[A case of callosal apraxia without agraphia and acquired stuttering associated with callosal infarction]

We report a 52-year-old right-handed man with cerebral infarction of the right anterior cerebral artery area. The MRI findings showed cerebral infarction in the trunk of the right corpus callosum, although some part of the posterior half of the trunk was spared. Some part of right precuneal gyrus, cingulate gyrus were also involved. The clinical feature of this case is characterized by following two points. First, although callosal apraxia is usually accompanied by agraphia, he showed apraxia with the left hand, but showed no agraphia. Secondary, he showed speech dysfluency mainly characterized by initial syllable repetitions. The nature of this speech dysfluency was determined as acquired stuttering. This case suggests that the pathway for praxis locates distinct portion from that for writing on corpus callosum. We analyzed callosal lesions of previous studies reporting callosal apraxia without agraphia, then compared to that of this case. And we also reviewed acquired stuttering report caused by callosal lesions. Consequently, we suggest that apraxia and stuttering were caused by damage of the trunk of the corpus callosum. While writing was preserved by the intact fibers in the posterior half of the trunk.