Agrammatism
Definition and Clinical Features
Agrammatism is a language disorder characterized by a reduction in, or loss of, the ability to produce or comprehend the syntactic elements of language. This results in the omission of function words—such as articles (a, the), prepositions (in, on), and conjunctions (and, but)—and grammatical markers, like verb endings (-ed, -ing).
In contrast, content words (nouns and verbs) are relatively spared. This leads to a simplified, effortful speech pattern often described as "telegraphic speech." For example, a person might say "Walk dog park" instead of "I am taking the dog for a walk in the park." Despite this impoverishment of language, the intended meaning is often still conveyed because of the high information content of the preserved nouns and verbs. Agrammatic speech may also be dysprosodic, lacking normal rhythm, stress, and intonation.
Agrammatism is a core feature of Broca's aphasia, associated with lesions in Broca's area in the posterior inferior frontal lobe of the dominant hemisphere.
Anatomical Basis and Clinical Significance
Agrammatism is a hallmark feature of Broca’s aphasia, a type of nonfluent aphasia. It is typically caused by damage to the posterior inferior part of the frontal lobe in the language-dominant hemisphere, an area known as Broca’s area. Recognizing agrammatism is crucial for diagnosing the type of aphasia and localizing the underlying brain lesion, which is often the result of a stroke, tumor, or trauma.
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