A case of startle epilepsy and SSMA seizures documented with subdural recordings

Purpose: To study the mechanisms of startle-induced supplementary sensorimo tor area (SSMA) seizures. Methods: We present a patient investigated with indwelling subdural grid el ectrodes covering both the SSMA and the dorsolateral frontal lobe. Results: We found a simultaneous seizure onset in the right dorsolateral pr emotor cortex and the right SSMA. High-resolution magnetic resonance imagin g (MRI) showed a small subcortical lesion adjacent to the right SSMA. The p atient became seizure free after resection of the lesion and the ictal-onse t zone. Conclusions: We conclude that an extended region of abnormally excitable ti ssue within the frontal lobe could facilitate the generation of startle-ind uced seizures. We speculate that a widespread epileptogenic zone could help to explain why some patients with SSMA or dorsolateral frontal lobe seizur es are more likely to have startle-induced seizures.