There is an entity called agrammatic aphasia.

Agrammatism as a phenomenon of neuropsychological relevance has been recently attacked--from conceptual and empirical angles. This article examines the facts, as they emerge from three recent experimental studies that have concluded that agrammatism does not exist (Miceli et al., 1989; Martin et al., 1989, Badecker et al., in press), and draws the opposite conclusion: that agrammatism is of interest to students of language and that patients belonging in this clinical category also reveal uniform patterns of aberrant behavior that are of great linguistic and psycholinguistic relevance.