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Fig.17.13SagittalT2-weightedturbo-gradientspin-echoofthebrainandbrainstem.Theredlineshowsthepositionofthenucleiinvolvedin
trigeminalsignalprocessing(sensory:nucleuspontinus,nucleusspinalis;motor:nucleusmesencephalicus,nucleusmotorius).
Fig.17.14CoronalT1-weightedsequenceafterintravenousadministrationofcontrastmaterialwithfatsuppression.Thispatientsuffersfrom
amassivetumor(squamouscellcancer)destroyinglargeareas oftheskull baseandinfiltratingthecranium.Boththeolfactorybulbandthe
olfactorytractaredestroyedbytheanteriorpartsofthelargemass(arrow).
GustatoryImaging
Gustationis the sum of afferents collected from the taste buds along the outeredgeof the tongueand
delivered viathe TN,the chordatympani (facial nerve,cranial nerve VII),the glossopharyngeal nerve
(cranial nerveIX),and thevagusnerve(cranial nerveX) toganglia andbrain.Single-sided conditions
affectingthechordatympaniare oneoftheunusualexceptionsfromthe factthat chemosensation isnot
usuallylateralized.Hence,incertainrare(andtypicallyverysensitive)patients,unilateralconditionsof
the chorda tympani may be perceived as disturbance of gustatory sensation. Gustation is far less
frequently affectedbyspecific pathologies than olfaction, and research into gustationhas not beenas
detailedasithasbeenintheolfactorysystem.Infact,disturbanceofthegustatorysystemisaquiterare
clinical symptom and mainly occurs in patients with very large tumors destroying most parts of the
peripheralgustatorysystemoftheheadandneckregion(Figs.17.14and17.15).Manyofthesepatients
are frequently and continuously exposed to certain toxins (e.g., alcohol, cigarette smoke), which
themselves reduce gustatory sensations. As a result, even with extensive tumors destroying large
(typically more peripheral) parts of the gustatory system, these patients commonly do not experience
modificationsorrestrictionsingustation.Tumorsandmetastasesaffectingtherespectivecranial nerves
traveling through the head and neck region and entering the skull should be considered and imaged.
Tumors and infections affecting the ganglia and nerve roots (mainly meningeal carcinomatosis,
meningiomas,andinfectiousdiseasesoftheposterior skull base)shouldalso be visualized.Lastly,the
brainstem andthe brainhaveto be evaluated,mainlytoexclude primary brain tumors and metastases.
Activationanddeactivationoftheprimarygustatorycortexisdependentonthesensoryinput:sweetand
saltytastesactivate,whilebitterstimulileadtodeactivation.
25
Fig.17.15AxialT1-weightedsequenceafterintravenousapplicationofcontrastmaterialwithfatsuppression.SamepatientasinFig.17.14.
Bothjugularforaminaareinfiltratedbytumormasses;cranialnervesIXandXonbothsidesaredestroyed(arrows).
AfastandsensitiveimagingprotocolvisualizingtheentiregustatorysystemwouldincludeaxialTIRM
sequencesoftheheadandneckregion,T2-weightedandT1-weightedsequencesofthebrainbeforeand
after intravenous administrationof contrast material (probably supplemented by FLAIR imaging), and
contrast-enhancedT1-weightedsequencesofthebrainandheadandneckregionwithfatsuppression.
Conclusion
Close communicationbetweenear,nose, andthroat doctors andradiologistsassures best imaging
qualityforthepatient’ssymptoms—identifythequestionyouwantimagingtoansweraspreciselyas
possible.
In the clinical context, structural imaging in chemosensory dysfunction in the first instance requires
nonspecificexclusion ofmalignancyandinflammationaffectingthebrain,the baseoftheskull,andthe
headandneck region.Especiallyinthe contextofolfaction,researchhasconfirmed thatmorespecific
visualization techniques, requiring highly adapted and optimized imaging and quantification of
chemosensorystructures,aremandatory.MRIisthemodalityofchoiceforbothfieldsandonlyveryfew
questionsmaybepreferentiallyassessedbyCT.Adequateselectionofimagingtechniquestakesaccount
ofthefactthatchemosensoryinputisnotlateralized;therefore,ingeneral,anosmiaorageusiawillonly
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develop ifthe peripheralinputofboth therightandthe leftside isimpaired,orifa centrallesionhas
evolved. For optimalresults inchemosensory imaging, details ofthe clinicalquestion forthe specific
patientshouldbediscussedwiththeinvolvedradiologist.
Acknowledgments
TheauthorsthankProfessorDr.RüdigervonKummer,ChairmanoftheDepartmentforNeuroradiology,
PDDr.Volker Hietschold, Institute andPoliclinics for Diagnostic Radiology, and Dr. Gabriele Hahn,
Pediatric Radiology, from the University Clinics and Medical Faculty Carl Gustav Carus, Dresden
UniversityofTechnology,fortheirsupportwithsomeoftheimagespresentedinthechapter.
References
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theinnerearandcerebellopontineangle.AJNRAmJNeuroradiol1993;14(1):47–57
3. ICRP. The 2007 Recommendations of the International Commission on Radiological Protection. ICRP publication 103. Ann ICRP
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4.AbolmaaliND,HietscholdV,Vogl TJ,Hüttenbrink KB,HummelT.MRevaluationinpatientswithisolatedanosmiasincebirthorearly
childhood.AJNRAmJNeuroradiol2002;23(1):157–164
5.YousemDM,GeckleRJ,BilkerWB,DotyRL.Olfactorybulbandtractandtemporallobevolumes.Normativedataacrossdecades.Ann
NYAcadSci1998;855:546–555
6.AbolmaaliN,KantchewA,VoglTJ,HummelT.Evaluationofthe“nasalcycle”usingMR-imaging.XVIInternationalCongressofHead
andNeckRadiology4–6September2003,Frankfurt/Main,Germany.EurRadiol2003;13:C2
7.AbolmaaliN,HummelT,DammM.Two-andthree-dimensional,morphologicandfunctionalMR-imaginginsmellingdisorders.[Articlein
German]Laryngorhinootologie2009;88(1):10–16
8.KernRC.Chronicsinusitisandanosmia:pathologicchangesintheolfactorymucosa.Laryngoscope2000;110(7):1071–1077
9.TrotierD,BensimonJL,HermanP,TranBa HuyP,DøvingKB,EloitC.Inflammatoryobstructionoftheolfactorycleftsandolfactory
lossinhumans:anewsyndrome?ChemSenses2007;32(3):285–292
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1993;14(4):839–843
11.Welge-LuessenA,TemmelA,QuintC,MollB,WolfS,HummelT.Olfactory functioninpatientswitholfactorygroovemeningioma.J
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12.YasudaM,HiguchiO,TakanoS,MatsumuraA.Olfactoryensheathingcelltumor:acasereport.JNeurooncol2006;76(2):111–113
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Radiol2006;36(2):97–107
14.YousemDM,GeckleRJ,DotyRL,BilkerWB.Reproducibilityandreliabilityofvolumetricmeasurementsofolfactoryeloquentstructures.
AcadRadiol1997;4(4):264–269
15.BakerH,Kawano T, AlbertV,JohTH,ReisDJ,MargolisFL.Olfactory bulbdopamineneuronssurvivedeafferentation-inducedlossof
tyrosinehydroxylase.Neuroscience1984;11(3):605–615
16.MargolisFL, RobertsN,Ferriero D,FeldmanJ. Denervationinthe primaryolfactory pathwayofmice:biochemical andmorphological
effects.BrainRes1974;81(3):469–483
17. MuellerA,Rodewald A, RedenJ, GerberJ, von Kummer R,HummelT.Reduced olfactory bulb volume in post-traumatic and post-
infectiousolfactorydysfunction.Neuroreport2005;16(5):475–478
18. Rombaux P, MourauxA, BertrandB,Nicolas G,Duprez T, HummelT.Olfactory functionand olfactory bulb volume inpatientswith
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20.ChenC,ShihYH,YenDJ,etal.Olfactoryaurasinpatientswithtemporallobeepilepsy.Epilepsia2003;44(2):257–260
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18ProvidingExpertOpiniononOlfactoryandGustatoryDisorders
BorisA.Stuck,AxelMuttray,TerenceM.Davidson
Summary
In discussing olfactory and gustatory disorders, it is often necessary to provide an expert legal
opinion—ataskthatdiffersgreatlyfromeverydayclinicalwork.Aseriesoffactorsmakesalegal
assessmentdifficult,particularlymissinginitialexaminationsandthelimitedpossibilitiestoobtain
objective examination results. The question of work-related causes of olfactory and gustatory
disordersisofparticularinterest,despitethefactthatthesedisordersareoftennotcitedinlistsof
occupationaldiseases (e.g.,inGermany). Presentingcomplaintsdepend greatly ontheir cause. In
general, the patient reports a limited capability of smell as well as of taste. It is important to
distinguishbetweenasubjectivegustatorydysfunction(generallyanolfactorydysfunction)andareal
dysfunctionintermsofhypogeusiaorageusia.
A thorough medical history is the basis of every assessment, supplemented by clinical
examinations,andcompletedbyspecifictestsofolfactoryandgustatorycapabilities.ForGerman-
speaking countries, the Olfactology and Gustology Task Force of the German Society of
Otolaryngology (Deutsche Gesellschaft für Hals-Nasen-Ohrenheilkunde) has published
recommendationsregardingtheprovisionofexpertopiniononolfactorydisorders,whichfacilitate
theassessmentinpractice.
Introduction
Itisoftennecessarytoprovideanexpertassessmentonpresumedorconfirmedolfactoryandgustatory
disorders.Intotal,olfactorydisordersoutnumbergustatorydisorders.Aseriesoffactorscomplicatesthe
assessment of olfactoryand gustatory disorders. Aside from missing initial examinations inalmost all
cases(convincingexaminationsofsmellingandtastingcapabilitiesarerarelyconductedandareusually
notamongthescreeningexaminationsoftheEmployers’LiabilitiesInsuranceAssociation),thisismainly
duetothelackofresultsfromolfactoryorgustatoryexaminations.Inthischapter,wewilldemonstratethe
assessor’sprincipaltasksaswellastheobligatoryexaminationsandbasicsofassessmentintheauthors’
view.Also,wewillpresentrecommendationsforprovidinganexpertopinion.Furthermore,thiscomplex
problemwillbeillustratedwithtwocasestudiesfromeverydaypractice.
ProvidingExpertOpinion
The task ofproviding an expertopinionis complex and differsgreatly fromthe everyday activities of
clinicalpractice.Withintheframeworkofsociallegislation,aphysicianisoftenaskedtofunctionasan
expert assessor for the Employers’ Liabilities Insurance Association, as well as for cases concerning
compensationandtheSeverelyHandicappedPersonsAct.Privateinsurershaveregulationsoftheirown,
whichwillnotbediscussedhere.Finally,itmightbenecessarytotakeastandinaliabilitysuitifthere
areallegationsoftreatmenterrorsandcompensationclaims(e.g.,afternasalorsinussurgery).Iatrogenic
olfactorydisorders,forexample,maybeduetooverzealousnasalsurgery,mostcommonlypolypectomy.
These may be litigated as malpractice. Experts are required to testify that the nasal surgery was
overzealousandsoadeparturefromthestandardofcare.Defenseexpertstestifytheopposite.
RegardingtheEmployers’LiabilitiesInsuranceAssociation’slegislation,thequestionofwork-related
causes of olfactory and gustatory disorders is of utmost significance. Table 18.1 gives an overview,
without claimingtobecomplete,ofsubstancesthat areabletocausetoxicolfactorydisorders. In each
case, an evaluation of the particular workplace is mandatory. Mixed exposures are numerous (e.g.,
chromates, bases and acids in electroplating). The precondition for toxic olfactory disorders is a
substantial overstepping of critical values defined by occupational medicine. Most of today’s toxin
exposuresarethereforetheresultofanacute,intenseinjury.Inthecaseofexposuretocausticorirritant
agents in very high concentrations, the possibility of a toxic olfactory disorder and rhinitis must be
considered.
Table 18.1Selectedworkingmaterialsthatcancauseolfactorydisordersinhumans
Me talsandtheircompounds Organicsolvents
Lead Interaliaseveralalloys,includingbenzenes
Chromium Esters(acetates)
Cadmium Carbondisulfide
Nickel Trichloroethylene
Mercury
Aldehydes
Dustandsmoke
Weldingfumes Acidsandbase s
Cement
Hydroge nsulfide
Irritantgases
Interaliaammonia Carbonmonoxide
Nitrousgases
Sulfurdioxide Cyanide
ReproducedfromStuckandMuttray(2008)
36
;notalloriginalpaperswereverified.
Anoverviewoftoxin-inducedanosmiamaybefoundinSmithetal2009.
1
Thisreviewpointsoutthat
inthepast,andpriortoOccupationalSafetyandHealthAdministrationprotection,anosmiawasseen
asaresultofchronicexposuretotoxinssuchasformaldehydeandphotodevelopingchemicals(seealso
Chapter9:MiscellaneousCausesofOlfactoryDysfunction).
Inaddition,zincgluconatenasalsprays,toutedasahomoeopathictreatmentforthecommoncold,are
reportedtocauseanosmia basedonnumerous patientcomplaintstotheFoodandDrug Administration.
Zincgluconatenasal sprays have beenremoved from themarketandpresumably theflurryof current
lawsuits will soon be resolved. Several scientific publications support the diagnosis of zinc-induced
anosmia.
2,3
Inthecaseofawell-foundedsuspicionofanoccupationaldisorder,itis usuallymandatory(e.g.,in
Germany,Switzerland,orAustria)toreportthistotheEmployers’LiabilitiesInsuranceAssociation,even
ifareductioninearningcapacitythatmayleadtoretirementisnotexpected.Theinsuredpatientmustbe
informed of this report by his physician. A comprehensive comment on the legal basis of assessment
cannotbegivenhere,asitdifferssubstantiallyamongdifferentcountriesandsocialsystems.
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ExpertOpinioninOlfactoryDisorders
Thesymptomsinvolvedintheassessmentofolfactorydisordersdependgreatlyontheircause.Persons
whohavelosttheircapacitytosmellinanaccidentcannormallydefinethecircumstancesandmomentof
the damageveryclearly. They oftenexperiencethe symptoms veryvividly, as inthemajority ofthese
cases,anuninhibitedabilitytosmellexistedpreviously.Ifanolfactorydisorderhasevolvedthroughthe
yearsbecauseofoccupationalexposuretotoxinsorisclaimedasaresultofamedicalinterventionwitha
possiblypreexistingimpairmentofsmell,thesituationclearlybecomesmoredifficultfortheassessor.
In general, not only an impairment of smell but also an impairment of taste is reported. The
differentiationbetweenaconcomitantdisorderoftastethatoccursasaresultofanolfactorydisorderand
arealgustatorydysfunctionintermsofhypogeusiaorageusiaisofsubstantialimportanceforanadequate
assessment. This differentiation is often difficultto explain to theparties concerned.Factual gustatory
disordersare relativelyrareandwillbediscussedlater.An appropriatemedicalhistoryandadiligent
gustatoryexaminationoughttobepartofeveryassessmentofolfactorydisorders.Itmustbepointedout,
however,thatdisordersofthefactualgustatorycapabilitiesandsubjectiveimpairmentoftastecanboth
occurwithapre-existingolfactorydisorder.Impairedsensitivitytoflavors,aswellasreducedtrigeminal
sensitivityinolfactorydisorders,
4–7
isascribedtothelossofreinforcingneuronalinteraction,andnotto
damagetoreceptivestructures.Areducedreactiontotrigeminalstimulicanbeassessedasanindication,
butnotasproof,ofanamplificationofexistingsymptoms,orofmalingering.
MedicalHistory
Atthebeginningofthemedicalhistory,thenatureandextentoftheolfactorydisordermustbeestablished,
and the origin and course must be ascertained. Qualitative olfactory disorders (e.g., parosmias and
phantosmias)withoutanassociateddeclineofolfactorycapabilities(hyposmiaoranosmia)arerareand
nottypicallyassessed formedicolegal purposes. For isolatedqualitative olfactory disorders, concrete
directivesforactiondonotexist;compensationis,therefore,usuallynotprovided.
Inolfactorydisordersthathavedevelopedovertheyears,aprecisedateofonsetcannotbegivenquite
frequently.Owingtotheirgradualonset,thesymptomsoftenarenotexperiencedordescribedasvividly
assuddenonsetdisorders,andquiteoftenolfactorydisordersarenotedasasecondarycomplainttoother
disorders that are tobe assessed. Questions regarding the accidental consumptionof spoiled food,or
occasionswhensmokeorhazardousmaterialsthat canbe smelledwerenotrecognizedintime, canbe
helpfulinchronologicaldetermination,assuchoccurrencesareoftenremembered.Thiscanbevitalfor
the assessment of correlation, as toxic olfactory disorders develop inclose chronological correlation
withthecausativeexposure.Quiteoften, patientscomplainofaloss ofappetiteinassociationwiththe
perceived taste disorders. However, some gain weight as a result of overeating to seek some taste.
Changeinbodyweightshouldbeascertained.
Additionally,specialattentionshouldbepaidifthepatienthaspreviouslyseenadoctorforolfactory
disorders or if appropriate examinations have already been performed. Generally, however, relevant
examinationresultsarenotavailable.Patientsareoftenassessedinitiallyforotheroccupationaldisorders
(e.g.,hardness ofhearing due to noise anddisorders of thelungandthe musculoskeletal system) and
work-relatedolfactorydisordersarenotdescribeduntillaterintheprocess.
Asarule,traumaticdamageresultingfromaccidentsleadstoanimmediatedefectinthefilaolfactoria
themselves,orinthe brainareasresponsible forprocessingolfactorystimuli.Themajorityofcases of
post-traumatic anosmia are a result of frontal or occipital trauma, but are occasionally the result of
temporalorparietaltrauma.Thegenerallyacceptedmechanismofinjuryisthatthetraumaresultsinan
abrupt anterior or posterior movement of the brain. The thin olfactory fila of the cranial nerve are
presumably stretched or torn as they exit the cribriform plate. If the fila are stretched, olfaction may
recover;iftorn,theolfactorydisorderwillusuallypersist.Somesuchpatientswilldevelopphantosmia,
whichmaydissipateafterseveralmonths.Lossofconsciousnessisnotaprerequisiteforpost-traumatic
anosmia.Isolatedintracranialinjuryisuncommon.
8
Althoughtheonsetisusuallyimmediate,patientswith
severecranialinjuriesormultipletraumamaynotperceivethedisorderuntiltheacutephaseoftheinjury
has resolved, which can takeupto several months depending on the severityofthe injury.A gradual
decreaseinolfactoryfunctioninthisperiodisnotimpossible,thoughveryunlikely.
Obviously,acomprehensivereviewofthecourseofeventsandtheresultinginjuriesmustbeattained
and, if indicated, examination findings (e.g., magnetic resonance imaging [MRI] or paranasal sinus
computedtomography[CT])shouldberequested.
Incasesofsuspectedoccupational olfactorydisorder duetoexposuretotoxicmatter, thecharacter,
duration, and extent of the exposure must be evaluated thoroughly, including use of any protective
measures.Forexample,mobilevacuumdevicesforweldingoutsidetheworkshopareoftennotused,and
paperscreensdonotprotectfromorganicsolventfumes.Questionsregardingwork-relatedsymptomsare
also important.Such symptomscould be duetoirritationofmucousmembranesbyirritantsubstances.
Organicsolventfumesacutelyaffectthecentralnervoussystemdependingondosage.Typicalsymptoms
arelossofappetite,nausea,dizziness,headaches,andintoxication(seeCaseStudy2).Olderpatients,in
particular,havebeen“used”tosuchsymptomsformanyyearsanddonotmentionthemspontaneously,so
it is important that the assessor asks about them directly. Investigations into occupational disorders
normallydonotregisterthesesymptoms.Aninquirywiththecompanymedicalofficercouldbehelpful.
As with any assessment, other possible causes for the disorder (e.g., inflammatory or structural
sinonasalcauses,or nonsinonasalorneurodegenerativecauses) mustbe excluded.Ifthe patientsuffers
fromacuteinflammatorydisorders(suchasacuterhinitisorrhinosinusitis)atthetimeofexamination,the
requiredolfactorytestsshouldbepostponeduntiltheacuteinflammationhasresolved.Theexistenceof
chronicparanasalsinusinflammationcanimpedetheassessmentsignificantly,asrecoveryofteniseither
notpossibleorprolonged,andthismustalwaysbeconsideredas adifferentialdiagnosis.Ontheother
hand,thereisthepossibilitythattoxinexposurecouldalsoberesponsibleforthedevelopmentofchronic
inflammationofthenoseortheparanasalsinus.
9,10
Ifthisisdefinitelythecase,thentheolfactorydisorder
wouldrankasadirectresultofanoccupationaldisorder.
Whentakingthemedicalhistoryofapatientpresentingwithanolfactorydisorder,itisimportanttoask
aboutprevioussurgicalinterventionsonthenoseorthecranium.Olfactorydisorderscanexistthatarenot
primarilyreported,particularly in patientswith chronic inflammation ofthe paranasal sinuses.
11
After
surgicalintervention,thesepatientsoftenascribetheir(quitefrequentlypersisting)olfactorydisorderto
the surgery. In view of subsequent legal claims based on an assumed malpractice on the part of the
surgeon(whichnormallyentailsanexpertopinion),theauthorsrecommendperformingolfactorytesting
before surgery (e.g., before septal surgery or surgery of the paranasal sinuses), andexplaining to the
patient the possible (potentially permanent) disorders associated with the intervention. Postinfectious
anosmiaisalsoacommoncauseofolfactorydysfunction.
Examination
ClinicalandTechnicalExaminations
During the clinical examination of the nose, special attention must be paid to inflammatory changes,
chronic inflammatory or atrophic changes of the mucous membranes, relevant structural abnormalities
(obstructingdeviationsoftheseptum,significanthyperplasiaofthenasalconcha),andsignsofacuteor
chronicinflammationoftheparanasalsinuses,includingnasalpolyposis.Aswellasanteriorrhinoscopy,
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endoscopyshouldbeincludedintheexamination;specialattentionshouldbepaidtothefossaolfactoria.
Furthermore, signs of previous surgical interventions (e.g., synechias or perforations of the septum)
shouldbesought.However,thelattercanalsobeattributedtochronicdamageofthemucousmembranes
duetooccupationalexposuretotoxicsubstancessuchaschromatesoracids.
Purely structural changes withreduced nasal airflow are very rarely the sole cause for a relevant
olfactory disorder, and rhinomanometric findings do not show any causal relationship with olfactory
capability.(Here,thepreviouslymentionedinspectionofthefossaolfactoriausingangularopticsisthe
most significant test.) However, owing to its minimal invasiveness and its widespread use,
rhinomanometryisusedfrequentlytodeterminenasalairflow.If,inthecourseofthemedicalhistoryor
clinicalexamination,signsofachronicdisorder(e.g.,chronicrhinosinusitis)arediscovered,additional
tests might be necessary, such as CT of the paranasal sinuses. These, however, should be discussed
beforehandwiththecommissioningparty.Additionalimagesofthecranium(CTorMRI)arerequiredto
rule out a space-occupying intracranial process or tumor of the skull base if there are no relevant
radiologicalfindings.
If there are complaints of disorders of taste (which usually exist), the clinical examination and
assessmentofgustatorydisordersshouldalsobeappliedasdescribedonp.168–178.
OlfactoryTesting
Quantitative validated tests of olfactory function are mandatory in all cases. In Europe, the authors
recommend the extended “Sniffin’ Sticks” test battery.
12
Other test systems that are recommended
(especiallyfortheUSA)aretheUniversityofPennsylvaniaSmellIdentificationTest(UPSIT)orthetest
of the Connecticut Chemosensory Clinical Research Center (for further details see Chapter 6: Smell
Testing).
Atestofretronasalolfactorycapabilitycanalsobeperformediftherelevantresourcesareavailable.
Qualitativeolfactorydisorderscannotbetestedtodate.Theymustbespecifiedindetail,inparticularthe
frequencyoftheiroccurrence.Testingwithmainlytrigeminalsubstancessuchasaceticacidorammonia
cangivecluesregardinganamplificationofexistingsymptoms,orsimulationofsuchsymptoms.
Inthiscontext,wewouldliketopointoutthatevenapatientwithanosmiacanscoreaminimalnumber
ofpointsintheSniffin’Stickstestbecauseoftheprobabilityofguessingcorrectlyinthe“forcedchoice”
test.Conspicuouslylowresults,oraTDI(threshold,discrimination,andidentificationscore)of0,points
tosimulationofsymptoms(malingering).TheprobabilityforaTDIscoreof0is0.002%;aTDIscoreof
1hasa probability of 0.02%. The UPSITis a 40-item multiple-choice test.Malingering in thistestis
definedasascoreof5correct,asitisstatisticallyextremelyimprobableforapatientwithanosmiato
score5.Nevertheless,malingeringisstillpossibleforbothtests.
In all cases ofdoubt andtorule outsimulation, intheauthors’opinion, the assessment ofolfactory
disordersshouldalsoincludeanobjective examination,primarilyusingolfactoryandtrigeminalevent-
related potentials (ERPs). The assessment may need to be performed by a specialized institution if
essential technical equipment is not available. Lack of ERPs with preserved responses to trigeminal
stimulisubstantiatesthediagnosisofanosmia(evenifitdoesnotanswerthequestionofitscause).The
persistenceofolfactorypotentials,however,clearlyspeaksagainstthepresenceofanosmia.Despitethe
publicationofstandardparametersforlatenciesandamplitudes,
13
areliableverificationofhyposmiais
notpossibleatthetime.
14
SpecialAspectsofAssessment
Germany
ExpertopinionsfortheStatutoryPensionInsuranceandwithintheSeverelyHandicappedPersonsActare
merelyassessmentsofthepresentstate.Inthecaseofoccupationalaccidentsandpotentialoccupational
diseases, however,the assessor mustalso commentontheir causes. As quantitative baseline physical
examination results are not usually available, the assessor must analyze the plausibility of the stated
causativemechanisms.Legislationdemandsthattheexposure(ortheoccupationalaccident) issecured.
At least, the work-related exposure must be a major cause of the olfactory disorder. The causative
correlationmustbeprobable.Ifthereare several competingcauses,possibleinteractionsmustalso be
considered.Itisusefulinsuchcasesifanexperiencedoccupationalphysiciancommentsonthecausative
mechanisms. If the given disorder is not cited in the list of occupational diseases and new medical
findingsexist,compensationmightbegrantedaccordingto§9,clause2,oftheCodeofSocialLawVII
(CSLVII).
15
Inaddition,wewouldliketomention§9,Chapter3,ofCSLVII:“Iftheinsurantwho,dueto
specific conditions of his insured occupation, was exposed to increased danger of falling ill with an
occupationaldisordercitedintheregulationsaccordingtoChapter1(i.e.,thediseaseisquotedinthelist
ofoccupational diseases)comesdown withsuch adisorder,andifindicationsfor acauseoutsidethe
insured occupation cannot be found, it is assumed that this disorder was caused by the occupation
insured.” This can be significant if the extent of the exposure cannot be ascertained accurately in
retrospect.
Regardingthelevelofreductioninearningcapacity,differentrecommendationsexist,whichamountto
10to20%inthecaseofcompleteanosmiawithoutparticularoccupationalimpact.
16,17
Theseamountsare
significantlylowerthanthosenormallygivenforthelossofvision(one-sidedblindness,25%;two-sided
blindness, 100%) or the loss of hearing (one-sided deafness, 20%; two-sided deafness, 70%). This
appliestocompensationlawaswellasthelawsregardingaccidentinsurance.Theregulationsregarding
the task of medical assessment within the social compensation laws and the Severely Handicapped
Persons Act state 15% for complete loss of olfactory capability and resulting impairment of taste
perception (see textbox on the recommendations of the German Task Force, p. 213). Within the
regulations of accident insurance, the level ofreduction inearning capacityis based on“the extent—
resulting from theimpairmentof the physical and intellectual capacities—of reduced possibilities for
occupationin the entire domain ofprofessionallife”(CSLVII,§56, Chapter2). However, the literal
implementationofthis is problematic. In practice, the assessor normallyrefers totables or to figures
based on experience.A 15% level of reduction inearning capacity is quoted—according to scientific
doctrine—for an anosmia with resulting subjective impairment of taste. Figures for hyposmia are
accordinglylower.
17–19
If, beyond that, a relevant disorder of gustatory capability (ageusia) is found
(whichrarelyhappens,however),a20%reductioninearningcapacitymaybeconsideredaccordingthe
OlfactologyandGustologyTaskForceoftheGermanSocietyofOtolaryngology(DeutscheGesellschaft
fürHals-Nasen-Ohrenheilkunde),
19
evenifalevelofonly15%isstatedinrelevantliterature.
18
Theparticularcircumstancesoftheindividualcasemustbetakenintoaccount.Forexample,adirect
eating disorder with substantial weight loss can result in an increased level of reduction in earning
capacity.Witholfactorydisorders,anywork-relatedimpacthastobeinvestigated.Forsomeoccupations
(e.g., bakers, confectioners, cooks, etc.), faultless olfactory capabilities are essential. The level of
reduction in earning capacity might have to be raised. The criteria, however, are defined rather
narrowly.
17
Also,inotherspecializedtrades,suchasperfumers,anosmiamightmakecontinuationofthe
occupation impossible. This might result in occupational disability. In other occupations where the
olfactory sense is essential for recognizing hazardous situations in time (e.g., chemical industry, fire
brigade,plumbers dealing withgas,etc.)the particularworksituationhastobe considered.Technical
devices(e.g.,gasalarmunits)mightenablethecontinuationoftheseoccupations.
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