What is an Evoked Potential? What does it add to a psychiatric workup?
Two common types of evoked potentials are Auditory Evoked Responses (AER) and Visual Evoked Responses (VER). Evoked response measurement is similar to an EEG, using the same electrodes on the scalp, the same EEG machine, and a similar measurement of the electrical activity of the brain. However, whereas the EEG measures the ongoing electrical activity of the brain, the Evoked Response (as the name implies) measures the electrical response evoked in the brain by either auditory (AER) or visual (VER) stimulation. For example, for the AER, the patient is presented a “click” from an headphone (many times) and the EEG machine measures the brain s electrical reaction evoked by that sound. For the VER, a flash of light is used instead of a sound. The advantage of this “evoked” response, for psychiatric conditions, is that it allows the doctor to see if there is any electrical abnormality deep inside the brain. Deep electrical disorders are important because the brain s systems for controlling
