2024
Stability of infraslow correlation structure in time-shifted intracranial EEG signals
Joshi R, Duckrow R, Goncharova I, Hirsch L, Spencer D, Godwin D, Zaveri H. Stability of infraslow correlation structure in time-shifted intracranial EEG signals. Frontiers In Network Physiology 2024, 4: 1441294. PMID: 39258030, PMCID: PMC11384574, DOI: 10.3389/fnetp.2024.1441294.Peer-Reviewed Original ResearchInfraslow activityContact pairsFrequency bandMagnitude-squared coherenceAntiseizure medicationsMedically refractory epilepsy patientsElectrode contact pairsHigher-frequency activityRefractory epilepsy patientsDC-coupled recordingsIcEEG epochsEEG frequency bandsEnvelope correlationOptimal parametersClinical relevanceSeizure riskIntracranial EEGEpilepsy patientsPatientsIntracranial EEG signalsTaperTraditional EEG frequency bandsSystematic 1 Hz direct electrical stimulation for seizure induction: A reliable method for localizing seizure onset zone and predicting seizure freedom
Sivaraju A, Quraishi I, Collins E, McGrath H, Ramos A, Turk-Browne N, Zaveri H, Damisah E, Spencer D, Hirsch L. Systematic 1 Hz direct electrical stimulation for seizure induction: A reliable method for localizing seizure onset zone and predicting seizure freedom. Brain Stimulation 2024, 17: 339-345. PMID: 38490472, DOI: 10.1016/j.brs.2024.03.011.Peer-Reviewed Original ResearchSeizure inductionSeizure onset zoneSurgical outcomesHabitual seizuresOnset zonePredicting seizure freedomExcellent surgical outcomesProspective cohort studyMann-Whitney testConsecutive patientsFisher's exactSeizure freedomRefractory epilepsyCohort studyPost-surgeryInsular regionsMann-WhitneyPatientsIntracranial EEGSeizuresLocalizing seizure onset zonesStimulationElectrical stimulationMedial temporal regionsTemporal regions
2022
Perspectives on Understanding Aberrant Brain Networks in Epilepsy
Sinha N, Joshi R, Sandhu M, Netoff T, Zaveri H, Lehnertz K. Perspectives on Understanding Aberrant Brain Networks in Epilepsy. Frontiers In Network Physiology 2022, 2: 868092. PMID: 36926081, PMCID: PMC10013006, DOI: 10.3389/fnetp.2022.868092.Peer-Reviewed Original ResearchDiscrete cortical areasAberrant brain networksGeneralized seizuresAdjacent cortexSeizure progressionCortical areasEpilepsyNeurological disordersSeizuresAnatomical configurationNetwork diseaseNeural activityBrainAberrant activityBrain networksHuman brainWidespread neural activityPatientsSurgeryCortexDiseaseNovel studyProgression
2021
Passive Localization of the Central Sulcus during Sleep Based on Intracranial EEG
Alkawadri R, Zaveri HP, Sheth KN, Spencer DD. Passive Localization of the Central Sulcus during Sleep Based on Intracranial EEG. Cerebral Cortex 2021, 32: 3726-3735. PMID: 34921723, PMCID: PMC9764437, DOI: 10.1093/cercor/bhab443.Peer-Reviewed Original ResearchConceptsCentral sulcusMotor cortexMotor areaLeg motor areaPrimary motor cortexIntracranial EEG monitoringTongue motor areaLocal network activityMotor/premotorSM cortexIntractable epilepsySensorimotor cortexAnterior bankNREM sleepSensory cortexEEG monitoringZ-scoreHigher EEGCortexIntracranial EEGSignificant differencesPatientsSleepNetwork activityPrimary handIncreased branched‐chain amino acids at baseline and hours before a spontaneous seizure in the human epileptic brain
Ong C, Damisah EC, Gruenbaum SE, Dhaher R, Deng Y, Sandhu MRS, Zaveri HP, Spencer DD, Eid T. Increased branched‐chain amino acids at baseline and hours before a spontaneous seizure in the human epileptic brain. Epilepsia 2021, 62: e88-e97. PMID: 33949690, PMCID: PMC11259155, DOI: 10.1111/epi.16920.Peer-Reviewed Original ResearchMeSH KeywordsAdolescentAdultAmino Acids, Branched-ChainBrain ChemistryChildChild, PreschoolChromatography, High Pressure LiquidDrug Resistant EpilepsyElectrocorticographyElectroencephalographyEpilepsies, PartialExtracellular SpaceFemaleGlutamic AcidHumansIsoleucineMaleMicrodialysisMiddle AgedSeizuresTandem Mass SpectrometryYoung AdultConceptsSpontaneous seizuresDrug-resistant focal epilepsyExtracellular brain glutamateHuman epileptic brainBranched-chain amino acidsBranched chain amino acids valineRefractory epilepsyBrain microdialysisGlutamatergic neurotransmissionFocal epilepsySeizure onsetBrain glutamateEpileptic brainHuman patientsSeizuresBrain regionsDialysis samplesMammalian targetEpilepsyLiquid chromatography-tandem mass spectrometryBaselineBCAAIntracranial electroencephalographyChromatography-tandem mass spectrometryPatients
2020
Beyond implantation effect? Long-term seizure reduction and freedom following intracranial monitoring without additional surgical interventions
Percy J, Zaveri H, Duckrow RB, Gerrard J, Farooque P, Hirsch LJ, Spencer DD, Sivaraju A. Beyond implantation effect? Long-term seizure reduction and freedom following intracranial monitoring without additional surgical interventions. Epilepsy & Behavior 2020, 111: 107231. PMID: 32615416, DOI: 10.1016/j.yebeh.2020.107231.Peer-Reviewed Original ResearchConceptsLong-term seizure freedomSeizure freedomSeizure frequencyElectrode implantationIntracranial studiesLong-term seizure reductionAdditional surgical interventionSeizure onset localizationIntracranial electroencephalogram monitoringSeizure reductionConsecutive patientsSurgical interventionEpileptogenic networksElectroencephalogram monitoringNeuromodulatory effectsRetrospective analysisIntracranial monitoringTransient improvementDepth electrodesPatientsYear 4ImplantationAdequate dataYearsCircadian-Like Rhythmicity of Extracellular Brain Glutamate in Epilepsy
Sandhu MRS, Dhaher R, Gruenbaum SE, Raaisa R, Spencer DD, Pavlova MK, Zaveri HP, Eid T. Circadian-Like Rhythmicity of Extracellular Brain Glutamate in Epilepsy. Frontiers In Neurology 2020, 11: 398. PMID: 32499751, PMCID: PMC7242976, DOI: 10.3389/fneur.2020.00398.Peer-Reviewed Original ResearchMesial temporal lobe epilepsyExtracellular brain glutamateSeizure onset regionTemporal lobe epilepsyType of epilepsyExcitatory neurotransmitter glutamateSeizure onset areaTranslational rodent modelEpileptogenic hippocampusLobe epilepsyIntracerebral microdialysisExtracellular glutamateBrain glutamateIndividual patientsRodent modelsControl animalsNeurotransmitter glutamateExtracellular levelsEpilepsySeizuresOnset areaCircadian-like rhythmGlutamateEssential modulatorPatients
2019
The connectivity index: an effective metric for grading epileptogenicity.
Yan Q, Gaspard N, Zaveri HP, Blumenfeld H, Hirsch LJ, Spencer DD, Alkawadri R. The connectivity index: an effective metric for grading epileptogenicity. Journal Of Neurosurgery 2019, 133: 971-978. PMID: 31561212, DOI: 10.3171/2019.4.jns195.Peer-Reviewed Original ResearchSingle-pulse electrical stimulationSeizure onset zoneSite of stimulationSOZ contactsIrritative zoneComprehensive Epilepsy CenterControl contactsStimulation current intensityHabitual aurasHabitual seizuresEpilepsy centersSeizure generationBrain sitesFrequency stimulationEpileptic activityElectrical stimulationOnset zonePatientsRecording contactsStimulation sessionsBrain regionsFunctional connectivityStimulationOutcome casesSeizures
2018
Resting state connectivity in neocortical epilepsy: The epilepsy network as a patient-specific biomarker
Marino AC, Yang GJ, Tyrtova E, Wu K, Zaveri HP, Farooque P, Spencer DD, Bandt SK. Resting state connectivity in neocortical epilepsy: The epilepsy network as a patient-specific biomarker. Clinical Neurophysiology 2018, 130: 280-288. PMID: 30605890, DOI: 10.1016/j.clinph.2018.11.016.Peer-Reviewed Original ResearchConceptsLocalization related epilepsyEpilepsy networkSeizure onset locationSingle-patient levelCorrelated network activityPatient-specific biomarkersRelated epilepsyConnectivity patternsNeocortical epilepsyPatient levelSeizure onsetInterictal periodAnatomic locationPatientsPossible biomarkersState connectivityCortical regionsSingle-subject levelTopographic distributionCohortNetwork disorderBrain networksEpilepsyNetwork activityBiomarkersSeizure susceptibility and infraslow modulatory activity in the intracranial electroencephalogram
Joshi RB, Duckrow RB, Goncharova II, Gerrard JL, Spencer DD, Hirsch LJ, Godwin DW, Zaveri HP. Seizure susceptibility and infraslow modulatory activity in the intracranial electroencephalogram. Epilepsia 2018, 59: 2075-2085. PMID: 30187919, DOI: 10.1111/epi.14559.Peer-Reviewed Original ResearchConceptsAED taperYale-New Haven HospitalAdult epilepsy patientsSeizure forecasting algorithmsElectrode contact pairsSeizure onset areaSeizure susceptibilityClinical recordsDrug taperElectrophysiological changesEpilepsy patientsIntracranial electroencephalographic dataMagnitude-squared coherenceModulatory activitySeizuresPatientsOnset areaPreseizurePostseizureProgressive desynchronizationIntracranial electroencephalogramDaysIctogenesisEffect of timeHospitalExpanding Brain–Computer Interfaces for Controlling Epilepsy Networks: Novel Thalamic Responsive Neurostimulation in Refractory Epilepsy
Gummadavelli A, Zaveri HP, Spencer DD, Gerrard JL. Expanding Brain–Computer Interfaces for Controlling Epilepsy Networks: Novel Thalamic Responsive Neurostimulation in Refractory Epilepsy. Frontiers In Neuroscience 2018, 12: 474. PMID: 30108472, PMCID: PMC6079216, DOI: 10.3389/fnins.2018.00474.Peer-Reviewed Original ResearchResponsive neurostimulationRefractory epilepsyThalamic nucleiComplex network disorderIntralaminar thalamic nucleiSubcortical brain structuresCortical onsetSeizure controlGeneralized epilepsySeizure networkSeizure onsetEpilepsy networkNeuromodulatory techniquesEpilepsyExcitatory eventsClinical treatmentBrain regionsBrain structuresSeizuresPotential targetIntracranial electroencephalographyNetwork disorderPatientsFeasible targetNeurostimulationThe roles of surgery and technology in understanding focal epilepsy and its comorbidities
Spencer DD, Gerrard JL, Zaveri HP. The roles of surgery and technology in understanding focal epilepsy and its comorbidities. The Lancet Neurology 2018, 17: 373-382. PMID: 29553383, DOI: 10.1016/s1474-4422(18)30031-0.Peer-Reviewed Original ResearchConceptsFocal epilepsyNeuropsychiatric disordersComplete seizure controlPoor postsurgical outcomeRole of surgeryRefractory focal epilepsyOnset areaComorbid neuropsychiatric disordersSeizure onset areaBehavioral seizuresSeizure controlSurgical outcomesPostsurgical outcomesEpileptogenic tissueEpilepsy networkHigh prevalenceStructural brain networksIndividualised therapyPatientsBrain regionsEpilepsyElectrophysiological recordingsIntracranial electrophysiological recordingsStructural MRIGold standard
2017
(Invited) Conjoint Measurement of Brain Electrophysiology and Neurochemistry
Zaveri H, Ganesh N, Goncharova I, Damisah E, Ong C, Perez E, Staib L, Hirsch L, Petroff O, Spencer D, Eid T. (Invited) Conjoint Measurement of Brain Electrophysiology and Neurochemistry. ECS Meeting Abstracts 2017, MA2017-02: 2329-2329. DOI: 10.1149/ma2017-02/55/2329.Peer-Reviewed Original ResearchInterictal EEG spikesBasal glutamateBrain excitabilityIntractable epilepsyEEG spikesBrain electrophysiologySpike rateBasal extracellular glutamate concentrationsIntracranial EEG monitoringExtracellular glutamate concentrationCo-localized measurementsPossible epilepsy surgeryBrain extracellular glutamateInterictal electroencephalographyMicrodialysis catheterEpilepsy surgeryExtracellular glutamateBrain neurochemistryDialysis probeNeurochemical basisEEG monitoringGlutamate concentrationBrain regionsEpilepsyPatients
2016
The relationship between seizures, interictal spikes and antiepileptic drugs
Goncharova II, Alkawadri R, Gaspard N, Duckrow RB, Spencer DD, Hirsch LJ, Spencer SS, Zaveri HP. The relationship between seizures, interictal spikes and antiepileptic drugs. Clinical Neurophysiology 2016, 127: 3180-3186. PMID: 27292227, DOI: 10.1016/j.clinph.2016.05.014.Peer-Reviewed Original ResearchConceptsFirst seizureSeizure occurrenceAED taperSpike rateEEG monitoringMarker of inhibitionIntracranial EEG monitoringOccurrence of seizuresScalp EEG monitoringConsecutive patientsAntiepileptic drugsDrug taperHigh spike ratesInterictal spikesSeizuresDay 4Intracranial electrodesPatientsAEDsSignificant relationship
2015
Inhibition of glutamine synthetase in the central nucleus of the amygdala induces anhedonic behavior and recurrent seizures in a rat model of mesial temporal lobe epilepsy
Gruenbaum SE, Wang H, Zaveri HP, Tang AB, Lee TS, Eid T, Dhaher R. Inhibition of glutamine synthetase in the central nucleus of the amygdala induces anhedonic behavior and recurrent seizures in a rat model of mesial temporal lobe epilepsy. Epilepsy & Behavior 2015, 51: 96-103. PMID: 26262937, PMCID: PMC4663049, DOI: 10.1016/j.yebeh.2015.07.015.Peer-Reviewed Original ResearchMeSH KeywordsAmygdalaAnalysis of VarianceAnhedoniaAnimalsBrainCentral Amygdaloid NucleusComorbidityDepressive DisorderDisease Models, AnimalElectroencephalographyEnzyme InhibitorsEpilepsy, Temporal LobeGlutamate-Ammonia LigaseHippocampusMaleMethionine SulfoximineNeuronsRatsRats, Sprague-DawleySeizuresConceptsMesial temporal lobe epilepsyTemporal lobe epilepsyRecurrent seizuresLobe epilepsyCentral nucleusMale Sprague-Dawley ratsPrevalence of depressionSprague-Dawley ratsGlutamine synthetase inhibitor methionine sulfoximineMeasures of anhedoniaRight CeA.Seizure activityAnhedonic behaviorDentate gyrusMedial amygdalaSucrose preferenceRat modelCommon causeAstrocytic enzymeBasolateral amygdalaLateral amygdalaOsmotic pumpPatientsEpilepsyAmygdala
2014
The spatial and signal characteristics of physiologic high frequency oscillations
Alkawadri R, Gaspard N, Goncharova II, Spencer DD, Gerrard JL, Zaveri H, Duckrow RB, Blumenfeld H, Hirsch LJ. The spatial and signal characteristics of physiologic high frequency oscillations. Epilepsia 2014, 55: 1986-1995. PMID: 25470216, PMCID: PMC5123742, DOI: 10.1111/epi.12851.Peer-Reviewed Original ResearchConceptsPhysiologic high-frequency oscillationsSeizure onsetEpileptic networkNon-rapid eye movement sleepComprehensive Epilepsy CenterMesial temporal structuresEye movement sleepHigh-frequency oscillationsHighest HFO ratesFirst seizureInvasive evaluationEpilepsy centersIntracranial evaluationMovement sleepPerirolandic regionEpileptiform dischargesParietooccipital regionOccipital lobeEpileptic sitesPatientsNonepileptic regionsPhysiologic eventsFast ripplesHFO ratesLonger duration
2013
Intracranially recorded interictal spikes: Relation to seizure onset area and effect of medication and time of day
Goncharova II, Spencer SS, Duckrow RB, Hirsch LJ, Spencer DD, Zaveri HP. Intracranially recorded interictal spikes: Relation to seizure onset area and effect of medication and time of day. Clinical Neurophysiology 2013, 124: 2119-2128. PMID: 23856192, DOI: 10.1016/j.clinph.2013.05.027.Peer-Reviewed Original ResearchSeizure localization using three-dimensional surface projections of intracranial EEG power
Lee HW, Youngblood MW, Farooque P, Han X, Jhun S, Chen WC, Goncharova I, Vives K, Spencer DD, Zaveri H, Hirsch LJ, Blumenfeld H. Seizure localization using three-dimensional surface projections of intracranial EEG power. NeuroImage 2013, 83: 616-626. PMID: 23850575, PMCID: PMC3815983, DOI: 10.1016/j.neuroimage.2013.07.010.Peer-Reviewed Original ResearchConceptsEpilepsy surgerySeizure localizationGood surgical outcomeEEG powerIntractable epilepsy patientsAgreement rateNormal brain functionOverall agreement ratePoor outcomeSurgical outcomesIntractable epilepsyIcEEG recordingsSeizure onsetSublobar localizationEpilepsy patientsIndependent reviewersClinical informationIcEEG dataPatientsBrain functionSurgeryImproved diagnostic methodIntracranial EEGDiagnostic methodsOutcomesIntracranial EEG evaluation of relationship within a resting state network
Duncan D, Duckrow RB, Pincus SM, Goncharova I, Hirsch LJ, Spencer DD, Coifman RR, Zaveri HP. Intracranial EEG evaluation of relationship within a resting state network. Clinical Neurophysiology 2013, 124: 1943-1951. PMID: 23790525, DOI: 10.1016/j.clinph.2013.03.028.Peer-Reviewed Original ResearchConceptsDefault mode networkIntracranial EEG evaluationMode networkLocalization-related epilepsyCross-approximate entropyNeuronal involvementHemodynamic measurementsIntracranial EEG recordingsEEG evaluationBackground activityGamma powerFMRI studyIntracranial EEGBrain activityPatientsEEG recordingsLow levelsT2EpilepsyMagnitude squared coherenceT1
2009
Spatial distribution of intracranially recorded spikes in medial and lateral temporal epilepsies
Goncharova II, Zaveri HP, Duckrow RB, Novotny EJ, Spencer SS. Spatial distribution of intracranially recorded spikes in medial and lateral temporal epilepsies. Epilepsia 2009, 50: 2575-2585. PMID: 19674048, DOI: 10.1111/j.1528-1167.2009.02258.x.Peer-Reviewed Original ResearchConceptsMedial temporal structuresInterictal spikesLT patientsCortical areasNeocortical seizure onsetsSleep-related increaseSpike rateLateral temporal epilepsyExtratemporal areasTemporal epilepsySeizure onsetIntracranial monitoringLT groupMT groupPatientsFrontal spikesSeizuresGreater numberSleepGroupTemporal structureEpilepsySpikes