File

VESTIBULAR DISORDERS
Joannalyn B. Juego
ANATOMY:
Peripheral Vestibular System
• Stabilizing the visual images on the fovea of
the retina during head movements to allow
clear vision
• Maintaining postural stability
• Providing information used for spatial
orientation
ANATOMY:
Peripheral Vestibular System
• Semicircular canals
• Otolith organs
• Central vestibular system
Vestibular System Dysfunction
• Peripheral
Pathology
• Central Nervous
System Pathology
Peripheral Pathology: Mechanical
• BPPV
– Most common cause of vertigo
– A biomechanical disorder
– Nystagmus & vertigo without change in head
position; nausea with or without vomiting; &
dysequilibrium
– Latency to onset of the vertigo & nystagmus
occurs within 15 seconds once the head is in the
provoking position; the duration is less than 60
seconds
Cupulolithiasis
• Fragments of the otoconia break away &
adhere to the cupula of one of the SCCs
• When the head is moved into certain
positions, the weighted cupula is deflected by
the pull of gravity
• The abnormal signal results in vertigo &
nystagmus, which persists as long as the
patient is in the provoking position
Canalithiasis
• Otoconia are freely floating in one of the SCCs
• When a patient changes head position, the
pull of gravity causes the freely floating
otoconia to move inside the SCC resulting in
endolymph movement & deflection of the
cupula
Peripheral Pathology:
Decreased Receptor Input
• UVH
– Viral insults, trauma, & vascular events
– Vertigo, spontaneous nystagmus, oscillopsia
during head movements, postural instability, &
dysequilibrium
– Resolves within 3-7 days assuming the patient is
exposed to common daylight conditions
Peripheral Pathology:
Decreased Receptor Input
• BVH
– Ototoxicity
– Meningitis, autoimmune DO, head trauma,
tumors on the 8th CN, transient ischemic episodes
of vessels supplying the vestibular system, &
sequential unilateral vestibular neuronitis
– Dysequilibrium, oscillopsia, & gait ataxia
Central Nervous System Pathology
• Cerebrovascular insults involving the AICA,
PICA, & vertebral artery
• Vertebrobasilar insufficiency (VBI)
• TBI due to labyrinthine or skull fractures
• Demyelinating diseases such as MS affecting
CN VIII
CENTRAL VESTIBULAR
PATHOLOGY
PERIPHERAL VESTIBULAR
PATHOLOGY
Ataxia often severe
Ataxia mild
Abnormal smooth pursuit & abnormal
saccadic eye movement tests
Smooth pursuit & saccades usually
normal; positional testing may reproduce
nystagmus
Sx usually do not include hearing loss; if
so, it is often sudden & permanent
Sx may include hearing loss (insidious –
may recover), fullness in ears, tinnitus
Sx might include diplopia, altered
conscious, lateropulsion
Sx of acute vertigo not usually suppressed Sx of acute vertigo usually suppressed by
by visual fixation
visual fixation
Sx of acute vertigo usually intense (more
than central vestibular pathology)
Pendular nystagmus (eyes oscillate at
equal speeds)
Nystagmus will incorporate slow & fast
phases (jerk nystagmus)
Pure persistent vertical nystagmus persists Spontaneous horizontal nystagmus
regardless of positional testing
usually resolves within 7 days in a patient
with UVH
PHYSICAL THERAPY EXAMINATION
• History & Systems Review
– Identification of symptoms
– Duration & circumstances of symptoms
Identification of Symptoms
• Dizziness
– Vaguely defined as the sensation of whirling or
feeling a tendency to fall
– Patients should be directed away from using the
word & to use more precise terms
– Vertigo, lightheadedness, dysequilibrium,
oscillopsia
Vertigo
• Illusion of movement
• Episodic
• Indicates pathology at one or more locations
along the vestibular pathways
– Acute stage of UVH
– Displaced otoconia (BPPV)
– Acute unilateral brainstem lesion
Lightheadedness
• Feeling that fainting is about to occur
• Causes
– Orthostatic hypotension
– Hypoglycemia
– Anxiety
– Panic disorder
Dysequilibrium
• Sensation of being off balance
• Causes
– BVH
– Chronic unilateral vestibular hypofunction
– Lower extremity somatosensation loss
– Upper brainstem/vestibular cortex lesion
– Cerebellar & motor pathway lesions
Oscillopsia
• Subjective experience of motion of objects in
the visual environment that are known to be
stationary
• Occur with head movements in patients with
vestibular hypofunction since the vestibular
system is not generating an adequate
compensatory eye velocity during the head
motion
Duration & Circumstances of
Symptoms
• How recent the attacks happened
• Whether the symptom is constant or episodic
– Episodic: average duration of the episodes
– Seconds to minutes – BPPV
– Minutes to hours – Meniere’s disease
– Days – vestibular neuronitis or migraineassociated dizziness
Duration & Circumstances of
Symptoms
• Whether the patient experiences symptoms
with particular movements, positions, or at
rest
– Is the patient sensitive to motion as the passenger
in a moving car?
– Does the patient experience a vigorous vertigo
when the head is moved into certain positions?
Tests & Measures
• Visual Analogue Scale
• Dizziness Handicap Inventory
• Functional Disability Scale
– Vestibular Rehabilitation Benefit Questionnaire
• Motion Sensitivity Quotient
• Examination of Eye Movements
Observation for Nystagmus
• Nystagmus is the primary indicator used in
identifying most peripheral & central
vestibular lesions
• The direction of the nystagmus is named by
the direction of the fast component
– Left beating nsytagmus: eyes move slowly to the
right & the resetting eye movement is to the left
Head Impulse Test (Examination of the
VOR at High Acceleration)
• Widely accepted clinical tool used to examine
semicircular canal function
• Patient first fixates on a near target
• When testing the horizontal SCC, the head is
flexed to 30 deg
Head Impulse Test (Examination of the
VOR at High Acceleration)
• Patient is asked to keep their eyes focused on
a target while his head is manually rotated in
an unpredictable direction using a
– Small amplitude (5 – 15 deg),
– Moderate velocity (~200 deg/sec), and
– High-acceleration (3,000 – 4,000/sec) angular
impulse
Head Impulse Test (Examination of the
VOR at High Acceleration)
• Normal
– Eyes will move in the direction opposite to the
head movement & gaze will remain on the target
• With a loss of vestibular function
– The VOR will not move the eyes as quickly as the
head rotation & the eyes will move off the target
– The patient will then make a corrective saccade to
reposition the eyes on the target
– Corrective saccade: rapid eye movement used to
reposition the eyes to the target of interest
Head Impulse Test (Examination of the
VOR at High Acceleration)
• Unilateral peripheral lesion or pathology of
the central vestibular neurons
– Patient will not be able to maintain gaze when the
head is rotated quickly toward the side of the
lesion
• Bilateral loss of vestibular function
– Patient will make corrective saccades after a head
impulse to either side
Head-Shaking Induced
Nystagmus Test (HSN)
• Useful aid in the diagnosis of a unilateral
peripheral vestibular defect
• Patient is instructed to close his eyes
• Clinician flexes the head 30 deg before
oscillating horizontally for 20 cycles at a
frequency of 2 repetitions per second
• On stopping the oscillation, the patient opens
the eyes & the clinician checks for nystagmus
Head-Shaking Induced
Nystagmus Test (HSN)
• Normal
– Nystagmus will not be present
• Presence of asymmetry between the peripheral
vestibular inputs to central vestibular nuclei
– May result in HSN
• UVH
– Horizontal HSN
– Quick phases of the nystagmus directed toward the
healthy ear & the slow phases directed toward the
lesioned ear
Positional Testing
• Commonly used to identify whether otoconia
have been displaced into the SCC, causing a
condition referred to as Benign Paroxysmal
Positional Vertigo (BPPV)
• Dix-Hallpike Test
– Patient is moved from a long-sitting position with
the head rotated 45 deg to one side, to a supine
position with the head extended to 30 deg beyond
horizontal, head still rotated to 45 deg
– Observe the eyes for nystagmus
Positional Testing
• Dix-Hallpike Test Side-lying
– Patient sits on the edge of the examination table
– Clinician turns the head horizontally 45 deg
– Patient is quickly brought down to the side
opposite the head rotation
– Examiner checks for nystagmus & vertigo, & then
slowly brings the patient to the starting position
– The other side is then tested
Positional Testing
• Roll test
– If horizontal SCC BPPV is suspected
– Patient is positioned supine with the head flexed
20 deg
– Rapid rotations to the sides are done separately &
the clinician observes for nystagmus & vertigo
Dynamic Visual Acuity (DVA) Test
• Measurement of visual acuity during
horizontal motion of the head
• Static visual acuity is first determined
– Patient is asked to “Read the lowest line you can
see” on a wall-mounted acuity chart
– Lighthouse ETDRS (Early Treatment Diabetic
Retinopathy Study) wall charts are recommended
• Patient then attempts to read the chart while
the clinician horizontally oscillates the
patient’s head at a frequency of 2Hz
Dynamic Visual Acuity (DVA) Test
• Normal
– Head movement results in little or no change of visual
acuity compared with the head still (less than 1 line
difference)
• Loss of vestibular function
– Eyes will not be stable in space during head
movements
– Decrement in DVA compared with visual acuity when
the head is still
– A 3-line or more decrement in visual acuity during
head movement is suggestive of vestibular
hypofunction
Examination of Gait & Balance
TEST
BPPV
UVH
Romberg
(-)
Tandem
Romberg
(-)
(+), eyes
closed
Singlelegged
stance
(-)
May be (+)
BVH
Acute: (+) Acute: (+)
Chronic: (-) Chronic: (-)
(+)
CENTRAL
LESION
Often (-)
(+)
Acute: (+)
May be
Chronic: (-) unable to
perform
TEST
BPPV
UVH
BVH
CENTRAL
LESION
Gait
Normal
Acute: widebased,
decreased arm
swing, &
rotation
Compensated:
(N)
Acute: wideMay have
based,
pronounced
decreased arm ataxia
swing, &
rotation
Compensated:
mild gait
deviation
Turn head
while walking
May produce
slight
unsteadiness
Acute: may
May not keep May not keep
not keep
balance or
balance,
balance
slows cadence increased
Compensated:
ataxia
(N)
Vestibular Function Tests:
Semicircular Canal Tests
• Electronystamography (ENG) &
Videonystamography (VNG)
– Oculomotor & inner ear function
• Rotational chair test
– Rotating subjects in the dark
– Standard test for bilateral vestibular dysfunction
Vestibular Function Tests:
Otolith Tests
• Vestibular-evoked myogenic potential (VEMP)
– Cervical VEMP
– Ocular VEMP
INTERVENTIONS
Benign Paroxysmal Positional Vertigo
• The otoconia will be returned into the
vestibule
• The patient will demonstrate reduced vertigo
associated with head motion
• The patient will demonstrate improved
balance
• The patient will demonstrate independence in
ADLs
Benign Paroxysmal Positional Vertigo
• Canalith repositioning maneuver (CRM)
– BPPV due to canalithiasis, posterior SCC
canalithiasis is the most common
• Liberatory (Semont) maneuver
– BPPV due to cupulolithiasis, posterior SCC
cupulolithiasis is the most common
• Brandt-Daroff exercises
– Persistent/residual or mild vertigo (even after
CRM); for the patient who may not tolerate CRM
Unilateral Vestibular Hypofunction
• The patient will demonstrate improved
stability of gaze during head movement
• The patient will demonstrate diminished
sensitivity to motion
• The patient will demonstrate improved static
& dynamic postural stability
• The patient will be independent in proper
performance of a HEP that includes walking
Unilateral Vestibular Hypofunction
• Gaze Stability Exercises
– Improve the VOR & other systems that are used to
assist gaze stability with head motion
– Designed to expose patients to retinal slip
Retinal Slip
• Occurs when the image of an object moves off the
fovea of the retina, resulting in visual blurring
• Necessary as this is the signal used to drive vestibular
adaptation within the brain
• Because the brain can tolerate small amounts of
retinal slip yet see a target clearly, the patient must
try to keep the target in focus
• Otherwise, head motion that is too rapid will result
in excessive retinal slip
Primary Paradigms of
Vestibular Adaptation
• x1 exercises
– Patient is asked to move the head horizontally as
quickly as possible while maintaining focus on a
stable target
– Patient must learn how to slow the head
movement if the target becomes blurred
– Starting target distance should be an arm’s length
away
Primary Paradigms of
Vestibular Adaptation
• x2 exercises
– Requires the patient to move the head & the
target in opposite directions
Postural Stability Exercises
• Stand with feet shoulder-width apart, arms
across the chest
– Progress to: Bring feet closer together. Close eyes.
Stand on a sofa cushion or foam.
• Practice ankle sways: medial-lateral & anteriorposterior
– Progress to: Doing circle sways. Close eyes.
• Attempt to walk with heel touching toe on firm
surface
– Progress to: Do the same exercise on carpet.
Postural Stability Exercises
• Practice walking 5 steps & turning 180 deg
(left & right)
– Progress to: Making smaller turns. Close eyes.
• Walk & move the head side to side, up &
down
– Progress to: Counting backward from 100 by
threes
Habituation Exercises
• Warranted when a patient with UVH has
continual complaints of dizziness
• Habituation: reduction in response to a
repeatedly performed movement
Habituation Exercises
• PT must determine the provoking positions first
• When a position elicits a mild to moderate
dizziness, the patient remains in the provoking
position for 30 seconds or until the symptoms
abate, whichever comes first
• The patient is provided with a HEP based on the
results of the positional test
• The provoking exercises are performed 3-5 times
each, 2-3 times a day
Habituation Exercises
• Patient keeps an activity diary to monitor
response to training
• The exercises are designed to reproduce the
dizziness & the patient should be encouraged
that the sxs normally decrease within 2 weeks
• If other 2 weeks the sxs are no better, the
habituation exercises should be first changed
Bilateral Vestibular Hypofunction
• The patient will demonstrate improved stability
of gaze during movement
• The patient will demonstrate reduced subjective
complaints of gaze instability
• The patient will demonstrate improved static &
dynamic balance
• The patient will be independent in proper
performance of HEP that includes walking
• The patient will demonstrate enhanced decisionmaking skills regarding performance of ADLs
Bilateral Vestibular Hypofunction
• Gaze stability exercises similar to the x1
paradigm
• Balance exercises
• Walking program
• Patient education is high priority
– 2 years may be necessary to ensure as complete a
recovery as possible
• Pool therapy
• Tai Chi
Abnormal Central Vestibular Function
• The patient will demonstrate enhanced decision
making skill regarding fall prevention strategies &
necessary safety precautions to allow safe
functioning within the home & the community
• The patient will demonstrate enhanced decision
making skills regarding use of compensatory
strategies to assist in gaze stability
• The patient will be independent in performance
of an HEP that includes walking
Abnormal Central Vestibular Function
• Patient education
– Time to recover will be 6 months or more, & may
be incomplete
• Habituation exercises
• Gait & balance exercises designed to
incorporate somatosensory, visual, &
vestibular contributions
Diagnoses Involving the
Vestibular System
•
•
•
•
•
•
•
•
Meniere’s Disease
Perilymphatic Fistula
Vestibular Schwannoma
Motion Sickness
Migraine-Related Dizziness
Multiple Sclerosis
Multiple System Atrophy
Cervicogenic Dizziness