Electromyography (EMG) is a technique for evaluating and recording the electrical activity produced by nerves and muscles. Interpreting EMG is a mandatory skill for neurologists and rehabilitation specialists. This textbook provides the reader with a detailed discussion of the concepts and principles underlying electrodiagnostic medicine. It is written for an audience without pre-existing knowledge in this discipline, including beginner technicians and physicians in training. It is an ideal review for seasoned practitioners and those preparing for board examinations. It begins with a review of the foundational sciences and works through the field in twenty chapters, including a large number of case studies demonstrating correct application and interpretation. Appendices of information frequently required in the EMG laboratory, such as Nerve Conduction Study techniques and their age-related normal values, anatomic regions assessed by each NCS and needle EMG studies, safety issues, and other important topics, are also included.
Author(s): Mark A. Ferrante
Edition: 1st
Publisher: Cambridge University Press
Year: 2018
Language: English
Pages: 542
Tags: Neurophysiology
Cover......Page 1
Half-title......Page 3
Title page......Page 5
Copyright information......Page 6
Dedication......Page 7
Table of contents......Page 9
Preface......Page 11
Acknowledgments......Page 14
Section 1 Introductory Chapters......Page 15
Introduction......Page 17
Charge......Page 18
Current......Page 22
Voltage......Page 24
Resistance......Page 25
Ohm’s Law......Page 26
Types of Circuits and Current......Page 27
Series DC Circuits......Page 28
Parallel DC Circuits......Page 32
Capacitors......Page 34
Alternating Current......Page 37
The Quantification of AC Signal......Page 38
Household Electricity......Page 40
Transformers......Page 44
Electromagnetic Radiation......Page 45
Recommended Reading......Page 46
Capacitance......Page 47
Filters......Page 48
Filter Arrangements......Page 54
Analog-to-Digital Converters and Digital-to-Analog Converters......Page 55
Stimulators......Page 57
Monopolar Amplifiers......Page 58
Differential Amplifiers......Page 59
The Common Mode Rejection Ratio......Page 61
Suggested Reading......Page 62
The Cell Membrane......Page 63
Motor Neurons......Page 64
Sensory Neurons......Page 65
Nerve Fiber Classification......Page 66
Ion Channels......Page 67
Transmembrane Potentials, Nernst Equilibrium Potentials, and Selective Permeability......Page 69
Depolarization and Repolarization......Page 71
The Absolute Refractory Period and the Relative Refractory Period......Page 72
Local Responses......Page 73
The Advantage of Myelin......Page 75
Action Potential Propagation Speed......Page 76
Connective Tissue Elements of Nerve Trunks......Page 79
References......Page 80
Introduction......Page 82
Synaptic Space......Page 83
Postsynaptic Region......Page 84
Postsynaptic Membrane Depolarizations......Page 85
References......Page 86
Structural Organization of Muscle......Page 87
The Sarcomere......Page 88
The CNS Influence......Page 90
Muscle Shortening......Page 91
Motor Unit and Muscle Fiber Physiology, Biochemistry, and Metabolism......Page 92
Motor Unit Size and Distribution......Page 93
References......Page 94
Section 2 Nerve Conduction Studies......Page 97
Introduction......Page 99
History......Page 100
Proper Placement of the Recording Electrodes......Page 101
The Basic Technique......Page 102
Volume Conduction......Page 104
Orthodromic versus Antidromic......Page 106
The Stimulating Electrodes and Their Proper Placement......Page 107
References......Page 108
Biphasic Morphology......Page 109
The E2 Electrode Is Not Inactive......Page 110
Positive Dip......Page 111
Nerve Stimulation......Page 112
Physiologic Temporal Dispersion......Page 113
What We Measure and What It Means......Page 115
Amplitude......Page 116
Negative AUC......Page 118
Distal Latency......Page 119
The Contributors to the Distal Latency Time......Page 120
Conduction Velocity......Page 121
References......Page 123
Technique......Page 125
Measurements......Page 126
Amplitude......Page 127
Orthodromic versus Antidromic Techniques......Page 128
Fixed Landmarks versus Fixed Distances......Page 130
Peak Latencies versus Onset Latencies......Page 131
Conduction Velocity......Page 132
Effects of Filtering......Page 133
Ideal Interelectrode Distance......Page 134
Mixed Nerve Conduction Studies......Page 135
References......Page 136
Effects of Focal Demyelination on Action Potentials......Page 137
Introduction......Page 138
The Pathology of Focal Demyelination......Page 139
Uniform Demyelinating Conduction Slowing......Page 140
Nonuniform Demyelinating Conduction Slowing......Page 141
Focal Demyelinating Conduction Block......Page 142
Conduction Failure......Page 145
The Major Advantages and Disadvantages of the Motor NCS......Page 146
The Sensory NCS Manifestations of Pathology and Pathophysiology......Page 147
The Timing of NCS Manifestations......Page 149
References......Page 150
The Effect of Focal Demyelination and Axon Disruption on the NCS......Page 151
Motor NCS......Page 152
References......Page 154
Introduction......Page 155
Technique......Page 156
Technical Errors......Page 157
Amplitude and Latency Measurements......Page 158
Utility of H Wave Testing......Page 159
Physiology and Technique......Page 160
Utility......Page 161
A Waves......Page 162
Blink Reflexes......Page 163
References......Page 164
Introduction......Page 166
Introduction......Page 167
Technique......Page 168
Postexercise Facilitation and Postexercise Exhaustion......Page 169
Technical Errors......Page 170
High-Frequency RNSS Technique......Page 171
References......Page 172
Section 3 The Needle EMG Examination......Page 173
Introduction......Page 175
Motor Unit Anatomy and Physiology......Page 176
Duration......Page 177
Motor Unit Recruitment (Force Generation)......Page 178
The Measurements We Make and Their Meanings......Page 183
Insertional Phase......Page 184
Miniature Endplate Potentials......Page 185
Endplate Spikes......Page 186
MUAP Amplitude (Peak-to-Peak)......Page 187
MUAP Duration......Page 189
The Number of Phases and Turns Composing the MUAP......Page 191
Needle Recording Electrode Types......Page 192
Concentric Needle Electrodes......Page 193
Monopolar Needle Electrodes......Page 194
References......Page 195
Chapter Organization......Page 197
Resting Phase......Page 198
Morphology and Duration......Page 199
The Auditory Characteristics and Firing Frequency of Fibrillation Potentials......Page 200
Specificity and Utility......Page 201
Fasciculation Potentials and Cramp Potentials......Page 202
Electrodiagnostic Features......Page 203
Myotonic Potentials......Page 204
Neuromyotonia......Page 205
Grouped Repetitive Discharges (GRDs) and Myokymia......Page 206
Activation Phase......Page 207
MUAP Duration......Page 208
Reinnervation via Collateral Sprouting......Page 209
MUAP Recruitment......Page 210
Grading Neurogenic Recruitment......Page 211
Decreased Spatial And Temporal Recruitment......Page 212
Non-Myopathic Motor Unit Disintegration Disorders......Page 213
MUAP Stability......Page 214
Motor Axon Loss Following Reinnervation via Collateral Sprouting......Page 215
References......Page 216
Single-Fiber Needle Electrodes......Page 218
Technique and Measurements Made......Page 219
Jitter Using a Concentric Needle Electrode......Page 220
Macro EMG Needle Electrodes......Page 221
References......Page 222
Section 4 Other Pertinent EDX Information......Page 225
The Importance of Proper Initial Management......Page 227
Correlations between Lesion Acuteness and the Underlying Pathophysiology......Page 228
Electrodiagnostic Grading......Page 229
Timing of the Study......Page 230
The Value of Motor Responses in the Assessment of Lesion Severity......Page 231
Collateral Sprouting......Page 232
Proximodistal Axon Regeneration......Page 233
Determining the Potential for Reinnervation......Page 234
Neurapraxia......Page 235
Sunderland Grade 2......Page 236
Sunderland Grade 5......Page 237
Surgical Intervention......Page 238
Approach to Axon Loss (Grades 2–5)......Page 239
Major Surgical Interventions......Page 240
Types of Nerve Injuries......Page 241
Compression Injuries......Page 242
Acute Compression......Page 243
Chronic Compression......Page 244
Ischemic Injury......Page 245
References......Page 246
Upper Motor Neuron Disorders......Page 249
Anterior Horn Cell Disorders......Page 250
Post-Poliomyelitis Syndrome......Page 251
Spinal Muscular Atrophy, Type 3......Page 252
Radiculopathies......Page 253
Plexopathies......Page 255
The Brachial Plexus......Page 256
The Lumbosacral Plexus......Page 259
Focal Neuropathies (Mononeuropathies)......Page 260
Acquired Axon Loss Polyneuropathies......Page 261
Acquired Demyelinating Polyneuropathies......Page 262
Chronic Inflammatory Demyelinating Polyradiculoneuropathy......Page 263
Hereditary Polyneuropathies......Page 264
Neuromuscular Junction Disorders......Page 265
Repetitive Nerve Stimulation Studies......Page 266
Needle EMG Study......Page 267
Myopathic Disorders......Page 268
References......Page 269
Studying Cool Limbs......Page 271
Nerve Conduction Studies......Page 272
Repetitive Nerve Stimulation Studies......Page 273
Nerve Conduction Studies......Page 274
Body Habitus–Related issues......Page 275
Introductory Comments......Page 276
MGA to the Hypothenar Eminence......Page 277
MGA to the Adductor Pollicis Muscle......Page 278
MGA with Concomitant Carpal Tunnel Syndrome......Page 279
MGA with a Concomitant Ulnar Neuropathy......Page 280
Atypically Proximal MGA......Page 281
Identifying an RCA......Page 282
Identifying an Accessory Deep Peroneal Nerve......Page 283
The Presence of a Positive Dip......Page 284
Stimulus (Shock) Artifact......Page 285
Stimulus Artifact Reduction......Page 286
Rotation of the Anode about the Cathode......Page 287
Submaximal Stimulation......Page 288
Excessive Stimulation......Page 289
60 Hz Power Artifact......Page 290
Measurement Errors......Page 291
Filtering Issues......Page 293
Needle EMG......Page 295
Changing the Sensitivity to Better Identify the Onset Latency......Page 296
Sweep Speed and Sensitivity......Page 297
Identifying Demyelination Based on the Latency of a Very Low Amplitude Response......Page 298
Measurement Errors......Page 299
References......Page 300
Electrical Injury......Page 304
Indwelling Medical Devices......Page 307
Bleeding......Page 309
Transmission of Infection......Page 310
Prevention......Page 312
References......Page 313
EDX Testing as an ‘‘Extension of the Neurological Examination’’......Page 316
The Timing of the EDX Examination......Page 317
The Limitations of Electrodiagnostic Testing......Page 318
The EDX Study Components Performed and Their Order of Performance......Page 319
Supervision......Page 320
Reviewing the Consult......Page 321
Explaining the EDX Study to the Patient (Verbal Informed Consent)......Page 322
Brief Discussion......Page 323
Tips to Lessen the Discomfort Associated with the Needle EMG Study......Page 324
Format of Report......Page 326
References......Page 327
Section 5 Case Studies in Electrodiagnostic Medicine......Page 329
Lesion Localization......Page 331
Identifying Nonorganic Lesions......Page 332
Initial Studies......Page 333
Abbreviations......Page 334
Needle EMG......Page 335
The Electrodiagnostic Exercises......Page 336
References......Page 493
Section 6 Appendices......Page 495
The Lumbosacral Plexus......Page 497
The Median Nerve......Page 498
The Ulnar Nerve......Page 499
The Radial Nerve......Page 500
The Obturator Nerve......Page 501
The Femoral Nerve......Page 502
The Sciatic Nerve Proper......Page 503
The Tibial Nerve......Page 504
The Peroneal Nerve......Page 505
Appendix 3: Myotome Tables for the Upper and Lower Extremities......Page 506
Appendix 4: The SNAP, CMAP, and Needle EMG Domains of the Brachial Plexus Elements^......Page 507
Reference......Page 509
The Median Sensory NCS, Recording Second Digit......Page 510
The Ulnar Sensory NCS, Recording Fifth Digit......Page 511
Superficial Radial Sensory NCS......Page 512
Median Motor NCS, Recording Abductor Pollicis Brevis (Thenar Eminence)......Page 513
Ulnar Motor NCS, Recording Abductor Digiti Minimi (Hypothenar Eminence)......Page 514
Radial Motor NCS, Recording Extensor Digitorum Communis......Page 515
Musculocutaneous Motor NCS, Recording Biceps......Page 516
Suprascapular Motor NCS, Recording Infraspinatus......Page 517
Superficial Peroneal Sensory NCS......Page 518
Peroneal Motor NCS, Recording Extensor Digitorum Brevis......Page 519
Tibial Motor NCS, Recording Abductor Hallucis......Page 520
Femoral Motor NCS, Recording Rectus Femoris......Page 521
Appendix 6: The Age-Related, Normal Control Values Used in Our EMG Laboratories......Page 523
Lower Extremity......Page 524
Needle EMG......Page 525
Myopathy......Page 526
Index......Page 527
