Visual evoked potential (vep) test for multiple sclerosis

A visual evoked potential (VEP) test is one test that a doctor may use to diagnose multiple sclerosis and monitor disease treatment and progression. Your brain and spinal cord make up your

central nervous system, and they both contain neurons. Parts of these neurons are protected by an insulating layer called a myelin sheath. If you have multiple sclerosis (MS), your immune

system attacks these myelin sheaths as if they were invaders. This can lead to a number of motor, sensory, and cognitive symptoms. If you or a doctor suspect you have MS, there are a number

of tests that might be performed to help confirm a diagnosis. While no one test can be used to definitively diagnose MS, the following tests can help rule out other conditions with similar

symptoms: * neurological exam * MRI * spinal fluid analysis (spinal tap) * blood tests Another test that’s sometimes used to help diagnose and monitor MS is a visual evoked potential (VEP)

test. This article takes a closer look at the VEP test, including how it’s used for MS, what the procedure is like, and what you can learn from the results. What is a visual evoked potential

test? VEP is the brain’s electrical response to visual stimuli. A VEP test measures the electrical activity in your brain. When light waves enter your eye, they’re absorbed by specialized

cells called cones and rods. These are located in the retina at the back of your eye. Your retina turns these light waves into electrical signals that then travel along your optic nerve to

the back of your brain, and your brain interprets this as visual information. During a VEP test, you’ll be shown high-contrast patterns that flash and alternate. While this happens, you’ll

have electrodes attached to your scalp. Using the electrodes, a computer measures the timing of the flashing patterns and the timing of the electrical activity in your brain. Doctors or

healthcare professionals can use these measurements to determine how long it takes for the flashing lights to turn into electrical impulses in your retinas and then travel down your optic

nerves. How is a visual evoked potential test used for multiple sclerosis? If you have MS, your immune system attacks the myelin sheath that insulates your neurons. This is called

demyelination. Demyelination makes it more difficult for electrical signals to travel across your neurons. This includes your optic nerves, which stretch from the back of your eyes to

pathways that reach the back of your brain. If the myelin along your optic nerves is damaged, a VEP test will find the delay — called latency — between when you’re shown a pattern and when

the signal reaches the back of your brain. A VEP test is one tool that a doctor might use to help diagnose MS. A significant delay could be an indicator of MS. For some people with MS, the

delay can be measurable by a VEP test, even if the demyelination is minimal and not causing any noticeable changes in your vision. What is the visual evoked potential test procedure like? A

VEP test is a simple and painless procedure. You won’t need to make any special preparations, such as fasting. The test will be performed in a medical setting, such as an examination room at

a doctor’s office or hospital. Several wires will be attached with an adhesive to your scalp, especially in the occipital region, which is at the back of your head. You’ll be seated in

front of a computer monitor. The monitor will display a high-contrast pattern, such as a checkerboard or alternating bars. This pattern will regularly flicker, with the dark parts changing

to light and vice versa. Each eye is typically tested individually. You can expect the whole procedure to last between 30 and 60 minutes. Most people go home the same day. If you’re able to

drive yourself to the test, you can expect to drive yourself home as well. What kind of results should you expect from a visual evoked potential test? A VEP test produces immediate results

in the form of a graph. It looks similar to the measurements from a heart rate monitor, with peaks and troughs representing electrical activity. Depending on where the test is taken and who

administered it, a doctor may be able to review the results with you right away. In other cases, a technician might need to send the results to a specialist, such as a neurologist, to review

before sharing the results with you. While VEP tests can find diminished or delayed electrical activity in your brain, they can’t necessarily determine the cause. For this reason, other

tests may be needed before you can get a diagnosis. Frequently asked questions about a visual evoked potential test CAN A VEP TEST CONFIRM A DIAGNOSIS OF MS OR ARE OTHER TESTS NEEDED? A VEP

test can provide evidence of damage or disruption of optic nerve function. MS causes demyelination, but so do other conditions such as optic neuritis and neuromyelitis optica spectrum

disorder. Any condition that affects the optic nerves or disrupts the visual pathways to the visual cortex in the brain can affect the brain’s VEP. You may need additional tests to rule out

other conditions. WHAT OTHER TYPES OF EVOKED POTENTIAL TESTS DO DOCTORS USE FOR MS? Sometimes doctors may want to run other evoked potential tests such as: * brainstem auditory evoked

response (BAER) * somatosensory evoked potential (SEP) * motor evoked potential (MEP) ARE VEP TESTS USED TO DIAGNOSE AND DETERMINE OTHER HEALTH CONDITIONS? Yes, there are several uses for

VEP tests. Some examples include monitoring vision when a person has gliomas and hydrocephalus. VEP tests can also be useful in certain circumstances such as during surgery or for monitoring

optic nerve function for people who are in comas. Other conditions where VEP tests may be used include optic nerve tumors, glaucoma, and strokes involving the visual cortex. A VEP test

showing a normal range of activity can usually rule out any abnormality of the optic nerves. Takeaway VEP tests are a quick, cost-effective, and noninvasive way to measure your brain’s

ability to interpret visual information. Electrodes on your scalp measure the electrical activity in your brain while you watch alternating patterns on a monitor. The results of the test can

tell you whether your brain is responding normally to visual information, but it can’t necessarily tell you the underlying cause. VEP tests can be used to help diagnose and monitor the

effects of MS on vision, though they’re also used in conjunction with other methods. And while they’re helpful tools for diagnosing MS, they can also be used for diagnosing and monitoring a

number of other conditions.