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What is Neurophysiology?

Clinical Neurophysiology is a medical specialty that studies the central and peripheral nervous systems through the recording of bioelectrical activity. The major diagnostic tests include EEG, EMG, and NCS.


Tests to Determine an Accurate Diagnosis and Treatment Plan


EMG (Electromyography) & NCS (Nerve Conduction Studies) are tests used to detect nerve and muscle disorders, which include symptoms such as muscle weakness, numbness, spasms, paralysis, and pain. They can also determine if the problem is related to nerves, muscles, or the spinal cord. EMG & NCS are often performed in the same appointment. They monitor and detect changes in electrical activity in nerves and muscles and help diagnose:

  • Pinched Nerves and Inflamed Muscles due to injury, ruptured disk, disease, or other conditions
  • Carpal Tunnel Syndrome pressure on a nerve causing pain in wrist or hand
  • Primary Muscle Disorders such as muscular dystrophy
  • Neuromuscular Disorders such as myasthenia gravis, which causes chronic muscle weakness
  • Motor Neuron Disorders such as Lou Gehrig’s disease

EEG An EEG (Electroencephalogram) is a test used to evaluate the electrical activity in the brain. Brain cells communicate with each other through electrical impulses, so an EEG is used to detect problems associated with that activity. EEG records patterns of brain activity and helps diagnose:

  • Several types of brain disorders. When epilepsy is present, seizure activity will appear as rapid spiking waves on the EEG.
  • Lesions of the brain, which can result from tumors or stroke
  • Disorders that influence brain activity, such as Alzheimer’s disease, certain psychoses, and narcolepsy
  • Overall electrical activity of the brain to evaluate trauma, drug intoxication, or extent of brain damage in comatose patients


What to Expect

EMG – One or more needle electrodes are gently inserted into the muscle. You may feel a dull ache or pressure. Other electrodes are attached to your skin. The muscle is tested at rest and while contracted. You may feel slight tenderness or soreness in areas tested for a few hours.

NCS – Recording electrodes are attached to your skin and stimulating electrodes are placed against your skin. A tiny electrical impulse is sent through your nerves. Responses are recorded. You may feel slight tingling during the procedure, but there aren’t any post-test side effects.

EEG – Electrodes will be attached to your scalp and your brain waves will be recorded. It is a painless procedure that usually takes up to 30 minutes. There aren’t any post-test side effects.


Frequently asked questions

  • Does it hurt? EMG or NCS tests cause a slight level of temporary discomfort. An EEG is painless. Anesthesia or sedatives are not necessary for these tests.
  • Are there risks involved? No, but people with certain medical conditions may face increased risks. Be sure to talk to your healthcare provider about all risks and benefits.
  • How effective are these tests? Very. These tests can help your healthcare provider make an accurate diagnosis and effective treatment plan for you.


How to prepare for testing

Avoid alcohol on the day of your test. Tell your healthcare provider about all medications you are currently taking.

EMG & NCS – Avoid tobacco a few hours before your test, wearing comfortable, loose fitting clothing, not using any lotions or creams the day of your test, and eating as you normally would.

EEG – Avoid caffeine on the day of the test, washing your hair the night before of day of the test but not using hair products (cream, spray, gel or oil), and not sleeping for a minimum of 24 hours before the test if you are instructed to be sleep deprived.


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