• EMG involves two primary methods:

  1. Needle EMG: Thin, sterile needles (electrodes) are inserted into specific muscles. The electrodes detect the electrical activity generated by muscle fibers during rest, slight contraction, and forceful contraction. These signals are recorded and analyzed for abnormalities.

  2. Surface EMG: In some cases, surface electrodes are placed on the skin to detect electrical signals in larger muscle groups. This method is less invasive but offers less precision compared to needle EMG.

EMG provides two main types of information critical to the process.

• Spontaneous Activity: Normally, muscles do not produce electrical signals when at rest. If electrical activity is detected during rest, it may indicate nerve or muscle damage, as seen in conditions like denervation or myositis.
• Motor Unit Potential (MUP): During contraction, the motor unit (nerve and the muscle fibers it innervates) generates electrical signals. The size, shape, and pattern of these signals provide information about the health of the muscle and its corresponding nerve.

EMG is instrumental in diagnosing a wide range of neuromuscular disorders, including:

• Peripheral Neuropathies: Such as carpal tunnel syndrome, where the median nerve is compressed, causing pain, numbness, and muscle weakness.
• Radiculopathy: Compression or irritation of spinal nerve roots, often due to herniated discs or spinal stenosis, which affects muscle function and causes pain or numbness in a specific dermatome.
• Motor Neuron Diseases: Such as amyotrophic lateral sclerosis (ALS), where nerve cells that control muscle movement degenerate, leading to progressive muscle weakness and wasting.
• Muscle Disorders (Myopathies): Such as polymyositis and muscular dystrophy, where muscle fibers become inflamed or degenerate, resulting in weakness.
• Neuromuscular Junction Disorders: Including myasthenia gravis, where communication between nerves and muscles is disrupted, causing muscle fatigue and weakness.

• Avoid using lotions or creams on your skin, wear loose clothing, and inform your doctor about any medications you are taking, especially blood thinners. Refrain from caffeine or nicotine for a few hours before the test. Mention any medical conditions like pacemakers or bleeding disorders.

Although the electrical stimulation may startle you initially, it isn’t painful.
The shock feels similar to a shock you experience from static electricity, or it may feel like a mild tingling. Most people can complete the test without issues.

The test usually takes between 30 to 60 minutes, depending on the number of muscles being tested and whether it’s combined with Nerve Conduction Studies (NCS).

In most cases, your doctor will review the results with you shortly after the test, or the findings will be sent to your referring physician within a few days. Interpretation of the results will help guide diagnosis and treatment.

Yes, EMG does not require sedation, so you can drive home after the procedure and resume normal activities.

EMG is a quick, outpatient procedure that generally doesn’t require assistance. However, if you’re anxious or uncomfortable with the procedure, you may want to bring someone for support.

EMG measures electrical activity in muscles, while Nerve Conduction Studies (NCS) evaluate how well and how fast electrical signals travel through your nerves. They are often performed together to get a complete picture of nerve and muscle function.

EMG is generally safe for individuals with pacemakers or other devices, but you should inform your doctor about these implants to ensure proper precautions are taken.