Neurological Tests

A general neurological exam assesses seven different parts of your body that may have been affected by your condition.

• Mental Status exam checks to see if you are aware and responsive to your surroundings, and assesses your mood and general behavior.
• Cranial Nerve exam looks at the nerves that relay messages between the brain and the head and neck.
• The Motor System exam includes the brain and spinal cord, and all the nerves that control muscles throughout the body.
• The Sensory System exam includes assessing how you see, smell, taste, and touch. Your doctor or healthcare provider may check if you have any pain, sensitivity to temperature or pressure.
• The Deep Tendon Reflexes of your knees and elbows assess muscle strength.
• Coordination and voluntary movements may be evaluated.
• Gait evaluation, or how you walk, can assess muscles and coordination.

Nerve conduction studies use flat sensors placed on the skin to measure the electrical activity of peripheral nerves. In nerve conduction studies, an electrical signal is sent from one sensor to another and a computer records how fast the signal travels. If the electrical signal is slowed down it may mean the nerve is damaged. This test will tell your healthcare team where nerve damage has occurred, and is used to evaluate conditions such as carpal tunnel syndrome, sciatic nerve problems, pinched nerves, and Guillain-Barré syndrome, in which the body's immune system attacks part of the peripheral nervous system causing weakness or tingling sensations in the legs.

An EMG test looks at the electrical impulses made by muscles. Special needles are placed through the skin into the muscle to record activity when the muscles move. This test is used to look for conditions such as amyotrophic lateral sclerosis (ALS), muscular dystrophies, nerve dysfunction, and diseases that cause muscle weakness or paralysis such as myasthenia gravis that causes fluctuating weakness in muscles, or Lambert-Eaton syndrome in which the immune system attacks the connection between nerves and muscles (the neuromuscular junction) and interferes with the nerve cells’ ability to send signals to muscle cells.

The somatosensory evoked potential is a test that measures the sensory nerve signals sent to the brain in response to physical stimulation, such as when a person is touched. To perform the test, electrodes are placed along various parts of the body, typically the arms, legs, back, neck, and head. The electrodes record responses which are observed as a reading on an electroencephalogram (EEG). A doctor or your healthcare team may recommend an SSEP test if a person has been experiencing numbness or weakness in their arms or legs. This test helps your care team identify conditions such as multiple sclerosis (MS), which can damage the myelin sheath insulating nerve fibers of the brain and spinal cord. The damage may cause the signal to take a longer time to be sent to your brain, or the signals may be blocked. There are no risks associated with the test, but some people may feel slight discomfort.

The VEP test measures the nerve signal sent from your eyes to brain in response to light stimulus to identify how well your vision system is working. Electrodes are place on certain places on the forehead and scalp, and visual stimuli come from a computer screen in different patterns and contrasts. The test measures how well a person may see in the central area of their field of vision, but is not a good way to measure peripheral vision problems. Your doctor or healthcare provider may request this test for patients who have been experiencing loss of vision, double vision, blurred vision, or weakness of the eyes. There are rarely any side effects from the test, which is painless; minor skin irritation from the electrodes may occur.

Autonomic testing is an umbrella term that describes testing of the nerves whose work is done “automatically” by themselves, and are not in response to a specific physical movement or conscience thought. Autonomic nerves control involuntary actions such as your heart beating, your breathing, or sweating. Using automated devices, these tests include measuring changes in heart rate, blood pressure, and breathing in response to certain tests such as lying on a table that is tilted, or trying to exhale when your mouth and nostrils are closed. Your doctor or healthcare provider may request one or more of these tests if a person has been experiencing dizziness, unusually low blood pressure, blood pressure that increases when lying down, or peripheral neuropathy.

Sleep testing may be performed when a person suffers from one or more of the following sleep disorders:

• Circadian rhythm disorders that affect a person’s natural biorhythms and sleep/wake cycle.
• Hypersomnias which can cause a person to be excessively sleepy during the day.
• Insomnias that interrupt natural sleep.
• Parasomnias such as abnormal movements, behaviors, emotions, perceptions, or dreams that occur while falling asleep, sleeping, or waking up.
• Sleep breathing disorders such as snoring, obstructive sleep apnea, or sleep related groaning.
• Sleep movement disorders such as clenching or grinding your teeth in your sleep (bruxism), sleep leg cramps, or restless leg syndrome.

Sleep tests allow your doctor or healthcare provider to monitor you and measure changes that occur in your brain and body while you sleep. EEG electrodes are placed on your head and body to monitor both your sleep stages and the sleep cycles (REM and nonREM) that you go through during the night. The results of these tests help your healthcare team to identify possible disruptions in the pattern of your sleep. Sleep tests are not invasive, and are done in a dark room that is designed to be comfortable.

Common sleep tests include:

• Polysomnogram test that records body functions during sleep such as, heart rate and rhythm, breathing rate and rhythm, brain activity, and eye movement.
• Multiple sleep latency test (MSLT) that measures how long it takes you to fall asleep and whether you REM sleep.
• Maintenance of wakefulness test (MWT) that measures whether you can stay awake during a time when you should normally be awake.

• Computerized tomography (CT) takes series of special x-rays of your whole body or just a part of your body from many different angles. A computer combines the x-rays to make images that show detail of bones, blood vessels, muscles, fat, and internal organs.
• CT scans of the brain can provide information about brain tissue and brain structures better than standard x-rays.
• This test is used to detect tumors, abscesses, abnormal blood vessels, internal injuries, internal bleeding, or to diagnose injuries or diseases in the brain.
• CT scans involve the use of radiation, which should be minimized over the patient’s lifetime.

• Magnetic resonance imaging (MRI) uses a large magnet and radio waves to create pictures of structures inside your body like bones and organs.
• These scans are very good at telling the difference between normal and abnormal tissues.
• MRI is used to diagnose a variety of conditions such as brain and spinal cord tumors, eye disease, inflammation, infection, and vascular (blood vessel) irregularities that may lead to stroke.
• MRI scans are also used to detect and monitor disorders that progress over time such as multiple sclerosis.
• Some patients may find standard MRI machines to be confining and claustrophobic; newer “open” MRI machines are available and may help reduce the feeling of confinement.
• No radiation is used in this type of imaging.

• Positron emission tomography (PET) uses a radioactive substance, called a radionuclide, to show how certain parts of your body are working.
• This type of scan is used to evaluate the biological processes in an organ or tissue to show changes in their structure or how they function.
• If it is used when the disease first starts, PET scans can help see when changes begin, before any changes can be seen on MRI or CT scans.
• PET scans are used to identify the exact location in the brain where seizures are happening because it can show the different brain activity before, during, and after a seizure.

• Dopamine transporter (DAT) scan is an imaging test that uses a radiative substance injected into the bloodstream to highlight areas of your brain so that images can be taken with a special camera (single-photon emission computed tomography [SPECT] camera).
• Your doctor or healthcare provider may order this imaging test if your movement difficulties are caused by Parkinson’s disease
• Some people may have allergic reactions to the injected substance