Your doctor may conduct many different exams or tests to help them diagnose and treat your disorder. The test or exam chosen often depends on your symptoms or condition. Some tests are used to assess specific parts of your nervous system and will give your care team information that helps diagnose or treat your specific condition.
General Neurological Exam
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.
An EEG measures brain activity while sleeping. It is used to diagnose conditions such as epilepsy, seizures, dizziness, head injuries, headaches, brain tumors, and sleeping problems.
Nerve Conduction Studies
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.
Somatosensory Evoked Potential (SSEP)
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.
Visual Evoked Potential (VEP)
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.
Different imaging tests are used in neurology to help your healthcare team to get detailed views of the structure or function of your body and nervous system. Sometimes it may be necessary to use more than one type of imaging test to get a thorough diagnosis or understanding of your condition.