Mixed transcortical aphasia without anatomic isolation of the speech area.

We report two patients with mixed transcortical aphasia following left frontal lobe infarctions. Although there was no evidence of anatomic isolation of the speech area on computed tomograms or magnetic resonance imaging scans, single-photon emission computed tomography in one case demonstrated diminished blood flow over the left parietal convexity suggestive of "functional isolation" of the posterior perisylvian language zone.