Abnormal peripheral action potential amplitude Reduced F-wave amplitude 2024-01-07T13:13:57Z Reduced strength (amplitude) of the F-wave, which is an electrophysiological artifact produced by antidromic activation of motoneurons following distal electrical stimulation of motor nerve fibers. Because F-waves traverse the entire length of a peripheral nerve between the spinal cord and muscle, F-waves provide a means of examining transmission between stimulation sites in the arm and the leg and the related motoneurons in the cervical and lumbosacral cord. The F-wave is so named because it was originally studied in the small muscles of the foot. It is one of several responses that may follow the direct motor (M) response evoked by electrical stimulation of mixed or motor nerves.