Trends in Bioelectric signal analysis

1. Trends in Bioelectric signal analysis By Dr. Ajat Shatru Arora Principal, DAVIET, Jalandhar Professor, EIE, SLIET, Longowal

2. Biomedical Engineering Description • “Biomedical engineering is a discipline concerned with the development and manufacture of prostheses, medical devices, diagnostic devices, drugs,, and other therapies. It is a field that combines the expertise of engineering with medical needs for the progress of health care. It is more concerned with biological, safety, and regulatory issues than other forms of engineering. It may be defined as "The application of engineering principles and techniques to the medical field.””-.Wikipedia.org

3. Challenges in Man-machine Interface • Ethical and human subject protection (externally applied energy interacting with living tissue) • Low rage measurement as compared to non-medical parameters • Many crucial parameter are inaccessible (cardiac output etc.) • Inherent variability ( most parameters vary with time even under similar conditions) • Harsh environment (Corrosive chemicals in body) • High risk of micro shock

4. Major Segments Biomedical engineering can be segmented in two major fields • – physiological • and industrial automation. The physiological field concentrates more on measuring, simulating, and analyzing bioelectrical signals as well as modeling body parts and processes. The industrial automation field focuses on the automation of labs and production lines along with the design and testing of medical devices.

5. Sub-disciplines • Bioinstrumentation • Biomaterials • Biomechanics • Biomedical computing & signal processing • Cellular, Tissue, and Genetic Engineering • Clinical Engineering • Medical Imaging • Orthopaedic Bioengineering • Rehabilitation Engineering • Biometrics • MEMS • Minimally invasive surgery

6. Bioinstrumentation • The application of electronics and measurement principles to develop devices used in diagnosis and treatment of disease. • A medical device is intended for use in: • the diagnosis of disease or other conditions, or • in the cure, mitigation, treatment, or prevention of disease, • EXAMPLES are the electrocardiogram, cardiac pacemaker, blood pressure measurement, hemoglobin oxygen saturation, kidney dialysis, and ventilators

7. Biomaterials • Describes both living tissue and materials used for implantation. • Choose appropriate material • Nontoxic, chemically inert, stable, and mechanically strong enough to withstand the repeated forces of a lifetime. • Metal alloys, ceramics, polymers, and composites

8. Biomechanics • Mechanics applied to biological or medical problems • Study of motion, material deformation, flow within the body and in devices, and transport of chemicals across biological and synthetic media and membranes. • EXAMPLES: artificial heart and replacement heart valves, the artificial kidney

9. Biomedical computing & signal processing • Computers are becoming increasingly important in medical signal processing, from the microprocessor used to do a variety of small tasks in a single-purpose instrument to the extensive computing power needed to process the large amount of information in a medical imaging system

10. Biomolecular engineering • Design molecules to achieve specific biological function • New drugs or therapeutic strategies for treating disease. • Cell biology, genetics, human physiology, chemistry • EXAMPLES: targeted drug delivery; directed evolution of inhibitors of viral growth

11. Micro-electromechanical systems (MEMS) • Microtechology and micro scale phenomena is an emerging area of research in biomedical engineering • Many of life's fundamental processes take place on the micro scale • We can engineer systems at the cellular scale to provide new tools for the study of biological processes and miniaturization of many devices, instruments and processes

12. Minimally invasive medicine & surgery • Uses technology to reduce the debilitating nature of some medical treatments. • Minimally invasive surgery using advanced imaging techniques that precisely locate and diagnose problems • Virtual reality systems that immerse clinicians directly into the procedure reduce the invasiveness of surgical interventions

13. Medical imaging • Medical/Biomedical Imaging is a major segment of Medical Devices. This area deals with enabling clinicians to directly or indirectly "view" things not visible in plain sight (such as due to their size, and/or location). This can involve utilizing ultrasound, magnetism, UV, other radiology, and other means.

14. Medical imaging Imaging technologies are often essential to medical diagnosis, and are typically the most complex equipment found in a hospital including: • Magnetic resonance imaging (MRI) • Projection Radiography such as X-rays and CT scans • Tomography • Ultrasound • Electron Microscopy

15. Medical Imaging Computers are applied in medical imaging to: • construct an image from measurements. • identify quantitative parameters of clinical interest such as certain distances, densities, etc • improve image quality by image processing, compensate for imperfections in the image-generating system, and reduce noise

16. Medical Imaging • store and retrieve images • reduce the amount of storage required and the transmission time via image compression techniques • indirectly improve patient cares

17. Implants • An implant is a kind of medical device made to replace and act as a missing biological structure (as compared with a transplant, which indicates transplanted biomedical tissue). The surface of implants that contact the body might be made of a biomedical material such as titanium, silicone or apatite depending on what is the most functional. In some cases implants contain electronics e.g. artificial pacemaker and cochlear implants. Some implants are bioactive, such as subcutaneous drug delivery devices in the form of implantable pills or drug-eluting stents.

18. Bioelectric Signals Bioelectrical signal measurements from the heart (electrocardiogram/ECG); muscles (electromyograph/EMG); skin (Galvanic skin response/GSR); scalp (electroencephalograph/EEG); eyes (electrooculogram/EOG These bioelectrical signals are typically very small in amplitude and require amplification to accurately record, display and analyze the signals. Depending on the hardware and software used, the biological amplifier serves not only to amplify the signal but also to apply a range of filtering options for the removal of unwanted signal artifacts.

19. Importance of Biosignals • Diagnosis • Patient monitoring • Biomedical research

20. Characteristics of Biosignals • Often hidden in a background of other signals and noise components. • Generated by highly complex and dynamic biological processes with parameters usually more than a few and varying continuously

21. Issues in biosignal acquisition • Signal Conditioning Amplification, Isolation, Filtering • Sampling Selection of sampling rate • Selection of Software and Hardware

22. Signal Conditioning

23. Amplification • Amplification is the set of techniques used to boost a signal's strength to better match the analog-to-digital converter (ADC) range • Increases the measurement resolution and sensitivity. • Improves the signal-to-noise ratio.

24. Isolation • Isolated signal conditioning devices pass the signal from its source to the measurement device without a physical connection. • Benefits of isolation include: a). Protection for expensive equipment, the user, and data from transient voltages b). Improved noise immunity c). Ground loop removal d). Increased common-mode voltage rejection

25. Isolation Techniques Inductive Coupling Optical Coupling Capacitive Coupling

26. Multiplexing Multiplexing is Transmission of multiple signals over a single medium

27. Filtering • Filtering is the process to reject unwanted noise within a certain frequency range. • All data acquisition applications are subject to some level of 50 or 60 Hz noise picked up from power lines or machinery. • Most signal conditioners include the filters specifically designed to provide maximum rejection of 50 to 60 Hz noise.

28. Nyquist Sampling Theorem • To reconstruct an analog signal waveform without error from sample point taken at equal time intervals, the sampling frequency (Fs) must be greater than or equal to twice the highest frequency(Fm) component in the analog signal or bandwidth or B. Fs ≥ 2Fm or B • Nyquist Rate

29. Sampling of Analog Signal

30. Sampled Analog Signal When Fs ≥ 2Fm

31. DAQ Hardware • DAQ hardware acts as the interface between the computer and the outside world. • It digitizes incoming analog signals so that the computer can interpret them • DAQ hardware includes Analog I/O, Digital I/O Counters/Timers Multifunctional:- combination of analog, digital, and counter operations on a single device.

32. Driver Software • Basic driver software allows us to: a). Bring data on to and get data off of the board. b). Control the rate at which data is acquired. c). Integrate the DAQ hardware with computer resources such as processor interrupts, DMA and memory. d). Integrate the DAQ hardware with signal conditioning hardware. e). Access multiple subsystems on a given DAQ. f). Access multiple DAQ boards

33. Biosignal Processing • In order to derive the required information from the bio signals: -Disturbance should be filtered out -The amount of data should be reduced by discriminating only the most significant ones related with the required information

34. Stages of Biosignal Processing • Signal acquisition • Transformation and reduction of the signals • Computation of signal parameters that are diagnostically significant • Interpretation or classification of the signals

35. Stages of Biosignal Processing Signal transformation • Noise component: • due to the electronics in the measuring device, • artifacts related to the patient’s movements, or • other background signals recorded simultaneously • More data than actually needed to derive parameters offering semantic information

36. Stages of Biosignal Processing Parameter selection • Usually, relevant information is not the direct result of a sample or recording of a signal. • Parameters bearing resemblance to the signs and symptoms that are used to make diagnosis are extracted from the signal.

37. Stages of Biosignal Processing Signal classification • the interpretation stage • derived features of selected relevant parameters used for human or computer-assisted decision making by means of decision support methods

38. Application Areas of Biosignal Analysis • in ICUs • integrating signals from multiple sources • presenting information in the most appropriate form • interpreting variations over prolonged time periods • learning and recognizing profiles • triggering “intelligent” alarms

39. Application Areas of Biosignal Analysis • Biosignals offer parameters that support medical decision making and trend analysis. • Bio signal analysis techniques help to extract these parameters accurately, analyze and interpret them objectively.

40. Biomedical Instrumentation Biomedical instrumentation contributes in following ways • Accurate measurement • Long Term monitoring • Understanding, Diagnosis and management of disease • Research

41. Biometrics • Automated methods of verifying the identity of a person based on physiological behavioral characteristics

42. Types of Biometrics

43. Biometric System

44. Salient Features of Biometrics • Biometric makes use of those characteristics, which are universal, that is, found in each and every human being. For instance, fingerprints, voice, face print and so on. • Distinct body odours, handwriting skills and other attributes are being included in biometrics analysis, as these characteristics don’t change with growing age of individuals.

45. Salient Features of Biometrics • The characteristics involved in biometrics analysis can’t be stolen or copied. So, you can’t expect anyone to steal your face or eye vessels to use them for illegitimate access. • Interestingly, even if someone is able to replicate your fingerprints and use it for biometrics analysis, these systems can instantly differentiate between a human body and a plastic cast, on the basis of body heat, temperature, blood flow and so on.

46. Applications of Biometrics • Biometric systems can be used as physical access granting systems. The biometric identifier serves as the key to open doors to buildings and vehicles or to gain access to computers and other devices. • Secondly, biometric systems can be used to establish entitlement to services and rights that are restricted to a certain group of individuals. In this case, the service or right in question is only provided or granted to individuals that are identified as

47. Applications of Biometrics belonging to the group of recipients and rights holders. Examples include social services (prevention of welfare fraud), the right to vote (voter registration), right of abode and work (immigration), and all kinds of private membership services or contractual rights. • Biometric systems can be used for the recording and association of facts. Such uses include employee attendance monitoring, surveillance of public places, forensics, archiving and retrieving personal information such as health records.

48. Applications of EMG

49. Applications of EMG in Ergonomics ►ANALYSIS OF DESIGN. ►RISK PREVENTION. ►ERGONOMIC DESIGN. ►PRODUCT CERTIFICATION.

50. Applications of EMG in Ergonomics