Electromyography

From WikiMD's Wellness Encyclopedia

Electromyography (EMG) is a diagnostic procedure used in medical practice to evaluate and record the electrical activity produced by skeletal muscles. This technology plays a significant role in detecting neuromuscular diseases, assessing muscle performance, and helping design rehabilitative therapies.

EMG - SIMI

Introduction[edit | edit source]

Electromyography provides a way to measure the electrical signals that muscles produce when they are at rest and when they contract. It can provide valuable data for diagnosing a variety of disorders affecting muscles or nerves.[1]

Procedure[edit | edit source]

During an EMG, fine needles or electrodes are inserted into a muscle to record electrical activity. The procedure can cause minor discomfort or pain. The electrodes detect the electrical signals your muscles send when at rest and when contracted. These signals are amplified and appear on a device called an oscilloscope in the form of waves. They are also heard on a speaker as crackling sounds when the muscle contracts.[2]

Types of Electromyography[edit | edit source]

  • There are two primary types of EMG:
  • Surface EMG: This non-invasive technique uses electrodes placed on the skin over the muscle being tested.
  • Intramuscular EMG: This involves inserting a needle electrode through the skin into the muscle tissue.[3]

Clinical Applications[edit | edit source]

  • EMG is used in the diagnosis of various neuromuscular disorders, such as:
  • Neuromuscular diseases: Including amyotrophic lateral sclerosis (ALS), myasthenia gravis, and Guillain-Barré syndrome.
  • Peripheral nerve injuries: Including carpal tunnel syndrome or peripheral neuropathy.
  • Muscular disorders: Including muscular dystrophy or polymyositis.[4]

Risks and Contraindications[edit | edit source]

While EMG is a relatively safe procedure, it may cause temporary discomfort or pain. Rarely, minor bleeding can occur at the needle insertion sites. Individuals with bleeding disorders or those taking anticoagulant medication should be evaluated carefully before undergoing an EMG.[5]

See Also[edit | edit source]

References[edit | edit source]

  1. Preston, D. C., & Shapiro, B. E. (2013). Electromyography and Neuromuscular Disorders. Elsevier Health Sciences.
  2. Boon, A. J., Smith, J., & Harper, C. M. Jr. (2008). Needle electromyography. In Physical Medicine and Rehabilitation Clinics of North America, 19(2), 361-78.
  3. Merletti, R., & Parker, P. A. (2004). Electromyography: Physiology, Engineering, and Non-Invasive Applications. Wiley-IEEE Press.
  4. Dillingham, T. R., & Chen, S. (2020). Electromyography in Neuromuscular Disorders. In Physical Medicine and Rehabilitation Clinics of North America, 31(1), 1-12.
  5. Al-Lozi, M. T., Pestronk, A., & Yee, W. C. (1998). Routine nerve conduction studies and electromyography in patients on anticoagulants. Muscle & Nerve, 21(11), 1528-1530.
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