Nerve Conduction Velocity Tests for Upper and Lower Limbs

"Measurement of Motor Nerve Conduction Velocity in Upper and Lower Extremities" examination?

Dear Dr.
Lin,
Thank you for your detailed explanation regarding the electromyography (EMG) and nerve injury during my last visit.
I went to the neurology department for an EMG examination due to slight tremors in my right thumb and mild twitching in the muscles of my right upper arm.
The cervical X-ray taken at the hospital ruled out the possibility of cervical degeneration.
The EMG results indicated signs of nerve injury in my limbs, leading to further testing for "motor nerve conduction velocity of the upper and lower limbs." Today, I reviewed the report for this test with the neurologist, who informed me that my motor nerve conduction velocity is normal.
Additionally, I had experienced involuntary muscle twitching in various parts of my body (such as my right thigh, right calf, and knee) in recent days.
Following your advice to engage in regular exercise, I have seen significant improvement (with a reduction in frequency and intensity).
Occasionally, when sleeping on my right side with my knee bent, I notice some twitching in the muscles of my right knee.
The hospital physician advised that for involuntary muscle twitching: 1.
If it occurs frequently, hospitalization for further examination is recommended; 2.
If it improves, no further hospital visits are necessary.
Therefore, I have a few questions for you, Dr.
Lin:
1.
Based on the above, am I simply experiencing nerve damage due to nerve compression or trauma, similar to most people? Besides regular exercise, what other precautions should I take in my daily life to enhance my health?
2.
Given the results from the EMG and motor nerve conduction velocity tests, can we currently rule out the possibility of neurological diseases? (Even though there are occasional involuntary muscle twitches.)
3.
What factors could influence the twitching of the muscles in my right knee? Is it related to nerve conduction in the brain and spinal cord? Also, do the nerves assessed in the motor nerve conduction velocity test of the upper and lower limbs include those related to the brain and spinal cord?
Thank you for taking the time to clarify these matters for me!

Fang, 30~39 year old female. Ask Date: 2008/03/25

Dr. Lin Zijing reply Neurology

According to what you described, your muscle twitching may be simple localized fasciculations, which are not a disease and will improve on their own.
However, since this phenomenon can also be an early symptom of some motor neuron diseases, it is important to monitor its progression.
If the twitching gradually increases and is accompanied by muscle atrophy and weakness, slurred speech, or even difficulty swallowing, it could indicate a motor neuron disease.
Diagnosis can be made through continued monitoring of nerve conduction studies and electromyography, as some degenerative neurological diseases may take time to manifest and can be difficult to detect in the early stages.
Regular exercise and a balanced diet are essential for good health.
Muscle contraction is initiated by signals from brain neurons that travel through the spinal cord to peripheral nerves and then to the muscles to complete the contraction.
Therefore, involuntary twitching is usually caused by increased activity in these tissues, and it may also be due to a deficiency of calcium ions leading to involuntary muscle contractions.
The nerve conduction studies assess peripheral nerves and do not include the nerve conduction of the brain and spinal cord.
Muscle twitching caused by lesions in the brain and spinal cord typically occurs in a confined group of muscles, and in your case, it seems unnecessary to conduct these tests.
Thank you.

Reply Date: 2008/03/25

More Info

Understanding nerve conduction velocity (NCV) tests is crucial for diagnosing various neurological conditions, particularly those affecting the peripheral nervous system. In your case, the NCV test results indicated that there were no issues with the conduction speed in your upper and lower limbs, which is a positive sign. This suggests that the peripheral nerves are functioning properly, and there is no significant demyelination or axonal damage present.

1. Regarding Your Symptoms: The involuntary muscle twitches you are experiencing, particularly in your right thigh, calf, and knee, could be attributed to benign fasciculations. These are often harmless and can occur due to various factors such as stress, fatigue, or even caffeine intake. They are not necessarily indicative of a serious neurological condition, especially since your NCV and electromyography (EMG) tests did not reveal any significant abnormalities. However, if these twitches become more frequent or are accompanied by other symptoms such as muscle weakness, atrophy, or changes in sensation, it would be prudent to seek further evaluation.

To enhance your overall health, in addition to regular exercise, consider maintaining a balanced diet rich in vitamins and minerals, particularly B vitamins, which are essential for nerve health. Staying hydrated and managing stress through relaxation techniques or mindfulness can also be beneficial.

2. Exclusion of Neurological Diseases: While your NCV and EMG results are reassuring, they do not completely rule out the possibility of neurological diseases. Some conditions may not present with immediate changes in nerve conduction or may take time to manifest. For instance, early-stage motor neuron diseases can sometimes show normal NCV results. Continuous monitoring of your symptoms is essential. If you notice any progression or new symptoms, it would be wise to consult your healthcare provider for further assessment.

3. Factors Affecting Muscle Twitches: The involuntary muscle movements you are experiencing can be influenced by several factors, including electrolyte imbalances (such as low calcium or magnesium), dehydration, or even overexertion of the muscles. These twitches are typically benign and can occur without any underlying neurological issues. However, they can also be related to the central nervous system if they are localized and persistent. The NCV test primarily assesses the peripheral nerves and does not evaluate the central nervous system directly, which includes the brain and spinal cord. If there are concerns about central nervous system involvement, additional imaging studies or tests may be warranted.

In summary, your NCV results are encouraging, and the muscle twitches you are experiencing may not be a cause for concern at this time. However, it is essential to remain vigilant and monitor any changes in your symptoms. Regular follow-ups with your healthcare provider will help ensure that any potential issues are addressed promptly. Maintaining a healthy lifestyle through diet, exercise, and stress management will also contribute positively to your overall neurological health.

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