CLINICALPRACTICEGUIDELINESINNEUROTOLOGYasproposedbyDrAnirbanBiswas

Clinical Practice Guidelines are as defined in the American Academy of Otolaryngology website“statementsthatincluderecommendationsintendedtooptimizepatientcarethatareinformedbyasystematic review of evidence and an assessment of the benefits and harms of alternative careoptions”. These are guiding principles derived by discussions and deliberations among a group ofprofessionals in an academic / scientific association /societywho are speciallywell versed and takespecial interest in a particular sub-speciality and have gathered enough clinical experience in thatsubject to opine on what is the best practice procedure and strategy to adopt in different clinicalconditionspertainingtothatparticularmedicaldiscipline.Guidelinesarejustbroadprinciplesbasedonavailableevidencesandthecliniciantreatingthepatientisexpectedtofollowtheguidelinesbutisnotmandatoryorbindingontheclinicianwhoisthebestjudgetodecideonthemanagementstrategyaspertheuniqueneedsandrequirementsoftheindividualpatient.However,thereisnodenyingthatitisalwaysprudentandjudicioustofollowrecommendedguidelinesanddeviatingfromsetprinciplesofmanagementasdecidedbyexpertsmay induceuntoward results thatmaybedeleterious to theobjectiveofthetreatment.Formedico-legalreasonsitiswisetodocumentreasonsforanydeviationsfromsetguidelines.Thepurposeofhavingdefiniteguidelines forbestclinicalpractice is to increaseimplementationofwhateverevidencewehave intopractice so that clinical practice is pursued in alogicalandscientificwayandonly thoseproceduresandmanagementstrategiesare followedwhichareofprovenvalue,have stood the testof timeandarebasedon scientificevidenceasmuchas ispossible and to avoid practices that are known to be ineffective and harmful. It is criminal to usemedications that researchhas shown tobe ineffectiveordeleterious to theobjectiveof treatment.Therearealotmanydrugsusedinneurotologicaldisordersthathavebeenscientificallyestablishedtobeineffectiveifnotharmfulbutareyetcommonlyprescribedbydoctors.Inbalancedisorderpatientstoomanybiologicalsystemsareinvolvedandthemanifestationi.e.,thepresentationdependsontheproportionof involvementofthedifferentsystems. Inbalancedisorders it isnotonlythevestibularsystem that is involved; there is involvement of the cognitive system, the psychic system, themusculoskeletal system, the neurological system, the auditory system and sometimes also theautonomic system and the involvement of the different systems will have different effects on thepatient’sphysicalandmentalhealth.Eachpatientneedsindividualisedandcustomisedtreatmentbutcertain broad principles of management based on scientific evidencemust bemaintained and anycontraventionoftheguidelinesisexpectedtohavedisastrousoutcomesduetothecomplexityoftheproblem. The guidelines are basically to ensure ethical, scientific and rational management be itdiagnosisor thetreatment.Wemustbeawarethatthat inthetruestsensenomedical treatmentfor vestibular disorders is 100% evidence-based validated but we have to follow a consensus andaccept what we have found to be logical, scientific and correct. They can serve as a guide to bestpractices, a framework for clinical decisionmaking, and a benchmark. These are recommendationsauthenticated by the INDIANACADEMYOFOTOLARYNGOLOGYHEAD andNECK SURGERY (IAOHNS)and are the joint consensus document of the designated group of professionals in the IAOHNS.Available recommendations of best practice issued by other professional bodies like the EuropeanAcademy of Otology and Neurotology (EAONO), the Indian Academy of Neurology, the AmericanAcademy of Otolaryngology and Head Neck Surgery and the Barany Society have been taken intoaccount, given special weightage (due to which there are some small portions where therecommendationsofsomeorganisationlikee.g.,thatoftheBaranySocietyhavebeentakenverbatim),butre-consideredanddeliberatedbytheneurotologygroupintheIAOHNStopreparetheguidelinesonbestpractice inneurotology inthe Indianperspective.Thoughhearingdisordersareverymuchapartofneurotology,yetotherthantinnitusmosthearingrelatedissuesarenotincludedinthissetofguidelines.Theguidelineswillbeupdatedfromtimetotimeandmoreneurotologicaldisorderswillbecoveredinfuture.

Whyguidelinesaresoimportantinthepracticeofneurotology?

Havingsomeformofastandardisedcriteriafordiagnosisbasedonconsensusandclinicalexperienceofexpertsisessentialfordisciplineslikeneurotologywherethediagnosisisprimarilysymptom-drivenvery much like psychiatry and headache, where quite often there is no fool-proof histopathologic,radiographic, physiologic, or other independent diagnostic standard available. Though a lot of highprecision vestibular function tests areavailablenowwhich canpinpoint thedefect in the vestibularsystem, yetthere is substantial overlap in clinical features or biomarkers across syndromes inneurotology.ThetestsmayshowanabnormalityinthecVEMPsignifyingadefectinthesacculeofonesidebutthesacculardefectmaybetheresultofmanydifferenttypesofneurotologicaldisorderseachof which may require a completely different therapeutic approach. This does not in any wayundermine the value of the vestibular function tests and rather emphasises the importance of thetestsbeinginterpretedintherightwaybytherightpersontakingintoconsiderationdifferentinputsobtained /extracted from the patient. In neurotology, diagnosis is based on a judicious mix ofpresentingsymptoms,chronologyofthedisease,findingsoftheclinicalteststhatneedtobedonebytheclinician,theinvestigativefindingsthemostimportantofwhicharethevestibularfunctiontests,the patient’s response to previous treatment received for the disorder and above all the clinician’sclinical judgementand insight inneurotology. This requireshuman interfacingand isnot somethingthatcanbedoneby thecomputerorby remotecontrol.Neurotology isacompleteevidencebasedsciencetodaybuttheevidencerequirescorrectclinicalinterpretation.Thetreatmentisbasedontheaetiology of the disease, the extent of morbidity induced by the disease, the concomitantpsychological and cognitive changes. Management of neurotological disorders need a holisticapproachwhich isbestpossiblebyatrainedandexperiencedastuteclinicianwithspecial interest inneurotology.

Theguidelinesincludethefollowing:-

1. Specifyingpersonnelwhoareauthorised tocarryout themanagement (investigationsand/ortreatment)ofpatientspresentingwithneurotologicaldisorders(vertigoandotherformsofbalancedisorders).

2. Specifyingtheminimumclinicaltestsandinvestigationsnecessaryinpatientspresentingwithvertigoanddocumentingthem

3. Specifyingthe minimum infrastructure (instruments and personnel)of clinics whereneurotological evaluation can be carried out. The minimum standards that are to bemaintainedinneurotologicalinvestigationreportswhichincludesaudiologicaltestsalso

4. Specifyingcriteriafordiagnosisandmanagementofdifferentneurotologicaldisorders5. Specifyingnomenclatureofsymptomstobeusedforreportingbalancedisorders

1) PERSONNELWHOAREAUTHORISEDTOCARRYOUTTHEMANAGEMENT(INVESTIGATIONSAND/ORTREATMENT)

Only medical persons specifically doctors with special interest in NEUROTOLOGY (physicians,neurologists, otolaryngologists, neurotologists) are authorised to do the vestibulometric tests andtreat patients of neurotology. Even if the doctor is not doing the test himself/ herself, thevestibulometric test should essentially be doneunder the supervision of a qualifiedmedical personwhoisadeptinmanagingbalancedisorderpatientsandhasspecialinterestinneurotology.Thetestsmaybedonebyatrainedtechnicianbutonlyunderthesupervisionofamedicaldoctorwhoistrainedand /or has special interest in neurotology. The interpretation of the test findings in neurotologicalinvestigations is dependent on the clinical profile of the patient and needs to be analysed in thecontextoftheclinicalfindings.ThesubjectofneurotologyandthebalancesystemisuniqueinmanywaysAnormalfindinginoneormoreofthevestibularfunctiontestsdoesnotruleoutadisorderinthebalancesystemandadisorderfoundinonetestmaynothaveanybearinginthepatient’sbalancefunctionandmaybeclinicallyinsignificantorjustanincidentalfinding.Thisinnowayunderminesthevalue of the vestibulometric tests but highlights the necessity of a medical person with insight inneurotology for the relevance of the vestibulometric tests. The findings of the (correctly done)vestibularfunctiontestshavetobeinterpretedinthelightofotherfindingstobeclinicallyrelevant.Neurotological diagnosis is dependentona combinationof thedetailedhistory, the clinical findingsandtheresultsofthedifferentneurotologicaltestsallcollatedtogether;interpretinganeurotologicalreport is very different from interpreting a blood report or a radiological report. As per therecommendations of the INDIAN ACADEMY OF NEUROLOGY (Ref Indian Academy of NeurologyGuidelines in VERTIGO published by Elsevier 2013, page 44) and as agreed by the authorisedcommittee making the current Practice guidelines for patients presenting with neurotologicaldisorders, only vestibulometric reports authenticated by a doctor with special interest in vertigoshould be accepted; hence medically unauthenticated reports should be summarily rejected. Investibulometry, thequalityandcalibrationof the instrumentaswellas theauthenticityof theplacewhere the tests are done are of paramount importance and the vestibulometric tests are only asreliableasthepersondoingthetestandtheclinicianinterpretingthetestresult.Faultyinstruments,wrong persons performing the tests and a clinician unable to read the graphs and verify theauthenticity of the reports and consequently relying on erroneous test reports (done by somebodyelsewhoisinallprobabilitynotevenamedicaldoctor)withouttallyingthemwithclinicalfindingsandothertestresultshasdisastrousconsequencesandarebestabhorred.Nosingletest isastandalonetestinvestibulometryandtocorrectlyinterpretthetestresultsamedicaldoctorwithspecialinterestinneurotologyisessential.

2) THE MINIMUM CLINICAL TESTS AND INVESTIGATIONS NECESSARY INPATIENTSPRESENTINGWITHVERTIGOANDDOCUMENTINGTHEM

Clinicaltests:-

Inpatientspresentingwithbalancedisordersfirstageneralclinicalexaminationthatincludeslookingfor any overt medical disorder like anaemia/pedal oedema/pulse/BP, including test for orthostatichypotension, is mandatory. Once this is done, a basic neurological examination that includes acomplete evaluation of cranial nerves (at least the third, fourth, fifth, seventh and eighth cranialnerves),testsforanymotororsensorylossinthelimbsandtrunk,testforplanterresponse,testsforcerebellar function viz., finger nose tests, heel knee test and test for dysdiadokinesia and the deeptendonreflexesshouldbecarriedout.Finally,theclinicaltestsforbalancefunctionthatcomprisesofthefollowingisundertaken:–

a)VESTIBULO-SPINALTESTS

-Standingtesti.e.,theRomberg’stest

-Unterburger’sSteppingtest

-Gaittest

-Walkingonthefloorwitheyesclosedandfeettandem

b)VESTIBULO-OCULARTESTS

-Spont.nystagmus&otherabnormaleyemovement

-Gazenystagmus

-Smoothtrackingtest

-Saccadetest

-Convergence-divergencetest

-Positional/Positioningtests

-Headshakingtests

-Headimpulsetest

-Testforskewdeviation

Whenapatientpresentswithacutevertigo, theminimumclinical tests thatareessentially requiredandthefindingsofwhichneedtobedocumentedintheclinicalnotesoftheprescriptionare:–

-Testforspontaneousnystagmus.

-Headimpulsetest

-Testforskewdeviation

o Investigations:-

Evaluating the structural and functional integrity of the vestibular system requires atest batteryapproachi.e.,acombinationofdifferenttestsasnotestisastandalonetestasmentionedintheprevioussection.Also,asmentionedintheprevioussection,thebalancesysteminvolvesnumerousstructuresandbiologicalsystemsinthehumanbodyandthefunctionalstatusofmostifnoteachoftheseorgans/systemsneedtobeevaluatedforacomprehensiveassessment.Eachofthestructuresandtheinvolvedsystemshasadifferentfunctionwhichisuniqueinitsownwayandthedifferenttestsevaluatethedifferentstructures

/systems.Thethreesemi-circularcanalsmonitorangularmovementsinthreedifferentplanes,theutriclemonitorsfronttoback/backtofrontandsidetosidemovement,thesacculemonitorsup-downmovement;soeachpartofthevestibularlabyrinthmonitorsaveryspecifictypeofmovement.Testingonepartdoesnotgiveany informationof the functionalityofanotherpart.Apatientmayhaveadefect insensingup-down and down –up movements i.e., a saccular defect with perfect function of all other parts of thevestibularlabyrinth.AVNGtestoraVHITtestwillbeperfectlynormalinsuchapatientandonlyacervicalVEMP will be able to detect this defect but this patient too will present with more or less the samecomplaintothedoctorasadefect inanyotherpartof thevestibular labyrinth.Hencethenecessityofatestbatteryapproach.TheENG/VNGtestevaluatesjustthelateralsemi-circularcanalatalowfrequencyofvestibularstimulation,theoculomotorsystemandinmanycasesalsohelpstodocumentpresence/absenceofanypositionalnystagmus.TheoculomotortestsofVNGtestonlytheoculomotorsystem,thepositionalteststestonlyforthepresenceofapositionalvertigoandthecalorictestevaluatesonlythelateralcanal.Thevideohead impulse test (VHIT),evaluates thestatusof the threesemicircularcanalsoneachsideathigh frequenciesofvestibularstimulation.TheocularVEMPevaluatesthe functionof theutricleandthecervical VEMP evaluates the function of the saccule. The subjective visual vertical test evaluates theperceptionofthevisualvertical,whichisaveryimportantvestibularfunction.Modernresearchhasshownthe importance of evaluating the functional status of the vestibular system at different frequencies ofstimulation as some diseases affect only low freq stimulation of the vestibular system and some otherdiseasesaffectonlyhighfreqstimulationofthevestibularsystem.Thedifferenttestsofposturographylikestabilometry or computerised dynamic posturography and craniocorpography evaluates the posturalstability of the patient. The nerve conduction studies and the somatosensory evoked potential testsevaluatetheperipheralnervesandtheneuralpathwayinvolvedinthemaintenanceofbalance.Acompleteophthalmologicalevolutionisalsooftennecessarytoruleoutanydefectinthevisualinputtothebalancesystem.Imagingstudieshelptoruleoutanyspace-occupyinglesionoranyinfarction/haemorrhageoranydegenerativechanges(likesyringomyelia)inthepartsofthebrainorspinalcordthatisconnectedwiththemaintenanceofbalance.Quiteoften thepatientmaynotactuallybehavinganybalancedisorder that isvertigo or imbalance at all and the patient may be having some condition like orthostatichypotension/neuro-cardiogenicsyncope/panicdisorderbutmaypresentedtothedoctorwiththecomplainof head spinning only. Not only this, even many patients having primarily neurological disorders likedegenerativechangesaffectingthecerebellumortheextrapyramidalpathwaysmaypresenttothedoctorcomplaining of instability or even head spinning. Hence all these issues have to be looked into whenevaluatingapatientofvertigo/imbalance.Manyofthediseasescausingvertigoor imbalancealsohaveaconcomitantauditorysymptomslikeMénière’sdisease/labyrinthitis/perilymphfistula/acousticneuromaetc.;henceaudiologicaltestslikepuretoneaudiometryelectro-cochleography(ECochG),brainstemevokedresponse audiometry (BERA) is also sometimes necessary. The astute clinician has to combine differentteststogetan insight intothestructuralandfunctional integrityofthebalancesystemandestablishtheexact site of lesion and the aetiology. It is not being suggested that and all patients presenting withneurotologicaldisorderswillrequireeachandeveryneurotologicaltestconceivable,buttryingtoestablishdiagnosis on the basis of one or two tests is usually not possible and the back bone of diagnosis inneurotologyisatestbatteryapproachwheretherightcombinationofdifferenttestsasthoughtprudentbytheclinicianshouldbeundertaken.Testsshouldbeadvisedliberallyandnotconservativelyasthebalancesystem is a very complex system and to fathom the correct diagnosis a lot of investigations are usuallynecessary.Wheneverindoubt,itisalwaysprudenttooverinvestigateratherthanmissdiagnosisespeciallyinpatientssufferingfrombalancedisorderswherethemorbidityisveryhighandthereisalwaysmorethanafairchanceofalife-threateningandsinisterunderlyingdisease.Howevertheinvestigationsareinnowayan alternative to a detailed history taking and clinical examination and the findings of the differentvestibularfunctiontestsonlymakessensewhencorrelatedwiththehistoryandclinicalfindings.

3) THEMINIMUMINFRASTRUCTURE(INSTRUMENTSANDPERSONNEL)OFCLINICSWHERENEUROTOLOGICALEVALUATIONCANBECARRIEDOUT

A neurotological clinic has the following infrastructure as regards personnel and investigativemodalitiesi.e.,instruments:–

a. Personnel– amedical doctorwith special interest in neurotology, qualified audiologist andtrained technicians (preferably qualified computer graduates) capable of operating thediagnosticequipment.Asaverydetailedclinicalhistory-takingisthefirststepintheapproachto the management of a vertigo patient, the setup must have a dedicated person or acomputer program with a proper format for detailed history taking which will be finallyevaluatedbythemedicaldoctor.

b. Instruments–

Vestibularfunctiontestsfacilitiesthatinclude:-

ENG-Electronystagmography

VNG-Videonystagmography

oVEMP-OcularVestibularevokedmyogenicpotentials

cVEMP-CervicalVestibularevokedmyogenicpotentials

VHIT-Videoheadimpulsetest

DVA-Dynamicvisualacuitytest

SVV-Subjectivevisualverticaltest

Posturography

CCG–Craniocorpography

thesetupshouldalsohavefacilitiesforthefollowing:–

PTAudiometrywithlocalisingtests

BERA-Brainstemevokedresponseaudiometry

ECochG–Electrocochleography

Theminimum requirementsshould be a Videonystagmography (VNG) setup complete withoculomotor tests, a set up for video head impulse test (VHIT) and a complete evoked potentialmachinecapableofECochG,BERAand theocularandcervicalVEMPtestsandaproperlycalibratedpuretoneaudiometrymachine.

c.Reportformats:-

1. AudiometryreportsMUSThavethelastdateofcalibration(whichisusuallyprintedbydefaultinmostmachine printouts of computerised audiometers or if amanual instrument is usedthenthecopyofthecalibrationcertificate)andtheMaskingvaluesusedduringbothairandbone conduction testsmentioned in the PTA report.No P T Audiometry report is completeuntilthemaskingvaluesindBarespecifiedinthereport

2. Allevokedpotentialreports(BERAECochGVEMPNCV)musthavethelastdateofcalibrationoftheinstrumentprintedinthereport

3. VHITreportsmustmentiontheinstrumentused

4. ENGVNGBERATympanometry reportsmusthave theprintoutsof all graphsattachedwiththereport

5. Allvestibulometricreportsmustbesignedandauthenticatedbyamedicaldoctor

4) MANAGEMENTofSOMECOMMONNEUROTOLOGICALDISEASES

A. MENIERE’SDISEASE:-a. Criteria:

Tobe labelledasMeniere’sdiseasethe followingcriteria (aspar theBaranySociety,EAONOandAmericanAcademyofOtolaryngology)mustbefulfilledviz

i.Twoormorespontaneousepisodesofvertigo,eachlasting20minutesto12hours;

ii. Audiometrically documented low- to medium-frequency sensorineural hearing loss in theaffectedearonatleastoneoccasionbefore,duringorafteroneoftheepisodesofvertigo;

iii.Fluctuatingauralsymptoms(hearing,tinnitusorfullness)intheaffectedearand

iv.Notbetteraccountedforbyanothervestibulardiagnosis.

b.Diagnosis:

A. Thediagnosisisbasicallyfromhistoryofepisodicattacksofunprovokedvertigothatfulfiltheabove mentioned criteria with ear symptoms of tinnitus and deafness mainly in the lowfrequencies (only high freq hearing loss with normal hearing in the low frequencies is notpathognomonicorisanacceptedcriteriaforMeniere’sdisease).TherearecriteriafordefiniteMeniere’s disease/probableMeniere’s disease / possibleMeniere’s diseaseoutlinedby theAmerican Academy of Otolaryngology which may be used in qualifying the suspectedMeniere’sdiseasebasedonthelevelofevidenceavailableforsuspicionofMeniere’sdiseasebutinclinicalpracticethefourabovecriteriashouldsufficeforstartingtreatmentofMeniere’sdisease

c.Investigations:

i. TheessentialinvestigationsinsuspectedMeniere’sdiseaseare1. the Pure Tone Audiometry to document the hearing loss(aswithout documentable

sensorineuralhearing loss it cannotbe labelledasMeniere’sdisease)with localizingteststoensurethatitisacochlearandnotaneuraldisorder,

2. aBERAforsiteoflesiontoconfirmativelyruleoutaneurallesion3. theGlyceroltestand4. ECochG.

ii. ApositiveglyceroltestandSP:APratioabove0.45inECochGincreasestheindexofsuspicionand all patients suspected of Meniere’s disease should be advised both glycerol test andECochGeveniffacilitiesmaynotbeavailableeverywhere.

iii. IndiseaseslikeMeniere’sdiseasewherealongtermmedicationwithdrugshavingprominentside–effectsarerequired,averystrongindexofsuspicionisnecessarybeforeembarkingonlongtermtreatment.

iv. Forconfirmationandindoubtfulcases,intra-tympanicgadoliniumenhancedMRIoftheinnerearofthesuspectedsideisnecessarybutisnotmandatory;theminimumisthetypicalhistoryand the audiological tests.However such facilities are not available everywhere and even ifavailableitneednotbealwaysdoneduetothecostsinvolvedandlackofstandardizationoftechnique.

v. VestibularFunctiontestsatleast1. VHIT,2. VNGwithcalorictestsand3. VEMPtest(bothcervicalandocular)withboth500Hzand1000Hzstimulus

is indicatedtodocumentthevestibularstatus.TheVHIT isoftennormal,thecaloricVNGmayormaynotbenormalandVEMPtoomayormaynotbenormal.NormalvestibularfindingsdonotruleoutMeniere’sdisease

vi. Documentationofvestibularstatusisimportantfortreatmentandtoascertainprognosisbutisnotessentialfordiagnosis.

vii. InearlycasesthecaloricVNGmayormaynotbeabnormalbutVHITisoftennormal.

viii. In advanced cases where there is permanent damage of the semicircular canals of thevestibularlabyrinth,theVHITisabnormal.

ix. In Meniere’s disease if there is evidence of otolithic organ involvement (as suggested byabnormalVEMPresults)thepatienthaschancesofdevelopingTumarkin’scrisisandispronetosuddenunprovokedfallswithseriousconsequencesandsuchpatientsshouldessentiallybeputonMeniere’sprophylactictreatmenteveniftheattacksareinfrequent.VEMPshoulddoneatboth500and1000HzasasignificantlyhigheramplitudeofVEMPwitha1000Hzstimulusascompared to thatwitha500Hzstimulus isverysuggestiveofMeniere’sdisease. InallotherdiseasesandinnormalearstheVEMPamplitudeisusuallyhighestwitha500Hzstimulus

d.Treatment:

i. Asregardstreatmentforpatientshavingjustoneorlessattacksinthreemonthsjustasingledoseofabortivetreatmentduringtheattackpreferably justbeforetheattack if thepatientcanpredictitbynoticingtheauralchangesorifnotpossiblethenimmediatelyatthestartofthe attack with one ormore of vestibular sedatives like DIMEMHYDRINATE/MECLIZINE /PROCHLORPERAZINEandaDIURETIClikefurosemideandinsomecasesaanxiolyticdruglikeCLONAZEPAM / DIAZEPAM usually suffices. The patient may remain slightly sick for somehoursaftertheattacksubsidesbutitdoesnotrequireanyothertreatment.

ii. If the attacks are more than 2 attacks in three months than a long term prophylacticmedicationiswarranted.

iii. Theprophylacticmedical treatment is for3months initially and if symptoms regressboth infrequencyofattacksaswellasinintensitythentobecontinuedfor6monthsasfollows:-

1. One or more DIURETICS like ACETAZOLAMIDE and SPIRONOLACTONE, FUROSEMIDE,AMELORIDE with no other medicines (i.e., vestibular sedatives) for suppression of vertigo.Dietarysaltrestrictionto2-4grams/daywhichisoftenadvocatedisnotevidencedbasedandisnotrecommended.

2. Iftheclinicianthinksitprudentorthereareveryfrequentrecurrentattacksofvertigoand/orifthereareproblemslikeelectrolyteimbalance,hypotensionorotherproblemswithdiuretics,thenBETAHISTINEatdosesabove144mg/day in3divideddosesmaybeprescribedbut thedosage (definitely above 144mg/day) needs to be titrated against symptoms. Thepharmacologyrecommendeddosagesof48mg/dayandhigherdosesofupto144mg/dayhasbeen shown to be completely ineffective and comparable to placebo inMeniere’s disease.(ref, BMJ 2016;352:h6816http://dx.doi.org/10.1136/bmj.h6816 Christine Adrion, CarolineSimoneFisher,MichaelStruppetal;EfficacyandSafetyofBetahistine treatment inpatientswithMeniere’sdisease:primaryresultsofalongterm,multicenter,doubleblind,randomized,placebo controlled dose defining trial (BEMED trial) ; British Medical Journal 2016:352).Hencethedosesofbetahistinebelow144mg/dayarenotrecommended

3. Dependingonseverityofsymptomstheclinicianmayintheinitialstagesusebothdiureticsaswellasbetahistine(above144mg/day)together.

iv. Avoidance of Nicotine and caffeine especially caffeine-containing food and drinks, such ascoffee,tea,andchocolate,isrecommendedalongwith.

v. Ifthistreatmentfails(nosignificantreductioninintensityandfrequencyofattacksofvertigo)then and only then Intratympanic Gentamicin(ITG) low-dosage (26.6mg/ml) treatment isrecommendedafteratrialofat least6monthsofmedicaltreatment. ITGtreatment istobe

attempted at a frequency not more than once every 7 days and the reduction (if any) insymptomsmonitored.

vi. Ifnosignificantimprovementtakesplacethenafter3injectionstheITGtreatmentshouldbestoppedandthepatientobservedforatleast3months.

vii. AfterthatadecisiononSurgicaltreatmentintheformofselectiveVestibularneurectomy(in case of serviceable i.e., residual hearing better than 70dB is present) but if there is noserviceable hearing then a Labyrintectomy is to be done. If surgical treatment (i.e.,labyrinthinede-afferentation)isdonethenrigorousanddiligentVESTIBULARREHABILITATIONexercisesaremandatoryforthefirst6weeksaftersurgery.

viii. InbilateralMeniere’sdisease,autoimmunebackgroundshouldbeconsidered;hearinglossisgenerallythemajorconcern,choiceoftreatment(especially infailureonmedicaltreatment)shouldbeindividualizedbutSteroidsshouldbeincludedbutotherwisetreatmentshouldbeinthesamelinesasunilateralMeniere’sdiseaseexceptthatITGtreatmentandlabyrinthectomyshouldbestbeavoidedasthereisadefinitechanceoffurtherhearinglossintheseproceduresespeciallyinthelater.

B. BPPV:-

a. tobesuspectedfromthetypicalhistoryofverybriefspellsofvertigoonlyonchangeofheadpositionanddiagnosedconfirmativelyonlybyclinicaltests;

b. If required a Video Frenzel glasses may be used for documentation but clinical naked eyeexaminationofthepatient’seyesissufficienttodiagnoseanypositionalvertigo.

c. Ordinarilythedetailedvestibular functiontests (i.e., investigationsofvestibular function likeVNG, VHIT, VEMP, SVV, DVA, posturography) are not recommended if history and clinicalpositionaltestslikeDixHallpiketestsaretypicalofBPPV.

d. Thefirst linetreatment inposteriorcanalBPPViseitherEpley’sorSemont’smaneuvers,notbothtogether.

e. MedicaltreatmentwithantivertigodrugshaveNOroleinthetreatmentofdefiniteposteriorcanal geotropicbenignpositional vertigowhich is the commonest formofpositional vertigoandevenifthepositionalvertigoisageotropic.

f. Mastoid vibration isnotrecommendedduringthemaneuversastheyhavenotbeenfoundtobeadditionallybeneficial.

g. Vestibularsedativemedications(antivertigodrugs)likeProchlorperazineorDiazepammaybeusedasasingledoseonlytoimprovecomplianceduringmaneuvers.

h. Incaseof failureof firstmaneuvertheothermaneuvermaybetriedor thesamemaneuverrepeated.Butifthefirstmaneuverfails,beforetryingamaneuveronceagainitisjudicioustore-think about the diagnosis and repeat the detailed history taking as well as the clinicalneurotologicalassessmentofthepatientandcarryoutadetailedvestibularfunctiontest.

i. Justonemaneuverifproperlydonesufficesinonesessionandrepeatingthesamemaneuverseveraltimesisbestavoided.

j. The Brandt-Daroff exercises at home are not to be adviced if the Epley’s or Semont’smaneuver is properly and successfully done. The Brandt-Daroff exercises at home are bestrecommendedforthosepatientswhohaveaverymildpositionalvertigooroncaseswherethe symptoom of vertigo only without any perceptable nystagmus is there during thepositionaltestsoriftheclinicianisnottoosureaboutthesideofthepositionalvertigoinDixHallpiketests.

k. Surgery(canalpluggingorsingularneurectomy)isnotrecommendedbefore1yearoffollow-up and is to be done only after themaneuvers have repeatedly failed but the diagnosis ofbenignpositionalvertigooftheposteriorcanalisverycertain.

l. Post maneuver movement restrictions are not recommended. There is no restrictions todrivingafewhoursafterthemaneuverisdone.

m. IngeotropiclateralcanalBPPVwhichisdiagnosedbythesiderolltestbymakingthepatientturntheheadlaterallytotheleft/rightinstraightsupinepositionfirstlinetreatmentisthe

Barbecue, Gufoni or Vannucchi maneuvers. Just one of the three maneuvers not all threetogetherisrecommended.

n. Like theposteriorcanalBPPVvestibularsedativemedications (antivertigodrugs)havea roleonly to improve compliance during maneuvers and may be given just once prior to themaneuver in very apprehensivepatientsbut there isNO roleof anti vertigodrugs in lateralcanalBPPV.

o. If one maneuver is ineffective then the same maneuver may be repeated or anothermaneuveri.e.,oneofthetwoothersmaybetried.Ifthefirstmaneuverfailsinspiteofdoingit satisfactorilya rethink on the diagnosis and a detailed vestibular function test isrecommended.Heretoomastoidvibrationandpostmaneuverrestrictionofheadmovementisnotrecommended.

p. Surgical plugging of the lateral canal is recommended after at least one year of repeatedlytrying the recommenedmaneuvers and repeatedly failing toprovide relief for a substantialperiodwiththeproperlycarriedoutmaneuvers.

q. In ageotropic lateral canal BPPV, try to transform the ageotropic nystagmus to geotropic toexclude central vestibular system involvement. This is often possible by vigourous headshaking.AfterthatGufoni/modifiedGufoniorVannucchimaneuversistobetried.WheneveronemaneuverisfoundineffectiveanothermaneuverforthesameBPPVtypeeistobetriedora repetition of the firstmaneuvermay be attempted but before that thae patientmust bethoroughlyreassessedforconfirmationofdiagnosisandtoexcludeanyotherpossiblecauseofvertigo.

r. Anterior canal BPPV is a controversial entity and there is currently no consensus ontreatmenmtthoughmanymaneuvershavebeenproposed.AdifferentiationfromacerebellardisorderistobecarriedoutwheneveranteriorcanalBPPVissuspected.

s. Wheneverthereisasuspecionofmultiplecanalinvolvementonecanalatatimeistobetriedandthemostsymptomaticcanalshouldbetriedfirstbytherequisitemaneuver.

t. Even in multiple canal BPPV there is no scope of continued medical treatment with antivertigodrugs.Justonedoseifrequiredhalfanhourbeforethemanueverinveryapprehensivepatientsisthemaximumpermissible.

C. VESTIBULARNEURONITIS:-

1. A better term is Acute Unilateral Vestibulopathy as the clinician is not sure about thepathophysiologywhenthepatientpresents.

2. Presentation:i. The presentation is usually of an acute onset of sudden severe vertigowhich often

persists formore than one day but definitely less than seven days the usual periodbeingonetothreedays.

ii. There is no accompanying deafness or any other aural symptoms and no CNSsymptomslikeheadache,diplopia,anymotor/sensorylossoranydrowsinessorlossofconsciousness.

iii. Classical features like this are not usually present as most patients have somevestibular sedatives or CNS depressants or some anti-emetics (because of theaccompanying nausea-vomiting along with the vertigo) which alters the presentingfeature.

iv. Theclassicalclinicalsignsareadirectionfixedhorizontalnystagmusbeatingeithertothe left or to the rightwithout any skew deviation of the eyes and a positive headimpulsetestonthesideoppositetothedirectionofnystagmus(i.e.,aleftsidedheadimpulsetest+vewitharightbeatingnystagmus).

v. Anyataxiamustalwaysbelookedforinvestibularneuronitisthepatientshouldnotatall be ataxic though a mild instability is not unusual. Ataxia or severe instability isstrongly suggestive of a central lesion. In all patients presentingwith sudden onsetacute vertigo a cerebellar stroke must be mandatorily ruled out as acute cerebro-vascular accident in the cerebellum often presents with a perfectly similar

presentationandmayperfectlymimicvestibularneuronitis.Themosteffectivewayofrulingitoutwithinthefirst24hoursistheHINTStest.

1. TheclinicianmustspecificallycarryoutA. thehead impulse testclinicallyorbetter still ifavailable thenaVHIT

test; - a +ve head impulse test rules out a cerebellar stroke andconfirms that the nystagmus is a due to a peripheral vestibulopathybutanegativeheadimpulseteststronglysuggeststhatthereisaCVAinvolvingthecerebellum,

B. look at the nystagmus at least for 2-3minutes and seewhether thedirection of the horizontal nystagmus is fixed i.e, always to onedirection or is it changing in direction i.e., a left beating nystagmusbecoming right beating and vice versa, the clinician should alsospecifically look for any vertical nystagmus - any direction changingnystagmus or any vertical nystagmus is pathognomonic of a centrallesionlikeacerebellarstrokeinsuchpatientsand

C. Theclinicianmustalsospecifically lookforanyskewdeviationoftheeyesoranyoculartiltreaction-anyskewdeviationoranyabnormaloculartiltsuggestsacentrallesion.

vi. Thedifferentialdiagnosis tobeconsidered in suchcaseswhere thepatientpresentswithacutevertigoare

1. firstattackofanattackofVestibularMigraine,2. first attack of Meniere’s disease where the aural symptoms may not be

present or are somild that they are not noticed by the patient andwhat ismostimportantis

3. Acerebellar/brainstemstroke.vii. Thediagnosis is primarily by a thoroughhistory anda clinical examinationwhere at

leasttheclinicaltestsmentionedabovearecarriedoutanddocumented.viii. However if there is any signof a central lesion like –vehead impulse test, direction

changingnystagmusorverticalnystagmus, skewdeviationordefiniteataxia thenanurgentMRIofthebrainespfocusonthecerebellumandbrainstemissuggestedandifthe MRI is normal then a repeat MRI with contrast after 24 hours of onset issuggested.

ix. ButifthecentralfeaturesarenotthereonclinicalexaminationthentheMRIofbrainisnotindicated.

x. Treatmentofvestibularneuronitisi.e.,ifacentrallesionhasbeenruledoutthen;-1. firstlinetreatmentissymptomatictreatmentwithprochlorperazineforfirst1-

3 days only and steroids (I.V. steroids for 1-2 days if patient is vomiting)otherwiseoralsteroidswhichisslowlytaperedoff.

2. Thepatient is encouraged tobe active and tomove about, stay in a lightedroomandtostartthevestibularrehabexercisesfromdayoneinitiallyonlytheexercises in sitting position and then as soon as possible the standing andwalkingexercises.

3. If some symptomspersist even after sevendays then a fresh neurotologicalassessment of the patient and a re-think on the diagnosis and the detailedvestibular function tests that include VNG, VHIT, ocular and cervical VEMP,dynamic visual acuity, subjective visual vertical test etc along with a puretoneaudiometryaretobecarriedout.

4. In all such patients rigorous Vestibular rehabilitation exercises ismandatoryandtheclinicianshouldinstructthepatientandfamilymembers/caregiversaccordingly.

5. Thereisnoindicationforsurgicaltreatmentinallsuchpatients.6. In case of long-term residual dizziness after unilateral vestibular loss, no

medical treatment is recommended and in all such patients’ propercounsellingandrigorousvestibularrehabexercisesisrecommended.

7. Of course in case the detailed vestibular function tests have not been donethen all the vestibular function testsmentioned above are to be essentiallydonealongwithimagingstudies(MRI)ofthebrain.

8. Vestibularsedatives/anti-vertigodrugsshouldneverbecontinuedinallsuchpatientsformorethan3-7daysatthemost.Theconsensusistolimititto3-5daysonlyandthisistherecommendationoftheIAOHNS.

9. Infactmanyauthoritiessuggestthatdrugsthatexertasedativeeffectonthevestibularsystemshouldbediscontinuedafterthefirst24hours.

D. MigraineRelatedVertigo/MigraineAssociatedVertigo/VestibularMigraine

a. History: History is the most important means to diagnose migraine-associatedvertigo.Patientswithmigraine-related vestibulopathy typically experiencea varied rangeofdizzysymptomsthroughouttheirlifeandtheattacksarenotnecessarilythesameeverytime;attacksmaybesimpleheadspinningi.e.,aspinning/rotatingsensation(truevertigo)ormaybephasesofjustataxia/imbalancewithoutanytrueheadspinningormayevenbephasesoflight headednessor may be a combination of vertigo, light-headedness and imbalance. Athoroughheadachehistory isalso importantwhenevaluatingpatients forpossiblemigraine-associatedvertigo.Nodefinitivediagnostic testsexistwhich ispathognomonic formigraine-associated vertigo. When the history is unclear, the diagnosis is made by a therapeuticresponse to treatment and by ruling out other possible causes. Due to its proteanmanifestationsandvariednatureofpresentationaswellasthe lackofanymarker/definitediagnostic test, diagnosis is difficult and Vestibular Migraine is basically a diagnosis byelimination. In a suspected case of Vestibular Migraine due to lack of definitive diagnosticcriteriarequisitenotesofhistoryandclinicalfindingsmustbedocumentedintheprescriptiontoavoidambiguitylater.AfamilyhistoryofMigraine,historyofmotionsicknessandhistoryoftypicalMigraineheadacheseithertime-lockedwiththevertigoorevenifoccurringseparatelyare important diagnostic parameters and thepresence / absenceof anyof these shouldbespecificallyaskedforanddocumented.

DiagnosticcriteriaforVestibularmigraineasproposedbytheBaranySocietyandotherorganisationslikeInternationalHeadacheSocietywithsmallchanges(numbersinsuperscriptdetailedbelow)areasfollows:-

1) CriteriaforDefiniteVestibularMigraine

A. At least5episodeswithvestibularsymptoms1ofmoderateorsevere intensity2, lasting5minto72hours3

B. CurrentorprevioushistoryofmigrainewithorwithoutauraaccordingtotheInternationalClassificationofHeadacheDisorders(ICHD)4

C. Oneormoremigrainefeatureswithatleast50%ofthevestibularepisodes5:

–headachewithatleasttwoofthefollowingcharacteristics:

• Onesidedlocation,pulsatingquality,

• Moderateorseverepainintensity,aggravationbyroutinephysicalactivity

• photophobiaandphonophobia6,

• visualaura7

D. NotbetteraccountedforbyanothervestibularorICHDdiagnosis8

2) CriteriaforProbablevestibularmigraine

A. At least5episodeswithvestibularsymptoms1ofmoderateorsevere intensity2, lasting5minto72hours3

B. Only one of the criteria B and C for vestibular migraine is fulfilled (migraine history ormigrainefeaturesduringtheepisode)

C. NotbetteraccountedforbyanothervestibularorICHDdiagnosis8

Notes:

1. Vestibularsymptomsinclude:

o spontaneousvertigoincluding

§ internalvertigo,afalsesensationofselfmotion,and

§ external vertigo, a false sensation that the visual surrounding is spinning orflowing,

o positionalvertigo,occurringafterachangeofheadposition,

o visually-inducedvertigo,triggeredbyacomplexorlargemovingvisualstimulus

o headmotion-inducedvertigo,occurringduringheadmotion,

o headmotion-induceddizzinesswithnausea.

Dizzinessischaracterizedbyasensationofdisturbedspatialorientation.Otherformsofdizzinessarecurrentlynotincludedintheclassificationofvestibularmigraine.

v Vestibular symptoms are rated “moderate”when they interferewith but do not prohibit dailyactivitiesand“severe”ifdailyactivitiescannotbecontinued.

v Durationofepisodesishighlyvariable:About30%ofpatientshaveepisodeslastingminutes,30%haveattacksforhoursandanother30%haveattacksoverseveraldays.Theremaining10%haveattacks lasting seconds only, which tend to occur repeatedly during head motion, visualstimulation, or after changes of head position but sometimes even completely unprovoked. Inthesepatients,episodeduration isdefinedas the totalperiodduringwhichonesingleattackofvertigo/dizziness/imbalancepersists.Attheotherendofthespectrum,therearepatientswhomaytakeafewweekstofullyrecoverfromanepisode.However,thecoreepisoderarelyexceeds72hours.However thoughaspermost guidelines attacksof vestibularmigraine shouldnot lastmorethan72hours

v Migraine categories 1.1 and 1.2 of the ICDH[International Headache Society ClassificationSubcommittee, International Classification of Headache Disorders.2ndEdition,Cephalalgia24(Suppl1)(2004)].

o 1.1 Migraine without aura: Previously used terms: Common migraine; hemicraniasimplex. Description: Recurrent headache disorder manifesting in attacks lasting 4-72hours. Typical characteristics of the headache are unilateral location, pulsating quality,moderateorsevereintensity,aggravationbyroutinephysicalactivityandassociationwithnauseaand/orphotophobiaandphonophobia.Diagnosticcriteria:A.At leastfiveattacksfulfillingcriteriaB–DB.Headacheattacks lasting4-72hours (untreatedorunsuccessfullytreated) C. Headache has at least two of the following four characteristics: 1. unilaterallocation .2 pulsating quality. 3moderate or severe pain intensity 4. aggravation by orcausing avoidance of routine physical activity (e.g. walking or climbing stairs) D. Duringheadache at least one of the following: 1. nausea and/or vomiting 2. photophobia andphonophobiaE.NotbetteraccountedforbyanotherICHD-3diagnosis.

o 1.2Migrainewith aura: Recurrent attacks, lastingminutes, of unilateral fully reversiblevisual,sensoryorothercentralnervoussystemsymptomsthatusuallydevelopgraduallyand are usually followed by headache and associated migraine symptoms. Diagnosticcriteria:A.At least twoattacks fulfillingcriteriaBandCB.Oneormoreof thefollowingfullyreversibleaurasymptoms:1.visual2.sensory3.speechand/orlanguage4.motor5.

brainstem6. retinal C. At least two of the following four characteristics: 1. at least oneaurasymptomspreadsgraduallyover5minutes,and/ortwoormoresymptomsoccurinsuccession 2. each individual aura symptom lasts 5-60 minutes 3. at least one aurasymptom is unilateral 4. the aura is accompanied, or followed within 60 minutes, byheadache D. Not better accounted for by another ICHD-3 diagnosis, and transientischaemicattackhasbeenexcluded.

v Oneaccompanyingsymptomissufficientduringasingleepisode.Differentsymptomsmayoccurduringdifferentepisodes.Associatedsymptomsmayoccurbefore,duringorafter thevestibularsymptoms.

v Phonophobia isdefinedassound-induceddiscomfort. It isatransientandbilateralphenomenonthat must be differentiated from recruitment, which is often unilateral and persistent.Recruitment leadstoanenhancedperceptionandoftendistortionof loudsounds inanearwithdecreasedhearing.

v Visualaurasarecharacterizedbybrightscintillatinglightsorzigzaglines,oftenwithascotomathatinterfereswithreading.Visualaurastypicallyexpandover5–20minutesandlastforlessthan60minutes.Theyareoften,butnotalwaysrestrictedtoonehemi-field.Othertypesofmigraineaura,e.g.somatosensoryordysphasicaura,arenotincludedasdiagnosticcriteria

v Historyandphysicalexaminationsdonotsuggestanothervestibulardisorderorsuchadisorderisconsideredbutruledoutbyappropriateinvestigationsorsuchdisorderispresentasacomorbidorindependent condition, but episodes can be clearly differentiated. Migraine attacks may beinduced by vestibular stimulation. Therefore, the differential diagnosis should includeothervestibulardisorderscomplicatedbysuperimposedmigraineattacks.

Thereisalsoaclassofpatientswhohaverecurrentepisodesoftruevertigo/ instabilitywithoutanyotheraccompanyingsymptomsrelatedeithertotheearsortothecentralnervoussystemanddonothaveanyhistoryofheadaches.Thedurationmaybeanythingbetweena fewsecs tomore than72hours. The important criteria are the recurrent episodic nature of the presentation with perfectlynormal symptom freeperiods. Though this doesnot fall directly into theBarany Societyor the IHScriteria, yet there are a large number of patients who fall in this category. These patientsmay bediagnosedasPossibleVestibularMigraineandwarrantsatherapeutictrialwithmigraineprophylactictherapy.Theverygoodresponseobtainedfrommostofthesepatientswithmigrainetherapyjustifiesthetherapeutictrialprovidedofcourseothercausesofvertigohavebeenruledout.

Transient auditory symptoms, nausea, vomiting, prostration, and susceptibility to motion sicknessmaybeassociatedwithvestibularmigraine.However,astheyalsooccurwithvariousothervestibulardisorders theyarenot includedasdiagnostic criteria.Provocationofanepisodecanbeadiagnosticclue. Menstruation, stress, lack of sleep, dehydration, and certain foods that are known to triggermigraineheadachesmayalltriggerattacksofMigraineassociatedVertigo/Vestibularmigraine,butarenotincludedasdiagnosticcriteria.Howeverthehistoryofsuchprecipitatingfactorsmustbeaskedforanddocumented.

Themaindifferentialdiagnosisisfrom:-

• Meniere’sDisease• BPPV• EpisodicAtaxiatype2• SpontaneousMaldedebarquementsyndrome• TransientIschemicAttacks

Requisite leading questions to rule out these clinical conditions need to be asked to every patientsuspectedof havingVestibularMigraine. The salient features of these abovementioneddisorders isbeyondthescopeofthisguideline.

The most difficult differentiation of Vestibular Migraine is from Meniere’s disease and positionalvertigo(BPPV).

a. Physicalexamination:

Complete neurotologic and Neurologic clinical examination Neurotologic examination are oftennormal. Horizontal rotary spontaneous nystagmus may be present during an acute attack ofvertigo be it VestibularMigraine orBPPV but in BPPV itwill only be in specific positions of theheadandforverybriefdurations.Therewillbenonystagmusinotherheadpositionsorwhenthepatientissittingstraightorlyingflat.Dix-Hallpikeexaminationmayelicitsymptomsofvertigowithor without nystagmus. When it is without nystagmus and in multiple head positions the firstdiagnosis should be Vestibular Migraine as migraine patient patients very often have motionintoleranceandsuddenchangeofheadpositionelicitsaseverediscomfortwhichtheyreportasvertigo;howeverpresenceofnystagmus indifferentheadpositionsdoesnotruleoutVestibularMigraine. Vestibularmigrainemay presentwith purely positional vertigo, thusmimicking BPPV;hencedifferentiationisimportant.Investibularmigraine,positionalnystagmusifatallpresentisusually persistent, occurs in multiple head positions and not aligned with a single semicircularcanal. Very often there is no nystagmus but patient complains of vertigo in vestibularmigrainebecauseofthemotionintoleranceasexplainedabove.Symptomaticepisodestendtobeshorterwith vestibularmigraine (minutes to days rather thanweeks) andmore frequent (several timesperyearwithvestibularmigraineratherthanonceeveryfewmonths/yearswithBPPV).InBPPVthereisdefinitenystagmusinonlyoneortwospecificheadpositionsandthehistoryisofvertigoof brief durations (secs only) that occurs recurrently for a few days at a stretch whereas inVestibularmigrainetheremaybeoneattackinafewdaysorafewmonthsandusuallynotoveraspan of several days followed by a symptom free period of several months which is typical ofBPPV. When in doubt it is wise to try a suitable liberatory maneuver like Epley’s / Semont’s/Guffoni’setc;BPPVshouldrespondverywelltotheliberatorymaneuversbutVertiginousMigrainewillnot;infactifapatientpresentingwithtypicalpositionalvertigodoesnotrespondadequatelytocorrectlydoneliberatorymaneuversVestibularMigraineshouldbethoughtofasthecauseanda therapeutic trial with Migraine prophylactic medication instituted. There is a complicatedrelationshipbetweenVestibularMigraineandBPPV.BPPVpatientsaremorelikelytohavemotionsickness and / or Migraine headaches. Patients with subjective positional vertigo but withouttypical signs aremore likely to havemigraine (ref Agarwal, Bronstein ‘Visual Dependence andBPPV’journalofNeurology2011;259:1117-24)Itishoweverpossiblethatasmigrainepatientsareusually very sensitive to motion they probably seek medical attention more easily than nonmigrainepatients.Vertigoattacksareknowntotriggermigraine.Therelationshipiscomplexandbecauseoftheoverlapofsymptomsthedifferentiationbetweenpositionalvertigoandvestibularmigraineisoftennotveryeasybutessentialinallpatientsofsuspectedvestibularmigraine.

Fluctuatinghearingloss,tinnitusandauralpressuremayoccurinvestibularmigraine,buthearinglossdoesnotprogresstoprofoundlevelsasinMeniere’sdisease

b. Investigations:Investigations suggested are (1)PT audiometry (even if the patient does not complain of anyhearing disorder), (2)Vestibular Function tests at least a VNGwith oculomotor tests and calorictest,cervicalandocularVEMPat500and1000Hz,VideoHeadImpulseTestand(3)Imagingofthebrain

1. Nopathognomonicabnormalitieson imagingstudiesorvestibulartestingeitherconfirmorruleoutmigraine-associatedvertigo.Theyarehelpfulonlytoruleoutothercausesofvertigo.

2. Audiometricevaluation

Pure-tone audiometry, word recognition scores, and reflex testing –is usually normal.Audiometry may show concurrent hearing loss which may be due to other causes orsometimes due to migraine induced spasm of the cochlear blood supply; hence thoughdeafness is not expected in Migraine associated vertigo, yet presence of deafness /earsymptomsdoesnotruleoutmigraineassociatedvertigo.Butinsuchcaseswheredeafnessispresent,differentiationfromMeniere’sdiseaseisdifficultbyhistoryalone.Whenthecriteriafor Meniere’s disease are met, particularly hearing loss as documented by audiometry,Meniere’sdiseaseshouldbe the firstdiagnosis,even ifmigrainesymptomsoccurduring thevestibular attacks. Under such circumstances where there is a diagnostic dilemma,investigationslikemulti-frequencyVEMPs,ECochGandGlyceroltestsarehelpfulastherearedefinitediagnosticfeaturesforalltheseinvestigationsinMeniere’sdisease

3. Electronystagmography(ENG) or videonystagmography (VNG)is typically not helpful indifferentiatingmigraine-associatedvertigofromMénièredisease.However,forpatientswithaseveral-yearhistoryofdizziness,normal findingsonENGaresuggestivebutneverdiagnosticof migraine-associated vertigo. Documentable oculomotor problems are suggestive ofMigraineassociatedVertigo

4. Electrocochleography

Patientswithaseveral-yearhistoryofMénièrediseaseoftenhaveareducedvestibularresponseonatleast1side.Electrocochleography(ECochG)mayhelptodifferentiateMénièrediseasefrommigraine-associatedvertigo.AhighSP:APratioisindicativeofMeniere’sdisease

5. Vestibularevokedmyogenicpotential

Cervical vestibular evokedmyogenic potentials (cVEMPs) : In vestibularmigraine and even normalears the amplitude of cVEMP is higher if 500Hz stimulus is used compared to 1000 hz stimulus. InMeniere’s disease the cVEMP amplitudewith 1000Hz is higher thanwith 500Hz stimulus. This is adiagnosticfeatureofMeniere’sdiseaseandhelpstoruleoutMigraineAssociatedVertigo

6. Caloric testing: Caloric unilateral or bilateral weaknessmay be seen but is not diagnostic.CalorizationmayinfacttriggeranattackofMigraineassociatedVertigo.

7. MRIofthebrainwithgadoliniumisnecessarywhenpatientspresentwithunilateralsymptomsorsignsorifthepatient'ssymptomsdonotrespondtoappropriatetreatment.Ifthepatient’ssymptomsarethoseofunilateralsensorineuralhearinglossortinnitusalongwithvestibularsymptoms,theMRI is indicatedwithspecialfocustotheinternalauditorycanals,brainstemand cerebellum. There is no diagnostic feature in brain MRI that is pathognomonic ofVestibularMigraine.

c. Treatment:

Dizzinesssecondarytomigraineusuallyrespondstothesametreatmentusedformigraineheadaches.Thechoiceofdrugsismainlyguidedbythefrequencyoftheattacksandthesideeffectprofile.

The 3 broad classes of migraine headache treatment include reduction of risk factors, abortivemedications,andprophylacticmedicaltherapy

I. Reduction of risk factors includes an attempt to avoid certain conditions (eg, stress,anxiety,hypoglycemia, fluctuating estrogen, certain foodsand smoking) that can triggermigraine. Elimination of birth control pills or estrogen replacement products. The followingfoodsshouldbeavoided:

• Monosodiumglutamate(MSG)• Certainalcoholicbeverages-eg,redwine,port,sherry,bourbon• Agedcheese,fermentedfood• Chocolate

• Aspartame

An elimination diet for 6 weeksminimummay be prescribed. If, after 6 weeks, symptoms are notbetter,dietmodificationonlyisnotconsideredtobehelpful.Iffoodsareatriggerforsymptoms,theoffendingfood(s)canbeidentifiedbyaddingback1foodatatimeuntilthesymptomsreturn.

B. Abortivemedicationandrisk-factorreduction

Ingeneral,drugsusedtoabortmigraineheadacheslikethetriptanshavenotbeenfoundeffectiveintreatingdizzinesssecondarytomigraine(i.e.,abortinganacuteepisodeofMigraineinducedvertigo).

C. Prophylacticpharmacotherapy

• First-lineprophylacticmedications(drugsestablishedaseffective) :DivalproexSodium(400-1000mg),topiramate(50to150mg/day),SodiumValproate,metoprolol(47.5to200mg/day),propranolol(80to160mg/day),venlafaxine(37.5to75mg/day),andmethysergide..

• Second-line treatments (drugs probably effective):calcium channel blockers (verapamil,flunarizine), tricyclic antidepressants (nortriptyline, amitriptyline (25-100mg/day)), riboflavin,atenolol.

Betablockers (metoprolol andpropranolol) induce lowBP, fatigue, constipationbradycardia,asthma, possibly mental depression in some patients; Tricyclic antidepressants inducetachycardia,tachy-arrythmia,andurinaryretention.Topiramitecauseswt.loss,paraesthesia,speechproblemsanddifficultywithmemoryandmayaggravatenarrowangleglaucomaandcausedepressionandpersonalitychange.SodiumValproateinduceswt.gain,andalsocausessedation,GI-upset,rarelytremorandveryrarelyhepaticdamage.Flunarizine inducesweightgainanddepressionandinadditionhasallthenegativitiesofaCachannelblockerandcausespedaledema,Parkinsonismetc

Acetazolamideandlamotriginearealsorecommendeddrugsprimarilyeffectiveforonlythevestibularsymptomsandnotheadaches

Ifdizzinessisnotcontrolledwithoneclassofmedication,anotherclassshouldbeused.Ifdizzinessiscontrolledwithoneofthesemedications,thedrugshouldbeadministeredcontinuouslyforatleast1year (except for methysergide, which requires a 3- to 4-week drug-free interval at 6mo). Themedicationcanberestartedforanotheryearifthedizzinessreturnsafterdiscontinuingtherapy.

Referral to vestibular rehabilitation should be considered for all patients, particularly if secondarycomplications such as deconditioning, loss of confidence in balance or visual dependence havedeveloped.

E. VESTIBULARPAROXYSMIApracticeguidelines

Vestibular paroxysmia (VP) previously known as disabling positional vertigo or vascular loopsyndromeisacontroversial,vestibulardisorder/syndromecausedbyneurovascularcrosscompressionof the vestibular nerve with features of recurrent, spontaneous, episodic very brief attacks ofsubjective / objective vertigo or even instability that generally last less than one minute (often asecondoreven lesser)butmay rarelybe fora fewminutesalsoandoccur ina seriesof clustersofrepeated identical attacks. If the attack is that of spinning in a particular direction it is always justspinninginthatdirectionorifitisamomentaryinstabilityorafeelingoflaterpopulsion(beingpushed)itisalwaysexactlythesamefortheparticularpatient.Consistencyofthenatureofsymptomsisoneofthe typical features of this difficult tp diagnose clinical entity. The number of attacks is anythingbetweennumerouseverydaytoafewdiscreteattacksamonth.Thesinglediscreteattackssubsideby

themselves without intervention but keeps on repeating. The attacks of vertigo/ instability aresometimesbutnotalwaysaccompaniedwithauditorysymptomswhichmayoccureither justduringtheattackofvertigoorsometimesbethereevenwhenthevertigoisnotpresent.Positiveresponsetocarbamazepine therapy strongly suggests but does not prove that the vestibular disorder is due tovestibular paroxysmia. When present with auditory symptoms (esp. tinnitus) the condition is alsoreferred as audio-vestibular paroxysmia. During the attack there is usually some documentableneurophysiologicchangeintheaudio-vestibulartests.Diagnosisbyinvestigationsonly isproblematicas (1) detectable audio-vestibular abnormalities may or may not be present i.e., though someabnormalitiesateoftenfoundyetinmanypatientsaudio-vestibularfindingsareperfectlynormal;(2)MRIhasveryhighsensitivityburpoorspecificityi.e.,radiologicalevidenceofaveryclosevascularlooponthe8thcranialnerveispresentinathirdofnormalpatientsandsojustthepresenceofavascularloopinverycloseproximityofthevestibularnervedoesnotmeanconformvestibularparoxysmia;and(3) side determination is very difficult if not impossible esp in patients who have only vestibularsymptoms.Diagnosisishencebyacombinationofclinicalfeatures(i.e.,history),audiovestibulartestsandspecialisedMRIstudiesandofcoursetheclinician’sstrongindexofsuspicion..

PATHOPHYSIOLOGYandFEATURES:

Abloodvessel,mostlytheanteriorinferiorcerebellarartery(AICA)orsometimestheposteriorinferiorcerebellar artery(PICA), vertebral arteryor vein, vascularmalformation,megalodolichobasilar artery,etc. which forms a loop around the vestibular branch of the cochleo-vestibular nerve (VIII cranialnerve) in the areaproximal to the “transition zone” is responsible for this syndrome, similar to theother neurovascular cross compression syndromes like hemi-facial spasm and trigeminal neuralgia.The site of lesion is the root-entry-zoneof the 8thcranial nervewheremy alienation is by Schwanncells. Thisneurovascular loopformationcausespressureonthenervealongwithcross-compressionresultinginlesionwithdemyelinationofthecentralmyelin,proximaltothe“transitionzone”i.e.first1.5 cm after the nerve exit. Consequently, short circuits (erratic stimulation) occur in the nerveconductionresultinginintermittentnerveblockwhichisresponsibleforthebriefattacksofspinningvertigo (quick spins), postural vertigo and/or instability. The attacks may also be accompanied byunilateralhearing lossandtinnitus ifneighbouringcochlearbranch is involved.Triggering factorsorworsening factors for these attacks may not be there but when present include certain headposition(s),hyperventilationandincludechangeinheadmovementsorcertainexercises.

Diagnosis:– as inmost other neurotological disorders, diagnostic criteria for vestibular paroxysmiahavebeenspecifiedfor(a)definite,and(b)probablevestibularparoxysmia.SincetherearesomegreyareasinourunderstandingoftheexactpathophysiologyandduetotheproteanmanifestationsofthediseaseverymuchlikeVestibularmigraine,differentschoolshaveproposedslightlydifferentcriteriaforlabellingadisorderasVestibularParoxysmia.Theauthor(s)afterexaminingalldifferentguidelinesanddiagnosticparametersproposedbydifferentauthorsandgroupshavethoughtitprudenttofollowtheproposalsoftheBaranySocietywithminormodifications.

Tobelabelledasdefinitevestibularparoxysmiathefollowingcriteriahavetobemet:-

1. theremustbeatleast10attacksofeithersubjectiveorobjectivespinningorinstabilityeachforlessthanoneminute

2. shouldoccurspontaneouslythatiscompletelyunprovoked

3. eachoftheattacksbesimilarinintensityandqualitythatisstereotyped

4. shouldrespondtoatherapeutictrialwithCarbamazepinoroxcarbazepine

5. notbetteraccountablebyothercausesofvertigo

Tobelabelledasprobablevestibularparoxysmiathefollowingcriteriahavetobefulfilled:–

1. at least five attacks of subjective or objective head is spinning none of them being for adurationofabovefiveminutes

2. attacks may be spontaneous, that is unprovoked or maybe precipitated in certain headpositionsbutdoesnotrespondtocorrectiveliberatorymanoeuvresandarenotinthetypicalDixHallpikeorotherBPPVspecificpositions

3. eachattackinanindividualissimilarinintensityandqualitythatisthevestibularsymptomsarestereotyped

4. notbetteraccountablebyothercausesofvertigo

Differentialdiagnosis:–asvestibularparoxysmia isnotoneof thecommonestcauseofvertigo, thefollowingclinicalconditions(espthefirstthree)whicharemorecommonbutmayhaveamoreorlesssimilarpresentationsneedtoberuledout.Ingeneral,thediagnosishastobeverystronglysuspectedonthebasisofhistory/clinicalexamination/investigationsbeforeventuringonatherapeutictrialwithCarbamazepin/oxcarbazepinewhichhaveofdangerousadverseeffects

1. vestibularmigraine

2. vestibularepilepsy/vestibularseizures

3. BPPV

4. transientischaemicattacksoftheposteriorcirculation

5. perilymph fistula (the trigger factor is very definite like increased intra-abdominal pressure,sneezing,coughing,liftingheavyweightsetc)

6. superiorsemi-circularcanaldehiscence

7. panicattacks

8. atypicalbrainstemeventsasinsomecasesofmultiplesclerosis

9. Tumarkin’scrisisprovidedatypicalhistoryofMeniere’sdiseaseispresent

10. Ifitoccursonlyonturningorrotatingtheheadtoonesideandthefeelingismoreofasinking/falling/blurringandnottypicallythespinningsensationthenocclusionofthevertebralarteryisaremotepossibilityandshouldbelookedforbyrequisiteimagingtestslikeangiography.Ifconfirmed,thenthediagnosisisRotationalOcclusionofVertebralArterySyndrome

Clinical diagnosis is no doubt difficult as this disease does not have any definite marker either onclinical tests or on investigations which are pathognomonic of vestibular paroxysmia. The clinicianshould understand that themereMRI finding of vascular compression of the proximal part of theeighthcranialnerveisnotasureshotevidenceofclinicalvestibularparoxysmiaasaboutonethirdofnormalsubjectsalsohavesimilarradiologicalfindingswithoutanysymptomsofvertigowhatsoever.PositivetherapeuticresponsetoCarbamazepin/oxcarbazepineisverysuggestivebutnotafoolproofevidence of vestibular paroxysmia as there is not enough of supportive randomised, double-blind,placebo-controlledmulticentrestudiesareavailableinclinicalliteraturetillnow.

Investigations:–Theaudio-vestibulartestswillshowdeficitsduringtheperiodsofattackswhichareless noticeable during asymptomatic intervals when there are no attacks.In symptom-free periodstheremaynotbeanydetectableabnormalityintheaudio-vestibulartestsandnormalfindingsinthesetestsdonotruleourvestibularparoxysmia.Theteststhatcanbeconductedincludeaudiogram,BERA,VNGwithoculomotorandcalorictests,VHIT,VEMP,SVV.Prolongationof I-III inter-peak latencycansometimesbe found inBERAbutonly if theauditorynervehasalsobeen involvedwhere therewillalsobesomeauditorysymptomsbutotherwisetheBERAisexpectedtobenormal.TheVNGcaloricweakness (canal paresis above 20%) and spontaneous nystagmus (time-locked to the attack andbeatingtowardtheaffectedear)maybenotedincalorictests.Lowamplitudeordelayedwavepeaksincervicaland/orocularVEMParealsopossiblebutnoneofthetestshavespecificroleinconfirmingor even in diagnosing Vestibular Paroxysmia. Nevertheless a complete vestibular function tests andsomeaudiological tests likePTaudiometryandBERAaremandatorynot somuch forconfirmativelydiagnosingVestibularParoxysmiabutmoreforrulingoutotherpossibleconditions.

High resolution MRI with 3D CISS (constructive interference in steady state) sequences of thebrainstemwithspecialinstructionstotheradiologisttolookforanyneurovascularcompressioninthefirst1.5cmofthe8thcranialnervecanconfirmandlocalisethevascularlooporneurovascularcontactwhichischaracterisedbyabsenceofdetectableCSFlayerbetweennerveandsurroundingvesselintherequired region i.e. proximal to the transition zone. In difficult to diagnose clinical conditions likesuspected Vestibular ParoxysmiatheMRI is also indicated for excluding differential diagnosis.Hencethe HR MRI of the brainstem with 3D CISSsequence is a must in all suspected cases ofVetibularParoxysmia. However just the radiological finding of neurovascular compression of the8thcranialnervewithouttypicalVestibularParoxysmiaclinicalfeaturesisnotdiagnosticofVestibularParoxysmia as in many normal patients also there is radiological evidence of neurovascularcompressionorthepresenceofavascularloopinverycloseproximityofthe8thcranialnerve.Hencean incidental radiological finding of neurovascular compression involving the 8thcranial nerve isclinicallyinsignificantanddoesnotsuggestvestibularparoxysmia.NotuncommonlyinmanypatientstheradiologicalevidenceofneurovascularcompressionispresentbilaterallyandthisisfoundnotonlyinpatientswithtypicalVPsymptomsbut inmaynormaltoo.Only ifbothclinical featuresaswellasradiologicalfeaturesarethereonlythenthediagnosisofVestibularparoxysmiaistenable.

Treatment:

NospecificlineofmanagementhasbeenproposedtilldatetotreatVP.Atherapeutictrialoflowdoseof carbamazepine (200-600 mg/day) or oxcarbazepine (300-900 mg/day) is recommended in allsuspected cases taking care of the adverse effects that can be caused by these drugs. The patientshould be strictly instructed to stop the drug and to seek urgent medical opinion if there is anyuntoward adverse effect as bothCarbamazeine and to a lesserextentoxcarbazepinemay sometimesinducelifethreateningallergicreactions.Theresponsetothesedrugsduringtheattacksisadiagnostictesttooandifthereisgrossmprovementinthecondition,thenitmoreorlessconfirmsthediagnosisofVestibularParoxysmiaYethow long thesedrugsshouldbecontinued, isnotwelldocumented tilldate.ThedosehastobetitratedagainstthesymptomsOtherdrugs(phenytoin,lamotrigine,baclofen,topiramate, valproate, gabapentin) can be used if intolerance occurs to Carbamazepine oroxcarbazepinebutnodocumentedevidence ispresent till todayaboutefficacyof thosedrugs inVPandtheircorrectmechanismofaction.

Inmedically intractable cases, surgery canbe theoptionbut shouldavoideddue to riskofdreadedcomplications like brainstem infarction (due to intra-opor post-op vasospasm).Also it is difficult todetectthesideaffected.

F. TinnituspracticeguidelinesCommon Definitions:As per the Clinical Practice Guideline: Tinnitus by American Academy ofOtolaryngology–HeadandNeckSurgery

Tinnitus:Theperceptionofsoundwhenthereisnoexternalsourceofthesound

Primary tinnitus:Tinnitus that is idiopathic and may or may not be associated with sensorineuralhearingloss

Secondary tinnitus:Tinnitus that is associated with a specific underlying cause (other thansensorineuralhearingloss)oranidentifiableorganiccondition

Recentonsettinnitus:Lessthan6monthsinduration(asreportedbythepatient)

Persistenttinnitus:6monthsorlongerinduration

Bothersome tinnitus:Distressed patient, affected quality of life and/or functional health status;patientisseekingactivetherapyandmanagementstrategiestoalleviatetinnitus

Nonbothersometinnitus:Tinnitusthatdoesnothaveasignificanteffectonapatient’squalityoflifebutmayresultincuriosityofthecauseorconcernaboutthenaturalhistoryandhowitmightprogressorchange

Evaluationofthepatient

A.Historytobetakencoveringthefollowingissues–

a.Unilateraltinnitus

i. Ruleoutfocalauditorylesionslikevestibularschwanomaorvasculartumours

b.Pulsatiletinnitus

i. Ruleoutvasculartumororsystemiccardiovascularillness

c.AssociatedwithHearingLoss

i. Veryfrequentassociation-findduration;type;severity;symmetry1. SNHLorCHL-frequentlytinnitusisassociatedwithSNHL2. SuddenSNHL–prompttreatmentreqd3. Asymmetric–maybeaVestibularSchwannoma

d. Newonsettinnitus–maydiminishordisappear

e. Associationwithvertigo

i. Meniere’sdiseaseii. SuperiorSemicircularCanalDehiscenceiii. VestibularSchwanomaiv. Otherconditions

f.Noiseexposure

g.Medicationsandototoxicdrugsexposure

h.SymptomsofAnxietyorDepression

i. veryimportanttoassesstheseverityasitwillguidethetreatmentandneedforreferral

i.Cognitiveimpairment

i. Willaffectthevarioustests

B.PhysicalExamination-

a. Objectivetinnitus:i. Rarely,tinnituscanbeheardbytheclinicianaswellasthepatient.ii. Vascularabnormalitiesandmyoclonus.

b. Heartmurmurs,carotidbruits,orvascularsoundsi. Cardiovasculardiseaseandvascularlesionsmaycausetinnitus.ii. Treatmentoftheunderlyingdiseasemayhelptinnitussymptomsiii. Cardiovasculardiseaserequiresappropriateevaluationandtreatment.

c. Focalneurologicsigns-i. mayrequirereferralorimaging

d. Otorrheai. Signofmiddleearinfectionorotitisexternaii. Treatmentmayimprovetinnitusaswellasassociatedhearingdifficulties.

e. Signsofotherexternalormiddleeardiseaseonexaminationand/orotoscopyi. Simple problems such as cerumen impaction or otitis media can be detected.

Cholesteatoma, glomus tumors, and other uncommon middle ear disorders can bedetectedbyotoscopy.

f. Headandneckmassesi. Promptinvestigationrequired

C.AudiologicEvaluation

1) PTA-ProperlymaskedAC&BCthresholds2) SRT-agreementbetweenPTA&SRTtocheckreliability3) SDS4) Tympanometry–ifindicated5) Tinnitusmatching for frequencyand intensity,maskability/ suppressabilitybyexternalnoise

etc

D.DifferentiateBothersomeTinnitusfromNonbothersome

a. TinnitusQuestionnaireandTinnitusEffectsQuestionnaire(Hallametal,1988)b. TinnitusHandicapQuestionnaire(Kuketal,1990)c. TinnitusReactionQuestionnaire(Wilsonetal,1991)d. TinnitusHandicapInventory(Newmanetal,1996)

E.Distinguishbetweenpatientswithbothersometinnitusofrecentonsetfromthosewithpersistentsymptoms

F.Education&Counselling

a. NoCureavailableb. Explainabouttinnitus–whatisit?c. Currenthypothesisonpathophysiologyd. Needtoinvestigateande. reassurancethatitisnotsinisteriftherequisiteinvestigationshavesuggestedso

G.HearingAidevaluation&recommendationifrequired

H.SoundTherapy

a. EnvironmentEnrichmentdevicesi. Tabletopsounddevices

b. HearingAidsi. Canhelpbypartialmaskingeffect

c. SoundGeneratorsi. Musicalpillows

d. CombinationDevicesi. HearingAidwithatinnitusmasker

I.CognitiveBehaviouralTherapy

The following are NOT recommended as they have not been found to be effective and is notevidencebased

A. Imagingstudiesarenottoberecommendedunlessa. Pulsatiletinnitusb. FocalNeurologicalAbnormalitiesc. AsymmetricHearinglossd. Headandneckswelling

B. Medical Therapy of the following categories are not to be recommended as they have notbeenfoundtoreducethetinnitus

a. Antidepressantsb. Anxiolyticsc. IntratympanicTherapy

Should not be routinely recommended just for the tinnitus unless there is someseparateadditionalindicationwhichmustbespecified

C.DietarySupplements

a. Gingkobab. Zincc. Multivitaminsd. Antioxidants

Shouldnotbegivenjustfortinnitusastheyhavenotbeenfoundtonehelpful

D.Acupuncture

E.TransCranialMagneticStimulation

5) NOMENCLATUREOFSYMPTOMSTOBEUSEDINBALANCEDISORDERSWith some changes customized according to the terms that are used inmedical communication inIndiaand theneighboring countries,wewill followmoreor less thenomenclatureproposedby theBaranySociety.Theclinicianistonotethatthisnomenclatureisrelatedtoreportingofsymptomsonlyandthisclassification/nomenclature is innowayassociatedto theunderlyingcausativepathology.The same pathology may sometimes present with any one or more of the symptoms enumeratedbelow.InternationallytheClassificationofVestibularDisordersiscodedasICVD-1andreportingofthesymptomsofvestibulardisordersasreportedbythepatient isbestdoneonthebasisofthis ICVD-1system introduced by the Barany society as it maintains a uniformity of nomenclature. As per thenomenclature proposed by the Barany Society (Ref A. Bisdorff et al. / Classification of vestibularsymptoms: Towards an international classification of vestibular disorders Journal of VestibularResearch 19 (2009) 1–13.) neurotological symptoms of balance disorder (with some changes) arebroadlyclassifiedintothefollowingcategoriesviz:-

1) VERTIGO2) DIZZINESS3) UNSTEADINESS

1) VERTIGO:- The term vertigo encompasses those sensations where there is a feeling ofmovement/motioneitheroftheselforofthesurroundings*.AspertheICVD-1classificationmovement of the visual surroundingswithout any selfmotion is termed as vestibulo-visualsymptomor‘externalvertigo’andtheterm‘vertigo’ indicatesonlythefeelingofselfmotionalso called ‘internal vertigo’. But this makes it unnecessarily too very complicated for useoutsidethevestibularcommunityandvertigoisbestusedtodenotebothselfmotionaswellasmovement of the visual surroundings as explained in the next paragraph. Vertigo is thesensation ofself-motion when no self-motion is occurring or thesensation of distorted orinappropriate self-motionduring anotherwisenormal headmovement. If there is an actualmovement/motionandthesubjectgetstheappropriatesensationofthemotionthenitisnotvertigo.Thesensationofmotionwhichisnotrotatory/spinninginnatureistermedas‘non-spinning vertigo’ and the sensation of spinningwhich is a rotatory sensation is termed as‘spinningvertigo’.Thetermincludesfalsespinningsensations(spinningvertigo)andalsootherfalse sensations of motion like swaying, tilting, bobbing, bouncing, or sliding (non-spinningvertigo). Terms like subjective vertigo, objective vertigo, true vertigo, false vertigo, rotatoryvertigoetc.thoughoftenusedincommonmedicalparlancearenotrecognizedclinicalentitiesaspertheBaranySocietyClassificationofVestibularsymptoms(ICVD-1)referencedaboveandit is prudent for us to also follow so. These terms are hence best discontinued. Vertigoaccordingtothisclassificationofvestibularsymptomsmaybespontaneousvertigowhenthereisnoknownorobvioustrigger(precipitatingfactor)oritmaybetriggeredvertigowherethereis a very definite relationship between some known stimulus and the vertigo. Examples of‘triggered vertigo’are e.g., Positional vertigo where change of head position in a particulardirectioncausesthevertigo,Head-motionvertigowherethere isaspinningsensationthat istime-lockedwith headmovement and occurs onlywhen the head ismoving and there is apervertedordistortedsenseofselfmotionduringactualself-motion,Visually-inducedvertigoisasenseofselfmotiontriggeredbyamovementofthevisual fieldoravisualstimulus likeseeing amoving train in a railway station, Sound-induced vertigo Is vertigo triggered by anauditory stimulation which was previously termed as tulio-phenomenon, Valsalva-inducedvertigoisvertigotriggeredbyincreaseofintracranialormiddleearpressure.Oscillopsiawhichisatoandfroup-downandevenfrontbackrepetitivemovementofthevisualsurroundingsoftendescribedbypatientsasajumpingorbouncingofvisualimageswhilewalkingisactuallya‘non-spinningvertigo’.

*As mentionedaboveanothergroupofvertiginoussensationswhichhavebeengroupedseparatelyasvestibulo-visual symptoms and not included in VERTIGO in the ICVD-1 Barany societyclassification,consistsofmotionofthevisualsurroundingstermedas‘externalvertigo’ortiltingofthevisual imagesorablurringofvisiononheadmovementisbest included inthisgroupofVERTIGOforconvenience. The term external vertigo strictly indicates a sensation continuous movement of thevisual surroundings usually jerky when there is actually no motion.This is the sensation of themovement of the visual surroundings onlywithout any senseof selfmotionbut very oftenbut notalwaysbothco-exist.Conditionslikeoscillopsiadetailedabove,visuallagwherethereisafeelingthatthevisualsurroundingsmoveslightly(asecondorso)laterafteraheadmovementanddoesnotoccurwith the headmovementwhich is normally expected andvisual blurring immediately after or evenduringheadmovementfallunderthisgroup.

2) DIZZINESS is different from vertigo as per the Barany classification and Vertigo andDizzinessmustbedealtwithasseparatesymptoms.Dizzinessisthejeopardisedorperverted/disturbedsenseofspatialorientationwithoutanysenseofmotion/spinning.Thereisneitheranyspinningnoranysenseofmotionindizziness.Lossofspatialorientationistheinabilityofthe subject to relate or to orient the self with the physical surroundings i.e., the threedimensional space surrounding the subject without any false sense of motion / spinning.Adizzypatienthasproblems incorrectlydetermininghis /herposition in spaceanddoesnothaveanytrackofaphysicalreferencepointinrelationtowhichthesubjectcandeterminehis/herposition.Notuncommonly thepatient canhavebothvertigoanddizziness togetherbuttheseare twocompletelydifferententities.Thesameconditions that inducevertigo (all thedifferent varieties like spontaneous / triggered and all the different triggers like positionchanging, loudsoundetc.)canalso inducedizzinessandthedescriptionofdizziness is tobedone in the same way as that of vertigo e.g., loud sound induced dizziness. Spatialdisorientationasoccurs indizziness isdifferentandshouldbedistinguished fromsensationslike (1) impending loss of consciousness/ pre-faint, (2) mental confusion when the patientbecomes mentally blank for a while or also (3) the sensation of depersonalisation when asubject feels detached from reality. None of these three symptoms are related to thevestibular system though quite often such patients report these symptoms as vertigo/dizzinesstothephysician.

3) UNSTEADINESS:-isthetermusedtodenotethefeelingofinstabilityorimbalancewherethepatientishelpedwhenhe/shegetsaphysicalsupport.Thepatientgetsafeelingoffallingand/or may even fall but there is no sense of motion or that of spinning or of any spatialdisorientation. The patient can have the feeling not only when walking but also whenstanding/ sitting. A patient of vertigo or of dizziness is not helped by getting somephysicalsupport likeholding tosomethingbut ifapatienthasunsteadiness thesymptomsdisappearcompletelybyholdingontosomething.Thoughvertigoanddizzinessareprimarilyvestibularsymptomsunsteadinessmaybepresent inpersonswithnormalvestibular functionandmaybecausedbynon-vestibularconditoonslikeLikedizziness,unsteadinessmaycoexistwiththeothersymptoms.Unsteadinesshasbeensub-classifiedintheICVD-1as:-

1) Directional pulsion i.e., being pushed to one particular side. If the feeling is that of beingpushedtotheleftorrightitistermedadlatero-pulsiontoleft/right.Ifthedirectionalpulsionisbackwardsitiscalledretro-pulsionandiftothefrontitiscalledantero-pulsion

2) Near falls are the feelingof an impending fall butwhichhasbeenpreventedorarrestedbycatchingontosomethingandacompletefallhasnotoccurred.Butunsteadinessmaybeduetonon-vestibularcausesalso.Onlythebalancesystemrelatednearfallsareinthiscategory.

3) Completefallsarewhenthefallhasnotbeenpreventedbycatchingontosomething.

All balance disorder symptoms are best reported under the hearings of vertigo/ dizziness /unsteadiness and if possible then further sub-classified as e.g., spontaneous internal vertigo ortriggeredpositionalvertigo,unsteadinesswithretropulsion,loudsoundtriggereddizzinessetc.