Abstract
We reported two cases of conduction aphasia with distinctive language disorder from early stage of stroke, as well as their cerebral blood flow and oxygen consumption investigated with PET.
The case was a 72-year-old right handed man whose speech disturbance began acutely. On admission, neurological examination revealed hand pronation sign on the right and speech disturbance. Other neurological findings including cortical functions were normal. Brain CT scan showed low density area in the white matter of the left supramarginal gyrus. The diagnosis was cerebral infarction.
The case 2 was a 64-year-old right handed man. He suffered right hemiparesis 2 months before. Neurological examination revealed mild right hemiparesis and speech disturbance. Other cortical functions were noncontributory. Brain CT scan showed old subcortical infarction of the left frontal lobe and new cerebral infarction with supramarginal gyrus. The low density area of the supramarginal cortex extended into the subcortical white matter.
The language performances in these two cases were similar. Two patients were definitely fluent, but the verbal output was contaminated by paraphasias which were predominantly literal. They performed poorly when attempting to repeat despite good comprehension. Thus, the primary characteristics of conduction aphasia were present.
PET studies resulted as follows. 1) rCBF reduced 36% in the supramarginal cortex, 50% in the white matter. 2) rCMRO2 reduced 37% in the supramarginal cortex, 45% in the white matter. 3) The CBF and the CMRO2 images indicated that cerebral blood flow and oxgen consumption reduced in wider range of area than that shown by brain CT.
These results indicated that not only the cortex but also the white matter were damaged in conduction aphasia and several methods including PET should be used to determine the locus of abnormality in conduction aphasia.
