Vestibular Disorders Flashcards
Lecture 14
the vestibular system is a somatosensory portion of the nervous system that provides?
awareness of the spatial position of the head and body (proprioception) and conscious awareness of active and passive limb movements and body position
3 components of the vestibular system
1) a peripheral sensory apparatus (inner ear)
2) central vestibular system (structures within the brainstem and cerebellum)
3) a motor output (connections with various motor nuclei and muscles)
the peripheral sensory apparatus is also called
vestibular labyrinth
the peripheral sensory apparatus is housed in the inner ear and consists of two types of motion sensors
three semicircular canals
two otolith organs - utricle / saccule
the semi circular canals are sensors for?
angular or rotational acceleration of the head
- detect movement in three dimensional space
otolith organs - utricle and saccule are sensors for?
Linear acceleration with respect to gravity
the utricle is sensitive to a change in ?
linear movement
sideways or up/down
the saccule gives information about?
vertical acceleration
- in a elevator
information regarding head movement is relayed peripheral to the central vestibular system by ?
vestibular portion of the vestibulocochlear nerve (Cranial nerve VIII)
why do disorders affecting the vestibular labyrinth often affect the cochlea to?
cochlea and vestibular labyrinth share blood supply
vestibular symptoms
dizziness and equilibrium
cochlear symptoms
hearing loss, tinnitus, or both
Central vestibular system receives input from ?
peripheral vestibular mechanism by vestibular division of CN VIII
input from vestibular labyrinth is processed in association with?
Visual sensory and somatosensory input
output from vestibular nuclei influences
eye movement
truncal stability
spatial orientation
motor output of the vestibular system is integrated into three vestibular reflexes
vestibulo ocular reflex (VOR) Gaze stabilizing reflex
vestibulospinal reflex (VSR)
vestibulocollic reflex (VCR)
when the head rotates about any axis (horizontal/vertical) distant visual images are stabilized by
rotating eyes about the same axis but in the opposite direction to stabilize
oscillopsia
disparity between head and eye movement is unstable gaze during head movement
illusion of unstable visual world , objects in visual field oscillate
vestibulospinal reflex (VSR)
stabilizes posture
vestibulocollic reflex
stabilizes head
the three components of the vestibular system work together to ?
Maintain balance by orienting a persons body position and motion in space
lesions in the cerebellum associated with?
nystagmus
gait ataxia
vestibular mechanism damaged, common manifestations are
sense of imbalance
dizziness/vertigo
nystagmus
vertigo is a type of dizziness specific to ?
vestibualr system disorders
self
subjective vertigo
environment
objective vertigo
true vertigo is almost always caused by deficits within the ?
peripheral labyrinth or its connections to the cental vestibular system
vertigo can be
peripheral or central origin
True vertigo it is
associated with an illusory sense of motion or rotation over which individuals have no control
major conditions that produce episodic vertigo include
menieres
reccurrent vestibular neuritis
benign paroxysmal positional vertigo
migraine associated vertigo
SSCD
posttraumatic vertigo - labyrinthine fracture
nystagmus refers to
disturbance of ocular movement characterized by rhythmic oscillations or rapid jerky movements of one or both eyes
what forms basis of detection, nature of nystagmus in response to eye gaze. positional changes, and vestibular stimulation
electronystagmography (VNG) tests
vestibular compensation involves changes in the
central vestibular nuclei that leads to partial restoration of lost neural activity within affected nuclei which reduces the asymmetry and rebalances vestibular activity
symptoms occur with acute unilateral peripheral vestibular injury because of?
asymmetry input between right and left central vestibular nuclei
bilateral peripheral deficits generally
DO NOT show vestibular compensation
central vestibular pathology
DOES NOT show vestibular compensation
what is vestibular labyrinthitis
inflammation of inner ear labyrinth
vestibular neuritis is?
inflammation of vestibular nerve
labyrinthitis and vestibular neuritis often preced by infections
cold/flu/otitis media
measles/mumps
meningititis
what is single most common complication of acute or chronic OME?
serous labyrinthitis
Cochlear symptoms are present in vestibular labyrinthitis or vestibular neuritis?
Vestibular labyrinthitis
Cochlear symptoms of in vestibular labyrinthitis
aural fullness
tinnitus
high frequency SNHL
Vestibular symptoms of vestibular labyrinthitis and neuritits?
actue vertigo
nausa/vommitting
nystagmus
electronystagmography (ENG) or videonystagmography (VNG) results indicate
peripheral vestibular anomalies
treatment of labyrinthitis and vestibular neuritis
antibiotic/antiviral drugs
vestibular suppressant drugs
steroids for HL
labyrinthitis and vestibular neuritis differential diagnosis
otitis media with effusion
perilymphatic fistula
benign paroxysmal positional vertigo - no HL
what is the primary arterial supply to cochlea?
Labyrinthine
vascular occlusion of labyrinthine artery
occlusion causes sudden and profound SNHL and vestibular dysfunction
migraine headaches is
severe, episodic, and disabling neurological condition
migrane charactersized by
unilateral head throbbing
fatigue
auditory/visual inputs
nausea/ vomitting
Migraine associated vertigo should have migraine symptoms in at least
50% of vertigo episodes
Benign paroxysmal Positional Vertigo is
most common cause of vertigo if peripheral origin
benign
not life threatening
Paroxysmal
sudden; brief spells
Positional
triggered by certain head movements or positions
Vertigo
false sense of rotational movement
BBPV etiology
55 average
idiopathic
head trauma
vestibular neurititis
menieres
migrane
diabetes
osteoporosis
Clinical presentation of BBPV
mild intense diziness
getting out of bed, HEAD POSITIONING
worse in morning and evening
what does BBPV involve?
posterior semicircular canal
BBPV takes one of three forms:
1) acute; resolves over 3 months
2) intermittent ; active and inactive
3) Chronic; continous
BBPV pathophysiology
otolith organs contain otoconia or otoliths, sensitive to gravity
otoliths become dislodged and migrate into fluid filled semicircular canals
otoliths move with gravity while fluid in semi circular canals do not, fluid moves when it is normally still
when particles accumulate in canals they interfere with normal fluid movement that canals use to sense head motion
inner ear sends false signals to brain that head is moving, resulting in diziness
BBPV evaluation
audiogram/MRI normal
DIX HALLPIKE TEST
BBPV management
Epley maneuver
surgery in cases to stop vertigo
Menieres Syndrome
idiopathic syndrome characterized by endolymphatic hydrops
Menieres pathophysiology
result of overproduction or under absorption of endolymph
Menieres epidemiology
peak age 30-60
unilateral but can become bi lateral
Menieres clinical presentation
intermittent episodes of vertigo
fluctuating SNHL
tinnitus
aural fullness
what is required for a definitive diagnosis of menieres
- two or more definitive episodes lasting 20 minutes or longer
- a least two of the four characteristic symptoms should be present
acute cases of menieres
vertigo lasts from 2-4 hours but can last up to 12 to 24
- vertigo of long duration with other smyptoms is indicative of menieres
- hearing can return to normal
as menieres progresses,
attacks more frequent
HL does not return to normal
WRS continues to deteriorate
recruitment becomes permanent
menieres disease and hearing loss
acoustic distortion at first, affecting speech understanding
- loudness recruitment
change in hearing that is considered significant is
shift of >15 dB HL for average threshold of 0.5, 1, 2,3 khz
shift in word rec scores of 15to 20% or greater
early state of menieres, audiometric configuration
- low frequency rising SNHL
worse from 250 to 1000 with normal hearing from 2000 and up - flat configuration ; moderate to moderately severe SNHL
W/ bi laterla disease an asymmetery of >25 dB HL reported
Middle stage, audiometric configuration
hearing sensitivity is reduced at all frequencies but worse at high and low frequencies
- reverse cookie bite configuration
Late (burn out stage) audiometric configuration
flat severe sensorineural hearing loss
- peaks at 1000 and 2000
menieres disease immittance
normal tymps
reflexes present at lower sensation levels
diplacusis
same tone presented to both ears sounds different and or distorted in menieres ear
loudness recruitment
abnormal growth of loudness for signals at suprathresholds itensities
-ARTs obtained at lower SL
electrocochleography
test that reflects elevation of inner ear pressure, distention of the basilar membrane of the inner ear
what is considered significant/positive for Menieres disease
> 0.42 0r 42%
menieres management during an acute attack
sedatives and tranquilizers to control vertigo and nausea
long term management of menieres
decreasing the endolymph - low sodium diet
increasing vascualr circulation of the inner ear
Are cochlear implants useful for menieres?
YESSS excellent option
menieres differential diagnosis
acoustic neuroma
labyrinthine viral infections
idiopathic vertigo
perilymphatic fistula
cogan syndrome
Superior Semicircular Canal Dehiscence
sscd creates a third mobile window into the inner ear that alters the normal fluid mechanics of vestibulocochlear system
Etiology of SSCD
developmental anomaly of temporal bone (congenital)
- head trauma such as skull fractures
idiopathic
SSCD signs and symptoms
vestibular symptoms alone or auditory systems alone
both symptoms
no symptoms
SSCD can mimic several auditory and vestibular systems (differential diagnosis)
Patulous (open) eustachian tube
SSCD vestibular symptoms can be evoked by loud noises or maneuvers that change middle ear intracranial pressure
S/S caused by excessive movement of perilymph
- vertigo/diziness
- nystagmus
- tullios phenomenon
- Oscillopsia
Conductive and/or fluctuating HL can occur with SSCD mimicking
otosclerosis or menieres
for SSCD patients show what kind of audiometric configuration 70%
low frequency air bone gap (worse at 250 through 1000 hz)
what is an important test for differential diagnosis of otosclerosis and SSCD
ARTS
otoslcerosis is abnormal SSCD
SSCD ARTS remain normal
diagnosis of SSCD
vestibular treatment
high resolution temporal bone CT scans
EcochG
Treatment of SSCD
mild to moderate
conservative treatment for mild to moderate symptoms
- ear plugs to avoid loud sounds
Treatment of SSCD
debilitating symptoms
surgical repair with bony cement or soft tissue plugging
Mal de debarquement
illusion of movement felt after long travel on water by boat
sickness of disembarkment
Etiology of mal de debarquement
middle aged women
symptoms of mal de debarquement
rocking, swaying, and disequilibrium after return to land
anxiety and depression
worse in enclosed spaces when motion less
Diagnosis of mal de debarquement
no specific tests
subjective history
objective diagnostic such as vestibular testing and radiologic imaging
Treatment of mal de devarquement
no treatment
standard drugs for motion sicknees
vestibular rehabilitation
vestibular dysfunction in children is often accompanied by
hearing loss
genetic conditions with HL that affect vestibular system
CHARGE
EVA
BOR
Bilateral waardenburg
Usher
if a child has a hearing loss of >60 dB HL and has not walked by 14.5 months
suspect vestibular dysfunction
