If you can’t find the reason for the numbness in your hands and feet, don’t worry, the secret tool is here!

Author: Zhang Lei Neurology Center, Beijing Tiantan Hospital, Capital Medical University

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

Numbness in the hands and feet is a common clinical symptom that many people have experienced. In severe cases, it may even affect grasping things or walking, and even worse, it may be accompanied by pain, which seriously affects daily life and even makes people unable to sleep all night, making people feel miserable.

If the numbness in the hands or feet is temporary, it may be related to nerve compression caused by maintaining a certain posture for a long time. Changing posture and taking a rest can usually relieve the symptoms, so there is no need to worry too much.

However, if the symptoms of numbness in the hands and feet persist, we need to pay attention to it.

1. Could it be a stroke?

Many people worry whether numbness in the hands and feet is related to cerebrovascular disease (stroke, commonly known as "stroke"), but in fact, the numbness caused by cerebrovascular disease (such as cerebral infarction or cerebral hemorrhage) is usually on one side of the body, and is usually accompanied by other symptoms such as limb weakness and incoordination. If you suddenly experience numbness in one upper or lower limb, you should consider whether it is related to cerebrovascular disease.

Second, most of the time it is a problem with the peripheral nerves

Most people experience numbness in their hands and feet due to peripheral nerve damage. For example, compression of the nerves in the wrist can cause numbness in the hands, also known as "carpal tunnel syndrome." Years of diabetes and long-term heavy drinking can also cause peripheral nerve damage, resulting in numbness in the hands and feet. So, how do we determine whether there is peripheral nerve damage? This requires our inspection tool - electromyography.

3. Electromyography: A powerful tool for analyzing neuromuscular electrical activity

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 the hands and feet, usually only a nerve conduction velocity test (involving sensory nerves and motor nerves) is required, without the need for a needle electromyography test.

IV. Application of electromyography in single nerve damage diseases

1. Carpal tunnel syndrome

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The most common single nerve damage disease that causes numbness in the hands is carpal tunnel syndrome. Long-term heavy labor and poor posture of the hands, such as riding a bicycle, kneading dough, washing clothes, etc., or long-term use of both hands to carry objects, long-term use of the mouse, etc., will cause the median nerve to be compressed in the wrist, and numbness and weakness will appear in the three and a half fingers on the thumb side (thumb, index finger, middle finger and half of the ring finger), which will worsen at night. Nerve conduction testing is the gold standard for diagnosing carpal tunnel syndrome. Through nerve conduction testing, we can observe that the conduction velocity of the sensory fibers and motor fibers of the median nerve is slowed down and the amplitude is reduced. For carpal tunnel syndrome, early diagnosis and treatment are very important to avoid sequelae.

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2. Cubital Tunnel Syndrome

Another common single nerve damage disease that causes numbness in the hands is cubital tunnel syndrome, also known as "tennis elbow." It is more common in people who work with their elbows bent for a long time or sleep with their elbows resting on their heads. In this case, the elbow is overloaded, which can cause compression of the ulnar nerve that runs in the ulnar nerve groove of the elbow, resulting in chronic damage. Symptoms include numbness and weakness of one and a half fingers on the little finger side. Similarly, nerve conduction testing is the gold standard for diagnosing elbow compression. Through nerve conduction testing, we can observe that the conduction velocity of the sensory fibers and motor fibers of the ulnar nerve above and below the elbow is slowed down and the amplitude is reduced. Early diagnosis and treatment are also crucial for elbow compression.

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3. Damage to the common peroneal nerve

The most common single nerve damage disease that causes foot numbness is damage to the common peroneal nerve, which is common in office workers who sit for long periods of time and often cross their legs. Symptoms include foot drop and numbness of the instep. Nerve conduction testing shows that the sensory and motor fibers of the common peroneal nerve below the peroneal head have slower conduction speeds and lower amplitudes.

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4. Diabetic peripheral neuropathy

In my country, there are a large number of diabetic patients, but most people may not be aware of diabetes-related peripheral neuropathy until they experience symptoms such as numbness in the hands and feet. In this case, electromyography can play a key role.

Peripheral neuropathy caused by diabetes is called diabetic peripheral neuropathy (DPN). 60% to 90% of diabetic patients will experience peripheral neuropathy, which manifests as numbness, pain, and weakness in the limbs. In severe cases, there may be loss of mobility. Literature reports that peripheral neuropathy will occur after 5 years of diabetes.

Electromyography can help determine if DPN is present and assess its severity. In the early stages of DPN, the EMG may show slowed sensory nerve conduction velocity and reduced amplitude. As the disease progresses, the EMG can also show muscle inactivation and changes. Through EMG, doctors can diagnose and monitor the progression of DPN early and take appropriate treatment measures to alleviate symptoms and avoid complications.

5. Chronic alcoholic peripheral neuropathy

my country has a long history of drinking culture, and many people love to drink. However, the problems caused by long-term drinking are gradually emerging. Alcohol is not only harmful to the liver and other organs, but also can damage the peripheral nervous system. Alcoholic peripheral neuropathy is one of the common diseases, characterized by numbness, pain and weakness in the limbs.

Electromyography (EMG) nerve conduction testing is one of the best ways to diagnose alcoholic peripheral neuropathy. Through EMG examination, 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. Therefore, EMG nerve conduction testing plays an important role in the management of alcoholic peripheral neuropathy. It can help doctors diagnose and monitor the progression of the disease in a timely manner, so as to develop personalized treatment plans and improve the quality of life of patients.

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In addition to the above diseases, some other potential causes may also cause numbness in the hands and feet, such as vitamin deficiency, side effects of drugs, environmental poisoning, etc. Electromyography can help rule out other possible causes, ensure a correct diagnosis, and guide subsequent treatment plans.

In short, EMG plays an important role in the diagnosis of peripheral nerve damage symptoms such as numbness in the hands and feet. It can help determine whether there is nerve damage and the severity of the damage, and guide doctors to develop appropriate treatment plans. If you experience persistent numbness in the hands and feet, please don't worry, consult a doctor as soon as possible and undergo an EMG examination to decipher the truth behind the symptoms and take appropriate measures to protect nerve health.