Abstract
Agrammatism is grammatical disease caused by brain injury. Agrammatic speech is characterized by omission and/or misuse of grammatical morphemes, for example, “case particles” in Japanese, “determiners” in English, omission and/or misuse of verbs, and reduced syntactic complexity. Many agrammatic patients also suffer from sentence comprehension deficits.
We administered a picture description test to ten individuals with aphasia, seven with left frontal lesion mainly(LF)and three with left temporal lesion mainly(LT). All subjects were impaired in understanding sentences and presented errors in case particles in their speech. We examined whether or not errors in case particles and arguments disappear from their picture description when an inflected verb is provided. All LF's and two LT's errors in case particles and semantic roles did not decrease when an inflected verb was given, whereas there was one LT whose errors disappeared completely.
The lesion location of the one LT with fluent aphasia whose errors disappeared completely when an inflected verb was given was the left temporal lobe only. The lesion location in all LF's whose errors remained involved the left inferior frontal gyrus, and the two LTs with fluent aphasia involved the left temporal lobe and left parietal lobe.
From these results, in these cases verb retrieval in sentence production was influenced by a left temporal lesion and syntactic processing was influenced not only by a left frontal lesion, but also a left temporal and parietal lesion.
