Evoked Potentials (VEP, ERG, BAEP, SEP)

Evoked potentials are the responses obtained from the brain cells through any external stimulus such as visual, auditory or sensual. This method is used to determine the suspicious sensory lesions.

Visual Evoked Potential (VEP)

It is a method based on examining the activities in visual pathways, beginning from the eye to brain, by applying visual stimuli. The visual stimuli can be applied in two ways in accordance with the compliance of the child. Easy going patients are requested to sit in front of a TV screen displaying changing squares like a checkerboard and to look at the square in the center of this image continuously. The changes occurred in the brain caused by the visual stimuli of changing squares are obtained with a less number of electrodes affixed to scalp with paste, as in EEG, and recorded on a computer. The average of obtained several responses are printed on a paper with the help of a computer.

In children who cannot adapt, the stimulus is created by the continuous blinks of a light device close to the eye of the patient whilesleeping. Similarly the effects of this blinking light are recorded. As in EEG The children who do not fall asleep by themselves will be made sleep with medications given by the technician.

Electroretinogram (ERG)

It is a method based on examining the activities in the pathways between the retina, which is a light-sensitive tissue, and the brain by applying visual stimuli. It is performed in the same way as VEP. In this method, the places of the affixed electrodes are different.

Brainstem Auditory Evoked Potential (BAEP): It is a method based on examining the activities in auditory pathways, from ear to brainstem, by applying auditory stimuli. An auditory stimulus is sent to one of the ears with an eartelephone and the response is obtained through the scalp. The changes occurred in the brainstem, which are caused by the auditory stimuli in variable frequencies are obtained with a less number of electrodes affixed along the scalp with paste, as in EEG, and recorded on a computer. The average of severalpicked up responses are printed on a paper with a computer. While the procedure takes 15 minutes in easy going children, it is extended as much as the time spent during falling asleep in children who are not.

Somatosensory Evoked Potentials (SEP)

It is picked up by stimulating sensory fibers. Stimuli are applied through the nerves in arms and legs and they may help in determining the places of peripheral nerves, neural networks, spinal cord, cerebellum, and brain lesions which comply with these. The changes occurred are obtained with a less number of electrodes affixed along the scalp with paste, as in EEG, and recorded on a computer. The average of several picked up responses are printed on a paper with a computer. While the procedure takes 15 minutes in easy going children, it is extended as much as the time spent during falling asleep in children who are not.

When will you receive the evoked potential results?

You can receive all evoked potential (VEP, ERG, BAEP, SEP) results in the afternoon (from 16:00) on the second working day following the test from the room where the test is performed. So, unless there is a national holiday during week days, the EEG results of tests which are performed on Monday are received on Wednesday afternoon, tests of Tuesday on Thursday afternoon, tests of Wednesday on Friday afternoon, tests of Thursday on Monday afternoon, tests of Friday on following Tuesday afternoon. You will be notified about the extraordinary situations.

Your compliance and assistance during the ST-EEG-VM test is very important for you to help your child’s health to get better. Thank you for your collaboration. Get well soon!