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Visual Evoked Potentials (VEP)

Visual Evoked Potentials

What is a VEP?

A visual evoked potential or VEP is a diagnostic test used for the detection of abnormalities related to vision within the brain. A computer visual evoked program records brain activity that is related to the nerves that make up the visual pathway. It is a simple, painless and non invasive procedure that envolves the placement of electrodes on measured points on a patients scalp to provide a recording of the electrical activity in that specific area. The test usually lasts between 30 - 45 minutes.

Indications for a VEP?

  • Suspected Multiple Sclerosis
  • Double Vision
  • Blurred Vision
  • Loss of part or all parts of your vision
  • Eye or head injury

How does one prepare for a VEP?

  • Wash your hair in the morning of the test and ensure no gels, pastes, or oils are used on the hair thereafter.
  • If one uses glasses or contact lenses bring it along for the test.
  • Rest and eat normal before the test to ensure that you are able to focus and concentrate for the duration of the VEP.

How is a VEP performed?

  • The patients head is measured and specific areas are marked out
  • These areas are cleaned and prepared to decrease any impedance to allow for a better recording
  • Electrodes are than placed on these areas on the scalp and an impedance test is performed for optimum functioning of the test.
  • An eye (left/right) is blocked and the patient will be asked to look at a dot on a monitor placed in front of him/her.
  • Each eye will then be tested individually
  • When the test is completed the remaining paste will be cleaned off.
  • The remaining paste can be washed off at the patients digression
  • The VEP is reported by a neurologist and the results are discussed with the patient.