Vestibular Issues in PT

Vestibular DisordersAnd dizzy 'tis to cast one's eyes …

William Shakespeare

Review Of FunctionProvides information concerning gravity, rotation,

and acceleration.

Serves as a reference for the somatosensory and visual systems

Contributes to integration of arousal, conscious awareness of the body via connections with vestibular cortex, thalmus, and reticular formation

Allows for:Gaze & postural stabilitySense of orientationDirection of linear & angular acceleration

04/11/23Robert Niemeier, DPT

Review Of AnatomyPeripheral Sensory Apparatus

Detects and relays information about head angular and linear velocity to central processing system

Orients the head with respect to gravity

Central Processing SystemProcesses information in conjunction with other

sensory inputs for position and movement of head in space

Motor Output SystemGenerates compensatory eye movements and

compensatory body movements during head and postural adjustments


Membranous Labyrinth

Normal Membranous Labyrinth

Semicircular canalsOtolith Organs

Utricle – detects linear acceleration and head tilts in the horizontal plane

Saccule - detects linear acceleration and head tilts in the vertical plane


Semicicular Canals

Spatial arrangement of the 6 semicircular canals cause 3 coplanar pairings R and L Lateral L anterior and R

posterior, L posterior and R anterior

R and L Horizontal

•Detects angular acceleration

•Advantages: •Common mode rejection/noise

•Sensory redundancy

•Assist in compensation for sensor overload


OtolithsHair Cells

Sensory structures for peripheral end organs

Affect firing rate of primary vestibular afferent to brainstem

Striola Otoconia arranged in

narrow trenches Allows otoliths to have

multidirectional sensitivity

•Utricle and Saccule

•Otolith sensory structures•Maculae

•Otolithic membrane

•Otoconia

•Movement of gel membrane and otoconia cause a shearing

action


Principles of the Vestibular System

Tonic Firing Rate

Vestibular Ocular Reflex

Push-Pull Mechanism

Inhibitory Cutoff

Velocity Storage System


Tonic Firing RateVestibular nerve and vestibular nuclei have a

normal resting firing rate

Baseline firing rate present without head movement

Tonic firing equal in both sides if not results in vertigo, tilt, impulsion, and spinning

Excitation and inhibition occur from stimulation of hair cells


Vestibular-Ocular Reflex (VOR)

Eyes move in opposite direction to head movement

Speed of eye movement equals that of head movement

Allows objects to remain in focus during head movements


Compensatory Eye Movements

Vestibular-Ocular Reflex

Optokinetic Reflex - allows the eye to follow objects in motion when the head remains stationary

Smooth Pursuit Reflex - allows the eye to closely follow a moving object

Neck reflexes - reflex movement of the limbs that bring the body into the normal position in relation to the head

Combine to stabilize object on the same area of the retina = visual stability 04/11/23Robert Niemeier, DPT

VOR DysfunctionDirection of gaze will shift with head movements

Causes degradation of visual image

Visual world will move with each head movement


OscillopsiaVisual illusion of oscillating movement of

stationary objects

Can arise with lesions of peripheral or central vestibular systems

Indicative of diminished VOR gain (maintained fixation, dynamic visual acuity)Motion of images on fovea (fovea (or fovea

centralis) denotes the pit in the retina which allows for maximum acuity of vision.)

Diminished visual acuity


CerebellumMonitors vestibular performance

Readjusts central vestibular processing of static and dynamic postural activity

Modulates VOR

Provides inhibitory drive of VOR


Vestibulospinal Reflex (VSR)

Generates compensatory body movement to maintain head and postural stability

Helps prevents falls!


DemographicsVestibular disorders manifested by vertigo are

secondary only to low back pain

NIH study estimates that 40% of population over 40 experience a dizziness disorder during lifetime


Fall Demographics•Fall experienced in community dwelling individuals

•28 to 35 % over age 65

•42 – 49% over age 75

•Greater than 60% will have bilateral vestibular lesion (BVL) in the 65 to 75 year age range


Fall Risk Factors4 or more risk factors? 78% risk of fall in older adult

Sedatives

Cognitive impairment

Palmomental reflex - The thenar eminence is stroked briskly with a thin stick, from proximal (edge of wrist) to distal (base of thumb) using moderate pressure. A positive response is considered if there is a single visible twitch of the ipsilateral mentalis muscle (chin muscle on the same side as the hand tested)

Lower extremity disability

Dizziness

Increased dependence on visual cues

Fear of falling

Orthostatic hypotension

Balance abnormalities

Foot problems


http://en.wikipedia.org/wiki/Thenar_eminence

http://en.wikipedia.org/wiki/Mentalis_muscle

Aging ChangesProgressive changes begin at age 40

Decreased number of hair cellsDecreased vestibular nerve fibers

Lead to dizziness and vertigo

Harder to deal with competing visual and somatosensory input


Vestibular Pathophysiology

Disorders of tone and or gain (vertigo / movement produced vertigo)

Vestibular nerve / nuclei give abnormal sensory information

Tone automatically recovers in a few days, doesn’t need visual input

Compensation for reduced gain depends on visual images, takes months to years to complete

Nystagmus transient sign of vestibular lesion

Movement induced symptoms can be chronic


Dizzy Patient Presentation Medical referral

Constant vertigo Lateropulsion - An involuntary movement of the body or

turning of the gait toward one side; seen principally with unilateral infarction of a cerebellar hemisphere or lateral medulla.

Facial asymmetry Speech & /or swallowing difficulties Oculomotor dysfunction - when one or both eyes do not

move smoothly, accurately, and quickly across a line or from one word to another

Vertical Nystagmus Severe headaches Recurrent Falls Unilateral hearing loss, tinnitus, fullness or ear pain


Vertigo

Vertigo - Hitchcock’s Finest

•An asymmetrical firing of the two vestibular systems

•Gives an illusion of spinning, movement


Peripheral or Central Vertigo?

Peripheral

Severe Nausea

Mild Imbalance

Common Hearing Loss

Mild Oscillopsia

Rare Neurologic Symptoms

Rapid Compensation

Central

Moderate Nausea

Severe Imbalance

Rare Hearing Loss

Severe Oscillopsia

Common Neurologic Symptoms

Slow Compensation


Peripheral Vestibular Disorders

Vestibular Neuronitis - a paroxysmal, single attack of vertigo, a series of attacks, or a persistent condition which diminishes over three to six weeks.

Labyrinthitis - an ear disorder that involves irritation and swelling of the inner ear

Meniere’s - episodes of vertigo and tinnitus and progressive hearing loss, usually in one ear

Acoustic Neuroma

Fistula - abnormal connection or passageway between two epithelium-lined organs

Benign Paroxysmal Positional Vertigo (BPPV)


Central Vestibular Disorders

Vascular Wallenberg’s Syndrome – Results in nystagmus and

vertigo, which may result in falling, caused from involvement of the region of Deiters’ nucleusand other vestibular nuclei. Onset is usually acute with severe vertigo

Head Injury Cerebellar Infarct

Postconcussive Syndrome

Demyelinating Disease

Congenital


Degenerative Cerebellar Disease

Abnormal Ocular Pursuit

Gradual Decline

Irregular Saccades

Gaze end point nystagmus

Ataxia


Clinical Exam Objectives Establish location and severity of lesion (Central or

Peripheral)

Examination History (hearing status) Cranial Nerves Vestibular

Spontaneous Nystagmus (Imbalance in Tone) Postural Instability (Abnormal tone and gain, proprioceptive

loss) VOR gain (maintained fixation, dynamic visual acuity) Head shaking (Compensated UVL; not necessarily PVL)

Pressure Sensitivity (Fistula) Position nystagmus (Halpike – Dix Maneuver) Hyperventilation (Anxiety, acoustic neuroma)


Nystagmus

Rapid alternating movement of eyes in response to continued rotation of the body

Primary diagnostic indicator in identifying vestibular lesions

Physiologic Nystagmus Vestibular, visual,

extreme lateral gaze

Pathologic nystagmus Spontaneous, positional,

gaze evoked

Labeled by direction of fast component


Hallpike-Dix Maneuver

Gold standard used to check for benign paroxysmal positional vertigo (BPPV)

Nystagmus induced by this test we can determine SSC Dysfunction and assess a response to treatment


Benign Paroxysmal Positional Vertigo (BPPV)

Signs & Symptoms Sudden, severe attacks of

vertigo precipitated by certain head positions and movements

Lightheadedness; nausea Anxiety Avoids Movement Direction and duration of

nystagmus differentiates between BPPV and Central Vestibular Lesion (CVL)

Five Criteria in Diagnosis Torsional/linear-rotary

nystagmus; reproduced by provocative positioning with affected ear down

Nystagmus of 1-5 sec latency

Nystagmus of brief duration (r-30 sec)

Reversal of nystagmus direction on returning to upright position

Response diminishes with repetition of maneuver (Fatigability) i.e. Hallpike-Dix Maneuver


BPPV Cupulolithiasis

Debris, probably form fragments of otoconia from the utricle, adhere to the cupula

TreatmentBrandt-Daroff - Habituation ExercisesSemont - Liberatory Maneuver


BPPVCanalithiasis

Debris floating freely in the endolymph in the long arm of posterior SSC

TreatmentCanalith Reposition Maneuver (Epley)84 – 90% remission rate


Vestibular Loss

Balance and Gait Deficits

Head movement-induced dizziness

Head movement-induced visual blurring (Oscillopsia)

LE dressing difficulty

Driving deficits

Disability related to work, social and leisure activities


Systems Approach to Exam

Examination of balance and mobility using a variety of tests & measurements to document functional abilities, determine underlying sensory, motor, and cognitive impairments that contribute to functional disabilities


BalanceViewed as a motor skill that emerges from

interaction of multiple systems

Systems are organized to meet functional task goals and are constrained by type of environment

Balance – like any skill, can improve with practice


Balance Components

Steadiness

Symmetry

Dynamic stability


Balance TrainingPostural symmetry and dynamic stability have

been consistently improved by training using force platform systems.

Can be as simple as Wii Balance Games


Clinical Test of Sensory Interaction in Balance (CTSIB)

Assesses pattern of sensory dependence for balance from timed stance tests during distortion of sensory environment


Berg Balance ScalePerformance oriented balance assessment

Interpretation:Greater than 45/56 score high specific (96%) for

nonfallersSubjects who fell most frequently were those

closer to cut offCorrelates with other balance tests.


Therapeutic Intervention Objectives

Changing impairments

Improving functional performance

Improving capacity to adapt performance to changing task and environmental demands


Mechanism of Recovery: Compensation

Results from changes in CNSRebalancing of tonic activity within vestibular

nuclei (Spontaneous Recovery)Recovery of VOR (Vestibular Adaptation)Habituation (Progressive decline in response to

same stimulus)Alternative strategies/substitution; in complete

loss of vestibular function

Enhanced by active movements and processing of visual, vestibular, and somatosensory stimuli


Result of Early Intervention

Functions are quicker to return

Increased Function

Decreased Gait Ataxia

Decreased perception of disequilibrium


Vestibular Exercise Program: Objectives

Complement CNS natural compensationDiminish Dizziness & VertigoEnhance gaze stabilizationEnhance postural stability in static and dynamic

situations

Increase overall functional activities

Patient educationNature of pathologyEpisodic nature, prognosisControl of exacerbations


Vestibular Program Components

Gaze stabilization exercises to retrain VOR function

Balance retraining to retrain VSR Function

Conditioning exercises to increase fitness level

Habituation of canal repositioning maneuvers as indicated, e.g. Epley, Semont, Brandt-Daroff, etc


Unilateral Vestibular Lesion (UVL)

Adaptation is stimulated by producing an error signal; work at limit of abilities

Incorporation of head movements and visual input

Provide context specific stimulation to promote adaptation

Adaptation is positively affected by voluntary muscle control


Benign Paroxysmal Positional Vertigo(BPPV)

Benign Paroxysmal Positional Vertigo (BPPV) dizziness is thought to be due to debris which has collected within a part of the inner ear. This debris can be thought of as "ear rocks", although the formal name is "otoconia". Ear rocks are small crystals of calcium carbonate derived from a structure in the ear called the "utricle" (figure1 ). While the saccule also contains otoconia, they are not able to migrate into the canal system. The utricle may have been damaged by head injury, infection, or other disorder of the inner ear, or may have degenerated because of advanced age.


Bilateral Vestibular Disease(BVL)

Bilateral peripheral vestibular disease with complete loss of function is characterized by symmetrical ataxia and loss of balance of either side, with strength preserved. Postural asymmetry is not present. A characteristic "side-to-side" head movement often accompanies these signs. Abnormal nystagmus is not observed, and with bilateral destruction of the receptor organs, normal vestibular nystagmus cannot be elicited by head movement or caloric testing.


Central Vestibular Disease Any signs of brain stem disease in association with

vestibular signs indicate that central involvement is present. The most frequent differentiating feature is a deficit in postural reactions, as central vestibular lesions most often result in paresis or loss of conscious proprioception. Alterations in mental status, or deficits in Vth or VIIth cranial nerves, also may be indicative of central disease. Nystagmus may be a key to differentiating central from peripheral disease. Nystagmus occurs in most central vestibular syndromes, and appears to be a permanent deficit. It is a positional nystagmus; therefore it may be present in some head positions (with respect to gravity), but not in others. Also the nystagmus may vary in direction with change in head position. Vertical nystagmus in any head position is most consistent with central vestibular disease.


Vestibular Function Recovery Rates

UVL: 6-8 weeks

BPPV: remission in one/few treatments

BVL: 6 months – 2 years

CNS Lesion: 6 months – 2 years


PrescriptionIndividualized vestibular rehabilitation program

Outpatient, 1-2 times/week for 4-6 weeksHEP, 5 minutes, 3 x / dayWalking program (Health & Fitness prescription)Exercise graduated for possible increase of

symptoms during first week


Date post:	07-May-2015
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Vestibular Issues in PT

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