subjective tests for vestibular dysfunction how to cite this article: lalsa shilpa p, subjective...

Subjective Tests for Vestibular Dysfunction

Glob J Otolaryngol 5(3): GJO.MS.ID.555664 (2017) 001

Basic Advantagesa) Well established - criteria for diagnostic testing

b) Insights into site of lesion

c) Alerts the examiner

d) Highspecificity

Basic Disadvantagesa) Require New and improvised versions of test

b) Not well supported for diagnosing

c) Lowsensitivity

d) Requiresobjectiveteststosupportfindings

Subjective Visual Vertical testGivenBy-BohmerA,RickenmannJ[1].

SVVisanestimationtechniquewherebyasubjectadjustsavisibleluminescentline,whileseatedincompletedarkness,towhattheyconsidertobeuprightortruevertical.

PrincipleSVVorSVHasmeasuredintheuprightpositionisinfluenced

bytheutricles,sacculesandhorizontalsemicircularcanals.

Purposea) To assess utricular function

b) central connections, including superior vestibularnerve.

c) To assess the degree of ocular torsion

Procedurea) Subjectismadetositinadarkroom.

b) Individual is asked to align a luminous bar with aposition that the individual judges to be vertical

c) 10 trials are given before the mean and standarddeviationsoftheoffsetfromtrueverticalaredetermined.

ResultsA. Normal: 2 degrees tilt is considered to be able to set

theSVVcorrectlywhenthelightbarhasaninitialinclinationrelativelyparalleltothebodyaxis.

B. Abnormal: More than 2 degrees tilt indicates the peripheral problem that is ipsilateral and offset is towards the sameside.

Indications

a) BrandtandDietrich[2] foundthatpontomedullary lesions produce ipsiversive tilts (deviation of subjective visual vertical toward the side of the lesion),Pontomesencephalic lesions produce contraversive tilts (awayfromthelesion).Thedeviationsaccompaniedbytheoculartiltreaction.

b) Disruption of both the otolithic and vertical semicircular canalpathwaysare thought tobe involvedinthedeviations.

c) Thalamic lesions mayproduceeither ipsiversiveorcontraversive tilts of subjective visual vertical. Lesionsof the parietoinsular vestibular cortex tend to produce contraversive deviations. Lesions at the level of the thalamus and above will not produce an accompanyingoculartiltreaction.

d) Lesions in the inner ear also produce deviation of subjective visual vertical due to differences in the tonic outputfromtheotolithicorgansintheinnerear[3].

e) Abnormal in headache sufferers, particularly thosewith migraine.

Limitationsa) Bilateral utricular defects are not assessed Findings tobesupportedwithothertestsSensitivityandspecificityquestionable

b) Inabilitytoproperlyestimatethetrueverticalwhenthelightbarwasinitiallyinclinedintheoppositedirection

c) SVV is subject tovariationover time,due tocentralcompensation

Fukuda Stepping Test GivenByFukuda[4]

Personswithunilateralperipheralvestibulardysfunctionwould turn to the side of lesion

History- middle ear pathology can influence results ofcaloric stimulation due to alteration of thermal conductivityacrossmiddleearspace.

Principlea) Body rotation results from the unbalanced staticactivityofthetwoendorgans

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Global Journal of Otolaryngology

b) Imbalance in theyawear is interpretedcentrallyasrotation plane towards the contra-lesioned

c) Deviation of body occurs towards the ipsi-lesionedside.

Purposea) Used to assess peripheral VS impairment manifested as asymmetry in lower extremity vestibulospinal reflextone

b) Labyrinthinedysfunction

c) Indicatespossibleacousticneuroma.

Procedurea) Withthearmsextendedata90˚angleinfrontofthebodyandtheeyesclosed,thepatientmarchesinplacefor50steps.

b) Steppingrate-110stepsperminute.

c) Theangle,direction,anddistanceofdeviation fromtheoriginshouldberecorded.

d) It ishelpful tomakeuseofareferencemarksystemsuch as a band of tape on the floor oriented along thesagittalplaneatthestartofthetestorathin,denserubbermatwithapolarpatternmarkedonit

ResultsA. Normal: 50 steps without significant angular

deviation from the starting position (i.e., normal rotation ≤30˚).

B. Abnormal: A rotation of greater than 45 degrees ineitherdirectionisconsideredtobeabnormal.[4,5].

Advantagesa) Useful test for peripheral VS lesion

b) Reveals deficits of VSR compensation when VORcompensationiscomplete.

c) A useful screening tool

Limitationsa) FSTwithandwithoutheadshakecomponentisnotareliablescreeningtoolforperipheralvestibularasymmetryinchronicdizzypatients

b) Reliabilityofpredictingimbalanceofthelabyrinthinesystembasedonthepoorreliabilityscores-questionable

c) Not reliable for lateralization and localization oflesion

d) Limiteduseinspontaneousnystagmuscases

Past pointing and falling testa) Past-pointing is considered to be a sign of tonic imbalance in the output of the peripheral vestibular

system.

b) GivenByBaranyin1910(RelatedarticlesinGerman)

c) Thepast-pointingtestwasoneofthefirstattemptstoclinicallyassessvestibularfunctions.

d) The past pointing falling and slow component of nystagmusareinthesamedirection.

I. AcuteVSfailure-nystagmusontheoppositesidebutpast pointing and slow component on ipsilateral side

e) Past pointing occurs on same side of target and will occur with either limb

I. Bothlimbs-vestibulopathy

Principlea) Asymmetric tonic signals from afferent system

manifestedasarelativeabundanceofactivityfromintactendorgan

b) Compensatory VSR elicited in order to maintainposition. Hence body rotates towards the lesioned organ,resultinginpastpointing.

Purposea) Used to assess tonic imbalance in the output of the peripheralvestibularsystem

b) Test for defective functioning of the vestibular nerve

c) Indicative of cerebellar signs

d) Usedforassessingvestibulospinalpathways.

Procedure The patient is instructed to extend the arms and place the

index fingerofonehandon the index fingerof theexaminerorastatictarget.Eyesarethenclosedandarmsraisedaboveheadandquicklyreturnedtotheperceivedstartingposition

Results

A. Normal: finger returns to the starting point withlittle lateral deviation

B. Abnormal: The patient’s handwill drift away fromthetargetasthetrunkrotates.

i. Peripheral VS lesion: deviation to one side and compensatedperipheralweaknessincaseoflessconsistentcase.

Advantages

a) Detects acute lesions

b) Gives insight about compensated and decompensated lesions

Limitations

a) Not reliable in case of chronic vestibulopathy after




compensation has occurred

b) Repeated testing produces variable results No lateralizationinformation

c) Lowsensitivity

d) Cannot detect compensated vestibular lesions

Vertical writing

a) Variant of past- pointing

b) DescribedbyFukuda-1959[4]

c) Deviation tendency is due to relative difference inafferent vestibular input to the brainstem

Procedure

Patients instructed to write a series of characters or symbols in vertical direction on a piece of paper.With eyesopenandthenwitheyesclosed.

Results

a) Eyesopen-NormalsandVestibularpatients-verticalline of characters

b) Eyes closed- Unilateral Peripheral lesions-slantingand deviation to the side of lesion

c) Central overcompensation of unilateral peripheral vestibular impairment-opposite side of lesion

Limitationa) CannotonlyconcludeasVestibularsiteoflesion

b) Some mild otologic disorders-otitis media-similar finding

Romberg Testa) FirstdescribedbyMoritzHeinrichvonRombergwho

found thatpatientswith tabesdorsalis (neurosyphilis)oftencomplainedofincreasedunsteadinessinthedark.

b) The test should be performed in all patients who complain of dizziness, imbalance or falls to rule out sensoryataxia

c) Romberg’s test is a test of the proprioception receptorsandpathwaysfunction.

Romberg signThe Romberg sign demonstrates loss of postural control

in the absence of visual input suggestive of proprioceptive deficitinthelowerlimbsasaresultofseverelycompromisedproprioception.

Principle

a) The physiology behind this test is that to maintainbalance we need at least 2 of the following 3 components:

vision,proprioceptionandvestibularfunction.

b) Vestibularproblem-eyesopenbalancemaintained

c) Eyes closed-only proprioception insufficient tomaintain balance

d) Only propioreception- eyes closed - improper VSfunctioning

Purpose

a) Identifiesimbalanceinthevestibulospinalreflexduetotonicimbalanceinperipheralvestibularsystem

b) To assess the integrity of the dorsal columns of thespinalcord.

Procedure

Thepatientisaskedtostandwithfeettogetherandarmsbysidewitheyesfirstopenedandthenclosed.

Resultsa) Openeyes-imbalance compensated

b) Closedeyes-relative reduction of vestibular input to cerebellum

c) Witheyesopenpoorbalance-cerebellar ataxia.

d) Eyes closed- problem in vestibular or proprioceptive systems.

e) Peripheral lesion-patientswaystosideoflesion

f) Central lesion-Instability

g) Bilateral or Unilateral Peripheral VS lesion-Negative(Table1).

Indicationsa) Vitamin B12 deficiency - Subacute combineddegenerationofthecord,

b) Diabeticperipherallargefibreneuropathy,

c) Friedrich’sataxia,

d) Tabes dorsalis

Table 1: Sensary Inputs.

Test Condition Description Sensory inputs

Eyesopen firmsurfaceVisual,

proprioceptive,vestibular

Eyesclosed firmsurface Proprioceptive,vestibular

Eyesopen compliant surface Visual,vestibular

Eyesclosed compliant surface Vestibularonly

Advantage

a) Differentiates between Peripheral VS disorder and propioreceptive anomalies




b) Differentiates between patients with muscle weaknessfromdorsalcolumndisease

Limitations

a) Oftenmisunderstoodwithcerebellarsigns

b) There is still no standard approach to applying theRombergtestinclinicalneurology

c) The criteria for and interpretation of an abnormal resultcontinuetobedebated.

d) Limited studies available that define its reliabilityandvalidity.

e) Data statistically showing its effectiveness is notreadilyavailable.

f) Insensitive to compensated vestibular lesions

g) Useful in assessment of dorsal column but not vestibularsystem

h) Cannot distinguish patients with cerebellar lesions and propioreceptive lesions

i) Sometimes cannot identify normals and patientswith peripheral lesions

Sharpened Romberg testa) AvariationoftheRombergTest,

b) Consists of support by position narrowing thepatient’s base of placing feet in a heel to toe

c) GivenbyFurman&Cass,2003[5]

Principlea) Propioreceptive input from ankle joints becomes

discordantrelativetovestibularandvisualinput.

b) Onlyvestibularinputcanbeusedtohelpmaintaintheupright position

PurposeToidentifyvestibularimpairment

Procedurea) In this, the patient standswith one heel in front of

toes and arms folded across chest

b) Testinstructionsdonotspecifywhichfoot,preferredornon-preferred,shouldbeplacedinfrontoftheother.

c) 2ndmethod-Thepatientshouldbeinstructedtokeephandsonhipsforthewhole30seconds.Ifthepatienttakesasteporremoveshandsfromhips,thetimerisstoppedandthepatientmayattemptthetestonemoretime.

ResultsInabilityindicatesvestibularimpairment

Advantage

a) This test is useful for assessing ataxia in mild mountainsickness

b) Helpful in diving test

c) WidelyusedinNavalforce

d) Providesbaselinefordysfunction

LimitationsThesharpenedRombergdoeshaveanearlylearningeffect

thatwillplateaubetweenthethirdandfourthattempts.

Patientswhoperform the test during several trialsmaybegin to adapt and perform better on each successive trial.Thiscouldskewtheresultsandprovideaninconclusiveresult

Gait testingAn individual’s gait is defined as his or her method of

walking.

Types of gaita) A tandem gait test is one where the individual has to walkheeltotoe.

b) Incordination indicative of ataxia and difficulty inmotor movements

c) UsedinDrunkendrivingtest

d) The Tinetti gait test is used for elderly individuals.Aspeopleage,theytendtolosetheirabsolutecontrolovermobilityandtheprecisionoftheirmobility.

e) The Tinetti gait test is also used to establish parametersrelatedtothebalanceoftheindividual.

f) Inabilitytoperform-balancedisorder

PurposeToidentifyperipherallesions

PrincipleGait involvesmultiple sensoryandmotor systems.These

include vision, proprioception, lower motor neurons, uppermotor neurons, basal ganglia, the cerebellum, and higher-ordermotorplanningsystemsintheassociationcortex.

ProcedureThepatientisaskedtowalkalongastraightlinetoafixed

point,firstwitheyesopenedandtheneyesclosed

ResultsPeripheral VS lesion- patient deviates to the affected side

Advantagesa) Verysimpleandrapidtest

b) Does not require prior preparation of the subject




Limitationa) Cannotidentifycentrallesions

b) Cannot identify person with underlying vestibulardisorder when the person is intoxicatedUnterberger test

a) SiegfriedUnterberger(1939)

b) MethodsimilartoFukudatest

c) The differences and controversies explained byGrommesC,andConwayD,(2011)intheJournalofHistoricalNeurosciences

Purposea) Identifieslabyrinthinedysfunction

b) AssessunilateralperipheralVestibulardisturbances.

ProcedureThepatient isaskedtomatchupanddownthespotwith

eyesclosedandhandsclaspedatarmlengthinfrontofthem.

ResultsA. Normal:Lesstendencytodeviatefromlefttoright.A

turnupto45degreesforevery50stepsisnormal

B. Abnormal:Rotationalmovementtowardsthesideoflesion

I. Deviationtoeitherofthesidedependingonthelesion:Peripheral VS lesion

II. Turninginvariousdirection:Cerebellar lesions

Limitationsa) The value of this test is questionable in the view of multiplicityofthefactorsthatinfluencetheresponse

b) Reliability questionable in case of compensatedvestibulardysfunction

c) Thebalancedisordercausedbynonvertigouscausesnot differentiated

d) Cannotidentifybilaterallesions

e) Cannotidentifycentralvestibularpathology

Head thrust testa) HalmagyiandCurthoysin1988[6]

b) The HTT, which is based on the the doll’s eyephenomenon, is used to evaluate the vestibular-ocularreflex(VOR)inthehorizontalplane

c) TodemonstratetheVOR,thepatientmoveshisorherheadfromsidetosidewhilefocusingonamidlinetarget.

d) Thiscausestheeyestomoveinavelocitylikethatoftheheadmovementbutintheoppositedirection.

Purposea) Used to evaluate unilateral vestibular function To

assesschronicvestibularloss[7-12]

b) Toidentifythesideofthehypofunctioninglabyrinth.

ProcedureThe patient’s head is turned 15-30 degrees from the

centreandthenrapidlyrotatedtotheothersidewithpatientfocussingontheexaminer’seyes

Resultsa) Patients with unilateral vestibular weakness willhaveacatch-upsaccadewhenrotatedrapidlytothesideofthe lesion

b) Complete loss of peripheral vestibular function- Positive

c) Mild loss indicated by low excitability differencesbetweensidesontheENGcalorictest-negative

d) Unilateral hearing loss-positive-acousticneuroma.

e) Chronic peripheral loss- central compensation that appearswithinthefirstfewdaysafteranacutevestibularinsultsuchasvestibularneuronitis,labyrinthitis,orskullbasefractures[13-17].

LimitationSensitivity is lower (35%-39%) for patients with

nonsurgicallyinducedunilateralvestibularhypofunction

a) Orthostatichypotension

Orthostatic hypotension is a reduction of systolic bloodpressureofatleast20mmHgordiastolicbloodpressureofatleast10mmHgwithinthreeminutesofstanding

b) P.C.RoweandJ.Bou-Holalgah(1995)

c) Dr.DavidStreetenwascalledthe«fatheroforthostatichypotension»

d) Orthostatichypotensionisdefinedasafallinsystolicbloodpressureofatleast20mmHgand/orinthediastolicblood pressure of at least 10mmHg between the supinereadingandtheuprightreading[18-26].

PurposeTo differentiate between true vertigo and non vertigo

AssessmentA. Tilt table test

a) Atilttabletest,occasionallycalleduprighttilttestingDysautonomiaorsyncope

b) Dizziness




c) Lightheadedness, with or without a loss ofconsciousness

d) Positionaltachycardia[27-35].

Procedurea) The patient will be strapped to a tilt table lyingflat and then tilted or suspended completely or almostcompletelyupright(asifstanding).

b) Mostofthetime,thepatientissuspendedatanangleof60to80degrees.

c) The test either ends when the patient faints or developsothersignificantsymptoms,orafterasetperiod(usuallyfrom20to45minutes,dependingonthefacilityorindividualizedprotocol).

d) Sometimes, the patient will be given a drug, suchas Glyceryl trinitrate or isoproterenol, to create furthersusceptibilitytothetest.

e) Symptoms,bloodpressure,pulse,electrocardiogram,andsometimesbloodoxygensaturationarerecorded.

ResultThis drop in BP indicates the presence of light-headedness

and non- vertigo disease

Dysdiadochokinesis testing

a) Inability toperform rapidly alternatingmovements,suchasrhythmicallytappingthefingersontheknee.

b) Cause-cerebellar lesion and is related to dysmetria,whichalsoinvolvesinappropriatetimingofmuscleactivity.

PurposeUsed to assess cerebellar lesions

ProcedurePatients are asked to slap knees with palm and dorsum

ofhandrapidlyandalternatelytheclinicianisexpectedtobeveryvigilantandexperienced[36-45].

ResultInappropriate timing of muscle activity. This is visibly

apparent when attempting to perform rapid alternating movementrequireefficientinitiationandcessation

Advantagesa) Provides insight into cerebellar lesions Rules out cerebellar ataxia

b) Identifies vertigo and dysequilibrium due to neuro-degerative disorder such as Freidreich’s ataxia and Multiple sclerosis

c) Helps suspect as having multiple sclerosis in undiagnosed patients

Limitationsa) Anexclusivetesttoidentifycentralvestibularlesion

b) Cannotidentifyperipheralvestibularlesions[46-50].

Spontaneous nystagmus

a) Nystagmus isan importantsign in theevaluationofvestibularsystem.

b) It is defined as involuntary, rhythmical, oscillatorymovementofeyes(Table2).

Table 2: Degree of Nystagmus.

Degree of Nystagmus

1st degreeItisweaknystagmusandispresentwhenpatientlooksinthedirectionof

fastcomponent.

2nd degreeItisstrongerthanthe1stdegree

nystagmusandispresentwhenpatientlooksstraightahead.

3rd degree

It is stronger than 2nd degree nystagmusandispresentevenwhen

patientlooksinthedirectionoftheslowcomponent.

PurposeToidentifyunderlyingorganiclesion

Principlea) SN occurs when the unilateral peripheral VS or VIIIth

nerve is affected because of reduced neural firing whichdecreasesinthatsideandtheothersideremainsintact.

b) Thisasymmetryb/wthetwoendorgansgeneratestheillusionofrotatorymotionintheabsenceofheadmovement.

c) BestidentifiedbeforeVScompensationoccurs.

Procedurea) Patient is seated in front of the examiner or lies supine onthebed.

b) The examiner keeps his finger about 30 cm fromthe patient’s eye in the central position and moves it totherightorleft,upordownbutnotmovingmorethan30degrees from the central position

c) Test to be repeated by using non visual fixations-frenzel’slensesordarkroom+patientvaguelystaringintothe distancewhen instructed to look to left and then toright.

d) Thisisdonetochecktheintensityofnystagmus[50-52].

Resultsa) Irritative lesion of the labyrinth-nystagmustosideoflesion,




b) Paretic lesion-nystagmustothehealthyside,

c) central lesion- nystagmus is vertical rotatory,dysconjugate,monocular.

d) Arnold chairi malformation- A down beating verticalnystagmus.

e) Peripheral vertigo-samedirectionnystagmusevenif the gaze is changed. It increases with visual fixationremoved.

f) Central vertigo-directionofnystagmuscanchangethe direction when looking in opposite direction and isunalteredevenifvisualfixationisremoved

g) Vestibular nystagmus (peripheral type) lesion oflabyrinthVIIIthnerve[25-26]

h) Vestibular nystagmus (central type), lesion in thecentral neural pathways (vestibular nuclei, brainstem,cerebellum).

AdvantageBest results obtained soon after VS damage

Limitationa) Cannot diagnose end organ disorder

b) SNcannotbeobservedafterafewdays

c) Cannot be used as bedside evaluation to diagnose unilateral vestibular dysfunction without quantitativetesting[53,54]

d) Degree and site of impairment from the direction of SN cannot be determined due to inter-subject variabilityandqualityofcentralcompensation

e) Only the presence or absence of spontaneousnystagmus to diagnose unilateral peripheral VShypofunctionisunacceptable.

f) ForUVHsensitivity-lessthan50%

g) IncaseoforganicVSdisorder the findingshouldbesupportedwithquantitativefindings

Head shake nystagmus

a) Firstdescribedin1907byRobertBárány(1907).

b) Head-shakingnystagmus (HSN) is a jerknystagmusthatmayfollowaprolongedsinusoidalheadoscillation.

c) Earlytest–Boertes(1923)

d) Contemprorarytest-KameiandKornhuber(1964)

PrincipleAclinicaltestthatlooksfornystagmusthatappearsafter

vigorous horizontal (horizontal SCC) head shaking for about15secondsatafrequencyof2Hz.Thetestisahigh-frequency

vestibularstimulus[55-60]

Purposea) EvaluatessymmetryinVOR

b) Evaluation for a peripheral vestibular systemdisorder.

Procedurea) Head isshakenvigorously for10-30cyclesandthenstopped.

b) Thepatientisaskedtotilthisorherownheaddown30degreestoallowmaximumstimulationofthehorizontalcanal and told to shake head back and forth rapidly asquicklyaspossiblefor30seconds[30-32].

c) Openeyesandobservenystagmusafterstopping

Patterns of HSNA. Peripheral

a) Primary phase beatsawayfrompareticear

b) Secondary phaseisuniversalbutweak

c) Horizontal HS-noorlittleverticalnystagmus

d) Vertical HS- elicits nystagmus which may beattowards paretic ear

e) Nystagmusmaynotappearexceptforprolongedandpowerfulheadshaking

B. Central

a) Directionofnystagmusnotwell correlatedwith theside of lesion

b) Secondaryphase-maybeasbigasprimaryphase

c) Nystagmusiscrosscoupled

d) Nystagmusmayappearafer1-2headshakes

Resultsa) Transient vestibular nystagmus- peripheral and central VS lesion

b) Unilateral VS dysfunction - unopposed stimulation of intact labyrinth resulting in slow phase to side of thelesionandarapidnystagmustointactside.

c) Verticalnystagmus-cerebellar dysfunction

d) Head shake nystagmus- peripheral vestibular dysfunction and cerebellar dysfunction.

AdvantageGoodscreeningtoolforuniversalvestibulardysfunction

Limitationa) Sensitivity - poor Unreliable screening test.




Specificity-poor

b) Poor predictor for moderate to low level of vestibular hypofunction

c) No criterion present that indicates how much loss is needed for a positive HSN test

Dynamic visual acuity

a) VOR helps stabilizing gaze during head movement.Thisvestibulardrivenreflexprocessallowstheobservertoretainvisualacuitywithheadmovement.Thisisdynamicvisualacuity.

b) GivenbyMillerandLudvigh(1962)[37]

c) Initial test- Oscillopsia test used to quantify theperformance of DVA

PurposeUsedtoevaluatebilateralvestibularweakness

ProcedureBaseline visual acuity is taken and then the same task

usingsnellen’schart, thepatient isaskedtoreadbyrotatingtheheadbackandforthat1-2Hzrate.

Resultsa) Normal- Loss of one line

b) Lossof2-3linessuggestsvestibular weakness.

c) This test should be abnormal in patients with bilateral vestibular weakness and can be used to diagnose these challengingpatients.

Advantagesa) AvailabilityofcomputerizedsystemofDVA

b) DVA testing during imposed head motion isa a quantitative and clinically feasiblemeasure that reflectsfunctionallysignificantabnormalVOR.

Disadvantagesa) Cannot be tested in patients in case of absence of corrected vision

b) Thesystemforassessmentisnotwidelyavailable

c) Standardprotocolforthesystemusedisnotavailable

d) Variedresultsandinconsistentfindings[40]

Why varied results and inconsistent findings?????a) Differencesinmethodology

b) Variability in the frequency of subject’s headmovement

c) Variation in the method to calculate DVA scores

d) Variation in the degree of vestibular system

compensation in patients with unilateral vestibular hypofunction

e) Bestperformedbyexperiencedclinician

Modified clinical test for sensory interaction of balance

a) The Modified Clinical Test of Sensory Interactionand Balance CTSIB is an accepted test protocol for Balance assessment on a static surface

b) Postural balance involves special sensory receptorsthat provide information in regards to various environmental andphysiologicalconditionsthatmayaffectaperson’sabilitytomaintainequilibrium.

Purposea) Usedtoassesstheintegrityofsensorysystem.

b) Functional compensation with respect to stance is obtained

c) Assesses patient’s balance under a variety ofconditionstoinferthesourceofinstability

Principlea) Maintaining postural balance involves complex coordination and integration of multiple sensory, motorand biomechanical components

b) The test progressively reduces the sensory inputsystemavailabletothepatientformaintainingquietstance.By4thcondition,onlyVS isavailabletoprovideaccurateinformationaboutthebody’spositionandmovement.

ProcedureHere, the patient’s ability to maintain quiet volititional

stanceisevaluatedastheysequentiallystandon

a) Aflatfirm

b) Aflatfirm

i. surfacewitheyesopened

ii. surfacewitheyesclosed

c) Acompressiblesurfacewitheyesopened

d) Acompressiblesurfacewitheyesclosed

ResultInability tomaintain postural control during the testing

indicatesthatthesensorysystemisdysfunctioning

Advantagesa) The breadth of the existing studies supporting and accepting the CTSIB as a valid clinical assessment of balance.

b) Well documented definitive correlations for mild




traumaticbraininjury.

c) The comprehensiveness of the test to address each of thesystemsthatcontributestobalance:Visual,vestibularandsomotosensory.

d) Ease and efficiency of doing the test and high interandintraraterreliability.

e) Clinicianfamiliaritywiththetest.

Hyperventilation induced nystagmusa) Thoughttobeofpsychiatricmanifestation

b) Hyperventilation can either activate a latentnystagmusincentralorperipheralvestibulardiseasesoritcaninteractwithaspontaneousnystagmus,byreducingitorincreasingit.

PrincipleDuringrapidperiodsofventilation,theconductionvelocity

ofademyelinatednervecanbetransientlyincreasedtherebycreating a situation where the affected ear will present as being hyperfunctionalcomparedtothe«normal»ear.Therefore,thenystagmuscommonlybeatstowardsthesideofdysfunction.

Purposea) Used to assess the integrity of entire vestibular

system.

b) Differentialdiagnosisofpatientswithpsychosomaticandanxietyrelateddisorders

c) Assessing demyelinating conditions Used to assessvestibular end organs

ProcedureFrenzellensesorlightoccludingVNGgogglesareworn.In

standing, the patient is asked to take rapid anddeep breathfor 30-60sec. The examiner should observe eyes beforehyperventilationandswayingofthepatient.

ResultsNonnystagmusandslightsensationoflightheadednessor

dizzinessappears.Aswayinsaggitalplane

Indicationsa) Nystagmus in horizontal plane for 60 sec or more-incomplete unilateral peripheral lesion.

b) Ipsi-lesion-Fastphasenystagmus.

c) Complete unilateral peripheral lesion-contralateral lesional beating nystagmus. Also indicatesbilateral incomplete lesions and central lesions but the direction is unpredictable

d) cerebellar lesion- slow phase velocity of downbeatingnystagmus

Advantagesa) Highsensitivity

b) Indicates site of lesion

Limitationsa) Littlelocalizingvaluelessspecificity

b) Should be supported with other diagnostic tests

Ocular tilt reaction/ skew deviation

a) GivenbyHertwig

b) Occursduetoimbalanceofutriculocularreflex

c) Ocular tilt is considered as a combination ofvestibulocular and vestibulospinal anomalies resulting in verticalmisalignmentoftheeyes,headtilttowardsthelowereyeandoculartorsiontowardsthelowereye[57-60]

Purposea) Usedtoassessconjugatemovementsoftheeyes.

b) The type and direction of skew can provideinformationvaluabletothedeterminationofthesiteoflesion.

Principlea) The primate oculomotor system produces

predominantly conjugate movements of the eyes; thusvariationfromthispatternareconsideredpathologic.

b) One suchvariation is characterizedby thepresenceof a vertical misalignment caused by an imbalance of thevestibule-ocular reflex and referred to as “Skew deviation”.When accompanied by head tilt in the roll plane and oculartorsion, the traid of symptoms is referred to as “ocular tiltreaction”.

Procedurea) An examination of static visual alignment should be

performed when the patient maintains gaze in the primaryor straight-ahead position. The examiner should look forthe presence of a vertical skew deviation where one eyedemonstrates an abnormal vertical orientation relative to the other. The examiner should also be alert for the presence ofa head tilt of 10 to 30 degrees toward the site of lesion andocular-torsiontowardthelowereye[12-20].

Resultsa) Normal: Careful observation of the patient will

reveal normal horizontal, conjugate eye position with gazedirectiondirectedstraightaheadandverticalheadalignment.The examiner should be careful to differentiate between facial asymmetries and thepresenceof a skewdeviationoroculartiltreaction.

b) Abnormal:Theexaminerwillnotethepresenceofaverticalmisalignmentoftheeyesfromthenormalhorizontal




gazeposition.Thepatientmayalsoexhibitheadtiltof10to30degreestowardthesideofthelowereye[15,18].

Indicationsa) Lesions of utricular nerve or at level of vestbular nulei- ipsilateral ocular tilt reaction

b) Lesions above the level of vestibular nuclei (due to decussationoffibers)-contralateraloculartiltreaction.

LimitationRequiressupplementarytestsforsupportingthefindings

Valsalva Induced nystagmusa) Self induced change in middle ear and intracranial

pressure is called valsava manaeuver

b) Causeseyemovementsinpatientswithcraniocervicaljunctionabnormalitiesanddisordersaffectinginnerear.

c) GivenbyAntonioMarioValsalva(1666-1723)

d) Hennerbert identified eye movements in valsalvamanaeuver

Hennerbert signa) Describes conjugate eye movement away from theaffectedearwithpositivepressureappliedtotheEAM

b) A movement towards the affected ear is expected with negative pressure

c) The presence of such movement allows the examiner todeduce thepresenceofanomalousconnectionb/wtheinnerearandtheexternalenvironment[20,45].

Principlea) Increased pressure in the middle ear acts as an abnormal connection b/w labyrinth and externalenvironment to induce pressure gradient in the cochlea

b) Increased pressure within the affected labyrinthstimulates neural firing by displacing the cupula of thesemicircularcanal.

c) IncreasedneuraldischargeratedrivestheVORsuchthatacompensatoryeyemovementawayfromtheaffectedearisgenerated.

d) Incaseofstrainingagainstaclosedglottis,increasedpressure within the middle ear fossa is generated through changesinthecentralvenouspressure.

e) Increasing and maintaining pressure within the thoracic cavity decreases venous return through thejugularveintherebyraisingintracranialpressure.

f) An abnormal connection b/w the middle ear fossaandthevestibularlabyrinthwillinduceapressurechangein the affected canal and elicit downbeating torsional nystagmustowardstheaffectedside

ProcedureA. Method1

a) Increaseairpressureinthesinusesandmiddleearbytakingdeepbreath.

b) Pinchnose,closemouththentightlyblow.

c) The patient should maintain pressure for 10-15seconds

BMethod 2

a) Increasingvenouspressurebyasking thepatient tostrainagainst the closedglottis and lips for10 -15 sec, as if,pressurizingthelungstohelpstabilizethetrunkwhileliftingweight.

ResultsA. Normal-VMshouldnotelicitsensationofdizzinessorvertigo

a) Careful observation to identify shift of the eyes(positive Hennerbert sign)

b) No elicited conjugate eye movement should beobservedunderfrenzelorVNGgoogle[50]

B.Abnormalresults

a) IncreasedMEor intracranialpressureasa resultofeither variant of valsalva manaever will elicit a conjugate movementofeyestowardsthecontra-lesionedearincaseoflateralandanteriorcanalinvolvement.

b) Increased intacranial pressure- corrective saccade-nystagmustowardsipsilateralear

c) Directionoffastphasenystagmus-siteoflesion

d) Torsional and downbeating vertical nystagmusindicate site of lesion in anterior canal

e) Vertical upbeating nystagmus with torsionalcomponent suggest involvelemnt of posterior canal

f) Direction of torsion provides information about lateralityofthelesion

g) Dehiscence of posterior canal will elicit upbeating andtorsionalnystagmuswithfastphaseorientedtowardstheaffectedear.

h) The fastphaseof torsionalnystagmuswillbeat inaclockwisedirectionforlesionsoftheleftearandcounterclockwiseforlesionsintherightear.

i) Horizontal nystagmus- involvement of lateral SCC-beating affected towards the ear

AdvantagesUsefulscreeningtestGoodSensitivity




Limitationa) Cannotdistinguishb/wnystagmusduetoVSdisorderandMEdisease

b) Not useful in the presence of upper respiratoryinfection[23,25]

Hallpike Manaeuver (positional test)a) DixandHallpike,1952

b) MostlyusedtoassessBPPV

Purposea) Usedtodifferentiateperipheralfromcentrallesion.

b) Identifyingvertigoincertainheadpositions

Procedurea) Patient sitsona couch.Examinerholds thepatients

head, turns it 45˚ to the right and then places the patientin a supine position so that his head hangs 30˚ below thehorizontal.Patient’seyesareobservedfornystagmus.Thetestis repeated with head turned to left and then again in straight head-hangingposition[30]

Resultsa) Incentrallesions(tumorsofIVthventricle,cerebellum,temporal lobe, multiple sclerosis, vertibrobasilarinsufficiency or raised intracranial tension) nystagmusisproducedimmediately,assoonastheheadisincriticalposition.

b) Direction of nystagmus also varies in different testpositions (direction changing) and is non-fatiguable on repetitionoftest.

c) Inbenignparoxysmalpositionalvertigo,nystagmusappearsafteralatentperiodof2-20seconds,lastsforlessthanaminuteandisalwaysinonedirection,i.e.towardstheearthatisundermost.

d) On repetition of the test, nystagmus may still beelicitedbutlastsforashorterperiod.

e) On subsequent repetitions it disappears altogether,i.e.nystagmusisfatiguable.

f) If the test is negative, central nervous systeminvolvementshouldbeconsidered.

Advantagesa) Although there are alternative methods to administeringthetest,Cohenproposesadvantagestotheclassicmaneuver.

b) The test can be easily administered by a singleexaminer,whichpreventstheneedforexternalaid.

c) Due to thepositionof thesubjectand theexaminer,

nystagmus, if present, can be observed directly by theexaminer.

Limitationsa) Thesensitivityofthistestisnot100%.SomepatientswithahistoryofBPPVwillnothaveapositivetestresult.

b) Specificity-75%.

c) ThetestmayneedtobeperformedmorethanonceasitisnotalwayseasytodemonstrateobservablenystagmusthatistypicalofBPPV[55-60].

d) Patients may be too tense, for fear of producingvertigosymptoms,whichcanpreventthenecessarybriskpassivemovementsforthetest.

e) A subject must have adequate cervical spine range of motion to allow neck extension, as well as trunk andhip rangeofmotion to lie supine.Cannotbeused in casemusculoskeletalandobesityissuesinasubject.

Modified Dix- Hallpike position

a) GansandHarrington-2002

b) ModifiedversionofDix-Hallpikepositionaltest

Procedurea) Theexaminerstandsbehindthepatient.Thepatient

turnstheheadslightlytowardthetestear,andtheexaminersupports the patient’s neck and back while the patient islowered into the provoking supine position with the neckslightly hyper extended andoff.Once in the supineposition,theexaminerhasaclearviewofthepatient’seyes.Becausetheprovocationofsymptomsisgravitybasedandduetochangingpositionsofthe involvedposteriorcanal,rapidpositioningisnotrequired.

Resultsa) If theresponse isdeterminedtobeclassic,abenignperipheral vestibular lesion in the undermost ear is suspected.

b) If the response is “non classical” (one or more oftheaboveconditionsareabsent), the lesioncanbeeitherperipheralorcentral.

c) If rotatorynystagmus, isobserved, theresultsmusthave the following 4 characteristics to be consideredclassicallypositive.

d) Delayedonset-Needtoobservepatientatleastfor20second

e) Transientburstofnystagmus-lastabout10-15sec

f) Subjective report of vertigo

g) Fatigability




Eye movement testEye movement (ocular motility) is the voluntary or

involuntary movement of the eyes, helping in acquiring,fixatingandtrackingvisualstimuli.Itmayalsocompensateforabodymovement,suchaswhenmovingthehead.

PurposeTo assess voluntary control of eye movement Useful in

assessingnystagmus

Principlea) A normally functioning vestibular system exhibitsvoluntarycontrolofeyemovement.

b) Italsotendstostabilizegazeduringheadmovement

Procedurea) Saccade tracking is assessed by having the patient

quickly shift gaze from one point to another, typically theexaminer’snoseandafingerheldtoside(Videos20-23)

Result

a) Assymmetricorgrosslyabnormalresponsesindicatethepossibilityofcerebellardysfunction

b) Beatingmovements-indicatesnystagmus

Advantagea) Quickandrapidtest

b) Provides basic information about Vestibular functioning

Limitationsa) Accuracy,speedandinitiationtimeshouldbejudged.

b) Age medication and inattention influences theactivity.

c) Cannot distinguish between eye movemntdisturbances due to improper vestibular functioning or opthalmic disorder

References1. Böhmer A, Rickenmann J (1995) The subjective visual vertical as

a clinical parameter of vestibular function in peripheral vestibular disease.JVestibRes5(1):35-45.

2. DieterichM,BrandtT(1993)Oculartorsionandtiltofthesubjectivevisualverticalaresensitivebrainstemsigns.AnnNeurol33(3):292-299.

3. BohmerA,MastF,JarchowT(1996)Canaunilaterallossofotolithicfunctionbeclinicallydetectedbyassessmentofthesubjectivevisualvertical?BrainResBull40(5-6):423-429.

4. FukudaT(1959)Thesteppingtest.ActaOtolaryngol(Stockholm)50:95-108.

5. Furman JM,CassSP (1999)Benignparoxysmalpositionalvertigo.NEnglJMed341(21):1590-1596.

6. HalmagyiGM,Curthoys IS (1999)Clinical testingofotolith function.AnnNYAcadSci871:221-230.

7. BendittDG,FergusonDW,GrubbBP,KapoorWN,KuglerJ,etal.(1996)Tilttabletestingforassessingsyncope.JAmCollCardiol28(1):263-275.

8. BohmerA,MastF(1999)Assessingotolithfunctionbythesubjectivevisualvertical.AnnNYAcadSci871:221-231.

9. BohmerA,MastF(1999)Assessingotolithfunctionbythesubjectivevisualvertical.AnnNYAcadSci871:221-230.

10.BohmerA,Mast F (1999) Chronic unilateral loss of otolith functionrevealedbysubjectivevisualverticalduringoff-centeryawrotation.JVestibRes9(6):413-422.

11.Bonanni M, Newton R (1998) Test-retest reliability of the Fukudasteppingtest.PhysiotherResInt3(1):58-68.

12.BoniverR(2008)Head-shakingnystagmusB-ENT4(8):9-12

13.BurgioDL,BlakleyBW,MyersSF (1991)Anevaluationof thehead-shakingnystagmustest.OtolaryngolHeadNeckSurg105(5):708-713.

14.BrandtT,StruppM(2005)Generalvestibulartesting.ClinNeurophysiol116(2):406-426.

15.Brignole M (2001) Task Force Report: Guidelines on Management(DiagnosisandTreatment)ofSyncope.EurHeartJvol22(15):1256-1306.

16.CohenH, Blatchly CA, (1993)A study of the clinical test of sensoryinteractionandbalance.PhysicalTherapy73(6):346-351.

17.Desmond Alan (2004) Vestibular Function: Evaluation andTreatment. ThiemeMedicalPublishers, INC,NewYork,USA,pp65-111.

18.(1994)Dizziness:procedureimprovescareforacommoncomplaint.MayoClinHealthLett.December12:1-3.

19.Drachman DA, Hart CW (1972) An approach to the dizzy patient.Neurology22(4):323-334.

20.FaralliM,ManzariL,PanichiR,BottiF,RicciG,etal.(2011)Subjectivevisual vertical before and after treatment of a BPPV episode. AurisNasusLarynx38(3):307-311.

21.FitzgeraldB(1996)AreviewofthesharpenedRombergTestindivingmedicine.SPUMSJournal26(3):142-146.

22.FriedmannG(1970)Thejudgmentofthevisualverticalandhorizontalwithperipheralandcentralvestibularlesions.Brain93(2):313-328.

23.Gall RM, Ireland DJ, Robertson DD (1999) Subjective visual verticalinpatientswithbenignparoxysmalpositional vertigo. JOtolaryngol28(3):162-165.

24.GarciaA, Jauregui-RenaudK (2003) Subjective assessment of visualverticalityinfollow-upofpatientswithvestibulardisease.ENTjournal82(6):442-446.

25.Hain T, Goebel J, Demer J, Eviatar L (2000) Assessment: vestibulartestingtechniquesinadultsandchildren:ReportoftheTherapeuticsandTechnologySubcommitteeoftheAmericanAcademyofNeurology.Neurology55:1431-1441.

26.HainTC,Spindler J (1993)Head-shakingnystagmus. InSharpe JA&BarberHO,(eds).Thevestibulo-ocularreflexandvertigo.RavenPress,NewYork,USA,pp.217-28.

27.HainTC,FetterM,ZeeDS(1987)Head-shakingnystagmusinpatientswithunilateral peripheral vestibular lesions.Am JOtolaryngol8(1):


https://www.ncbi.nlm.nih.gov/pubmed/7711946

















































http://www.neurology.org/content/55/10/1431








36-47.

28.Herdman SJ (2010) Computerized dynamic visual acuity test in theassessmentofvestibulardeficits.InSDZEggers&DSZee(Eds.),Vertigoand imbalance: Clinical neurophysiology of the vestibular systemhandbook of clinical neurophysiology (vol. 9). Elsevier, Amsterdam,USA.

29.Herdman SJ, Tusa, RJ, Blatt P, Suzuki A, Venuto PJ, et al. (1998)Computerized dynamic visual acuity test in the assessment ofvestibulardeficits.AmJOtol19(6):790-796.

30.Hickey SA, Ford GR, Buckley JG, Fitzgerald O’Connor AF (1990)Unterbergersteppingtest:ausefulindicatorofperipheralvestibulardysfunction?JLaryngolOtol104(8):599-602.

31.HirschC (1940)Anew labyrinthine reaction: thewaltzing test.AnnOtolRhinolLaryngol49:232-238.

32.Honaker Julie A, Shepard Neil T (2009) Fukuda Stepping Test:Sensitivity and Specificity. Special Education and CommunicationDisordersFacultyPublications.Paper20.

33.Honaker JA, Boismier TE, Shepard NP, Shepard NT (2009) Fukudasteppingtest:sensitivityandspecificity.JAmAcadAudiol20(5):311-314

34.JacobsonGP,NewmanCW,Kartush JM (1993)HandbookofBalanceFunctionTesting.SingularPublishingGroup,SanDiego,USA.

35.JacobsonGP&ShepardNT (Eds.),Balance functionassessment andmanagement.Plural,SanDiego,CA,USA,p.63-97.

36.JongkeeLB,MaasJ,PhilipszoonA(1962)Clinicalnystagmography:adetailedstudyofelectronystagmographyin341patientswithvertigo.PractOtorhinolaryngol(Basel)24:65-93.

37.Jordan P (1963) Fukuda’s stepping test: a preliminary report onreliability.ArchOtolaryngol77:243-245.

38.LanskaDJ,GoetzCG(2000)Romberg’ssign:development,adoption,andadaptationinthe19th century.Neurology55(8):1201-1206.

39.LanskaDJ, RemlerB (1997)Benignparoxysmal positioning vertigo:classicdescriptions,originsoftheprovocativepositioningtechnique,andconceptualdevelopments.Neurology48(5):1167-1177.

40.Lornes Parnes, Sumitk Agrawal, Jason Atlas (2003) Diagnosis andmanagement of benign paroxysmal positional vertigo (BPPV). CMAJ169(7):681-693.

41.BhattacharyyaN,BaughRF,OrvidasL,BarrsD,BronstonLJ,etal.(2008)Thebedsideassessmentofthevestibularsystem.NeilBhattacharyya.Clinical practice guideline: Benign paroxysmal positional vertigo.OtolaryngolHeadNeckSurg139(5Suppl4):S47-S81.

42.PagarkarW,BamiouDE,RidoutD,LuxonLM(2008)Subjectivevisualvertical and horizontal: effect of the preset angle. Arch OtolaryngolHNS134(4):394-401.

43.Pavlou,WijnbergN,FladonM,BronsteinA(2003)EffectofSemicircularCanalStimulationonthePerceptionoftheVisualVertical.AcaNeuro-otology.

44.Peitersen E (1963) Vestibulospinal reflexes: acute disturbancesof vestibular function after operations on the stapes, especially asevaluatedbythesteppingtest.ActaOtolaryngol78:642-684.

45.PeitersenE(1964)Vestibulospinalreflexes:alterationsinthesteppingtest in variousdisordersof the inner ear andvestibularnerve.ActaOtolaryngol79:481-486.

46.PeitersenE(1967)Vestibulospinalreflexes.X.Theoreticalandclinicalaspectsofthesteppingtest.ArchOtolaryngol85(2):192-198.

47.Pérez P, Llorente JL, Gómez JR,Del CampoA, LópezA, et al. (2004)Functional significance of peripheral head-shaking nystagmus.Laryngoscope114(6):1078-1084.

48.ShepardNT, Telian SA (1996) PracticalManagement of the BalanceDisorderPatient.SingularPublishingGroup,SanDiego,USA.

49.Tabak S, Collewijn H, Boumans LJ (1997) Deviation of thesubjective vertical in long-standing unilateral vestibular loss. ActaOtolaryngologica117(1):1-6.

50.Tseng HZ, Chao WY (1997) Head-shaking nystagmus: a sensitiveindicatorofvestibulardysfunction.ClinOtolaryngol22(6):549-552.

51.Vereeck L, Wuyts F, Truijen S, Van de Heyning P (2008) Clinicalassessmentofbalance:normativedataandgenderandageeffects.IntJAudiol47(2):67-75.

52.Vibert D, Hausler R, Safran AB (1999) Subjective visual vertical inperipheralunilateralvestibulardiseases.JVestibRes9(2):145-152.

53.VibertD,HauslerR (2000)Long-termevolutionof subjective visualvertical after vestibular neurectomy and labyrinthectomy. ActaOtolaryngol120(5):620-622.

54.MichaelvonBrevern,TanjaSchmidt,UweSchönfeld,ThomasLempert,AndrewHClarke(2005)Utriculardysfunctioninpatientswithbenignparoxysmalpositionalvertigo.OtolNeurotol27(1):92-96.

55.Wetzig J, Hofstetter-Degen K, Maurer J, von Baumgarten R (1992)Clinicalverificationofaunilateralotolithtest.ActaAstronaut27:19-24.

56.Wolfe (1993)Head-upright Tilt Test: American Fam. Physician 149-158.

57.WolfM,HertanuT,NovikovI,KronenbergJ(1999)Epley’smanoeuvrefor benign paroxysmal positional vertigo: a prospective study. ClinOtolaryngol24:43-46.

58.WuytsFL,HoppenhrouwersM,PauwelsG,VandeHeyningP(2002)Unilateralotolithfunctiontesting-istheutricularfunctionadditive:JVestibRes11:304.

59.Zhang YB,WangWQ (2011) Reliability of the Fukuda stepping testtodeterminethesideofvestibulardysfunction. J IntMedRes39(4):1432-1437.

60.ZwergalA,RettingerN,FrenzelC,DieterichM,BrandtT,etal.(2009)Abucketofstaticvestibularfunction.Neurology72(19):1689-1692.









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