Objective examination in ENT medico legal expertise. (Congrès Portugal)

7/31/2019 Objective examination in ENT medico legal expertise. (Congrs Portugal)

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Objective examination in ENTmedico legal expertise

Prof. Dr. Raymond BONIVER

Lige University, Belgium

A.P.O. June 2012


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In expertise, we have to obtain objective data from thepatients complaints. Those, in certain cases, are voluntary

exaggerated, either because the subject has atemperament by which he always tends to exaggerate hissymptoms, or because he estimates to be injured in hisintegrity of its physical status and to be entitled to a repair

for which he will do the test in the way to have the bestadvantages.

We shall consider three pathologies for which we are mostfrequently consulted in ENT:

- Hearing disorders- Balance disorders- Smell disorders


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Hearing disorders

The first evaluation of the patient with hypoacousia canbe done easily without any instrument.

How does he understand the voice during theanamnesis?Does he understand the whispered voice?Is it necessary to speak loud or very loud?

It is also important to observe the patient: does he

have an auditory prosthesis? Is it open? Is it workinggood? Is the battery good? How does he react to thequestions?


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AudiometryIn pure tone audiometry, whenever the subject exaggerates his

handicap, the audiogram doesnt fit with the responses he gaveduring the anamnesis. For example, with an average of 80 dBloss on the audiogram, the subject cant understand thewhispered voice.

Then, in suspected cases, the audiogram can be delivered in twosessions:

- Descending step: from loud to level of perception, decreasing bystep of 5 dB

- Ascending step: from 0 dB to level of perception, increasing bystep of 5 Db.

In the normal subject, the two levels of perception should be thesame in the ascending and descending pathways and shouldcorrespond to the discrimination level obtained during speechaudiometry.


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When we suspect a functional hearing loss, further testing

is necessary:Historically, the following tests were used in simulationscreening :

-Lombard or Voice-Reflex test

-Azzi test

-Stenger test

-Bekesy audiometry

The DAF test (delayed auditory feedback test) introducedby Demanez can detect hearing losses of sizeable degreebut not the minor exaggerations that can occur in medico-legal situations.


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Nowadays, several objective tests can be done and are

helpful in assessing auditory function in patients who areunable or unwilling to cooperate.

The most common used tests are

-Acoustic reflex thresholds-Otoacoustic emissions (OAE)

-Brain stem evoked-response audiometry (BERA or ABR)

-Cortical evoked-response audiometry (CERA)


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Acoustic reflex threshold

-Normally, the reflex for pure tones is elected at about 90 dB above the hearingthreshold. For broad-band noise, it occurs at about 70 dB above threshold.

-In patient with cochlear damage, the reflex may occur at sensation levels less than60 dB above the audiotory pure-tone threshold. (Metz recruitment)

-It is absent:. In conductive losses. In case of impairment of the VII-VIII reflex arch.. In case of cophosis

Otoacoustic emissions

Evoked otoacoustic emissions may be conceptualised as an echo in response to asound stimuli. These emissions are generally absent in hearing loss greater than30 dB from 500 to 2000Hz.

Then, if the subject has a hearing loss of 60 dB in pure-tone audiometry withnormal evoked otoacoustic emissions on the same ear, it is a functional hearingloss.

Otoacoustic emissions is not a tool to determine the degree of hearing loss byfrequency, even with the distorsion product emissions.


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BERA

Brain Stem Evoked-Response Audiometry

The test measures electrical peaks generated in the brainstem along the auditory pathways. Testing can be done withpure tones, broad-band noise or clicks. In any case, thebrain stem does not react to a determined frequency.

The measure is objective, consistent and approximatethreshold levels can be determined. In suspected cases of

exaggeration, ABR testing is reliable. If the BERA gives younormal peaks at 20 dB and the threshold on pure toneaudiometry is 80 dB, it is a functional hearing loss.


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CERA

Cortical Evoked-Response Audiometry (CERA)

This method focuses on electrical activity at thecerebral-cortex level. The patient must be kept awarewith images projection or reading. It is a valuable tool inevaluating thresholds frequency by frequency. Theresults in normal subjects are in correlation with puretone audiometry findings.


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Tinnitus

Tinnitus is an otological condition in which sound is perceivedwithout any external auditory stimulation. It may be a whistling,ringing, roaring, buzzing, This challenging pathology is difficultto assess in expertise. Tinnitus may be either objective orsubjective. Objective tinnitus is comparatively easy to detect and

localize because it can be heard by the examiner using astethoscope. It may be caused by glomus tumor, palatalmyoclonus and other conditions. Subjective tinnitus is much morecommon by far. All the tests described above can be done in theassessment of subjective tinnitus to recognise a causal

relationship. Nevertheless, in a large number of cases in which anormal patient with normal hearing complains of head noises,functional tinnitus has to be considered. The expertise of apsychotherapist is helpful to determine the problem with thepatients that can sometimes have distressing proportions.


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Conclusion

Actually, objective hearing tests are accurate and reliableto define the hearing threshold of the patient withfunctional hearing loss.

These objective tests are of great value in expertise.


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Vertigo

It is important to rule out all the organic causes that canlead to vertigo and dizziness.

It is important to keep in mind that the balance is the resultof miscellaneous informations collected in the vestibularnuclei arising from proprioceptive, visual, vestibular,cortical and emotional pathways. The cerebellum isregulating the vestibular nuclei.

All these informations are integrated and sent to the motorpathways to control eye movement, static and dynamicposture.


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The assessment of the dizzy patient:

-Anamnesis-Physical examination

-How he stands-How he walks-Otoscopy

-Audiology testing-Pure-tone audiometry-Acoustic reflex-Otoacoustic emissions-BERA

-Vestibular testing-Oculomotor examination-Clinical vestibular evaluation-Index deviation and Romberg

-Spontaneous nystagmus and positional nystagmus-Rotational testing with ENG/VNG control-Caloric testing with ENG/VNG control-Vestibular evoked myogenic potentials (VEMP)-Posturography

ENG = electronystagmographyVNG = videonystagmography


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Objectif Subjectif

Oculomotricity

Pursuit +

Saccades +

OPK

Vestibular Examination

Tonic Dviation

Romberg +

Finger +

Cerebellar test

Fingers-nose +

Adiadococinesy +

Musculair Tonus

Spontaneous nystagmus +

Positional nystagmus +

Head Shaking +

Hamalgyi

Vibratory nystagmus +

Rotatory tests +

Caloric proofs +

BERA

CERA

+

+

VEMP


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Recommandations for vestibular testing

Stop for alcohol, any sedative or antidepressive drug 48hbefore the examination.

Control the attention of the patient.

Dont speak with the patient during rotatory test becauseorientation effects disturb the vestibulooculair reflex.

With ENG control the calibration before each caloric proof.

In case of week response only for one irrigation it is

necessary to repeat it.


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Positionnal and Spontaneous

Nystagmus in ENG or VNG

A spontaneous nystagmus is pathologic if :- slow phase speed is > 7/sec- one nystagmus without artefact is > 14/sec during the

registration

A position nystagmus is pathologic if :- slow phase speed > 6/sec.- it exists minime in 3 positions

- it is a benign paroxystic nystagmus- its direction change during the position

IT IS NECESSARY TO SUSTAIN THE SUBJECT ATTENTIONDURING THE TESTS.


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Rotatory and Caloric ProofsSome considerations

ALWAYS SUSTAIN THE SUBJECT ATTENTION

Closed Eyes Opened Eyes in ENG

Closed eyes

Bell phenomen : it means a transitory upmovement of the eyes that disturb the nystagmus.

Opened eyes in darckness must give.

Directionnal Preponderance :+ > 26% (meta-analyses)

Labyrinthic paresis :+ > 25% ENG+ > 22% VNG


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Objective signs of central lesion of

vestibulo-oculomotric pathways

(Demanez J.P.) Alteration of pursuit ocular without spontaneous nystagmus

Horizontal OPK asymetry

Failure Fixation Index 50 %

Hyperreflexy : a average slow speed phase for 4 irrigations > 200/sec.!!! If the 1e irrigation is particularly intense, it is necessary to repeat.

Hypo- or hypermetry of saccades.

Spontaneous or positional nystagmus abnormal

Dissociated nystagmus

Slowness of the nystagmus quick phase

Slowness of the slow phase

Distorted nystagmus

!!! One anormality : central lesion possible

2 anormality : central lesion probable

3 anormality : central lesion.


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Olfaction

Actually, the tests we use nowadays can confirm thecomplete loss of smell (anosmia).

Unfortunately, it is still a challenging procedure to detect thelittle variation of smell (dysosmia). Even in a normal subject,the sense of smell is variable, depending on variousconditions: digestion, hormonal, metabolic disorder,smoking,

The testing must be completed with a detailed interrogatoryto have the maximum level of success in defining thediagnosis of anosmia or hyposmia.


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Psychophysical testTESTS PSYCHOPHYSIQUES (SUBJECTIF)

SniffinSticks Hummel, ChemSenses 1997

UPSIT (University of Pennsylvania Identification Test) Doty, PhysiolBehav1984

CCCRC (Connecticut Chemosensory Clinical Research Center) Cain,Laryngoscope 1988

Zrcher Geruchstest Briner, Rhinology 1999

Biolfa Lecanu, Ann ORL Chir Cervicofac 1999

T & T olfactometer Zusho, Auris, Nasus, Larynx 1981

SOIT (Scandinavian Odor Identification Test) Nordin, Acta Otolaryngol1998

etc.


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Smell Identification Test (UPSIT)


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The measurement of the time related respiratory flow

In this method, we record the variation of nasal air flow withan anterior rhinomanometer and some different olfactivesubstances are introduced in the airflow channel.

Four flavours are tested after a normal air test recording:

eau de rose, lavander, pyridine, ammoniac 30%.

We observe the variations of the respiratory rhythminduced by the presentation of the different flavours.

This test is reliable to detect an anosmic: the smell ofpyridine is so intense that only the true anosmic patient canbreathe it. If the patient block his respiration with pyridine,he still can smell.


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Olfactory Evoked Potentials

The olfactometer can stimulate the olfactive fibers and thenasal mucosa with the diffusion of different odoroussubstances. The patient sits and is administred by a nasaltube during twenty to forty minutes different flavours, some

purely olfactive, some sensitive (trigeminal sensitive).

The patient must be relaxed and not disturb.

The computer analyses the results and can tell if thepatient has a normal sense of smell. But it is not reliable todetect the quality of the olfaction of an individual subject.

This objective test is time consuming and is actuallydeveloped by Rombaux at the University of Louvain in

Belgium.


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In a recent paper (Rhinology 2012, 50, 13-21),Rombaux concludes that this technique has a poorsignal-to-noise ratio and cancels out stimulus-inducedchanges in the EEG signal that are not strictly phased-locked to stimulus onset. The fact that consistentchemosensory event-related brain potentials (CSERP)are not systematically identifiable in healthy subjectscurrently constitutes a major limitation to the use of thistechnique for the diagnosis of chemosensory

dysfunction.


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Conclusion

The development of new technique and the use ofmore powerful computer assisted technology lead us toreach the diagnosis of most disease more and moreobjectively.

No doubt, it will be even better in the future.

The simulator has a particular psychologic profile thatthe examiner has to take in account and it needs a lotof patience and tact to tests these patients.

Simulating is a lie, a fraud, and all fraud must berevealed.

It is in fact our opinion.


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Objective examination in ENT medico legal expertise. (Congrès Portugal)

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