Needle electromyography. Fundamentals, normal and abnormal patterns.
The needle electromyographic (EMG) examination is a challenging component of the electrophysiologic study. Knowledge of anatomy and physiology, sound EMG technique, and good patient rapport are required. Every muscle sampled by needle EMG is assessed for insertional activity, spontaneous activity, and voluntary motor-unit action potentials. Key pieces of information obtained from the needle EMG examination include the localization of the disorder, its chronicity, severity, and whether or not the underlying pathophysiology is neuropathic, myopathic, or associated with a neuromuscular junction disorder.
Preston
David C
DC
Department of Neurology, Case Western Reserve University, Department of Neurology, University Hospitals of Cleveland, Cleveland, OH, USA. david.preston@uhhs.com
Shapiro
Barbara E
BE
D004566:Electrodes; D004576:Electromyography / Q000379:methods*; D006801:Humans; D009046:Motor Neurons / Q000502:physiology; D009431:Neural Conduction / Q000502:physiology*; D009468:Neuromuscular Diseases / Q000175:diagnosis* / Q000503:physiopathology; D010525:Peripheral Nerves / Q000503:physiopathology; D010523:Peripheral Nervous System Diseases / Q000175:diagnosis* / Q000503:physiopathology; D012680:Sensitivity and Specificity