EMG Painful Limb
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Transcript of EMG Painful Limb
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EMG NerveEMG Nerve
Studies in PainStudies in Pain
AmmarAGilani,MD,DABPNAmmarAGilani,MD,DABPNAssociateProfessorandStaffNeurologistAssociateProfessorandStaffNeurologist
DepartmentofMedicine/NeurologyDepartmentofMedicine/NeurologyMcMasterUniversity/HamiltonHealthSciencesMcMasterUniversity/HamiltonHealthSciences
Hamilton,ONHamilton,ON
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PfizerPfizer
AstraZenecaAstraZeneca
AllerganAllergan
PurduePurdue
TevaNeurosciencesTevaNeurosciences
Lilly/BoehringerIngelheimLilly/BoehringerIngelheim
ayerayer
ValeantValeant
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BasicDescriptionofthelaboratoryproceduresBasicDescriptionofthelaboratoryprocedures
NerveconductionstudiesNerveconductionstudies
E ectromyograp yE ectromyograp y
ElectrodiagnosticabnormalitiesinpainfulperipheralnerveElectrodiagnosticabnormalitiesinpainfulperipheralnerve
diseasesdiseases
Pitfalls/limitationsoftechniquePitfalls/limitationsoftechnique
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SomatosensoryEvokedSomatosensoryEvoked
o en a so en a s
thePostthePostMRIera.MRIera.
A.SSEP
stimulation
to
the
left
A.
SSEP
stimulation
to
the
left
MediannerveMediannerve
B.SSEPstimulation totheleftB.SSEPstimulation totheleft
TibialnerveTibialnerve
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EMG and Nerve ConductionEMG and Nerve ConductionStudiesStudies
An
extension
o
the
Physical
ExaminationAn
extension
o
the
Physical
Examination Quantitatesnerveand/ormusclein urQuantitatesnerveand/ormusclein ur
ProvidesUsefulDataRegardingNerveInjuryProvidesUsefulDataRegardingNerveInjury SiteSite TypeType SeveritySeverity
ura onura on PrognosisPrognosis
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Goals of EDX Testing
Localization Severity
NerveNMJ Anterior HornMuscle
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erve on uct on tu es Studies
of
the
waveforms
generated
in
the
.
Motornerveconduction
fromamuscleinnervatedbythatnerve.
Sensorynerveconduction
Stimulationamixed
nerve
while
recording
from
a
mixedorcutaneousnerve
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LATENCY(DL)LATENCY(DL)IntervalbetweentheonsetofastimulusandtheonsetofaIntervalbetweentheonsetofastimulusandtheonsetofaresponseresponse
ThemaximumvoltagedifferencebetweentwopointsThemaximumvoltagedifferencebetweentwopointsItisproportionaltothenumberandsizeofnervefibersthatareItisproportionaltothenumberandsizeofnervefibersthatare
depolarized.depolarized.
electricallyactiveelectricallyactive
DURATIONDURATIONThetimefromonsettotermination.Thetimefromonsettotermination.
.
.MeasuresthedifferencesinconductionofthenervefibersMeasuresthedifferencesinconductionofthenervefibers
CONDUCTION VELOCITY(CV)CONDUCTION VELOCITY(CV)ThespeedatwhichthenervefibersarecarryingtheelectricalThespeedatwhichthenervefibersarecarryingtheelectrical
s mu us e ween wos es.s mu us e ween wos es.ComparisonofconductionbetweentwosegmentsofthesameComparisonofconductionbetweentwosegmentsofthesame
nervecanlocalizealesion.nervecanlocalizealesion.
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studies
Sensory:typically
antidromic
Commonly
examinednerves:
Sural,ulnar,median,
occas ona yra a
orsuperficial
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OnsetandpeakOnsetandpeaklatencieslatencies
ConductionvelocityConductionvelocity determinedbydeterminedby
velocityofaveryfewvelocityofaveryfewas ersas ers
AmplitudeAmplitude determinedb thedeterminedb the
numberoflargenumberoflargesensoryfiberssensoryfibersactivatedactivated
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Motor Nerve Conductions
Vital
part
of
EDX
as
this
importantforidentifyingdemyelination,compression
Needtodoproximalanddistal
studies
to
evaluate
for
conductionvelocit ,
conductionblock,temporaldispersion
, ,peroneal,
tibial
Lesscommon:radial,femoral,phrenic,spinalaccessory,facial
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F-waves and H-reflex
Usefulfor
identifying
proximalsegmental
demyelination
Canonly
be
done
w enmotoramplitudeis>1mV
epen en
onpatientsheight
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MotorFwavestudies roximalroots:
Antidromic motor
to
the
anterior
horn
of
the
spinal
cord;
orthodromically tothe
muscle.
. AprolongedasymmetricFwavessuggestaproximal
rootlesion.
Clinicalapplicationbestforplexopathy. Quiteprolongedindemyelination,AIDP,mild
rolon ationinaxonalin ur .
Lesssensitive
than
EMG
for
radiculopathy
since
only
shortsegmentofnerveisdemyelinatedin.
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Re lexloo : Orthodromicsensor andmotor Utilized
to
assess
for
radiculopathy
of
S1,
*C6/7
S1;Poplitealfossa,recordinMedialGastrocnemeus
C6/7;Mediannerveatwrist,recordatFlexorCarpiRadialis
,
,
,
sacralplexus,cord,S1motororsensoryroots. Onceabnormal,maynotnormalize;
O tenabsent
in
polyneuropathy
or
>60
years
o
age.
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Needle Electrom o ra h : Techni uesNeedle Electrom o ra h : Techni ues
NeedleelectrodeisinsertedintothemuscleNeedleelectrodeisinsertedintothemuscle Needleisdisposable,singleuseNeedleisdisposable,singleuse
MultiplemusclesareaccessibleforexaminationMultiplemusclesareaccessibleforexamination
CombinationofmusclestestedCombinationofmusclestested DependentuponclinicalquestionDependentuponclinicalquestion
LevelofdiscomfortismildLevelofdiscomfortismild
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NeedleElectromyography:DataNeedleElectromyography:Data
InsertionalActivityInsertionalActivity
SpontaneousActivitySpontaneousActivity
MotorUnitConfi urationMotorUnitConfi uration
MotorUnitRecruitmentMotorUnitRecruitment
Inter erencePatternInter erencePattern
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EMGFin ings
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InsertionactivityInsertionactivityincreaseswithinafewdaysofmuscleincreaseswithinafewdaysofmuscledenervation,whereasdenervation,whereasabnormalspontaneousactivityabnormalspontaneousactivityta es2ta es24 3 wee sto eve op, epen ngont e stance4 3 wee sto eve op, epen ngont e stance
betweenthenervelesionandthemusclebetweenthenervelesionandthemuscle
norma spontaneousact v tyan ncrease nsert onnorma spontaneousact v tyan ncrease nsert on
activityarenotpathognomonicofdenervation,mayoccuractivityarenotpathognomonicofdenervation,mayoccurincertaindisordersofmuscleortheneuromuscularincertaindisordersofmuscleortheneuromuscular
junctionjunction
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: ecru tment
Whenamuscleisvoluntarilycontractedasinglemotorunitmayfire.
Asthemuscleisfurthercontractedmoremotorunitsareaddedorrecruited.
Normall recruitmentofadditionalmotorunitsoccursatrelativelylowlevelsofeffort
IfthereisalossofMUAPswithanydiseaseprocessthen recruitmentisreduced.
Lossof
nerve
axons
ConductionblockattheneuromuscularjunctionSufficientlossofmusclefibers
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The
electromyographic
findings
may
provide
a
guide
to
the
time
of
The
electromyographic
findings
may
provide
a
guide
to
the
time
of
onsetofthelesionandtoitschronicity,onsetofthelesionandtoitschronicity,
apa en repor s a awr s rop as eve ope mme a e yapa en repor s a awr s rop as eve ope mme a e yafteranoperativeprocedureandneedleelectromyographyafteranoperativeprocedureandneedleelectromyographyperformedshortlythereafterrevealsabnormalspontaneousperformedshortlythereafterrevealsabnormalspontaneousactivit fibrillation otentialsand ositiveshar waves intheactivit fibrillation otentialsand ositiveshar waves intheextensormuscleofthewrist,itislikelythatthelesionisatleastextensormuscleofthewrist,itislikelythatthelesionisatleast223weeksoldandtherefore itprecededthesurgery.3weeksoldandtherefore itprecededthesurgery.
,, ,, ,,polyphasicmotorunitpotentialsindicatesthatthedenervationpolyphasicmotorunitpotentialsindicatesthatthedenervationoccurredseveralweeksormorebeforesurgerybecausesomeoccurredseveralweeksormorebeforesurgerybecausesomereinnervationhasoccurred.reinnervationhasoccurred.
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MononeuropathyMononeuropathy
PolyneuropathiesPolyneuropathies
MultiplexMultiplex
Radiculo athRadiculo ath
TrigeminalMononeuropathyTrigeminalMononeuropathy
(BlinkReflex(BlinkReflex))
Plexopathy(BrachialPlexopathy(BrachialorLumbosacral)orLumbosacral)
MyopathyMyopathy
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AxonalAxonal Sensory+/Sensory+/ MotorMotor NormalCVNormalCV
DemyelinatingDemyelinating Motor+SensorychangeMotor+Sensorychange SlowNCVSlowNCV
NormalDLNormalDL
ReducedtoabsentAmp.ReducedtoabsentAmp.
NormalFNormalFWave(ifamp.>1Wave(ifamp.>1
ConductionBlockConductionBlock
DistalLatency:LongDistalLatency:Long
SlowFSlowFwaveswavesMV)MV)
NeedleEMGinmotororNeedleEMGinmotororsensorimotor;Denervationsensorimotor;Denervationandreinnervationchan esandreinnervationchan es
Amplitude:NormaltoAmplitude:Normaltoreduced(late)reduced(late)
NeedleEMG:Normal(lateNeedleEMG:Normal(late
(slowlyprogressivecan(slowlyprogressivecanshowonlyreinnervationshowonlyreinnervationchanges)changes)
Denervationand/orDenervationand/orreinnervation)reinnervation)
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PAINFULNEUROPATHIES:PAINFULNEUROPATHIES:
ToxicToxic AlcoholAlcohol
Metals:Thallium;ArsenicMetals:Thallium;Arsenic
HereditaryHereditary galactosidase(Fabry's)galactosidase(Fabry's) GM2gangliosidosis:LateGM2gangliosidosis:Lateonsetonset Sensor Neuro ath ILancinatin ainsSensor Neuro ath ILancinatin ains
ciscisplatinum;Disulfiram;Ifosfamide;platinum;Disulfiram;Ifosfamide;Nitrofurantoin;Dilantin;Perhexiline;Nitrofurantoin;Dilantin;Perhexiline;Taxol;Thalidomide;VincaalkaloidsTaxol;Thalidomide;Vincaalkaloids
ImmuneImmune
MotorMotorSensoryNeuropathyI&IIFootSensoryNeuropathyI&IIFootdeformitydeformity
BurningfeetsyndromeBurningfeetsyndrome
AmyloidosisAmyloidosis
AcuteonsetAcuteonset
GuillainBarrGuillainBarr
DiffusepainduringacutecourseDiffusepainduringacutecourse
DistalpainwithincompleteDistalpainwithincompleterecover recover
ParaesthesiasinlegsParaesthesiasinlegs
Carpaltunnelsyndrome:PaininCarpaltunnelsyndrome:Paininhandshands
PorphyriaPorphyria
ImmobilityImmobility
AcutepanautonomicAcutepanautonomic
AntiAntiSulfatideAntibodyassociatedSulfatideAntibodyassociatedpolyneuropathiespolyneuropathies
PNSinvolvementPNSinvolvement Hereditary(Acromelalgia):12qHereditary(Acromelalgia):12q HSN1HSN1
HMSN5HMSN5
onnect vet ssue seaseonnect vet ssue sease
HIV(DILS)HIV(DILS)
MMproteinprotein
Ganglionopathies:Sjgren's;ParaneoplasticGanglionopathies:Sjgren's;Paraneoplastic(Hu)(Hu)
HuntingtondiseaseHuntingtondiseaselike1like1 Also:RenalfailureAlso:Renalfailure
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PAINFULNEUROPATHIES:PAINFULNEUROPATHIES:
D erent a D agnos sD erent a D agnos s
MetabolicMetabolic DiabeticDiabetic
Acute:LumbarorThoracicAcute:LumbarorThoracic
Motor
disorders
with
pain
Motor
disorders
with
pain
DiabeticamyotrophyDiabeticamyotrophy PolioPolio
InfectionsInfections
Chronic:"Smallfiber"Chronic:"Smallfiber"neuropathyneuropathy
Alcoholic:AcuteAlcoholic:Acute Pella ra niacin Pella ra niacin
PolioPolio HIVHIV
LocalizeddisordersLocalizeddisorders Nervelesions:Nervelesions:
TrigeminalTrigeminal BrachialplexusBrachialplexus
Beriberi(thiamine)Beriberi(thiamine) Strachansyndrome(CubanStrachansyndrome(Cuban
neuropathy)neuropathy) PostgastroplastyPostgastroplasty
LumbosacralplexopathyLumbosacralplexopathy ThoracicoutletsyndromeThoracicoutletsyndrome MedianMedian Posteriortibial(Tarsaltunnelsyndrome)Posteriortibial(Tarsaltunnelsyndrome) Radiculopathies:Upper&LowerExtremitiesRadiculopathies:Upper&LowerExtremities
Burnin mouths ndromeBurnin mouths ndrome
HypertriglyceridemiaHypertriglyceridemia ChronicmountainsicknessChronicmountainsickness IdiopathicIdiopathic
DistalsensorypolyneuropathyDistalsensorypolyneuropathy
Diabetic
Amyotrophy
Diabetic
Amyotrophy
ReflexSympatheticDystrophy (ComplexregionalReflexSympatheticDystrophy (Complexregionalpainsyndrome)painsyndrome)
Infections:HerpeszosterInfections:Herpeszoster Neoplasticinfiltration:BurningpainwithNeoplasticinfiltration:Burningpainwith
dysesthesiainareaofsensorylossdysesthesiainareaofsensorylosssyn romessyn romes
ErythromelalgiaErythromelalgia
MononeuritismultiplexMononeuritismultiplex
PostsurgicallocalizedpainsyndromesPostsurgicallocalizedpainsyndromes
Acuteonsetofpain&paresthesiasAcuteonsetofpain&paresthesias AcuteporphyriaAcuteporphyria
Toxic:Thallium;Arsenic;Perhexiline;VincaToxic:Thallium;Arsenic;Perhexiline;Vincaalkaloidsalkaloids
GuillainGuillainBarrBarr
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Diabetes
and
PNS
DiseasesS mmetric Pol neuro athies
Chronic Distal sensory +/- AutonomicAutonomic
-
Acute PainfulReversible
As mmetric neuro athies
Lumbosacral plexopathy
Mononeuropathies i.e., CTS
Mononeuritis multiplex
Predisposition to immune PNCIDP
Diabetic amyotrophy
Muscle infarction
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MedianattheWrist(CTS)MedianattheWrist(CTS)
UlnarattheElbow (TardyUlnarPalsy)UlnarattheElbow (TardyUlnarPalsy)
PeronealPalsyattheFibularHeadPeronealPalsyattheFibularHead
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Plexopathy: SelectedPlexopathy: Selected
EtiologiesEtiologies
CompressionCompression (CABG)(CABG)
InflammatoryInflammatory (Parsonage(ParsonageTurnerTurnerSyndrome)Syndrome)
RadiationInjuryRadiationInjury (Radiotherapy)(Radiotherapy)
, ,, ,
missile)missile)
sc em asc em a a et camyotrop ya et camyotrop y
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prolongationofthemediannervemotor/sensorylatencyuponprolongationofthemediannervemotor/sensorylatencyuponstimulationatthewrist("terminal"or"distal"latency),stimulationatthewrist("terminal"or"distal"latency),
normalmedianmotorconductionvelocityintheforearm,normalmedianmotorconductionvelocityintheforearm,
slowmediansensor conductionvelocit acrossthewrist slowmediansensor conductionvelocit acrossthewrist
normalmotorandsensoryNCSoftheulnarnerve(notinvolvednormalmotorandsensoryNCSoftheulnarnerve(notinvolvedinCTS).NCSarepositivein91inCTS).NCSarepositivein9198%ofpatientswithclinicalCTS98%ofpatientswithclinicalCTS
DiagnosedbycomparingMediantoUlnarsensoryandmotorDiagnosedbycomparingMediantoUlnarsensoryandmotorDLsDLs
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58YearoldpatientwithLowBack58YearoldpatientwithLowBack
pa nan e t oot roppa nan e t oot rop
RetiredsteelworkerwithlongstandinghistoryoflowbackfromworkRetiredsteelworkerwithlongstandinghistoryoflowbackfromworkrelatedinjuryandS/Pbacksurgery10yrs.Ago. Presentedwith2relatedinjuryandS/Pbacksurgery10yrs.Ago. Presentedwith2monthhistoryofnumbnesstinglingandpainofdorsalaspectofleftmonthhistoryofnumbnesstinglingandpainofdorsalaspectofleft
. .
NerveConductionStudiesNerveConductionStudies
MotorNerveConductionstudies: CMAPsonLeftMotorNerveConductionstudies: CMAPsonLeft TibialTibial NormalNormal Amp.,DL&CVAmp.,DL&CV
DeepPeronealDeepPeroneal ReducedAmp,NormalDLandCVbelowfibularReducedAmp,NormalDLandCVbelowfibularheadand12m/sslowingacrossfibularhead,Dispersionan55%dropinheadand12m/sslowingacrossfibularhead,Dispersionan55%dropinampl.ampl.
SensoryNerveConductionStudies:SNAPsonLeftSensoryNerveConductionStudies:SNAPsonLeft Sural:Sural: NormalAmp.,DL&CVNormalAmp.,DL&CV
Sup.Peroneal:Sup.Peroneal: Slightlyreducedamp.,NormalDLandCVSlightlyreducedamp.,NormalDLandCV
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58YearoldpatientwithLowBack
NeedleEMGLeftLowerExtremitNeedleEMGLeftLowerExtremit
Muscle Insertional Spontaneous Configuration Recruitment Interfennce
Vastus
Lateralis
N N N N N
Anterrior Lar e/
Tibialis Poly
Peroneus
MedialGast. N N Large/poly
. .
Large/Poly
Glut.Med. N N Large/Poly
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Guideline:NeedleEMGexaminationofatleast1muscleinnervatedb theC C6 Guideline:NeedleEMGexaminationofatleast1muscleinnervatedb theC C6 C7,C8,andT1spinalrootsinasymptomaticupperlimb,andL3,L4,L5,andS1C7,C8,andT1spinalrootsinasymptomaticupperlimb,andL3,L4,L5,andS1
spinal
roots
in
the
symptomatic
lower
limb.
spinal
roots
in
the
symptomatic
lower
limb.
Paraspinalmusclesat1ormorelevels,asappropriatetotheclinicalpresentation,Paraspinalmusclesat1ormorelevels,asappropriatetotheclinicalpresentation,s ou eexam ne excep npa en sw pr orcerv ca am nec omyus ngas ou eexam ne excep npa en sw pr orcerv ca am nec omyus ngaposteriorapproach).posteriorapproach).
If
a
specific
root
is
suspected
clinically,
or
if
an
abnormality
is
seen
on
the
initial
If
a
specific
root
is
suspected
clinically,
or
if
an
abnormality
is
seen
on
the
initial
needleEMGexamination additionalstudiesasfollows:needleEMGexamination additionalstudiesasfollows:
Examinationof1or2additionalmusclesinnervatedbythesuspectedrootandadifferentExaminationof1or2additionalmusclesinnervatedbythesuspectedrootandadifferentperipheralnerve.peripheralnerve.
Demonstrationofnormalmusclesaboveandbelowtheinvolvedroot.Demonstrationofnormalmusclesaboveandbelowtheinvolvedroot.
OptionaOptional:
Perform
Fl:
Perform
F
Wave
and
HWave
and
H
Reflex
(C6,C7
and
S1).
Compare
with
the
Reflex
(C6,C7
and
S1).
Compare
with
the
contralateralsideifnecessary.contralateralsideifnecessary.
Abnormalonlywithaxonalinvolvement.Abnormalonlywithaxonalinvolvement.
Dennervationin2Dennervationin23weeks,reinnervation43weeks,reinnervation46weeksafteronsetofsymptoms.6weeksafteronsetofsymptoms.
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What to Expect From anWhat to Expect From an
EMG ReportEMG Report
AclinicallyandphysiologicallyrelevantAclinicallyandphysiologicallyrelevant
Anoutlineofthelocalization,severity,andacuityofAnoutlineofthelocalization,severity,andacuityof
NotationofotherdiagnosesthatareNotationofotherdiagnosesthataredetected excludeddetected excluded
ExplanationofanytechnicalproblemsExplanationofanytechnicalproblems
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NerveConductionStudies:limitationsNerveConductionStudies:limitations NCSassessdistalsegmentsofnervesNCSassessdistalsegmentsofnerves PainfulstimulationsPainfulstimulations
empera uresens ve > empera uresens ve > AssessmainlylargefibersAssessmainlylargefibers MostusefulfornerveconditionsMostusefulfornerveconditions
SkillsoftheelectromyographerSkillsoftheelectromyographer Timing(Walleriandegeneration) fewweeksuntilfullpictureTiming(Walleriandegeneration) fewweeksuntilfullpicture
emergesemerges
MultiplemusclesneedtobeexaminedMultiplemusclesneedtobeexamined SamplingerrorscanleadtoerroneousconclusionsSamplingerrorscanleadtoerroneousconclusions
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DetectsdynamicandfunctionalinjurymissedbyMRIDetectsdynamicandfunctionalinjurymissedbyMRI
rov es n orma onregar ngc ron c yo nerve n uryrov es n orma onregar ngc ron c yo nerve n ury
ProvidesprognosticdataProvidesprognosticdata
g y oca z ngg y oca z ng
ClarifiesclinicalscenarioswhenonedisordermimicsanotherClarifiesclinicalscenarioswhenonedisordermimicsanother
en escom ne muen escom ne mu s e n ury,avo ngm sse agnosess e n ury,avo ngm sse agnoses
IdentifiesmoreglobalneuromuscularinjurywithfocalonsetIdentifiesmoreglobalneuromuscularinjurywithfocalonset
Prov es ong tu na ata orc art ngcourse,responsetot erapyProv es ong tu na ata orc art ngcourse,responsetot erapy
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ThankyouThankyou