Syed Shahid Habib
Electrodiagnostic (EDX) studies play a key role in the evaluation of patients with neuromuscular disorders. Among these studies are included nerve conduction studies (NCSs), repetitive nerve stimulation, late responses, blink reflexes, and needle electromyography (EMG). In clinical practice, EDX studies serve as an extension of the clinical examination. The information gained from EDX studies often leads to specific medical or surgical therapy. NCSs and EMG are most often used to diagnose disor¬ders of the peripheral nervous system. These include disorders affecting the primary motor neurons (anterior horn cells), primary sensory neurons (dorsal root ganglia), nerve roots, brachial and lumbosacral plexuses, peripheral nerves, neuromuscular junctions, and muscles. In addition, these studies may provide useful diag¬nostic information when the disorder arises in the central nervous system (e.g., tremor or upper motor neuron weak¬ness). Electrodiagnosis is the applied physiology of the fringe nerve and muscle frameworks. Just neurons, muscle, and Schwann cells, in addition to a few related structures, straightforwardly take an interest in fringe nerve conduction. These structures display just a constrained collection of electrodiagnostically recognizable reactions to injury. As though to stress the effortlessness of the NCS, the entirety of the signs utilized in clinical NCS are produced by just one structure, the cell layer. Underneath this facade of straightforwardness lies a billion years of transformative adjustment of the phone structures that create nerve signals. On the off chance that our development started in a substance soup of progressively complex proteins and associated concoction cycles, at that point an important advance to life is the bundling of this soup inside a vessel that can convey it into less steady situations. The cell film gives that work, and the self-get together quality of its phospholipids is probably going to have assumed a key transformative job in making the living cell. While walled in area can make a self-governing cell, it likewise makes a requirement for the way to keep up a stable interior condition. The cell layer is made out of a 5-nm-thick, requested, bilayer sheet of phospholipid particles. Phospholipids are clothespin-molded particles with a charged, hydrophilic phosphorus-based head and two uncharged, hydrophobic, straight-chain hydrocarbon legs. Whenever suspended in water, these amphipathic particles normally structure into container like micelles with the water-cherishing, phosphoric heads outward confronting, or they structure into twofold sheets with every outside surface made out of all phosphorus heads and an inward twofold layer of the water-dodging hydrocarbon legs; in this manner, the inside of the film is profoundly hydrophobic. Such layers are semipermeable. They bar huge particles, water-solvent atoms, and every charged atom (e.g., Na+, K+), while little, unpolarized, lipid-dissolvable particles and a few gases can diffuse through the film. The layer inside is in certainty a fluid, as portrayed in the liquid mosaic film model of Singer and Nicholson (1), with the phospholipids ready to move about effectively inside the layer and the blended proteins ready to move about, though more gradually. The phospholipid sub-atomic structure and the sort and volume of proteins situated in the film shift among various cell types. The ease of the layer is influenced by the incorporation of atoms, for example, cholesterol into the film, which solidifies in a warm layer and expands the smoothness of a cool film, and by wrinkling of the hydrocarbon tail chains of the lipoproteins (twofold holding), which lessens the tight pressing of the lipoprotein sheets by diminishing the Van der Waals holding powers between the hydrocarbons and in this way builds layer ease. NCS are regularly done alongside the EMG to decide whether a nerve is working ordinarily. The specialist directing the test will tape wires (cathodes) to the skin in different places along the nerve pathway. At that point the specialist animates the nerve with an electric flow. As the present goes down the nerve pathway, the cathodes set en route catch the sign and time how quick the sign is voyaging. In sound nerves, electrical signs can head out at up to 120 miles for each hour. On the off chance that the nerve is harmed, notwithstanding, the sign will be increasingly slow. By invigorating the nerve at different spots, the specialist can decide the particular site of the injury. Nerve conduction concentrates likewise might be utilized during treatment to test the advancement being made. In spite of the fact that you may at first be surprised by the suddenness of the incitement, it isn’t difficult and a great many people are open to during the testing technique. The stun is like one got when you contact a door handle subsequent to strolling across covering. Your orthopaedist may suggest electrodiagnostic testing for different conditions that can result from pressure on a nerve, especially in the arm, elbow or wrist. These conditions are designated “compressive neuropathies” and include: • Carpal passage disorder—pressure on the middle nerve as it goes between the wrist bones and under the transverse tendon • Thoracic outlet disorder—pressure on the brachial plexus, a bunch of nerves that goes under the collarbone at the shoulder • Ulnar nerve captures—pressure on the ulnar nerve as it goes behind the elbow • Cervical or lumbar radiculopathy—pressure on the nerve roots as they leave the spinal segment from the neck or lower back • Numerous specialists will arrange electrodiagnostic testing before suggesting medical procedure for these conditions. • Electrodiagnostic testing likewise can be utilized to decide the degree of injury to a nerve after a mishap and to contemplate the impacts of sicknesses, for example, diabetes. It can likewise appear if a harmed nerve is recuperating. Learning Objectives At the end of this workshop the participants should be able to: • Know the basic techniques and procedures for routine nerve conduction studies • Develop a logical approach to the use of standard clinical electrophysiological techniques in the evaluation of common neuromuscular disorders • Identify technical pitfalls associated with nerve conduction studies and understand methods to correct and minimize technical problems • Interpret the findings and clinical significance of abnormalities on nerve conduction studies
