Tense processing in Broca's and Wernicke's aphasia

Background: Broca's aphasic or agrammatic participants are assumed to have problems with the inflection of moved verbs. Recently, Bastiaanse (2008) has shown that verb inflection in base position is also difficult for these participants, especially if reference to the past is involved. However, Bastiaanse only examined the data of Broca's aphasic participants and restricted herself to verb production. In the current study we will examine the existence of a more central deficit in tense marking in production and comprehension in aphasic participants. Aims: The production and comprehension of tensed verbs will be studied in a group of Broca's aphasic participants. The data of a group of participants suffering from Wernicke's aphasia will be used for comparison. Methods Procedures: Seven participants with Broca's aphasia and five with Wernicke's aphasia performed a sentence-to-picture matching task for comprehension and a sentence completion task for production with present or past tense as the crucial conditions. Both tests contained 40 items. Results on the tests were analysed quantitatively and qualitatively. Outcomes Results: Although production was more impaired than comprehension in Broca's aphasic participants, past tense was more difficult to interpret than present tense, especially for those participants who showed comprehension problems. Problems with the interpretation of tense were also found in the group of Wernicke's aphasic participants. Furthermore, for these participants past tense forms were also more difficult to produce than present tense forms. Conclusions: The results suggest that past tense in general is difficult to process for aphasic participants. We relate this finding to the semantic notion of past tense.