Ictal speech arrest and parasagittal lesions.

Lesions in the parasagittal region may cause seizures with speech arrest. To correlate lesion localization within the parasagittal region with ictal speech function we studied 11 patients with parasagittal lesions. The exact lesion localization was assessed with magnetic resonance imaging. In all patients with speech arrest the lesion involved the left superior frontal gyrus (n = 6), in 3 patients the lesion was confined to this gyrus. Speech arrest did not occur in patients with right-sided lesions (n = 4) or left-sided lesions outside the superior frontal gyrus (n = 1). Our data suggest that a small lesion confined to the left superior frontal gyrus (the supplementary motor area) is sufficient to cause speech arrest.