IntracorticalBrain-ComputerInterfaces(iBCIs)aimtorestorecommunication,mobility,and independencetoVeteransandotherswithparalyzingdisorderssuchasamyotrophiclateralsclerosis (ALS),stroke,orspinalcordinjury.InthelatestagesofALS,theprogressivelossofmobilityis accompaniedbyalossofspeech,resultingintetraplegiaandanarthria,orlocked-insyndrome. Thoughassistiveandaugmentativecommunication(AAC)devicespartiallyaddressthisproblem,such devicesbecomelessusefulandeventuallyfailasmotorpowercontinuestodecline.Incontrast,iBCIs canrecordtheneuralactivityassociatedwithintendedmovementdirectlyfromcortex.Inthisrenewal MeritReviewapplication,weproposetoexpanduponthetremendousprogressmadeinthe developmentoftheinvestigationalBrainGateNeuralInterfacesystemtowardprovidingVeteranswith intuitive,always-available,wirelesspoint-and-clickcontroloveracomputer,tablet,oranyothersoftware- basedcommunicationsystem. Intheproposedresearch,wewillrecruittwoVeteransorotherpeoplewithALSattheProvidenceVA MedicalCentertoparticipateintheongoingBrainGatepilotclinicaltrial.Afterplacementoftwo4x4x1.5 mm,96-electrdodeBlackrock(Utah)recordingarraysinthedominantmotorcortex,participantswill engageintwoorthreerecordingsessionsperweek,intheirplaceofresidence.Theresearch,whichwill alsoleverageotherparticipantsinthemulti-siteBrainGatetrial,willfocusoverayearormorewith eachparticipantonthedevelopmentofimproved,robustneuraldecoders.
Asa firstaim, wewillextend thestabilityofneuralcontrolbydevelopinganewclassofrelationaldecoderswithimprovedflexibility, adaptability,andnoisetolerance.Thiswillbefacilitatedbytheuseofadiscriminativeratherthan generativedecodingapproachthatfocusesonmodelingtheprobabilitydistributionofthe(low- dimensional)volitionalstateoutputsbasedon(high-dimensional)neuralsignals.Thisstrategydoesnot relyuponanunderlyingassumptionofcosinetuningtoendpointvelocity,andallowsforflexible,non- linearmappingacrossdifferentintendedmovementsandeffectorswithincreasedtolerancetonoise.In thesecondaim,wewilldevelopnewstrategiestorapidlycalibrateandcontinuouslyupdateneural decoders.Ournewmethodologywillallowustotransitiondirectlytoclosedloopcontrolandtocalibrate functionalneuraldecoderswithin~1minuteofactivatingthesystem.Wewillalsoimplementnew strategiestomaintaincontinuouslybothintendeddirectionandclickdecodingbyupdatingthedecoder aftereverysuccessfultargetselection,ausefulsteptowardthedesignofembeddedneuroprosthetic systemsandpractical,independentuseofaniBCI.Inbothoftheseaims,decoderswillbecomparedto thecurrentstateoftheartapproachesforBCIcontrol.Finally,wewilldevelopaclosedloopsupervisor systemcapableofdetectingidlestates,automaticallyswitchingbetweendesiredeffectorsandtriggering decoderrecalibration.Theseinnovations,togetherwiththefirstuseofahigh-bandwidthwirelessneural signaltransmitterinhumaniBCIs,willresultinanautonomous,self-regulatingsystem,helpingtorestore independencetousersbyreducingtherelianceonanable-bodiedcaregiver.Thecombinationofthese innovations,rigorouslytestedbyahighlyexperiencedandtightlycollaborativeteamofclinicians, neuroscientists,andengineers,willtranslatethecurrentiBCIsystemtowardenablingindependent, intuitive,iBCI-enabledcommunicationbyVeteranswithALS.
AmyotrophicLateralSclerosis,alsoknownasALSorLouGehrig?sdisease,isaprogressivedisorderof thenervoussystem.VeteranshaveanincreasedriskofdevelopingALS,thelaterstagesofwhich impedetheabilitytomoveone?slimbs,tospeak,andtobreathewithouttheassistanceofamechanical ventilator.IntracorticalBrain-ComputerInterfaces(iBCIs)arebeingdevelopedtoallowVeteransand otherpeoplewithALStocontrolexternalcommunicationdevices-suchasacomputerforemail,text messaging,ornavigatingtheweb-simplybythinkingaboutthemovementoftheirownhand.A?neural decoder?translatesrecordedbrainactivityassociatedwiththeintenttomoveintoacommandsignalfor acomputercursororanotherassistivedevice.Inthisresearch,wewilldevelopimproved,stableneural decoderstowardaniBCIthatprovidesVeteranswithALSwithintuitive,robust,at-homecontrolof computersandotherassistivecommunicationtechnologies.
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| Milekovic, Tomislav; Sarma, Anish A; Bacher, Daniel et al. (2018) Stable long-term BCI-enabled communication in ALS and locked-in syndrome using LFP signals. J Neurophysiol 120:343-360 |
| Young, D; Willett, F; Memberg, W D et al. (2018) Signal processing methods for reducing artifacts in microelectrode brain recordings caused by functional electrical stimulation. J Neural Eng 15:026014 |
