[Electrophysiologic tests of human reflexes: diagnostic values and limitations].

Traditional nerve stimulation techniques used in an electromyography laboratory primarily assess the distal segments of the peripheral nerves. Methods of testing the proximal nerve segments or the central nervous system include the F wave, H reflex, T reflex, tonic vibration reflex, and blink reflex. These studies reveal conduction characteristics along the entire course of the sensory and motor axons as well as the excitability of the neuronal pool in the brainstem and spinal cord. Extensive studies have proven the practical value of these late responses in certain neurologic disorders. Even though clinical applications of the techniques mentioned here await further clarification, they have already contributed substantially as a means of quantitating physiologic studies of motor and sensory systems. This report will review the basic physiology, diagnostic values and technical limitations of the newer methods in evaluating the regions of the nervous system not accessible by the conventional methods.