VESTIBULAR DISORDERS Joannalyn B. Juego
VESTIBULAR DISORDERSJoannalyn 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 by visual fixation
Sx of acute vertigo usually suppressed by visual fixationSx 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 regardless of positional testing
Spontaneous horizontal nystagmus 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 migraine-
associated 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 & BalanceTEST BPPV UVH BVH CENTRAL
LESION
Romberg (-) Acute: (+)Chronic: (-)
Acute: (+)Chronic: (-)
Often (-)
Tandem Romberg
(-) (+), eyes closed
(+) (+)
Single-legged stance
(-) May be (+) Acute: (+)Chronic: (-)
May be unable to perform
TEST BPPV UVH BVH CENTRAL LESION
Gait Normal Acute: wide-based, decreased arm swing, & rotationCompensated: (N)
Acute: wide-based, decreased arm swing, & rotationCompensated: mild gait deviation
May have pronounced ataxia
Turn head while walking
May produce slight unsteadiness
Acute: may not keep balanceCompensated: (N)
May not keep balance or slows cadence
May not keep balance, increased ataxia
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 & anterior-
posterior– 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 decision-making 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