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Electricity was used therapeutically long before it took on a diagnostic role. Historically, electrodiagnosis began after the twin births of neurophysiology and the physics of electricity itself in the late eighteenth century. Their early developments were closely related, the first battery being designed after the electric fish, and early theories of motility imagining muscles much like condensers. When each subject evolved to independent and reliable principles, then one (electrical measurement) could be used to study the other (neurophysiology) and electrodiagnosis began. This chapter relates the confused but determined efforts of brilliant and above all determined individuals, at times generating more heat than light, but always seeking to understand our subject. [ABSTRACT FROM AUTHOR]

Chapter 7 of the book "Pediatric Rehabilitation: Principles and Practice," Fourth Edition, edited by Michael A. Alexander and Dennis J. Matthews is presented. It explores the aspects to consider in pediatric electrodiagnosis. It discusses the technical factors associated with each type of electrodiagnosis. It tackles the clinical problems associated with such diagnosis of children with disabilities.

Chapter 3 of the book "Clinical Adult Neurology," Third Edition, is presented. This chapter explores the electrodiagnosis of neuromuscular disorders using nerve conduction studies (NCS) and electromyography as a diagnostic tool. The separate principles of NCS and EMG are discussed, along with the use of EMG in validating a neurologic diagnosis. The role of NCS in the evaluation of myopathy is also explored.

The article discusses the significance of ultrasound which generates visual images from inside the human body like the fetus, malignant tissue and other diagnosis from the test medium. Ultrasound is based on a wave-material interactive phenomena which determines material characteristics such as density, thickness, mechanical properties and level sensing. Ultrasound provides a nondestructive characterization of materials and noninvasive diagnostics applications in the medical field.

The article studies the cellular basics of neuronal membrane potentials and conductance. Studies must rely on noninvasive measurements of mass activity that originates from many neurons simultaneously. To detect brain activity at some distance using large electrodes, many neurons must be activated synchronously, and only activity that originates from open intracranial electrical fields can be assessed by scalp recordings.

This article presents information on electromyography (EMG). The EMG or myoelectric signal is the voltage detected with two electrodes within the volume conductor or on the surface of the skin. Surface detection provides global information with poor morphological details. Distant but large muscle portions may provide signal contribution comparable to those of smaller and closer portions. Today the main clinical application of the EMG techniques is based on the use of needles for diagnosing neuromuscular diseases that modify the morphology of MU action potentials. However, surface techniques are becoming more popular because they are noninvasive and inexpensive and provide global information.

This article presents information on electroencephalogram (EEG). EEG is a record of electric signals generated by the cooperative action of brain cells or, more precisely, the time course of extracellular field potentials generated by synchronous action of brain cells. The most successful models of EEG developed so far are based on the consideration of neural populations characterized by pulse density and slow electrical activity amplitude due to postsynaptic potentials. In the search for chaotic behavior of EEGs, it is important to check the results by comparison with surrogate data, since the procedures of calculation of attactor dimensions and Lyapunov coefficients are subject to large systematic and statistical errors.

An encyclopedia entry for "intracranial encephalography" (EEG) or "electrocorticography" is presented. It is used primarily for epilepsy surgical planning and for functional cortical mapping. Intracranial EEG is also used in the surgical evaluation of patients with intractable LRE only after noninvasive evaluations with scalp EEG yield discordant or nonlocalizable information. The depth recordings of EEG illustrate the variability of spread of the seizure discharge from seizure to seizure.

An encyclopedia entry for "EEG (electroencephalography)" is presented. It states that EEG has played a significant role in the evaluation of seizures and is composed of an amplified electrical signal derived from cerebral neuronal activity. It notes that EEG also offers information on the classification of the seizure type and syndrome as well as the characterization of seizures for the purposes of epilepsy surgery.

An encyclopedia entry for "hyperventilation" is presented. It refers to an activating technique used in clinical practice to represent a stimulus that may trigger abnormalities clinically or on the electroencephalography (EEG). A bilateral increase in theta or delta build-up that is frontally predominant and high amplitude is normally produced by hyperventilation. Patients with severe cardiac or pulmonary disease, cerebral infarction, sickle cell anemia and pregnancy should not hyperventilate.

An encyclopedia entry for "delta activity" is presented. It refers to a frequency bandwidth seen on electroencephalography (EEG) that occurs with frequencies under 4 hertz (Hz). Some of the diffuse cerebral dysfunctions associated with diffuse delta activity include toxic, metabolic, or infectious encephalopathies, frontal delta activity with midline tumors, hydrocephalus, hypoglycemia and dialysis dementia. Examples of structural abnormalities that focal delta activity can help highlight include tumors, intracranial bleeds or strokes.