2016 Volume 36 Issue 2 Pages 236-243
Damages to the medial frontal lobe (MFL) often elicits disorders of speech; not only aphasias, including transcortical motor aphasia, but also disturbances of more fundamental vocalization functions, such as stuttering or the inhibition of speech, and rarely, kanji agraphia. In this symposium, we explored the involvement of the right MFL in speaking and writing by discussing a case that manifested with a transient disturbance of speech initiation and persistent kanji agraphia associated with an infarction that included the right pre-supplementary motor cortex. It could not be concluded that the right MFL was the region responsible for speech initiation, because the deficit quickly abated. According to our review of published referential cases, verbal symptoms persisted only among those with left MFL damage were transient among those with right MFL damage. This is the first documented case of agraphia associated with damage to right MFL. Furthermore, kanji agraphia persisted in this case. Kanji writing performance did not depend on the number of orthographia strokes or the frequency of each kanji character, but instead varied with the number of radicals and structural elements of each kanji character. These findings suggest that the right MFL is involved in the selection and arrangement of structural elements of kanji characters, probably occurring in the latest stages of kanji writing.
