Common Neurological Tests

Image or sound wave tests

Computerized tomography or computer assisted tomography (CT or CAT scan)
This test uses x-rays and computers to create two-dimensional pictures of selected body parts. Dye may be injected into a patient's vein to obtain a better picture. Other than needle insertion for the dye, this test is painless.

Magnetic resonance imaging (MRI)
An MRI is an advanced way of taking pictures of the inner brain. It is harmless and involves magnetic fields and radio waves. It is performed when a patient is lying in a small chamber for about 30 minutes. Because MRI utilizes a very strong magnet, if you have metal in your body other than dental fillings, notify your physician. Be sure to tell your physician if you suffer from claustrophobia (fear of closed areas). A physician can offer recommendations that can help you relax. This test is painless.

Electrical activity or response tests

Nerve Conduction Studies
NCSs test how well signals travel along a nerve and can help find the cause of abnormal nerve function. Signals are made to travel along the nerve by applying small electric pulses to the nerve at one site and recording the response at a different place along the nerve. The small electric pulses cause a short, mild tingling feeling. The nerve's response is picked up by a recording instrument and then is measured by the physician or technologist performing the test. Several nerves may need to be tested depending on the type of problem.

Needle Examination (EMG or electromyogram)
During the needle EMG portion of the examination, the physician inserts a small needle into a muscle to record the electrical activity of the muscle. The electrical activity of the muscle is fed into the recording instrument and the physician then analyzes it by looking at a signal on the scope and listening to the sounds the activity makes through the speaker. This test can help determine if there are abnormalities in the muscle or the nerve going to it.

There may be mild discomfort when the need is inserted into the muscle. The needles are discarded after use to prevent the transmition of infections.

• Special Precautions
  You should inform the physician prior to the examination if you are on blood thinners or have hemophilia. The physician should also be informed if you have a cardiac pacemaker or use a transcutaneous electrical nerve stimulator(TENS) unit. Avoid using skin lotions the day of the test. If you have myasthenia gravis you should ask your physician whether or not to take medications, such as Mestinon, before the examination.

• Results
  When the examination is completed, the eclectrodiagnostic medicine consultant will analyze the results and report them to the physician who referred you for the tests. Your referring physician will use the test results to help decide on proper managment.

Electroencephalography (EEG)
EEG measures the electrical activity of the brain.  It is primarily used in the evaluation of seizures and other transient alterations of awareness and consciousness.  Activity of the brain is passively recorded, no electrical stimulation is given.  The test typically takes 20-30minutes.  You may be asked to take deep breaths and may be exposed to flashing lights during the EEG.  Once the technician completes the recording, a physician will review the test and send a report to your doctor.

Sleep studies
Involve tests that diagnose specific causes of sleep problems. To perform the tests, it is often necessary for a patient to spend the night in a sleep laboratory. Brain wave activity, heart rate, electrical activity of the heart, breathing and oxygen in the blood are all measured during the sleep test. The test is painless.

Another common test

Cerebral spinal fluid analysis (Spinal tap or lumber puncture)
This test is used to check for bleeding, hemorrhage, infection or other disorder of the brain, spinal cord and nerves. In this test the lower back is numbed with local anesthesia, and a thin needle is placed into the space that contains the spinal fluid. The amount of spinal fluid needed to diagnose the specific problem is removed and the needle is withdrawn. Discomfort may be associated with this test.