Autonomic Nervous System DiseasesAutonomic Nervous SystemHeart RateDiabetic NeuropathiesValsalva ManeuverHypotension, OrthostaticAdie SyndromeCerebral ArteriesMultiple System AtrophyShy-Drager SyndromeVagus Nerve DiseasesBaroreflexTilt-Table TestCerebral InfarctionPrimary DysautonomiasReflex, AbnormalBlood PressurePseudoephedrineElectrocardiography, AmbulatoryDiagnostic Techniques, NeurologicalCerebral PalsyCerebrovascular CirculationPostureCardiovascular SystemPostural Orthostatic Tachycardia SyndromeTonic PupilDysautonomia, FamilialMiddle Cerebral ArteryBrain3-IodobenzylguanidinePain Insensitivity, CongenitalHypotensionElectrocardiographyArrhythmia, SinusHeartPolyneuropathiesParasympathetic Nervous SystemLewy Body DiseaseGuillain-Barre SyndromeDizzinessSympathetic Nervous SystemParkinson DiseaseIodobenzenesNeuroleptic Malignant SyndromeFludrocortisoneGalvanic Skin ResponseSweatingTachycardiaErectile DysfunctionVentricular Dysfunction, LeftCerebral AngiographyInfarction, Middle Cerebral ArteryPupilTime FactorsMalaria, CerebralCase-Control StudiesReflexDisease Models, AnimalCerebral VeinsPolyradiculoneuropathySupine PositionVagus NerveBrain IschemiaAtaxiaBradycardiaArrhythmias, CardiacDiabetes Mellitus, Type 1Severity of Illness IndexNeurologic ExaminationSyndromeCerebral HemorrhageRespirationNeural ConductionCardiovascular DiseasesNorepinephrineAnalysis of VarianceProspective StudiesHemodynamicsBlood Pressure Monitoring, AmbulatoryCircadian RhythmRisk FactorsPeripheral Nervous System DiseasesIodine RadioisotopesStatistics, NonparametricMagnetic Resonance ImagingSjogren's SyndromeFollow-Up StudiesTreatment OutcomeDiabetes Mellitus, Type 2HypertensionIschemic Attack, TransientCross-Sectional StudiesCerebral Amyloid AngiopathyAnterior Cerebral ArteryBlood Flow VelocityRetrospective StudiesEndothelium, VascularExercise TestPosterior Cerebral ArteryBrain Diseases