Visual evoked potentials (VEP)

Visual evoked potentials (VEP) are a neurophysiological examination that measures the electrical response of the occipital visual cortex to a standardised visual stimulation. The examination consists of recording, using electrodes placed on the scalp over the occipital cortex, the electrical signals generated by the brain in response to a visual stimulus, most often an alternating checkerboard displayed on a screen. This examination explores the functional integrity of the entire visual pathways, from the retina to the occipital cortex, passing through the optic nerve, the optic chiasm and the optic radiations. The main wave analysed is the P100 wave, whose latency (time of appearance) and amplitude are measured. A lengthening of the P100 wave latency is a very sensitive marker of demyelination of the optic nerve. VEP have a privileged place in the diagnosis of multiple sclerosis, where they make it possible to detect optic neuritis even when clinically silent. A unilateral lengthening of the P100 latency strongly suggests retrobulbar optic neuritis, whether symptomatic or subclinical. The Clinique Pasteur in Tunis carries out VEP according to the standardised protocols of the International Federation of Clinical Neurophysiology (IFCN), ensuring reliable results that are comparable over time.