““Victor Babes” Victor Babes” UNIVERSITY OF MEDICINE UNIVERSITY OF MEDICINE

AND PHARMACY AND PHARMACY TIMISOARATIMISOARA

““Victor Babes” Victor Babes” UNIVERSITY OF MEDICINE UNIVERSITY OF MEDICINE

AND PHARMACY AND PHARMACY TIMISOARATIMISOARA

DEPARTMENT OFDEPARTMENT OF

MEDICAL INFORMATICS AND BIOPHYSICSMEDICAL INFORMATICS AND BIOPHYSICS

Medical Informatics DivisionMedical Informatics Divisionwww.medinfo.umft.ro/dimwww.medinfo.umft.ro/dim

2004 / 20052004 / 2005

BIOSIGNAL PROCESSING.BIOSIGNAL PROCESSING. NON-PERIODICAL NON-PERIODICAL

SIGNALS.SIGNALS.

COURSE 8COURSE 8

1. EEG SIGNAL1. EEG SIGNAL

• 1.1. EEG SIGNAL ELEMENTS:1.1. EEG SIGNAL ELEMENTS: • a) TYPICAL WAVES: a) TYPICAL WAVES:

– DELTA : 0.5 - 3 HzDELTA : 0.5 - 3 Hz• large; in pathological states, normal in babies onlylarge; in pathological states, normal in babies only

– THETA : 4 - 7 HzTHETA : 4 - 7 Hz• large amplitude, dominant in some sleep stageslarge amplitude, dominant in some sleep stages

– ALPHA : 8 - 12 HzALPHA : 8 - 12 Hz• medium amplitude, normal in relaxed brain, originating medium amplitude, normal in relaxed brain, originating

in occipital areain occipital area

– BETA : 13 - 30 Hz (18 - 22)BETA : 13 - 30 Hz (18 - 22)• small amplitude, associated with brain activity, typical small amplitude, associated with brain activity, typical

for frontal areasfor frontal areas

• b) TRANSITORY ELEMENTSb) TRANSITORY ELEMENTS• PEAK - WAVE COMPLEX (pathological)PEAK - WAVE COMPLEX (pathological)

• ARTIFACTS: blinking, ECG, EMG etcARTIFACTS: blinking, ECG, EMG etc

• c) RECORDING TYPESc) RECORDING TYPES• SPONTANEOUS SIGNALSPONTANEOUS SIGNAL

– AWAKEAWAKE– ASLEEPASLEEP

• EVOKED POTENTIALS EVOKED POTENTIALS

1.2. ANALYSIS METHODS 1.2. ANALYSIS METHODS CLASSIFICATIONCLASSIFICATION

a) ELEMENTARY METHODSa) ELEMENTARY METHODS• TEMPORALTEMPORAL

• FREQUENTIALFREQUENTIAL

• PARAMETRICALPARAMETRICAL

b) INTEGRATIVE METHODSb) INTEGRATIVE METHODS• PATTERN RECOGNITIONPATTERN RECOGNITION

• SYNTACTIC ANALYSIS SYNTACTIC ANALYSIS

c) EVOKED POTENTALSc) EVOKED POTENTALS

1.3. TEMPORAL ANALYSIS1.3. TEMPORAL ANALYSIS

a) AMPLITUDE ANALYSIS - histogramsa) AMPLITUDE ANALYSIS - histograms– low / normal / high amplitude (voltage)low / normal / high amplitude (voltage)

Amplitude HistogramAmplitude Histogram

• b) INTERVAL ANALYSIS - level crossingb) INTERVAL ANALYSIS - level crossing– zero crossingzero crossing

• c) AMPLITUDE / INTERVAL - areas c) AMPLITUDE / INTERVAL - areas

• d) SEQUENTIAL ANALYSIS – peak-to-peakd) SEQUENTIAL ANALYSIS – peak-to-peak

e) CORRELATION FUNCTION e) CORRELATION FUNCTION

– – shows the potential sourceshows the potential source– inter-correlation or self-correlation (auto-correlation)inter-correlation or self-correlation (auto-correlation)

1.4. FREQUENTIAL ANALYSIS1.4. FREQUENTIAL ANALYSIS

• SIGNAL REPRESENTATION:SIGNAL REPRESENTATION:– TEMPORAL TEMPORAL

Ampl = f (time)Ampl = f (time)

– FREQUENTIAL (spectrum) FREQUENTIAL (spectrum)

Ampl = f (freq)Ampl = f (freq)

Examples: 1 Hertz sine signal and its spectrum

A 2 Hz signalA 2 Hz signal

Mixed signalsMixed signals

Shortcut to St.exe.pif

• b) FILTER ANALYSISb) FILTER ANALYSIS• BAND - PASS FILTERS (BAND - PASS FILTERS (• WAVES PROPORTIONS - mingographsWAVES PROPORTIONS - mingographs

• c) FOURIER ANALYSISc) FOURIER ANALYSIS• Definition: SIGNAL DECOMPOSITION Definition: SIGNAL DECOMPOSITION

INTO FREQUENCIAL COMPONENTSINTO FREQUENCIAL COMPONENTS

• Domain: 0 - 30 HzDomain: 0 - 30 Hz

• Types of spectra: Types of spectra: – AMPLITUDEAMPLITUDE– POWER (proportional to APOWER (proportional to A22))

• c) SPECTRAL RESOLUTIONc) SPECTRAL RESOLUTION– DEFINITION: DEFINITION: distance between two neighbour distance between two neighbour

points in the spectrumpoints in the spectrum– RELATION WITH EPOCH LENGTH RELATION WITH EPOCH LENGTH (recorded (recorded

signal duration, in seconds)signal duration, in seconds)

f = 1 / f = 1 / T (5)T (5)• d) TIME CONSTANT d) TIME CONSTANT • e) TESTS FOR SIGNALSe) TESTS FOR SIGNALS

– STATIONARITY, NORMALITY AND TREND STATIONARITY, NORMALITY AND TREND TESTSTESTS

• g) TRANSITORY PHENOMENA g) TRANSITORY PHENOMENA DETECTIONDETECTION

• SPIKES CONTRIBUTION IN SPECTRASPIKES CONTRIBUTION IN SPECTRA• MOBILE WINDOW METHOD (BERG)MOBILE WINDOW METHOD (BERG)

• h) GRAPHICAL REPRESENTATIONSh) GRAPHICAL REPRESENTATIONS• CURVES, HISTOGRAMSCURVES, HISTOGRAMS

• BICKFORD REPRESENTATION (time course)BICKFORD REPRESENTATION (time course)

• i) OTHER FREQUENTIAL ANALYSESi) OTHER FREQUENTIAL ANALYSES• WALSH, HAAR, ZERO CROSSINGWALSH, HAAR, ZERO CROSSING• KALMAN RECURSIVE FILTERINGKALMAN RECURSIVE FILTERING• CONVOLUTION FUNCTIONCONVOLUTION FUNCTION

Bickford ReprezentationBickford Reprezentation

1.5. PARAMETRIC ANALYSIS1.5. PARAMETRIC ANALYSIS

• a) STOCHASTIC PARAMETERSa) STOCHASTIC PARAMETERS• PEAKS NUMBER AND INTENSITYPEAKS NUMBER AND INTENSITY

• STATISTICAL PARAMETERS (m,s)STATISTICAL PARAMETERS (m,s)

• b) HJORTH PARAMETERSb) HJORTH PARAMETERS• ACTIVITY - amplitudeACTIVITY - amplitude

• MOBILITY - frequency ( 1st derivative)MOBILITY - frequency ( 1st derivative)

• COMPLEXITY - frequency variations COMPLEXITY - frequency variations (2nd derivative)(2nd derivative)

• 1.6. PATTERN RECOGNITION1.6. PATTERN RECOGNITION

• 1.7. SYNTACTIC ANALYSIS1.7. SYNTACTIC ANALYSIS• SHORT EPOCHS (non-stationary)SHORT EPOCHS (non-stationary)• EPOCHS LABELING EPOCHS LABELING • SIGNAL = LABELS SEQUENCE (sentence)SIGNAL = LABELS SEQUENCE (sentence)

• 1.8. EEG MAPPING1.8. EEG MAPPING• 16-108 ELECTRODS16-108 ELECTRODS• INTERPOLATION METHODSINTERPOLATION METHODS• TYPES OF MAPS:TYPES OF MAPS:

– AMPLITUDE / POWERAMPLITUDE / POWER– FREQUENCYFREQUENCY– HJORTH PARAMETERS, ETCHJORTH PARAMETERS, ETC

1.9. EVOKED POTENTIALS1.9. EVOKED POTENTIALS

• a) TYPES OF STIMULATION:a) TYPES OF STIMULATION:– IN STANDARD RECORDINGSIN STANDARD RECORDINGS

• OPEN / CLOSED EYESOPEN / CLOSED EYES

• HYPERVENTILATIONHYPERVENTILATION

• STROBOSCOPIC LIGHTSTROBOSCOPIC LIGHT

– IN EVOKED POTENTIAL RECORDINGSIN EVOKED POTENTIAL RECORDINGS• VISUAL PATTERNS (chessboard like)VISUAL PATTERNS (chessboard like)

• AUDITORY STIMULIAUDITORY STIMULI

• SOMATIC STIMULISOMATIC STIMULI

1.9. EVOKED POTENTIALS1.9. EVOKED POTENTIALS

b) EVOKED POTENTALS b) EVOKED POTENTALS DETECTIONDETECTION

• VERY SMALL AMPLITUDES VERY SMALL AMPLITUDES

(2-5 (2-5 V compared with 50-100 V compared with 50-100 V ground)V ground)

• AVERAGING METHODAVERAGING METHOD– RANDOM SIGNAL MEAN = 0RANDOM SIGNAL MEAN = 0– REPEATED STIMULATIONSREPEATED STIMULATIONS– EPOCHS SUPERPOSITION EPOCHS SUPERPOSITION

• RANDOM STIMULATIONRANDOM STIMULATION

Evoked potential extraction by Evoked potential extraction by “averaging”“averaging”

1.10. BIOFEEDBACK1.10. BIOFEEDBACK

• a) RHYTHM ADAPTATIONa) RHYTHM ADAPTATION

• b) STATE ADAPTATION ???b) STATE ADAPTATION ???

• c) Extension of relaxation procedures:c) Extension of relaxation procedures:- band pass filter- band pass filter

background modulated mild soundbackground modulated mild sound

intensity controlled by intensity controlled by waves amplitude waves amplitude

self-control trainingself-control training

therapeutical effectstherapeutical effects

2. OTHER BIOSIGNALS2. OTHER BIOSIGNALS

• 2.1. NEUROMUSCULAR 2.1. NEUROMUSCULAR INVESTIGATIONSINVESTIGATIONS– EMG (electro-myography)EMG (electro-myography)

– NCV (nervous conduction velocity)NCV (nervous conduction velocity)

• 2.2. RESPIRATORY 2.2. RESPIRATORY INVESTIGATIONSINVESTIGATIONS– SPIROGRAPHYSPIROGRAPHY

– VENTIALTION TESTSVENTIALTION TESTS

• 2.3. EXERCISE TESTS2.3. EXERCISE TESTS– MULTIPLE SIGNALMULTIPLE SIGNAL

• 2.4. PLETISMOGRAPHY2.4. PLETISMOGRAPHY– MULTIPLE SIGNALMULTIPLE SIGNAL– COMPLEX INVESTIGATIONCOMPLEX INVESTIGATION

• 2.5. CARDIOVASCULAR 2.5. CARDIOVASCULAR EXPLORATIONEXPLORATION– PHONOCARDIOGRAPHYPHONOCARDIOGRAPHY– RHEOGRAPHYRHEOGRAPHY

• 2.6. SENSE ORGANS 2.6. SENSE ORGANS INVESTIGATIONSINVESTIGATIONS– RETINOGRAMSRETINOGRAMS

– AUDIOGRAMS AUDIOGRAMS

• 2.7. ULTRASONOGRAPHY2.7. ULTRASONOGRAPHY– a) ECHO SIGNALSa) ECHO SIGNALS

• SYSTEMS : A, B, MSYSTEMS : A, B, M• ECHOCARDIOGRAPHYECHOCARDIOGRAPHY• PHOETAL ULTRASONOGRAPHYPHOETAL ULTRASONOGRAPHY

– b) DOPPLER SIGNALSb) DOPPLER SIGNALS

2.8. EXTRAVERBAL 2.8. EXTRAVERBAL COMMUNICATIONCOMMUNICATION

• GAIT ANALYSISGAIT ANALYSIS– WALKING PATTERNSWALKING PATTERNS

• WRITING / DRAWINGWRITING / DRAWING

• GESTUREGESTURE– POSITION MAPPING POSITION MAPPING

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