Abstract
We report two cases of aphasia after infarctions restricted in the inferoposterior region of the left frontal lobe. The two patients showed clear differences in speech fluency and repetition capability despite nearly the same extent of lesion. Both became mute soon after onset. However, whereas case 1 showed an atypical nonfluent (mild anarthria, mild dysprosody, and short phrase length) aphasia with impaired oral repetition after six days, case 2 exhibited a mild transcortical sensory aphasia with relatively intact ability to repeat sentences within 20 days after onset. We speculate that the difference in deficits between the two cases was due to variation in transient dysfunction around the infarcted region, such as acute edema during the early phase. We suppose a subtle difference in involvement of the precentral gyrus was responsible for the observed language symptoms (articulation, repetition). In case 2, despite relatively good repetition performance, digit span was impaired, suggesting that syntactic processing is independent of phonological processing in a repetition task. Furthermore, the atypical nonfluent aphasia in case 1 demonstrated improvement toward a fluent aphasia approximately six months after onset, indicating that recovery is possible within a relatively short period of time, when lesion is circumscribed, even if the inferoposterior region in the left frontal lobe is damaged.
