Principles of Biomedical Instrumentation

Contents
Preface
List of Abbreviations
1 Biomedical Instrumentation and Devices
	1.1 Classification of Biomedical Instruments and Devices
	1.2 Outline of the Design Process: From Concept to Clinical Device
		1.2.1 Engineering Design
	1.3 Regulation of Biomedical Instrumentation and Devices
	1.4 Safety of Biomedical Instrumentation and Devices
		1.4.1 ISO and IEC Standards
		1.4.2 Biological Testing
	1.5 Evaluation of a New Device
2 Sensors and Transducers
	2.1 Micro-Electro-Mechanical Systems
		2.1.1 Noise in MEMS Devices
	2.2 Voltage Sensors: Example – Biopotential Electrodes
		2.2.1 Clinical and Biomedical Voltage Measurements
		2.2.2 Action Potentials and Cellular Depolarization
		2.2.3 Surface Electrode Design
	2.3 Optical Sensors: Example – a Pulse Oximeter
		2.3.1 Clinical Blood Oxygenation Measurements
		2.3.2 Measurement Principle Using an Optical Sensor
		2.3.3 Optical Transmitter and Detector Design
	2.4 Displacement/Pressure Sensors and Accelerometers
		2.4.1 Clinical Pathologies Producing Changes in Internal Pressure
		2.4.2 Resistive and Piezoresistive Transducers
		2.4.3 Piezoelectric Sensors
		2.4.4 Capacitive Transducers
		2.4.5 Inductive Transducers: the Linear Voltage Differential Transformer
	2.5 Chemical Sensors: Example – a Glucose Monitor
		2.5.1 Clinical Need for Glucose Monitoring
		2.5.2 System Requirements for Glucose Monitoring
		2.5.3 Basic Detection Principles of Glucose Monitoring
		2.5.4 Designing a Portable Device for Glucose Monitoring
	2.6 Acoustic Sensors: Example – a Microphone for Hearing Aids
		2.6.1 Clinical Need for Hearing Aids
		2.6.2 Microphone Design for Hearing Aids
3 Signal Filtering and Amplification
	3.1 Frequency-Dependent Circuit Characteristics: Bode Plots
	3.2 Passive Filter Design
		3.2.1 First-Order Low-Pass and High-Pass Filters
		3.2.2 Higher Order High-Pass, Low-Pass, Band-Pass and Band-Stop Filters
		3.2.3 Resonant Circuits as Filters
	3.3 Operational Amplifiers
		3.3.1 Circuit Analysis Rules for Op-Amps
		3.3.2 Single Op-Amp Configurations
		3.3.3 The Instrumentation Amplifier
	3.4 Active Filters
		3.4.1 First-Order Low-Pass, High-Pass and Band-Pass Active Filters
		3.4.2 Higher Order Butterworth, Chebyshev and Sallen–Key Active Filters
	3.5 Noise in Electrical Circuits
	3.6 Examples of Signal Amplification and Filtering
		3.6.1 Signal Conditioning in the Pulse Oximeter
		3.6.2 Amplification and Filtering in a Glucose Sensor
4 Data Acquisition and Signal Processing
	4.1 Sampling Theory and Signal Aliasing
	4.2 Dynamic Range, Quantization Noise, Differential and Integrated Non-Linearity
	4.3 Electronic Building Blocks of Analogue-to-Digital Converters
		4.3.1 Sample-and-Hold Circuits
		4.3.2 Comparator Circuits
		4.3.3 Shift Register Circuits
	4.4 Analogue-to-Digital Converter Architectures
		4.4.1 Flash ADCs
		4.4.2 Successive Approximation Register ADCs
		4.4.3 Pipelined ADCs
		4.4.4 Oversampling ADCs
	4.5 Commercial ADC Specifications
		4.5.1 ADC for a Pulse Oximeter
		4.5.2 ADC for a Glucose Meter
	4.6 Characteristics of Biomedical Signals and Post-Acquisition Signal Processing
		4.6.1 Deterministic and Stochastic Signals
		4.6.2 The Fourier Transform
		4.6.3 Cross-Correlation
		4.6.4 Methods of Dealing with Low Signal-to-Noise Data
5 Electrocardiography
	5.1 Electrical Activity in the Heart
	5.2 Electrode Design and Einthoven’s Triangle
		5.2.1 Standard Twelve-Lead Configuration
	5.3 ECG System Design
		5.3.1 Common-Mode Signals and Other Noise Sources
		5.3.2 Reducing the Common-Mode Signal
		5.3.3 Design of Lead-Off Circuitry
		5.3.4 Filtering and Sampling
	5.4 Signal Processing of the ECG Signal and Automatic Clinical Diagnosis
		5.4.1 University of Glasgow (Formerly Glasgow Royal Infirmary) Algorithm
	5.5 Examples of Abnormal ECG Recordings and Clinical Interpretation
	5.6 ECG Acquisition During Exercise: Detection of Myocardial Ischaemia
	5.7 High-Frequency (HF) ECG Analysis
6 Electroencephalography
	6.1 Electrical Signals Generated in the Brain
		6.1.1 Postsynaptic Potentials
		6.1.2 Volume Conduction Through the Brain
	6.2 EEG System Design
		6.2.1 Electrodes and their Placement on the Scalp
		6.2.2 Amplifiers/Filters and Digitizing Circuitry
		6.3 Features of a Normal EEG: Delta, Theta, Alpha and Beta Waves
	6.4 Clinical Applications of EEG
		6.4.1 EEG in Epilepsy
		6.4.2 Role of EEG in Anaesthesia: the Bispectral Index
	6.5 EEG Signals in Brain–Computer Interfaces for Physically Challenged Patients
		6.5.1 Applications of BCIs to Communication Devices
		6.5.2 Applications of BCIs in Functional Electrical Stimulation and Neuroprostheses
	6.6 Source Localization in EEG Measurements (Electrical Source Imaging)
7 Digital Hearing Aids
	7.1 The Human Auditory System
	7.2 Causes of Hearing Loss
	7.3 Basic Design of a Digital Hearing Aid
	7.4 Different Styles of Hearing Aid
	7.5 Components of a Hearing Aid
		7.5.1 Earmoulds and Vents
		7.5.2 Microphones
	7.6 Digital Signal Processing
		7.6.1 Feedback Reduction
		7.6.2 Adaptive Directionality and Noise Reduction
		7.6.3 Wind-Noise Reduction
		7.6.4 Multi-Channel and Impulsive Noise-Reduction Algorithms
		7.6.5 Compression
		7.6.6 Multi-Channel Compression: BILL and TILL
		7.6.7 Frequency Lowering
	7.7 Digital-to-Analogue Conversion and the Receiver
	7.8 Power Requirements and Hearing Aid Batteries
	7.9 Wireless Hearing Aid Connections
	7.10 Binaural Hearing Aids
	7.11 Hearing Aid Characterization Using KEMAR
8 Mobile Health, Wearable Health Technology and Wireless Implanted Devices
	8.1 Mobile and Electronic Health: Mobile Phones and Smartphone Apps
	8.2 Wearable Health Monitors
		8.2.1 Technology for Wearable Sensors
	8.3 Design Considerations for Wireless Implanted Devices
		8.3.1 Data Transmission Through the Body
	8.4 Examples of Wireless Implanted Devices
		8.4.1 Cardiovascular Implantable Electronic Devices
		8.4.2 Continuous Glucose Monitors
		8.4.3 Implanted Pressure Sensors for Glaucoma
	8.5 Packaging for Implanted Devices
	Appendix: Reference Standards and Information Related to Wireless Implant Technology
9 Safety of Biomedical Instruments and Devices
	9.1 Physiological Effects of Current Flow Through the Human Body
	9.2 The Hospital Electrical Supply
		9.2.1 Hospital-Grade Receptacles
	9.3 Macroshock, Microshock and Leakage Currents: Causes and Prevention
		9.3.1 Macroshock
		9.3.2 Protection Against Macroshock
		9.3.3 Microshock
		9.3.4 Protection Against Microshock
	9.4 Classification of Medical Devices
		9.4.1 Classes of Equipment
		9.4.2 Types of Equipment
	9.5 Safety Testing Equipment
		9.5.1 Leakage Current Measurements
		9.5.2 Earthbond Testing
	9.6 Safety of Implanted Devices
		9.6.1 Biocompatibility
		9.6.2 Electromagnetic Safety
		9.6.3 Clinical Studies
	9.7 Design of Devices That Can Be Used in a Magnetic Resonance Imaging Scanner
	Appendix: Safety Policy Documents
Glossary
Index