• Photosensitive;
  • Outcome;
  • Partial seizure;
  • Pocket Monster;
  • Photoparoxysmal response

Summary: Purpose: To identify the short-term outcome of patients who had seizures while watching an animated cartoon TV program, “Pocket Monster,” on December 16, 1997.

Methods: One and three years after the incident, questionnaires were sent to physicians of each patient about seizure recurrence, EEGs, and medication.

Results: Among 103 patients in whom epileptic seizures occurred during the TV program and information on the outcomes was available, 25 (24%) patients had a history of unprovoked seizures before the incident (Epilepsy Group), and 78 (76%) did not (Non-Epilepsy Group). Twenty-three (22%) patients were reported to have seizures after the incident, and 15 of them had visually induced seizures. Patients of the Epilepsy Group had more seizure recurrence than did those of the Non-Epilepsy Group (56% vs. 9%; p < 0.0001), either for unprovoked (44% vs. 4%; p < 0.0001) or visually induced seizures (28% vs. 9%; p < 0.05). Of nine patients of the Non-Epilepsy Group who had seizures after the incident, only three developed recurrent unprovoked seizures. In the Non-Epilepsy Group, no difference was found in seizure recurrence between patients in whom valproate (VPA) was prescribed immediately after the incident and in those without medication (one of five (20%) vs. seven of 73 (10%); p > 0.05). EEG was performed at least once in 98 patients after the incident. Photoparoxysmal response (PPR) was present in 45 (46%) patients, and spontaneous epileptiform discharges, in 49 (50%). PPR did not have any correlation with recurrence of seizures, neither spontaneous nor visually induced seizures, whereas spontaneous epileptiform discharges showed a good correlation with seizure recurrence (34% vs. 8%; p < 0.01), including visually induced seizures (24% vs. 2%; p < 0.01).

Conclusions: Short-term outcomes showed that 70 (68%) of 103 patients who had a seizure during the incident had no seizures before and during ≤3 years of follow-up.