EEG Technology

ForewordPreface to Second EditionPreface to First Edition1. Origins of the Electroencephalogram 1.l. Historical Introduction 1.2. Physical Structure of the Brain 1.2.1. Gross Anatomy 1.2.2. Physical Structure of Tissue 1.3. Electrical Activity of the Brain 1.3.1. Introduction 1.3.2. Resting Membrane Potential 1.3.3. Action Potential 1.3.4. Origin of the Cortical EEG 1.4. Relation between Scalp and Cortical EEG2. Electrodes 2.1. Introduction 2.2. Types of Electrodes 2.2.1. Scalp Electrodes 2.2.2. Sphenoidal Electrodes 2.2.3. Nasopharyngeal Electrodes 2.2.4. Electrocorticographic Electrodes 2.2.5. Intracerebral Electrodes 2.3. Chloriding of Silver Electrodes 2.4. Measurement of Electrode Resistance 2.5. Electrode Characteristics 2.5.1. Electrode Potential 2.5.2. Polarization 2.5.3. Reversible Electrodes 2.6. Equivalent Circuit of an Electrode in a Solution 2.7. Measurement of Electrode Characteristics 2.8. Electrodes for d.c. Recording 2.9. Electrodes for a.c. Recording3. Connecting Electrodes to Amplifiers 3.1. Introduction 3.2. Bipolar Derivations 3.3. Common Reference Derivations 3.4. Common Average Reference Derivations 3.5. General Qualifications4. Recording Systems 4.1. Introduction 4.2. Characteristics of the Input Circuit 4.2.1. The Input Circuit 4.2.2. The Balanced Amplifier 4.2.3. Analysis of the Balanced Amplifier Input Circuit 4.3. Characteristics of the Recording System 4.3.1. Introduction 4.3.2. Sensitivity 4.3.3. Linearity 4.3.4. Frequency Response 4.3.5. Phase Response 4.3.6. Noise 4.4. The Frequency Response Controls 4.4.1. Introduction 4.4.2. The Low-frequency Filter and its Time Constant 4.4.3. The High-frequency Filter 4.5. The Writer and Pen Damping Effects 4.6. The ‘Electrode-amplifier’ Recording System 4.7. The Overall System 4.7.1. Frequency Characteristic 4.7.2. Master Controls 4.7.3. Amplifier Blocking 4.7.4. Paper Drive and Time Marking 4.8. Testing the Recording System 4.8.1. Introduction 4.8.2. Sensitivity 4.8.3. Linearity and Dynamic Range 4.8.4. Discrimination 4.8.5. Frequency Response 4.8.6. Input Resistance 4.8.7. Noise 4.8.8. Paper Speed 4.9. Fault Finding5. Operational Techniques 5.1. Introduction 5.2. Electrode Placement 5.3. Design of Montages 5.4. Application of Electrodes 5.5. Recording Procedure 5.6. Evocative Techniques 5.6.1. Introduction 5.6.2. Hyperventilation 5.6.3. Photic Stimulation 5.6.4. Sleep 5.6.5. Intravenous Administration of Drugs 5.7. Use of Operational Controls 5.8. Artefacts 5.8.1. Introduction 5.8.2. External Electrical Interference 5.8.3. Artefacts from Electrodes and Leads 5.8.4. Artefacts from the Patient6. Visual Analysis of the EEG 6.1. Introduction 6.2. Temporal Patterns 6.2.1. Describing the Signal 6.2.2. Sine Waves 6.2.3. EEG Frequency Bands 6.2.4. Complex Wave Patterns 6.2.5. Specific Waveforms 6.3. Spatial Patterns 6.3.1. Stationary Potential Fields 6.3.2. Moving Potential Fields 6.4. Spatial Analysis 6.4.1. Introduction 6.4.2. Derivation of Potential Distribution from Pen Deflections 6.4.3. Mapping of Small Potential Fields 6.4.4. Mapping of Widespread Potential Fields 6.5. Describing the EEG Record7. Special Techniques 7.1. Use of Special Electrodes 7.1.1. Sphenoidal Electrode Recordings 7.1.2. Nasopharyngeal Electrode Recordings 7.1.3. Naso-ethmoidal Electrodes 7.1.4. Electrocorticographic Recordings 7.1.5. Intracerebral Electrode Recordings 7.2. Recording in Intensive Care Units 7.3. Overnight Sleep Recording 7.4. D.C. Recording 7.5. Recording of Variables Other than the EEG 7.5.1. Introduction 7.5.2. Electrocardiogram and Heart Rate 7.5.3. Respiration 7.5.5. Muscle Activity and Body Movement 7.5.6. Skin Resistance and Potential 7.5.7. Blood Pressure 7.5.8. Monitoring of Sensory Stimuli 7.6. Connecting Ancillary Equipment to EEG Machines 7.7. Recording of EEG Signals on Magnetic Tape 7.8. Recording of Evoked Responses 7.8.1. Introduction 7.8.2. Superimposition 7.8.3. Averaging 7.8.4. Factors Determining Signal-to-Noise Enhancement 7.8.5. The Median Response 7.8.6. The Variability of Evoked Responses 7.8.7. Calibration for Average Evoked Response Measurement 7.8.8. The Contingent Negative Variation 7.9. Telemetry 7.9.1. Introduction 7.9.2. Modulation Systems 7.9.3. Radio Telemetry 7.9.4. Telephonic Transmission8. EEG Signal Analysis 8.1. Introduction 8.2. Analogue and Digital Methods 8.3. Amplitude Measures 8.4. Measurement of Wave Indices 8.5. Frequency Analysis—Theoretical Basis 8.6. Frequency Analysis—Analogue Methods 8.6.1. Selective Filtering 8.6.2. Functional Description of a Wave Analyzer 8.6.3. Other Types of Analogue Analyzer 8.6.4. Display of Analyzer Output 8.7. Correlation Analysis 8.7.1. Theoretical basis 8.7.2. The Cross-correlation Function 8.7.3. The Auto-correlation Function 8.7.4. Application and Interpretation of Correlation Analysis 8.8. Frequency Analysis—Digital 8.8.1. Theoretical Basis 8.8.2. Description of the Method 8.8.3. Practical Methods 8.9. Spatial Analysis 8.10. Phase and Time Delay Analysis 8.11. Some other Methods of Processing EEG Signals 8.11.1. Introduction 8.11.2. Hjorth Analysis 8.11.3. Autoregressive Analysis 8.11.4. Pattern Recognition Applied to EEG Signals 8.11.5. Pattern Recognition Applied to Factual EEG Reports 8.12. Statistical Treatment of EEG Data 8.13. ConclusionAppendices A. Preparation of Isotonic Electrode Jelly B. Preparation of Bentonite Paste C. Calculation of Amplitude and Timing Errors due to Arc Distortion D. Binary Notation E. An Example of Numerical Fourier Analysis F. Factual ReportIndex