ECG,EEG,EMG measurements

1. Unit-II Bio Signal Characteristics
and Electrode configurations
Prepared By
Dr.K.UMA MAHESWARI /ECE

2. ECG Electro-Cardiogram- Heart activity
EEG
EMG
EOG
GSR
Electro-Encephalogram- Brain Signals
Electro-Myogram - Muscle movement
Electro-Oculogram - Eye movement
Galvanic Skin Response
● Measured with electrodes:
skin-electrode interface: Ions <--> Electrodes
Breathing, temperature, movement etc.
● Measured with other sensors / transducers:
Types of Bio electric signals

3. Primary Characteristics of Bio electricsignals
Parameter Frequency range Amplitude Type of
Electrode
Electrocardiogrpahy
(ECG)
0.05 to 120 Hz 0.1 to 5µV
1µV
Surface
Electroencephalography
(EEG)
0.1 to 100 Hz 2 to 200µV
50µV
Scalp
Electromyography
(EMG)
5 to 2000 Hz 0.1 to 5µV Needle
Electroretinography
(ERG)
Dc to 20Hz 0.5 to 1µV Contact
Electro-oculography
(EOG)
Dc to 100 Hz 10 to
3500µV
Contact

4. ECG – Electrocardiogram
Standardised electrode positions
1. Bipolar limb leads(or) standard leads
2. Augmented unipolar limb leads
3. Chest leads(or) precordial leads
4. Frank lead system(or) corrected
orthogonal leads

7. Augmented voltage
aVR = -VI - VIII / 2
aVL = VI - VII / 2
aVR = VII - VI / 2

10. ECG: Heart- vector, QRS Complex

13. ECG - applications
● Diagnostics
● Functional analysis
● Implants (pace maker)
● Biofeedback (Heartrate variability, HRV)
● Peak Performacne Training, Monitoring

14. EMG - Electromyogram

22. EMG surface (glue-) electrodes EMG - signal (up to 3mV, 1kHz)

25. EMG electrodes
(passive)
EMG electrodes
(active)

26. EMG electrodes
(active)

28. Recording locations for facial EMG

29. Needle electrodes adhesive electrode

30. EMG activity: averaging absolute vaues

31. EMG - applications
● Rehabilitation
● Functional analysis
● active Prothetics, Orthesis
● Biomechanics, Sports medicine

32. EEG - Electroencephalogram

39. EEG Electrode – cap locations of
the 10/20 system

40. Unipolar measurement
( indifferential right ear
electrode )
Bipolar measurement

46. EEG, dominant frequencies, < 300 uV

47. EEG, Alpha bursts when eyes closed,
alpha desynchronisation when eyes opened

52. EEG - applications
● Diagnostics (Epilepsy, Oncology, ..)
● Cognitive Sciences
● Sleep Analysis
● Human Computer Interfaces (BCIs)
● Pharmacology
● Intensive Care, Monitoring

53. Summary bioelectric signals
Frequency Amplitude (mV)
ECG 0,2 – 300 0,1 - 3
EEG DC – 100 0,005 - 0,2
EEG (cortical) 10 – 100 0,015 - 0,3
EMG 10 – 1000 0,1 - 5
EMG (needle) 10 – 10000 0,05 - 5
EOG 0 – 30 0,1 - 2
Intracell. 0 – 10000 50 .. 130

54. Video Links:
EEG 10-20 Electrode System:
https://www.youtube.com/watch?v=YfjRhoC2V0E