Aphasia in left-handers: lesion site, lesion side, and hemispheric asymmetries on CT.

Language in left-handed aphasics with left (n = 27) or right (n = 4) hemisphere lesion was examined. Left occipital CT asymmetry was the most common asymmetry and could not be used to predict handedness or which hemisphere, if damaged, would produce aphasia. When left hemisphere lesion sites were matched between eight left-handed and eight right-handed aphasics, there were no significant group differences on language measures. Two nonfluent cases with good comprehension and large right frontal, parietal, and temporal lesions appeared to have "Broca's area" in the right hemisphere, but "Wernicke's area" in the left. Results suggest separate hemispheric loci for handedness, speech output, and/or comprehension dominance in some left-handers.