1992 Volume 12 Issue 4 Pages 285-293
Two cases of pure agraphia following a left parieto-occipital lesion are described.
Case 1 is a 50-year-old male afflicted by a left parieto-occipital subcortical hemorrhage ; case 2 is a 62-year-old male with a left occipital brain tumor.
In both cases agraphia was noted in both the right and left hands. The subjects were able to express “ on-readings ” and “ kun-readings ” for Kanji characters even though they could not write them. This suggests that the auditory engram of Kanji characters was preserved. They were also able to express gross graphemic figures of Kanji and Kana characters which they could not write. This implies that visual representation of characters was also preserved. It is known that transformation from the auditory engram to the motor engram is the main pathway in the Kana-writing process. Our findings suggest that there is a pathway from auditory to visual representation and then to motor representation in the Kana-writing process, just as in the Kanji-writing process.
The auditory and visual engrams were preserved in both cases since the Wernicke's area and the left angular gyrus were intact. Pure agraphia in both cases may reflect disruption of a pathway from the visual to the motor engrams.
