Non-MetallicHumanVagusNerveStimulatorMengqiaoLi,Sijian Yan,MEng‘16
Advisor:Dr.BruceLand,Dr.AdamAndersonSchoolofElectricalandComputerEngineering,CornellUniversity
Overview DesignandImplementation Evaluation
Experimental Results
ConclusionApproach
Acknowledgements
References
Thevagus (or“wandering”)nerveis
cranialnerve10,connectingthebrainwith
vitalorgans(heart,lungs,gut).
• Varyheartrate
• Controlfooddigestion
• Relievestress
• Improvememory
[1]“Courseanddistributionoftheglossopharyngeal,vagus,andaccessorynerves.”Quotefrom:https://en.wikipedia.org/wiki/Vagus_nerve[2]“Vagusnervestimulation”,MAYOCLINIC.Quotefrom:http://www.mayoclinic.org/tests-procedures/vagus-nerve-stimulation/home/ovc-20167755[3]“CompletePanTompkinsImplementationECGQRSDetector”,MathWorks.Quotefrom:http://www.mathworks.com/matlabcentral/fileexchange/45840-complete-pan-tompkins-implementation-ecg-qrs-detector/content/pan_tompkin.m[4]“ValuesoftheChi-squareddistribution”,MadCalc,Quotefrom:https://www.medcalc.org/manual/chi-square-table.php
WewouldliketothankouradvisorDr.BruceLandforhisadvice,encouragement,andcontinuedsupportofthisproject.WealsoneedtothanktoDr.AdamAndersonandhisPhDstudentRossMarkello fortheirexternalhelpwithusingmedicalequipment.
PeakLocation– Left PeakLocation– Right PeakLocation– Still
• Pan-Tompkinspeakanalysis
• IntervalDistributionAnalysis
Existinghighlyinvasive(implantsbetween
carotidandjugular)vagus stimulatorshasbeen
• GenerateVaryingFrequenciesCircuitBoard
• CircuitTesting• HeartRateDataCollectionunderDifferentStates
Experiments
CircuitImplementation
EKGExperiment
StatisticalAnalysis
Encapsulation
Ourdevicehasachievedfundamentalfunctions.Statisticalanalysis
ofexperimentalresultsusingthisstimulatordoesn’tindicateamore
varyingheartrateundervagusnervestimulatingcircumstances so
morefurtherevaluationsareneeded.Itcouldbecausethenumberof
testersistoosmalltobeanalyzestatistically.
Furtherworkwillbetomakeabettershaped,morecompatible
endofthedevice,aswellastestmultiplesubjects.Furthermore,
improvementcouldbemadetomeettheneedofMRIcompatibility
sincethepotentialapplicationinmedialstillexists.Thefiguresaboveshowtheheartbeat(fromsinglesubject)versustime.EachX-axisrepresentsthreeminutesandtheplots
fromtoptobottomaremeasuredunder10Hz,30Hz,and60Hzstimulationrespectively.
Tragus andCavity
ofconcha both
contain45%ofvagus
nervereceptors.
Antihelix contains
75%andallofthe
receptorsinCymba
Conchac arevagus
nervereceptor.
• Pan-TompkinsAlgorithm• IntervalDistributionAnalysis
StatisticalAnalysis
• Blackbox• MRIcompatiblematerialsEncapsulation
InordertoevaluatethecorrelationsofstimulatingleftearV.S.still
andstimulationrightearV.S.still,weusedChi-squaredtodetermine
whetherthereisasignificantdifferencebetweentheexpected
frequenciesandtheobservedfrequenciesinourexperiments.
…...
Herethedegreeoffreedomis226sincethenumberofsampleis
227.Allofthenumbersexceedthestandardvalueinthetableabove.
Therefore,itisnotconvincingtoconcludeanyrelationshipbasedon
Chi-Squarecalculation.Furthertestisneeded.
Thesethreefiguresrepresenttheheartbeatintervaldistributionunderdifferentstimulationfrequencies.Normallythewider
thepeakis,themorevariabletheheartrateisconsideredtobe.
approvedbyFDAforavarietyofconditions,includingMajor
Depression.ButHumanecologyscientistsatCornellarelookingfora
non-invasivedeviceutilizingthefactthatthevagus receivesinputfrom
touchreceptorsaroundtheear.
Goalsofthisproject:
• Buildanaround-the-eardevicethatiscapableofgeneratingvarying
vibratoryfrequencies
• Discoverthevibrat frequency ofaround-the-earvagus nerve
stimulation thathasthemostsignificantinfluencetohumanheart
rate
• FigureoutawaytomakethedeviceMRIcompatible– non-metallic
Greaterstandarddeviationof
beat-to-beatintervalsindicatesa
morevaryingheartrate.Herewe
canseethatheartratevariesthe
mostwhenstimulatingrightear
with60Hzfrequency.
