**1.2. Measurement of H- and M-wave**

is called H-wave or H-response. With soleus or flexor carpi radialis muscle the H-wave is observed at rest, but in other muscles the H-wave can only be induced with mild voluntary

M-wave: Excitement is conducted to efferent. H-wave: Excitement is conducted via the monosynaptic reflex. F-wave:

Alpha motor neurons are activated directly by a gradual increase in the intensity of electrical stimulation, which occurs as the activity of Ia fiber is enhanced. The action potential of the

If an alpha motor neuron receives a strong electrical stimulation, its antidromic impulse is conducted to axons of all motor neurons that have received the stimulus. The impulse is to

skeletal muscle caused by this excitement is called M-wave or M-response.

contraction.

196 Electrodiagnosis in New Frontiers of Clinical Research

Excitement is conducted to antidromic.

*1.1.2. M-wave (M-response)*

*1.1.3. F-wave (F-response)*

**Figure 1.** Evoked EMG

With evoked EMG, the action potential is derived from a skeletal muscle that is innervated by electrical stimulation conducted to peripheral nerves.

In this section, we briefly introduce the measurement method of H-wave in soleus muscle in accordance with the guidelines of clinical neurophysiology test as stipulated by International Federation of Clinical Neurophysiology. Kaeser advocated that the measurement of H-wave be standardized in the study of spinal reflex (Kaeser 1973). It is not always easy to apply his method in clinical situations, but we recommend that you should examine his method carefully because it is considered to be a correct way of recording the H-wave.
