Neurophysiology

Electromyography (EMG) & Nerve conduction studies (NCS)

Electromyography & Nerve Conduction Studies are electro-diagnostic procedures to examine your nerves and muscles. It is normally a two-part procedure that consists of nerve conductive studies and an electromyogram (EMG) for electrical muscle testing.

Nerve conduction studies 

Nerve conduction studies are performed by taping electrodes on the skin. These electrodes send miniscule electrical current through the skin. While slightly strange, the procedure is not painful at all. The measurements are then recorded of how fast the nerves transmit messages. 

Electromyogram

The electrical activity in muscles is tested by inserting a fine needle electrode into the muscle. The electrode then picks up the electricity normally present in the muscle, allowing for a digital and audible display.

Patients are advised to refrain from using lotion or oil prior to the test as the Skin must be clean and dry. An EMG test is safe for patients with pacemakers, stimulators and blood thinners. Patients taking Coumadin should have a recent INR.

You may take prescribed pain medication on the day of the test.

Electromyogram (EMG): Useful for diagnosis of neurogenic conditions like radiculopathy, brachialplexopathy, and muscle disease.

  • Nerve Conduction Studies (NCS): Useful for diagnosis of nerve diseases like carpal tunnel syndrome, peripheral neuropathy due to diabetes and other causes.
  • Repetitive Nerve Stimulation Study (RNS): Useful for diagnosis of myasthenia gravis and neuromuscular transmission defects.
  • Facial nerve conduction Study with blink reflex.

Electroencephalogram (EEG) 

The EEG is a recording device that tracks your brain's electrical activity by placing electrodes on your scalp. The test is painless, safe, and takes approximately one hour to complete. The EEG can assist in the diagnosis of a variety of neurological problems from the common headache to seizure disorders, strokes, and degenerative brain disease. 

EEG Instructions

Please read the following instructions prior to your appointment:

Hair must be freshly washed, clean, and dry within 12 hours of the test.

  • Don’t use hair products or braid your hair.
  • You must eat within two hours of your appointment. For example, if your appointment is at 9 a.m., please eat between 7 and 9 a.m. If your appointment is later in the day, please eat a snack before your appointment.
  • Sleep deprivation, if advised, is a partial sleep deprivation. This means that you can sleep only for 3-4 hours on the night prior to the test. Another way to do that is to sleep 2 hours later and wake up 2 hours earlier than your usual sleep schedule on the night prior to the test.
  • Partial sleep deprivation is done because the test requires the patient to sleep briefly during the EEG.
  • Electroencephalography (EEG): For evaluation of seizure disorder.
  • Visual Evoked Potential Study (VEP): Useful for diagnosis of optic nerve diseases like multiple sclerosis.
  • Brainstem Electric Response with Audiometry (BAER, BERA): Useful for evaluation of auditory function.
  • Somatosensory Evoked Potential Study (SSEP): Useful for diagnosis of conditions like myelopathy; e.g. due to Vitamin-B12 deficiency, intervertebral disc disease, etc.
  • Intraoperative Neuro-monitoring: In high risk surgery; eg- scoliosis.

Dr. Poornima Shah

MD (PAED), INTERNATIONAL DIPLOMATE OF AMERICAN BOARD OF CLINICAL NEUROPHYSIOLOGY Area of Expertise: Clinical Neurophysiology

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