Data Exchange Standards for Clinical Neurophysiology - PhysioNet

Data ExchangeStandards for ClinicalNeurophysiologySusan T. Herman, M.D.Assistant Professor of NeurologyDirector, Epilepsy Monitoring UnitPenn Epilepsy CenterUniversity of Pennsylvania

Purpose of StandardizedFormatFormatting and transmission of digitized waveformsto facilitate portable exchange between dissimilarcomputer systemsAssociated identifying and other annotative textualdata incorporated into the data streamComplete context for clinical diagnosis as well asbasic and clinical research purposes

Clinical NeurophysiologyDataElectroencephalograms (EEG)Magnetoencephalograms (MEG)Polysomnograms (PSG)Multiple sleep latency tests (MSLT)Evoked potentials (EP)Evoked magnetic fields (EMF)Event-related potentials (ERP)Electromyograms (EMG)Nerve conduction studies (NCS)

Common “Reader” ProgramRV - EEG ReviewDV - Digital Video ReviewPAT - Reads patient demographicsOLEV - Online event detectionDTEV - Outputs detection events to OEM databaseRSEV - Reads recording system eventsRSMNT - Reads recording system montages

Alpha­Trace digitalEEGAstroMed TwinBio­logic BrainAtlasBio­logic CEEGraph V1Bio­logic CEEGraph IV, V, VI,and XLBIOMEC (via Persyst Layout)BioSemi BDFBrainLabCadwell Spectrum32Cadwell EasySystemCadwell EasyWindowsCleveland Medical Devices Crystal­EEGCompumedics LimitedDigiTraceEBNeuro GaINTEuropean Data Format 90Excel Tech Ltd.Grass­Telefactor AS40/CometGrass­Telefactor CTEGrass­Telefactor EDFRV, PAT, OLEV, RESVRV,PATRV, PATRV, PAT, RSEVRV, DV, PAT, OLEV, RSEV, RSMNTRV, PAT, OLEV, RSEV, RSMNTRV, PATRV, DV, PATRVRV, PAT, OLEV, DTEV, RSEV, RSMNTRV, PAT, OLEV, DTEV, RSEV, RSMNTRV, PAT, OLEV, RSEV, RSMNTRV, DV, PAT, OLEV, DTEV, RSEV, RSMNTRV, PATRV, PAT, OLEV, RSEVRV, PATRV, DV, PAT, OLEV, RSEV, RSMNTRVRVRV, PAT*.alpLogfile.qqq*.datE*.dat*.eeg*.lay.bdf*.sig*.00?*.log,*.eas*.eas*.crl*.raw*.w18,*.r27,*.w27*.gnt*.edf*.erd.dat.dat*.edf

Grass­Telefactor TUFFGrass­Telefactor TwinLexicorLifelines/Trackit/EDFMicromedNEC SynafitNervusNetwork Concepts UniquantNeuroScanNeuro Data NDFNeuroKard BrainLabNicolet AllianceWorksNicolet Alliance NTNicolet BEAMNicolet BMSI 3.0+Nicolet BravoNicolet Endeavor 3.xNicolet NicoletOne cEEGNicolet NicoletOne nEEG/LTM/MonitorRV,PATRV,PATRV, PAT, OLEV, RSEV, RSMNTRV, PAT, RSEVRV, PAT, RSEVRV, PATRV, PAT, RSEV, RSMNTRV, PAT, OLEV, RSEV, RSMNTRVRV, PATRV, DV, PATRV, PAT, RSEVRV, DV, PAT, OLEV,RSEV, RSMNTRVRVRV, DV, PAT, OLEV,RSEV, RSMNTRV, DV, PAT, OLEV,RSEV, RSMNTRV, DV, PAT, OLEV,RSEV, RSMNTRV, DV, PAT, OLEV,RSEV, RSMNT*.refLogfile.qqq*.dat*.edf*.trc*.dat*.e*.sif*.cnt*.eeg.datdata*.eegd*.*.eeg*.eeg*.xew*.one*.e

Nicolet SatelliteNicolet Satellite ESNicolet VoyagerNihonKohden 1100/2100/9100Oxford 9200Oxford/Teca/Medelec DG32Oxford/Teca/Medelec Valor (Nervus)Oxford/Teca/Medelec ProfileQSI 9X00NeuroscanRembrandt EDF format exportStellate Monitor/RhythmTelefactor CTE64Telediagnostic (via Persyst Layout)VanguardWalterGraphtek/Dantek PLEEGXLTech/Excel TechRV, PAT, RSEVRV, PAT, RSEVRV, PAT, OLEV, RSEV, RSMNTRV, DV, PAT, OLEV, DTEV, RSEV, RSMNTRVRV, PAT, RSEV, RSMNTRV, PAT, RSEV, RSMNTRV, PAT, RSEVRV, PATRV, PATRVRV, PATRVRV, PAT, OLEV, RSEV, RSMNTRV, PATRV, PAT, OLEVRV, DV, PAT, OLEV, RSEV, RSMNT*.dat*.ebmdata*.pnt*.**.mod*.e*.eeg*.ano*.cnt*.edf*.eeg*.dat*.layb**.wg1*.erd

Primary DataDigitized waveforms for multiple channelsChannel identifications, sensitivities, filter settings, andsampling frequencyAveraging parameters for averaged dataDate and time of day labelsElectrode or transducer locations and attributesMeasured distancesStimulation parameters (visual, auditory, electrical, or other)Calibration dataTechnical comments or annotations created before or duringthe studyMedications administeredSpecial procedures performedInstruments used

Modified 10-20 System

Evoked Potentials

Derived DataMeasured feature or peak latencies, amplitudes, andother characteristicsEither automatic algorithms or technician orphysician scanResults of computer processing up the primary data(e.g. spectral analyses)Quantitative or qualitative resultsComparison to normal ranges for laboratoryText reports, interpretations, diagnoses, andrecommendations sent back to ordering physician

Computerized analysis of 2 hours of EEG shows extremely frequent seizures(status epilepticus). Each “blue bump” indicates a 3 minute seizure.A large amount of EEG data can be reviewed quickly, and nurses andphysicians who do not read EEG can easily interpret this study at the bedside

Desired FeaturesNonproprietaryInternational language supportHeader information compatible with HL7Support for unlimited number of channelsChannel specific sampling rate, sensitivities, filtersettings, etc.Standardized nomenclature for electrode positionsSingle / common reference (reformatting of data)Standardized nomenclature for common annotations Provision for non-standard annotations

Desired FeaturesBinary format Compatible with EDF Fast retrieval and processingTime and date annotations for noncontiguous data Ability to take subsets of data (“clips”) Ability to concatenate dataProvision for data encryptionAbility to “strip” patient identifying information forresearch purposesSmallest possible file size, few other filesOriginal uncompressed signal

TS1 (Technical Standard 1)American Clinical Neurophysiology Society MedicalInstrumentation Committee www.acns.org/guidelines.cfmAmerican Society for Testing and Materials (ASTM)Committee E-31 on Computerized Systems Subcommittee E31.16 on Interchange ofElectrophysiologic Waveforms and Signals Revised edition was published as ASTM E 1467-94

TS1 (Technical Standard 1)Level 1: Waveforms only Decoding of digital waveform data and labeling ofchannelsLevel 2: Waveforms or procedure annotations or both Waveform data Required data elements (e.g. patient identification) Optional data elements, including site-specific dataLevel 3: Coded information Associates standard alphanumeric codes with textual dataelements (e.g. ICD-9 code) Translated by receiving system into a defined text stringby means of an internal table of diagnoses (code tables) More structured and standardized medical record Facilitate automated machine processing