1. ECE4552: Medical Electronics By Ijlal Haider
Intro to Biosignals
ECE4552: Medical Electronics
By Ijlal Haider

2. BioSignals
Human body is a complex system comprising many Electrical, Mechanical and Chemical subsystems
The electrical, chemical, and Mechanical activity that occurs during these biological event often produces signals that can be measured and analyzed.
These signals are space, time, or space–time records of a biological event such as a beating heart or a contracting muscle.
They contain useful information that can be used to understand the underlying physiological mechanisms of a specific biological event or system, and which may be useful for medical diagnosis.

3. Major Systems of Human Body
Neuromuscular (Electromechanical & Electrochemical)
Information processing, control & communication
Cardiovascular (Electromechanical)
Transportation, blood is the carrier
Digestive (Chemical)
Respiratory (Chemical)
Lymphatic (Chemical)
Reproductive (Chemical)
Endocrine (Chemical)
Also controls several mechanisms

4. Information from Biosignals
Functional Information
Electrical
EEG
EMG
ECG
Other
MEG
fMRI
fNIRS
Structural Information (Images)
X-Ray
CT Scan
Ultrasound
MRI

5. Bioelectric Signals Traditional Non Traditional EMG, ENG: Muscles
ECG (or EKG): Heart
EEG, ECoG: Brain
Non Traditional
EGG: Stomach
EOG: Eyeball
ERG: Retina
GSR: Skin
Some other signals such as breathing, temperature, movement etc.

6. Neuromuscular System Nervous Subsystem Muscular Subsystem Central
Brain, Spinal Cord
Peripheral
Nerves (motor, sensory)
Muscular Subsystem
Muscles

7. EMG - Electromyogram

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

9. EMG electrodes
(active)
EMG electrodes (passive)

10. EMG electrodes
(active)

11. Recording locations for facial EMG

12. Needle electrodes adhesive electrode

13. EMG activity: averaging absolute vaues

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

15. EOG - Electrooculogram

16. Electrooculogram (EOG), Eye Dipole

17. Saccadic eye movements to the left and right

18. EOG - applications ● Diagnostics ● Functional analysis
● Human Computer Interfaces

19. EEG - Electroencephalogram

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

21. Parts of Brain and Functions
3 Major Parts
The Medulla Oblongata helps in control of Autonomic Functions, Relay of Nerve Signals Between the Brain and Spinal Cord Coordination of Body Movements
The Cerebellum is involved in the coordination of voluntary motor movement, balance and equilibrium
The Cerebrum is the newest (evolutionarily) and largest part of the brain as a whole.  It is here that things like perception, imagination, thought, judgment, and decision occur (consists of many lobes, links on next slide)

22. Cortical Areas

23. Motor & Somatosensory Cortices

24. Further Readings
For interesting information on different parts of brain and their functions, visit
(for Cerebrum in detail how it controls )

25. Configuration of Electrodes
Needs a standard configuration of electrodes on the brain
10-20 system is accepted worldwide
The top of head is divided into grids of 20%, 20% and 10% from the center to the sides

26. 10-20 System

27. Configuration of Electrodes

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

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

32. Quantitative EEG (QEEG), many EEG channels (up to 256) source / dipole localisation

33. EEG artifacts: Eye blinks, muscle tension

34. EEG artifacts: movement, electrode drifting

35. EEG artifacts: mains interference, 50/60Hz noise

36. Intracortical / chronical electrodes

37. Active EEG- electrode Singe disk gold plated electrodes
Ear clip electrode

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

39. ECG - Electrocardiogram

40. ECG: Heart- vector, QRS Complex

42. Origination of the QRS - Signal

43. Composition of ECG Signal

44. ECG measurement: Goldberger (left) and Einthoven (right)

45. ECG measurement: Wilson

46. 12 (and beyond) Lead ECG

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

48. Other (nonelectric) Biosignals

49. Electrogastrogram (EGG)- Gastric Myoelectric Activity

50. Electroretinogram (ERG)

51. Blood pressure sensor Infrared plethysmography
blood volume amplitude

52. Galvanic Skin response (GSR) Electrodermal Activity (EDA) Skin Conductance Level (SCL)

53. Summary bioelectric signals
Frequency Amplitude (mV)
ECG –
EEG DC – ,2
EEG (cortical) 10 – ,3
EMG 10 –
EMG (needle) 10 –
EOG DC –