Basics of Electrodiagnostics
The two major types of tests used in electrodiagnostics to evaluate the peripheral nervous system.
What are, (i) Nerve Conduction Studies (Motor, Sensory) and (ii) Needle Electromyography (EMG)?
This ion is found in high concentrations outside the axonal membrane, crucial for generating an action potential.
What is Sodium (Na+)?
The primary purpose of performing electrodiagnostic tests.
What is to evaluate if there is a problem with the peripheral nervous system/neuromuscular disorder, localize the lesion, and identify the involved fiber type and pathology? (accept any of these)
It's a bundle of axons that transmit signals to and from various parts of the body.
What is a nerve?
This term refers to the electrode known as "the green one" in nerve conduction studies.
What is the ground electrode?
The influx of this ion presynaptically leads to the release of acetylcholine at the neuromuscular junction.
What is Calcium (Ca2+)?
This nerve conduction pattern is characterized by reduced amplitude in CMAP or SNAP but with normal or slightly decreased conduction velocity.
What is Axonal Loss?
This term refers to a single motor neuron and all the muscle fibers it innervates.
What is a motor unit?
This is what the abbreviation CMAP stands for in motor nerve conduction studies.
What is Compound Motor Action Potential?
This term describes when the electrical impulse travels in the opposite direction of normal physiological conduction.
What is Antidromic?
A prolonged distal latency greater than 130% and uniform slowing of conduction velocity below 75% normal, indicates this type of nerve pathology.
What is Demyelination?
This space between the presynaptic and postsynaptic regions contains an enzyme that degrades acetylcholine.
What is the synaptic cleft?
This term refers to the time interval between the onset of a stimulus and the onset or peak of response in NCS.
What is latency?
This is the term to describe the type of nerve fibers that have the fastest conduction velocity.
What is large diameter and/or myelinated axon?
This EMG parameter represents the compound action potential from muscle fibers of a single motor unit within the recording range of a needle electrode.
What is Motor Unit Action Potential (MUAP)?
This is the connective tissue surrounding the entire nerve, holding the fascicles together and protecting it from compression.
What is epineurium?
This measurement in NCS represents the maximal height of an action potential from the baseline to the negative peak.
What is Amplitude?
This term describes the direction of electrical impulse travel that is the same as normal physiological conduction.
What is Orthodromic?
This type of needle EMG finding includes fibrillation potentials and positive sharp waves.
What is abnormal spontaneous activity?
These muscle fibers are larger, have a higher innervation ratio, and produce higher amounts of torque for relatively short duration.
What are Type II or Fast/Fatigable muscle fibers?