closed = illiusion of self spinning
Eyes open - illusion of environment spinning
NOTE: they’ll also have lateropulsion to the side of the lesion - lean to the side of the lesion
Medications are used for symptoms of acute vertigo and include antihistamines, anticholinergic agents, antidopaminergic agents, steriods, and antivirals such as acyclovir
Gluccocorticoids adminsterid within 3 days after onset of vestibular neuronitits improve long-time recovery of vestivular function and reduce length of hospital stay
PT plays a role
slow recovery 4-6 months
Knowledge check: acute vistibular neuritits lateral pulsion =
side of the lesion
Benign Paroxysmal Positional Vertigo (BPPV)
Benigns = not life threatening
Paroxysmal = it comes on suddenly, brief spells or intensification of symptoms
Positional - it gets triggered by certain head positions or movements
Vertigo - a false sense of rotational movement
What is the most common cause of vertigo
BPPV
who is more affected by BPPV men or women?
Women
NOTE: most is idiopathic
* also had traumma and viruses can cause it
BPPV is resolved for 20% of people within 1 month and 50% in 3 months
* however it reoccurs in 40-60% of cases
BPPV may trouble the individual intermittently for years, but in this condition, a close examination of potential causes will often identify an underlying medical disorder, and recurrences decline when the underlying disorder is managed
BPPV
change in head position causes the symptoms
objective findings on testing –> nystagmus
canalithiasis vs cupulolithiasis
* Canalithiasis: free floating otoconia in SCC, latency 3-5 seconds, nystagmus and vertigo to follow, fatigues with repetition, more common
* Cupulolithiasis: otoconia stuck in cupula of affect SCC, immediate onset of nystagmus and vertigo, long lasting symptoms (greater than 1 minute), weaker nystagmus
posterior canal = 85-95% of the time
Clinical manifestations of BPPV
* strong sense of falling or spinning out of control
* Complain of breif episodes of vertigo precipitated by head movement in a specific direction such as bending over, looking up to take an object off a shelf, tilting the head back to shave, lying back to get a haircut, or turning the head rapidly while backing up a car
Episodes of vertigo occur suddently and typically last 20 seconds, but no more than a minute
Important to note that vertigo or the true sensation of the “room spinning” is not always present in BPPV. Some patients only report lightheadedness, sensation of floating, dizziness, imbalance, and/or nausea.
this is peripheral
knowledge check: how long do episodes of BPPV last?
1 few seconds (20-60 seconds)
What are symptoms like w/ Mal De Debarquement syndrome?
* when is it worst
* what is it triggered by?
* how long do symptoms last
* what age / sex
Syndrome that is named essentially for the symptoms releated to “getting off the boat” - rocking sensation worse during rest
Triggered by a long time spent on a ship, such as during a cruise, or by an extended train ride
The complaints occasionally occur after international or extended air travel, especially if there is turbulence
Dizziness and disequilibrium that usually subside within hours after exiting a boat, train, or plane become presisent and can last for weeks, months or even years
Women in their third and fourth decade represent the highest percentage of people reporting symptoms
Poor prognosis tends to limit activity or overmedicate to dapmen the sensation
* because you feel so sick that you basically cant move
what is a fistula?
abnormal connection between two areas in the body
What is a perilymph fistula?
* what can it cause
* what is it caused by
*
An abnormal communication of the innter and middle ear spaces
can cause vertigo, vestibular and/or hearing issues
Some stupids report veztibular symptoms as the major presenting complaint, whereas others idnicate hearing loss equal to or more common than balance releated symptoms
caused by pressure changes internally or externally, congenital malformations, prior ear surgery
conjugate contralateral slow deviation of the yes with vertigo occurs with positive pressure applied to the suspected ear
reduction in vesitbular releated complaints has been reported in more than 50% of surgeries. Hearing is imporved about 25% of the time
Head elevation during bed rest, laxatives to reduce the risk of increased intracranial pressure, and monitoring of both hearing and vestibular function
In those isntances in which hearing loss worsen or vestibular symptoms persist, surgical exploration is warranted
On quiz surgery indicated for superior canal diabesis (i spelled this wrong, in notes prior)
is nystagmus longer in a central or peripheral vestibular disorder?
central
KNOW: In mild traumatic brain injury BPPV is common
On quiz: Mild traumatic brain injury = GCS 13-15
how long does it take to recover from a milk traumatic brain injury?
7-10 days
KNOW: w/ a mild TBI can develop post concussion syndrome (deficits for months to years) if initial symptoms not resolved in a couple weeks after injury
most common setting for mild tbi = sports
Recovery from mTBI should include a graded progression of icnreasing PA/EX that does not exacerbate symptoms and balance rest
Knowledge check: Mild to traumatic brain injury on glasnow scale
13-15
with non-otogenic dizzines what are symptoms lke what are vestibular tests like?
symptoms = vague
vestibular tests = normal
Is there 1 set test for Non-otogenic dizziness?
No definititve test, eval upper quarter if no apparent neurological or otologic causes for the symptoms
address impaired cervical kinesthesia along with MSK impairements
* the awareness of the cervical spine during movement
The cervical spine plays a role in gaze stability and postural contorlm focus on pain reduction and resotration of cervical mobility (not largely on VRT), most dont complain of vertigo but of imbalance/lightheadedness/disequilibrium
cervical ROM, pain
* Limit positional testing
* Impact VOR movement
* Fear avoidance behaviors
* Clear VBI
What is disuse disequilibrium?
Similar to deconditioning with fear of falling
- typically odler pt
functional effects of aging nervous system = skeletal mm atrophy, less precise contorl of movement, decreased sensitivity of somatosensory system, processing speeds slow
Disuse deconditioning can be age-releated
* when we get older we arent stimulating the vestibular system as much which causes it to change its tolerance
need to carify these symptoms w/ the pt
syncope = fainting
might not even be a vestibular issue = might be a BP issue
chronic subjective dizziness and PPPD
Might be a maldaptive loop where some trauma happened
stuck in this dizziness loop where theres not anything physiologically wrong anymore
* need to work on ways to increase confidence / mobility
PPPD = persistent postural perceptual dizziness
* Starts shortly after an acute event that leads to vertigo/balance issues etc
* Presentation: Dizziness w/o vertigo and fluctuating unsteadiness that is provoked by environmental or social stimuli
treatment = vestbiular habiutation, cognitive behavior therapy, medication
Primary carcinoma can directly involve the end organ, the midle ear, or the mastoid
Neoplasia
the most common tumor of the middle ear, arising from the chemoreceptor system of the ninth through 12th cranial nerves and producing focal symptoms
glomus tumors
tumor that arises from the nerve sheath of the vestibular nerve, The term acoustic neuroma is commonly used to describe this tumor, especially with regard to surgery.
Schwann cell tumors
acoustic neuroma = vestibular schwannoma
meningioomas can cause displacement of cranial nerves
Glimoas from brainstem interupting craniala nerves
metastatic neroplasms
know icnreased intracranial pressure will lead to a severe HA
knowledge check: another name for an acoustic neuroma
vestibular schawnoma
know icnreased intracranial pressure will lead to a severe HA – maybe not all the ins and outs here
