Electro-neurodiagnostic tests

Electroencephalogram (EEG)

An electroencephalogram is a test used to measure the brain's electrical activity. Electrodes are placed on the head and connected by wires to a computer. These detect and record brain waves on a digital computer. An EEG can help diagnose seizures, sleep disorders, dementia and other neurological conditions. There are several types of EEGs, including sleep deprived, 24-hour ambulatory, routine and long-term EEG monitoring. EEG monitoring is used to monitor brain activity and predict outcomes for patients who have experienced a cardiac arrest, especially those in a coma.

Evoked response

An evoked response test measures the length of time it takes for nerves to respond to stimulation. Electrodes are attached to the head to record brain waves. In a visual evoked response test, looking at test patterns stimulates a patient's eyes. In a brainstem auditory evoked response test, the patient's hearing is stimulated with test tones. Both tests are used to diagnose multiple sclerosis, as well as other abnormalities in optic or auditory nerves. In the operating room, further monitoring can be provided to watch a patient for any changes during some neurosurgeries.

Nerve conduction

A nerve conduction test measures how well the nerves send electrical signals to the muscles. These signals control the way muscles react. Slow or broken signals can cause the muscles to weaken or malfunction. In this test, electrodes are attached to the skin - one to release a small electrical pulse into the nerve and another to record the muscle's response. Nerve conduction tests can help diagnose muscle and nerve problems such as muscular dystrophy or carpal tunnel syndrome. Doctors perform nerve conduction tests at the hospital or in the neurologist's office.