Abstract
A 49-year-old right-handed Japanese woman exhibited transcortical motor aphasia associated with cerebral hemorrhage. Magnetic resonance imaging revealed a lesion involving the medial aspect of the left frontal lobe, part of the anterior cingulate gyrus, and the body of the corpus callosum.
This study was undertaken to investigate the mechanism of speech dysfluency in this case. The subject's speech dysfluency was thought to be stuttering. The stuttering features included aspects of both neurogenic and psychogenic stuttering.
In the present case, the neurogenic stuttering may be caused by (1) neural disconnections between the right and left hemispheres resulting from damage to the body of the corpus callosum, as well as by (2) collapse of the basal ganglia circuits resulting from damage to the prefrontal and pre-supplementary motor areas. We concluded that the neurogenic stuttering may be associated with motor feedback loops from the cortex to the basal ganglia, to the thalamus, and back to the cortex.
