Table Of ContentFrom Neurology to Methodology and Back
Natasha Maurits
From Neurology to
Methodology and Back
An Introduction to Clinical
Neuroengineering
NatashaMaurits
DepartmentofNeurology
UniversityMedicalCenterGroningen
Groningen,TheNetherlands
[email protected]
ISBN978-1-4614-1131-4 e-ISBN978-1-4614-1132-1
DOI10.1007/978-1-4614-1132-1
SpringerNewYorkDordrechtHeidelbergLondon
LibraryofCongressControlNumber:2011936974
#SpringerScience+BusinessMedia,LLC2012
Allrightsreserved.Thisworkmaynotbetranslatedorcopiedinwholeorinpartwithoutthewritten
permissionof the publisher (SpringerScience+Business Media, LLC, 233 SpringStreet, New York,
NY10013,USA),exceptforbriefexcerptsinconnectionwithreviewsorscholarlyanalysis.Usein
connectionwithanyformofinformationstorageandretrieval,electronicadaptation,computersoftware,
orbysimilarordissimilarmethodologynowknownorhereafterdevelopedisforbidden.
Theuseinthispublicationoftradenames,trademarks,servicemarks,andsimilarterms,evenifthey
arenotidentifiedassuch,isnottobetakenasanexpressionofopinionastowhetherornottheyare
subjecttoproprietaryrights.
Printedonacid-freepaper
SpringerispartofSpringerScience+BusinessMedia(www.springer.com)
Preface
There are many textbooks that teach the basics and more advanced concepts of
mathematical techniques and engineering approaches or the pathophysiology
of neurological disorders. But for some readers, such a specialized treatise is
more than bargained for. A medical doctor, who wants to interpret an EEG
spectrum, does not need to know all intricacies of Fourier theory. On the other
hand,anengineerwhowantstoemployspectralanalysistechniquestoimprovethe
differential diagnosis of tremor, does not need a full understanding of tremor
pathophysiology. Yet, both for physicians and engineers, it is important to bridge
thegapbetweentechnologyandmedicine.
With this book, I hope to provide a guide for those interested in crossing over
from the field of medicine – neurology in particular – to the field of technology
andviceversa.Neurologistsandresidentsinneurology,medicalengineers,medical
students, biomedical engineers and students, technical medicine students, or
studentsofotherinterdisciplinaryfieldsmaythereforeallfindthisbookinteresting
anduseful.
This text is inspired by a lecture series that I started teaching to residents in
neurologybackin2006.Thegoalofthatlectureserieswastoexplainmathematical
and physical principles underlying neurological diagnostic techniques to medical
doctors.Beingamathematicianbytraining,Inoticedthatmyinitialmoreconven-
tionalapproachwasnotoptimal;onlybyintroducingtheabstractconceptsthrough
concrete neurological cases I was able to get my educational message across.
Thisexperiencemotivatedmetochooseanuncommonapproachforthisbook.
Eachchapterstartswithanoutlineofwhatshouldbeknownafterstudyingthe
chapter.Then theneurological problems ofinterest areintroduced throughoneor
more patient cases. Subsequently, the neurodiagnostic technique that can help
establish a diagnosis is outlined and the necessary mathematics, physics, or engi-
neering principles are explained. Finally, the new knowledge is applied to the
patientcasesandotherapplicationsoftheneurodiagnostictechniquearediscussed.
To help understand the essentials of each chapter, questions with answers are
provided throughout the text. For the interested reader, mathematical details are
v
vi Preface
provided in separate boxes, but they can be easily skipped by those with less
background in mathematics. Furthermore, each chapter is completed with many
illustrations, a list of easily accessible additional reading material and a glossary.
This set-up is intended to make the book suited for self-study, but also for use in
classroomlectures.
This book would not have existed without Janne Geraedts and Aaldrik Sillius,
whosupportedmeintransformingalong-existingideaintoabookproposalaspart
of a faculty development programme I was participating in 2008. I am also very
grateful to Michael Weston, senior editor at Springer, for receiving my book
proposal with such great enthusiasm and for his and his assistant’s (Eric Farr)
continuing support during the writing process. I highly appreciate the critical
feedbackonthemanuscriptbymycolleagues(JanKuksandHanvanderHoeven)
andPh.D.students(CarolienToxopeusandEstherSmits)attheUniversityMedical
Center Groningen (UMCG) and thank my colleagues Han van der Hoeven, Jan
WillemElting,FieteLange,andAngelavanLoonattheUMCGforprovidingme
withinterestingpatientcases.MycolleagueFleurvanRootselaarattheAcademic
Medical Center(AMC) in Amsterdam provided a patient case and many valuable
comments on the manuscript. My Ph.D. student Marja Broersma provided some
photographs and supporting staff members Lukas Dijck, Janneke Sikkema, and
Janette Bijmolt helped in obtaining the patient data. I thank you all for being so
helpful.Iwouldliketothankmyparentsfortheircontinuinginterestinandloving
support for my education, academic training, and work. Last but not least: Johan,
thankyouforbeingsopositivelycritical,understanding,andsupportive(technically
aswellasbycatering)whenIwaswritingforhoursinarowinourstudy.
Groningen,TheNetherlands NatashaMaurits
Contents
1 Introduction.............................................................. 1
2 CarpalTunnelSyndrome,Electroneurography,
Electromyography,andStatistics...................................... 3
2.1 PatientCases........................................................ 3
2.2 Electroneurography:AssessingNerveFunction.................... 4
2.2.1 NervePhysiologyandInvestigation........................ 4
2.2.2 DiagnosingCarpalTunnelSyndrome...................... 9
2.3 Electromyography:AssessingMuscleFunction.................... 11
2.4 DiagnosticMeasures:WhatIs(Ab)normal? ....................... 13
2.4.1 SamplingthePopulation.................................... 13
2.4.2 NormalDistributions........................................ 14
2.4.3 DescriptiveStatistics........................................ 15
2.4.4 Correlations................................................. 16
2.4.5 TipsandTricksWhenUsingDescriptiveStatistics........ 19
2.5 ElectroneurographyinIndividualPatients ......................... 24
2.6 OtherApplicationsofElectromyographyinNeurology ........... 28
2.7 AnswerstoQuestions............................................... 29
Glossary................................................................... 29
References................................................................. 30
3 Tremor,Polymyography,andSpectralAnalysis ..................... 33
3.1 PatientCases........................................................ 33
3.2 TremorRecording:PolymyographyandAccelerometry........... 34
3.3 SpectralAnalysis.................................................... 35
3.3.1 TremorFrequencyandPeriod.............................. 35
3.3.2 TowardSpectralAnalysisofTremorbyComputer:
Sampling.................................................... 37
3.3.3 ObtainingFrequencyContentfromaDigitizedSignal:
FourierTransform........................................... 41
vii
viii Contents
3.3.4 TipsandTrickswhenInterpretingSpectra................. 45
3.4 TremorAnalysisinIndividualPatients............................. 52
3.5 OtherApplicationsofSpectralAnalysisinNeurology ............ 61
3.6 AnswerstoQuestions............................................... 64
Glossary................................................................... 65
References................................................................. 66
4 Epilepsia,Electroencephalography,Filtering,
andFeatureExtraction ................................................. 67
4.1 PatientCases........................................................ 67
4.2 Electroencephalography:MeasuringtheBraininAction.......... 68
4.3 Filtering............................................................. 72
4.3.1 BiologicalArtifacts......................................... 74
4.3.2 TechnicalArtifacts.......................................... 76
4.3.3 FilteringintheFrequencyDomain......................... 78
4.3.4 TypesofFilters ............................................. 82
4.3.5 FilteringintheTimeDomain:Smoothing ................. 84
4.3.6 RelationshipBetweenFilteringintheFrequency
andTimeDomain........................................... 85
4.3.7 DosandDon’tsofFiltering................................. 87
4.4 FeatureExtraction................................................... 87
4.4.1 TemplateMatchingandWaveletAnalysis................. 89
4.4.2 EEGSpikeDetection ....................................... 89
4.5 EEGFindingsinIndividualPatients ............................... 91
4.6 OtherApplicationsofEEGRecordingsinNeurology............. 93
4.6.1 MonitoringofCarotidArteryEndarterectomy.............. 94
4.6.2 MonitoringofStatusEpilepticusinIntensive
CareUnits.................................................... 96
4.6.3 ConfirmationofBrainDeath ................................ 98
4.7 AnswerstoQuestions................................................ 99
Glossary................................................................... 100
References................................................................. 101
5 MultipleSclerosis,EvokedPotentials,andEnhancing
Signal-to-NoiseRatio.................................................... 103
5.1 PatientCases........................................................ 103
5.2 EvokedPotentials:AssessingSensoryPathwayFunctioning...... 104
5.3 ObtainingEvokedPotentials........................................ 104
5.3.1 EnhancingSignal-to-NoiseRatio........................... 104
5.3.2 StimulationProtocols....................................... 105
5.3.3 AssessingReliability........................................ 107
5.3.4 QuantifyingandInterpretingEPs........................... 108
5.3.5 StepsinCalculationofEvokedPotentialAverages........ 111
Contents ix
5.4 TypesofClinicalEvokedPotentials................................ 112
5.4.1 VisualEvokedPotential .................................... 112
5.4.2 SomatosensoryEvokedPotential........................... 115
5.4.3 BrainstemAuditoryEvokedPotential(BAEP)............. 117
5.5 EvokedPotentialsinIndividualPatients........................... 119
5.6 OtherApplicationsofEvokedPotentialsinNeurology............ 121
5.6.1 IntraoperativeMonitoring:SEPinScoliosisSurgery...... 123
5.6.2 BAEPtoAssessHearingThreshold........................ 125
5.7 AnswerstoQuestions............................................... 125
Glossary................................................................... 126
References................................................................. 127
6 CorticalMyoclonus,EEG-EMG,Back-Averaging,
andCoherenceAnalysis................................................. 129
6.1 PatientCases........................................................ 129
6.2 SimultaneousEEG-EMGRecording:Relating
BrainandMuscleActivity.......................................... 130
6.3 Back-Averaging..................................................... 132
6.3.1 PrinciplesofandPrerequisitesforBack-Averaging ....... 132
6.3.2 Back-AverageCalculation.................................. 133
6.3.3 TipsandTricksWhenIdentifyingEMGOnsets........... 134
6.4 CoherenceAnalysis................................................. 137
6.4.1 Coherence:SignalCorrelation
intheFrequencyDomain................................... 138
6.4.2 TipsandTricksWhenCalculatingCoherence............. 139
6.5 EEG-EMGAnalysisinIndividualPatients......................... 142
6.6 OtherApplicationsofCoherenceAnalysisinNeurology.......... 147
6.6.1 EEG-EEGCoherenceinAlzheimer’sDisease............. 149
6.6.2 EEG-EMGCoherenceAnalysis
forTremorDiagnosis....................................... 150
6.6.3 BloodPressure-CerebralBloodFlowCoherence
inCerebralAutoregulation.................................. 150
6.7 AnswerstoQuestions............................................... 152
Glossary................................................................... 152
References................................................................. 153
7 PsychogenicMovementDisorders,Bereitschaftspotential,
andEvent-RelatedPotentials........................................... 155
7.1 PatientCase......................................................... 155
7.2 TheBereitschaftspotential:RecordingtheIntention
toMovebySimultaneousEEG-EMG.............................. 156
7.3 CalculatingEvent-RelatedPotentials............................... 158
7.3.1 AreEvent-RelatedPotentialsDifferent
fromEvokedPotentials?.................................... 158
