Tense and agreement in German agrammatism.

This study presents results from sentence-completion and grammaticality-judgment tasks with 7 German-speaking agrammatic aphasics and 7 age-matched control subjects examining tense and subject-verb agreement marking. For both experimental tasks, we found that the aphasics achieved high correctness scores for agreement, while tense marking was severely impaired. To account for the observed tense-agreement dissociation, we suggest that the functional category T(ense)/INFL(ection) is tense-defective in agrammatic aphasia, i.e., it is specified for [+/-Realis], but not for [+/-Past]. It will also be argued that other accounts, specifically the tree-pruning model, do not explain our findings.