[Medical Q&A] What are the applications of electromyography in single nerve damage diseases that cause numbness in the hands and feet?

Author: Zhang Lei Beijing Tiantan Hospital, Capital Medical University

Reviewer: Pan Hua, Chief Physician, Beijing Tiantan Hospital, Capital Medical University

Electromyography is a method of recording neuromuscular electrical activity. Generally speaking, electromyography includes two types: "nerve (nerve conduction velocity)" electromyography and "muscle (needle electromyography)" electromyography. For the diagnosis of peripheral nerve damage in numbness of hands and feet, usually only nerve conduction velocity examination (involving sensory nerves and motor nerves) is required, and needle electromyography is not required.

The most common single nerve damage disease that causes numbness in the hands is carpal tunnel syndrome, and nerve conduction studies are the gold standard for diagnosing carpal tunnel syndrome. Through nerve conduction studies, we can observe slowed conduction velocity and reduced amplitude of the sensory and motor fibers of the median nerve.

Another common single nerve damage disease that causes numbness in the hands is cubital tunnel syndrome, also known as "tennis elbow". Nerve conduction testing is the gold standard for diagnosing elbow entrapment. Through nerve conduction testing, we can observe slowed conduction velocity and reduced amplitude of the sensory and motor fibers of the ulnar nerve above and below the elbow.

The most common single nerve damage disease that causes foot numbness is damage to the common peroneal nerve. Nerve conduction testing can show that the conduction velocity of the sensory fibers and motor fibers of the common peroneal nerve below the fibular head is slowed down and the amplitude is reduced.

Peripheral neuropathy caused by diabetes is called diabetic peripheral neuropathy, and an EMG can help determine if diabetic peripheral neuropathy is present and assess its severity. In the early stages of diabetic peripheral neuropathy, an EMG may show slowed sensory nerve conduction velocity and reduced amplitude. As the disease progresses, an EMG can also show muscle deactivation and changes.

Electromyography (EMG) nerve conduction testing is one of the best ways to diagnose alcoholic peripheral neuropathy. Through EMG, doctors can detect slowed conduction velocity and reduced amplitude in nerves related to the disease (such as the median nerve, ulnar nerve, tibial nerve, common peroneal nerve, and sural nerve). These abnormal indicators are critical for early detection, early treatment, and early diagnosis.