Reflex petit mal absence?

The importance of tactile somatosensory stimuli as a triggering mechanism in provoking epileptic seizures is widely acknowledged. These seizures are mostly partial ones with secondary generalization, but may also be, rarely, primary generalized seizures. Up to now, no case of petit mal absence, triggered by somatosensory stimuli, has been described. The subject of this report is a 15-month-old girl, who for a period of 3 months presented absence induced by finger tapping on her forehead or in the parietal region; the duration of the attacks ranged from 6 to 12 seconds. The EEG showed a characteristic pattern of diffuse discharges of 3 Hz/sec spike and wave complexes. During this critical period, the child was well, except for the seizures. Possible mechanisms for triggering this type of seizure are discussed.