Electromyography is a test that detects and studies muscle bioelectrical activity to determine changes in the function of the neuromuscular system. The normal EMG is at rest and increases in amplitude with increasing frequency of discharge as movement increases. Electromyography is useful as an aid to distinguish between neurogenic and myogenic damage, and also to identify whether peripheral neuropathies are dominated by axonal or myelin damage. Each myopathy has its own unique EMG manifestation, and the specific disease should be analyzed based on the EMG results combined with other clinical data. The following precautions should be taken for electromyography examination: 1. Patients should have clean skin before examination and wear loose clothing to easily expose the extremities for operation; 2. The examination should not be performed on an empty stomach, as hunger can easily induce hypoglycemia, dizziness and other discomfort; 3. Patients with a clear bleeding tendency and coagulation disorders should avoid needle pole determination before examination; 4. Keep the needle site clean to avoid infection. Local swelling and pain may occur at the needling site, which can generally be relieved on its own without special treatment; 5, older patients or patients suffering from cardiovascular disease, sensitive to current stimulation and weaker tolerance, should pay attention to any uncomfortable symptoms during the process.