1991 Volume 9 Issue 2 Pages 147-153
It is well-known that visual stimulation induces epileptic seizures in some patients. However, the details of its mechanism are so far not clear. In a patient with photosensitive epilepsy, cognitive function was estimated by a method of distinguishing the presented numbers, whether each one was odd or even. It was also evaluated that the cognitive disturbances were due to whether visual stimulation as an inducer of epileptogenic activity or epileptic discharges themselves induced by the stimulation.
The response time was significantly prolonged when the epileptic discharges were enhanced. On the other hand, the response errors were significantly increased while inducer stimulation were given regardless the incidence of the discharges.
If the effect of the seizure inducing factor is only the result of excitement in the origin of epileptic discharges, all changes of the brain function during stimulation may depend on paroxysmal discharges. It is conceivable that visual stimulation gives an effect to another abnormal mechanism to activate or inhibit the origin of epileptic discharges.
