Neurological Testing

Botulinum Toxin (Botox) Injection
This is a procedure performed to alleviate a variety of neurological conditions such as spasticity, torticollis, hemi facial spasm, blepharospasm, and occupational cramps (e.g., writer’s cramp). A very small amount of toxin is injected directly into the involved muscle(s). The procedure takes ½ to 1 hour and is only a little uncomfortable. Side effects are minimal but can include bruising or infection from the needle and less than 24 hours of generalized malaise. Of note, the muscles injected will become weakened in about 5-7 days. The weakness is designed to reduce the activity of the overactive muscle(s). In some cases, insufficient weakness may require a reinjection and in some cases, excessive weakness may temporarily interfere with the injected muscle’s functioning. There is also the risk of toxin spreading to adjacent muscles and making them weak as well. However, all weakness is temporary as the effect of Botox lasts for about 3 months. If the effect is beneficial, repeated injections will be recommended.

Computerized Tomography (CT)
Computerized tomography is a way to take a picture of the brain using x-rays. The test takes about 30 minutes. It may require an intravenous line (IV) if your doctor ordered the administration of a contrast agent to enhance the pictures.

Electroencephalography (EEG)
This test records brainwaves and may be able to diagnose conditions such as epilepsy. The recordings are obtained from electrodes pasted to the scalp. The test takes about 1 hour and is painless. You may be asked not to sleep the night prior to the test. Several procedures may be used to enhance the test, including hyperventilation, sleeping, and exposure to a flashing light with eyes closed.

Nerve Conduction Studies/Electromyography (EMG)
This test determines whether there is a problem with muscles or nerves. It can help diagnose very diverse disorders, such as carpal tunnel syndrome, a pinched nerve in the neck or back, or very serious conditions such as Lou Gehrig’s disease (ALS). The test has 2 parts. During the nerve conduction studies, small electrical impulses are delivered to the arm or leg. During the electromyography, a small needle will be inserted into different muscles. The test takes 1 to 2 hours depending on the complexity of the problem and is usually very well tolerated; the impulses and needles can be uncomfortable.

Evoked Potentials (EP)
These tests determine whether there is a problem with conduction in the nervous system. Each test takes about 1 hour.

Brainstem Auditory (BAEP)
A clicking noise is heard through headphones and recordings are obtained from electrodes pasted to the scalp.

Somatosensory (SSEP)
Electrical impulses are delivered to the arm or leg and recordings are obtained from electrodes pasted to the skin and scalp. The impulses can be uncomfortable.

Visual (VEP)
A flashing checkerboard pattern is displayed and recordings are obtained from electrodes pasted to the scalp.

Lumbar Puncture or Spinal Tap
This test is performed by obtaining a specimen of the fluid that surrounds the brain and spine. It is done to check for infection, bleeding, or inflammation in the nervous system. During the test, a thin hollow needle is placed into the space that contains the fluid and the fluid is removed via this needle. This test is somewhat uncomfortable. It takes about ½ hour, but you may be asked to lie flat for several hours after the test. There is a very small risk of persistent headache after the test, which would require a blood patch placed by an anesthesiologist. There is an extremely small risk of bleeding or infection due to the needle.

Magnetic Resonance Imaging (MRI)
Magnetic resonance imaging is a way to take a picture of the brain using magnetic fields. There is no radiation. The test takes 30 minutes to 1 hour. It may require an intravenous line (IV) if your doctor ordered the administration of a contrast agent to enhance the pictures. The test is generally very well tolerated except if you are particularly claustrophobic; if this is the case, your doctor may prescribe a medication to help you relax. If you have any metal in your body other than dental fillings, you should inform your doctor prior to the test, because it utilizes a very strong magnet.

Positron Emission Tomography (PET Scan)
A computerized scan of the brain is obtained after injecting a radioactive isotope into a vein. This test maps the physiological, biochemical and hemodynamic processes of the brain. It is used in selected cases of epilepsy, dementia and brain tumors.

Sleep Studies (Polysomnogram, Multiple Sleep Latency Test)
These tests record brain and body function during sleep and may be able to diagnose a variety of conditions associated with sleep such as sleep apnea and narcolepsy. The recordings are obtained from electrodes pasted to the scalp, face, chest and legs. These tests may require spending the night sleeping in the laboratory.

Visit National Institute of Neurological Disorders and Stroke for more information about these or other Neurological Tests.