What does F-wave stand for?
What does F-wave stand for?
In neuroscience, an F wave is one of several motor responses which may follow the direct motor response (M) evoked by electrical stimulation of peripheral motor or mixed (sensory and motor) nerves. Thus, the F-wave is considered a wave, as opposed to a reflex.
What causes F-waves?
The F wave is a late CMAP evoked intermittently from a muscle by a supramaximal electrical stimulus to the nerve, and it is due to antidromic activation (backfiring) of alpha motor neurons. F waves can be elicited from practically all distal motor nerves.
What causes absent F-waves?
Absence of the F-wave may represent the inability of spinal motor neurons to be excited after periods of inactivity. Repetitive stimulation in an otherwise immobile patient acts as a voluntary movement therefore allowing for the production of an F-wave in a patient with previously demonstrated absent F-waves.
What is the difference between H-reflex and F-wave?
F waves can help determine the presence of a polyneuropathy. A waves can reflect axonal damage. H reflexes provide nerve conduction measurements along the entire length of the nerve, demonstrating abnormalities in neuropathies and radiculopathies.
What does abnormal F wave mean?
The F-wave is a compound action potential evoked by supramaximal antidromic stimulation of a motor nerve16). The absence or slowing of F-waves may be an isolated conduction abnormality, especially during the early stages of illness17).
What is a normal F wave?
Maximum normal F wave latency for median nerve was 25.7 ms for women and 28.5 ms for men with stimulation at the wrist. It was 23 ms for women and 25 ms for men with stimulation at the elbow. Maximum normal F wave latency for ulnar nerve was 26.45 ms for women and 28.9 ms for men with stimulation at the wrist.
What is a normal F-wave?
What does a prolonged F wave mean?
Electrodiagnostic study The F-wave is a compound action potential evoked by supramaximal antidromic stimulation of a motor nerve. Prolonged F-wave latencies and the absence of an F-wave in nerves with a normal compound muscle action potential amplitude are highly specific for demyelination.
What does abnormal F-wave mean?
What is M Wave?
The tracing of the earliest EMG response to the stimulation of a motor nerve, which corresponds to muscle excitation through the motor axon.
Why was my EMG so painful?
Pain is commonly associated with EMG, because the procedure involves the use of needles and electric shock. Not only friends and relatives who have had a previous EMG experience, but also physicians can sometimes discourage patients from undergoing EMG, believing that the test is very painful and of little benefit (1).
