Seizure-induced neglect.

A man with intermittent right parieto-occipital seizures was monitored by electroencephalography while he received 60 trials of being touched on the right, left, or both hands. Half of the trials were given during a focal seizure, and half were given interictally. While the patient was having seizures, he appropriately responded to all 10 stimuli delivered to the right hand, but four of 10 responses were incorrect (allaesthetic) when he was stimulated on the left. With bilateral simultaneous stimulation he neglected the left hand in all 10 trials. His interictal performance was flawless. When given a line-bisection task on two occasions during a seizure, the patient attempted to make a mark to the left of the entire sheet of paper. Immediately postictally he made a mark at the right end of the line. The case illustrates that focal seizures may induce elements of the neglect syndrome and that attention (to contralateral stimuli) and intention to perform (in the contralateral hemispatial field) may be dissociable phenomena.