The H-reflex is a reflectory reaction of muscles after electrical stimulation of sensory fibers in their innervating nerves. The H-reflex test is performed using an electric stimulator, which gives usually a square-wave current of short duration and small amplitude, and an EMG set, to record the muscle response. That response is usually a clear wave, called H-wave, 28-35 ms after the stimulus, not to be confused with an F-wave. An M-wave, an early response, occurs 3-6 ms after the onset of stimulation. The H and F-waves are later responses. As the stimulus increases, the amplitude of the F-wave increases only slightly, and the H-wave decreases, and at supramaximal stimulus, the H-wave will disappear. The M-wave does the opposite of the H-wave. As the stimulus increases the M-wave increases. There is a point of minimal stimulus where the M-wave is absent and the H-wave is maximal. H-reflex is analogous to the mechanically induced spinal stretch reflex. "The primary difference between the H-reflex and the spinal stretch reflex is that the H-reflex bypasses the muscle spindle, and, therefore, is a valuable tool in assessing modulation of monosynaptic reflex activity in the spinal cord." Although stretch reflex gives just qualitative information about muscle spindles and reflex arch activity; if the purpose of the test to compare performances from different subjects, H-reflex should be used. In that case, in fact, latencies and amplitudes of H-wave can be compared.
U.S. National Library of Medicine
A monosynaptic reflex elicited by stimulating a nerve, particularly the tibial nerve, with an electric shock.
The numerical value of h-reflex in Chaldean Numerology is: 6
The numerical value of h-reflex in Pythagorean Numerology is: 6
Examples of h-reflex in a Sentence
I didn't try to hurt anybody. It was a reflex from the pain.
Who wears the skin of the predator has no predator reflex. (Qui porte la peau du prédateur - N'a pas réflexe de prédateur.)
Trust me, it’s like a reflex, everybody does it. Everybody does. They take Snapchats. Why not? People take video of them in cars like all the time.
They've been hypothesized to act as sun shades, dust catchers and blink-reflex triggers, but there's been no really systematic study of what their true benefits are.
It’s due to the vagal reflex, in which a nerve signal from your testicles travels up your spinal cord and brain stem and activates the nausea and vomiting centers in your brain.
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