vestibular function test and its clinical examination

VESTIBULAR FUNCTION TESTS AND ITS CLINICAL EXAMINATION

By: Khushali JoganiThe Sarvajanik College Of PhysiotherapyRampura,Surat

CONTENTS Introduction Anatomy Physiology Examination -History -scales -physical examination -Bedside testing and

manuevers -Laboratory testing References

INTRODUCTION Incidence of dizziness is 5.5 percent or

greater than 15 million people per year in united states

It increases as age increases Cawthorne and Cookey were the first one

to introduce exercises for dizziness Accurate diagnosis –minimization of

functional limitation-prevention of disability Mostly peripheral vestibular system is the

origin for patients signs and symptoms

Function of peripheral vestibular system -stabilization of visual images on the

fovea of retina during head movement to allow clear vision

-maintaining postural stability, especially during movement of head

-providing information used for spatial orientation

ANATOMY

PHYSIOLOGY Important for understanding the

signs and symptoms Principles are: -tonic firing rate -Vestibular reflexes -push-pull mechansim -inhibitory cut off -velocity storage system

1. Tonic firing rate resting firing rate is 70 to 100 spikes/s increase tonic firing rate means each

vestibular system detects head motion through excitation or inhibition

2. Vestibular reflexes vestibulospinal reflex ( it helps to

maination centre of gravity) vestibulocollic reflex(it helps to

maintain stability of head during movement of torso)

(VOR) vestibular ocular reflex( it helps in maintaining stability of an image on the fovea of retina during rapid head movements)

-pathway can be describes as three neuron arc

-horizontal head rotation about the vertical Z-axis (yaw)

- head extension or flexion about the horizontal Y-axis(pitch)

-lateral head tilt about the horizontal X-axis (roll)

VOR gain eye velocity/head velocity= -1 VOR phase described as zero phase shift VOR operates at head velocities as great

as 350 to 400 degree/s

3. Push pull mechanism

Faulty interpretation will lead to difficulty in gaze stabilization,postural stability and motion perception.

4. Inhibitory cut off5. Velocity storage system

EXAMINATIONHISTORY It can be divided into:- -elements that help with diagnosis -elements that lead to goals for

management including physical therapy

Elements that help with diagnosis are : -tempo -symptoms 1.vertigo 2.dysequilibrium 3.oscillopsia 4.light headedness 5.rocking or swaying 6.motion sickness 7. nausea and vomiting -circumstances -how it affects the patients life -medications

Elements that lead to goals for management, including physical therapy

-obtaining patient subjective complaints

-Using VAS (visual analogue scale ) to quantify the intensity of specific symptoms

-impact on functional activities using MULTIDIMENSIONAL DIZZINESS INVENTORY

-perceived disability

-fall history -where, when, what was thinking about - frequency of falls, any injuries

associated with that -confidence in balance using ABC

scale(Activities Specific Balance Confidence Scale)

-interference with daily activities-interference with recovery -PANAS scale( Positive Affect Negative

Affect Scale) if anxiety or depression is affecting

-Dizziness Handicap Inventory

-Motion Sensitivity Quotient

PHYSICAL EXAMINATION - what is nystagmus -observation for nystagmus tools used are 1. frenzel lenses 2.infrared camera

system 3.opthalmoscope 4.ganzfeld -skew eye deviation -problems with VOR -static imbalance -dynamic imbalance

BED SIDE TESTING

Head Thrust test Head Shaking Nystagmus

Test Clinical Vestibular Dynamic

Visual acuity Test

1.Head Thrust Test - used to examine semicircular canal

function - it can give indication for complete

loss of function in affected labyrinth -less sensitive in detecting

hypofunction in patients with incomplete loss of function

2.Head Shaking Induced Nystagmus Test

-useful in diagnosis of unilateral peripheral vestibular defect.

3. Dynamic Visual Acuity Test -it is measurement of visual acuity

during horizontal motion of head

Maneuver –Induced vertigo and eye movements

if mechanical problem (BPPV) dan certain manuevers should be performed that evoke nystagmus

1. positional testing( Hallpike-Dix test)

Hallpike –dix test

Roll Test for Horizontal Semicircular Canal

Visual tracking -smooth pursuit eye movement -cancellation of vestibulo ocular reflex -saccadic eye movement

Stance and gait examination

-Romberg test -Sharpened romberg (heel to toe tandem

stance) test -Fukuda’s Stepping test -Retropulsion test

LABORATORY TESTS Electronystagmography(ENG) or

Videonystagmography (VNG) Caloric Testing Rotatory Chair Testing Quantified Dynamic Visual Acuity Subjective Visual Vertical Computerised Dynamic Posturography Vestibular Evoked Myogenic Potential

Test(VEMP)

Electronystagmography

Caloric Testing

Rotatory Chair Testing

Quantified Dynamic Visual Acuity Test

Computerised Dynamic Posturography

REFERNCES Physical Rehabilitation By Susan B O’ Sullivan(fifth edition) Vestibular Rehabiliation By Susan J. Herdman( third edition) Rehabiliation Medicine :Principles

and Practice By Joel A Delisa and Bruce M.

Gans(third edition)

General vestibualr testing By T. Brandt, M.

Strupp/ClinicalNeurophysiology American physical therapy association By Barbara Susan Robinson

THANK YOU