My hands and feet are dull, numb, and burning, why is the test result normal?
Jun 15, 2025
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The diagnosis of peripheral neuropathy utilizes neuroconductivity (NCS) and electromyography (EMG). The nerve conduction test is a test that measures the conduction speed and potential size of the peripheral nerve by applying electrical stimulation to the skin along the path of the peripheral nerve, and can determine the location and degree of damage to the damaged nerve. Electromyography is a test that measures the electrical activity of the muscle by inserting needle electrodes into the muscle. It is possible to check the condition of the nerve-dominated muscle and determine whether the muscle is denatured due to nerve damage.
However, even if the symptoms of peripheral neuropathy are correct, the results may be normal if the above tests are performed in the acute phase. Immediately after nerve damage, the neurophysiological changes may not be clear enough to be detected by the test. This depends on the type of damage, the speed of disease progression, and the timing of the examination.
If the nerve is damaged by trauma, at least five days after the injury (more than seven days in the case of sensory nerves) must elapse before abnormalities in the rate of nerve conduction begin to appear. Within 1 to 3 days immediately after the damage, the conduction result may look normal.
In consideration of this, when nerve damage is clinically suspected, additional imaging tests such as peripheral nerve ultrasound or MRI are performed to determine the location and degree of damage.
Even in the case of peripheral nerve diseases with only microfiber nerves or autonomic nerves, the test results may be normal. This is because the nerve conduction test is a test that mainly measures the function of nerve fibers wrapped in a membrane called myelin. In addition, fibromyalgia, rheumatoid disease, and complex pain syndrome are accompanied by numbness in the form of neuralgia if they last for more than three months, but there is no pathology of the peripheral nerve itself, so even if the test is performed, it will be normal.
In general, two to three weeks after peripheral nerve damage, the typical change of the lesion is evident in the nerve conduction test, and spontaneous potential is also observed in the electromyography test, so it is the time of the test with high diagnostic value.
However, the key to treating peripheral neuropathy is to find the cause, prevent it from worsening further, and properly control the symptoms. Therefore, in actual treatment, rather than waiting for nerve damage by artificially delaying the test period for diagnosis, the test is performed first, and the treatment plan is made after comprehensive interpretation in light of the test timing, the timing of the disease, and clinical symptoms.
Son Seong-yeon, head of the neurology department at Ceran Hospital, said, "Even if the acute test results are normal, peripheral neuropathy is not excluded, and if the clinical possibility of damage to the peripheral nerve is high, a re-test is required after two to three weeks." "Later-stage neuropathy should be interpreted and diagnosed by comprehensively considering clinical symptoms, progression speed, underlying diseases such as diabetes, and the timing of the test from the time of occurrence.", he explained.
Director Son Seong-yeon said, "If symptoms of end-of-stage neuropathy persist, it is recommended to determine the treatment direction and perform follow-up tests for the purpose of determining prognosis."Since end-of-life neuropathy is a common disease and greatly hinders daily life, it is better to objectively evaluate whether the disease does not progress or spread, and plan long-term treatment directions rather than neglecting the symptoms.'
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This article was translated by Naver AI translator.
