0000000000319785

AUTHOR

Juan J. Pérez

showing 3 related works from this author

Quantification of intracranial contribution to rheoencephalography by a numerical model of the head

2000

Abstract Objectives : Partial contributions of intracranial and extracranial circulation to rheoencephalography (REG) remain uncertain. The main goal of this work is to determine theoretically the capability of REG techniques to reflect intracranial blood flow. Methods : Head and current injection electrodes were computationally modeled to assess REG sensitivity to brain and scalp conductivity changes. Data obtained were related to tissue perfusions to calculate the partial contribution of cerebral blood perfusion to REG I, REG II and monopolar REG and to assess their amplitudes. Results : When REG I and monopolar REG were used, the theoretical maximum of intracranial contribution was reach…

chemical and pharmacologic phenomenaModels BiologicalSensitivity and SpecificityRheoencephalographyimmune system diseaseshemic and lymphatic diseasesPhysiology (medical)HumansComputer SimulationPlethysmography ImpedanceElectrodesPhysicsMeasurement methodbusiness.industryElectric ConductivityBrainElectroencephalographyhemic and immune systemsBlood flowSensory SystemsNeurologyCerebral blood flowCerebrovascular CirculationAnesthesiaRegression AnalysisNeurology (clinical)Nuclear medicinebusinessHeadClinical Neurophysiology
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Suppression of the cardiac electric field artifact from the heart action evoked potential

2006

The study of heart action-related brain potentials is strongly disrupted by the presence of an inherent cardiac electric artifact. The hypothesis is presented that most of the electric current coupled to the cardiac field surrounds the skull and flows through the scalp tissue without crossing the cranial cavity. This pseudo two-dimensional conduction model contrasts with the volumetric conduction of the brain electrical activity, and this property is exploited to cancel the cardiac electric artifact. QRS loop vector-cardiographic projections on saggital planes were recorded in 11 healthy subjects in the head and neck areas. Comparative analysis of the projection eccentricities, estimated by…

AdultMaleField (physics)Biomedical EngineeringQRS complexElectric fieldCranial cavitymedicineHumansEvoked potentialEvoked PotentialsPhysicsArtifact (error)SkullElectric ConductivityElectroencephalographyHeartSignal Processing Computer-AssistedMiddle AgedComputer Science ApplicationsAmplitudemedicine.anatomical_structureFemaleElectric currentArtifactsBiomedical engineeringMedical and Biological Engineering and Computing
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Influence of the scalp thickness on the intracranial contribution to rheoencephalography

2004

In spite of the great efforts made by the scientific community, up to now there is no agreement about the rheoencephalography (REG) capability to reflect cerebral blood flow (CBF). Moreover, a standard procedure and the optimal electrode arrangement have not been established yet. In a previous study, we found, using a classical four-shell spherical model of the head and solving it by numerical methods that, theoretically, there could exist an electrode arrangement to register an REG II free of extracranial contribution. In this paper, we have studied the influence of scalp thickness on the intracranial contribution to REG II. The study has been performed by solving the head model, using in …

Brain MappingScalpRadiological and Ultrasound TechnologyModels NeurologicalMathematical analysisModels CardiovascularBrainElectroencephalographyStandard procedureRheoencephalographymedicine.anatomical_structureCerebral blood flowCerebrovascular CirculationScalpHead modelmedicineHumansComputer SimulationRadiology Nuclear Medicine and imagingDiagnosis Computer-AssistedPlethysmography ImpedanceAlgorithmMathematicsPhysics in Medicine and Biology
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