Репозиторий Университета

© 2020 Elsevier Ltd Background: Grammar includes not only the ability to use verbs but also the ability to express and understand the relationships existing among the words in a sentence. Since the initial description of agrammatism (Kussmaul, 1877) it was proposed that there are two different types of agrammatism: Aktaphasie and Agrammatismus. The first one has been extensively studied, while the second one has been mostly overlooked. Aims: To analyze the brain areas involved in understanding the relationships existing among the words in a sentence. Its disturbances would correspond to the second type of agrammatism. Outcomes & results: Prepositions, adverbs, and grammatical cases are used to indicate the relationships among sentence words. This is a quasi-spatial ability supported by the left posterior parietal lobe. Almost one century ago a type of aphasia referred to as “semantic aphasia”, associated with left posterior parietal damage and characterized by the inability to use and understand the relationships among the language words, was described. Excepting a few papers, this type of aphasia has been usually ignored in the contemporary neuroscience literature. From the historical perspective, it has been proposed that grammar evolved in two steps: (1) proto-grammar, consisting of flat verb-noun compounds, and (2) hierarchical syntax or complex grammar. The first one is associated with the ability to use and understand verbs. The second one can be related to the ability to use verbally mediate spatial concepts. Some recently published cases of semantic aphasia corroborate its clinical manifestations and the locus of pathology. Functional studies support the participation of the left posterior parietal lobe in grammar. Conclusions: It is concluded that evidence suggests that semantic aphasia is a real type of aphasia and indeed there are two grammatical subsystems in the brain and two agrammatic types of aphasia.