Crossed aphasia elicited by direct cortical stimulation.

摘要

Language representation restricted to the right cerebral hemisphere in right-handed subjects is rare. Crossed aphasia is an unusual aphasic syndrome in right-handed subjects with right brain damage. There is little information regarding the precise localization of crossed aphasia. We report functional mapping by direct cortical stimulation for exclusive right-hemisphere dominance in a right-handed patient undergoing surgery for a recurrent brain tumor in the right frontal lobe.Case report. A 32-year-old man was diagnosed with a brain tumor in the right frontal cortex in 1999. The tumor was removed and the pathologic diagnosis was oligodendroglioma. In May 2005, MRI showed a new enhancing area in the right frontal white matter, which we considered indicative of recurrence. We therefore proceeded with examinations in preparation for surgical treatment.The patient performed all activities on the Edinburgh Hand-edness Inventory with his right limbs. During the follow-up period, the patient experienced two episodes of short-lasting motor aphasia, suggesting simple partial seizure. According to the patient, meaningless words would automatically be spoken without any disturbance of consciousness. We performed Wada testing with injection of propofol. After injection of the right internal carotid artery (ICA), the patient was unable to respond to any orders or to engage in spontaneous speech. The patient was able to speak 2 minutes later and recovered completely from this global aphasic status 5 minutes later. The patient showed no language deterioration after injection of the left ICA.