On the basis for the agrammatic's difficulty in producing main verbs.

Area of Science:

• Neuroscience
• Linguistics
• Psychology

Background:

• Agrammatism presents with co-occurring omissions of grammatical markers and main verbs.
• Current theories inadequately explain this dual symptom presentation.

Purpose of the Study:

• To test the hypothesis that verb omission and grammatical marker omission in agrammatism have distinct underlying causes.
• To investigate if lexical deficits contribute to main verb omission in agrammatic speech.

Main Methods:

• Agrammatic aphasics, anomic aphasics, and normal controls participated.
• Participants completed an object and action naming test.

Main Results:

• Agrammatic patients exhibited significant impairment in naming actions.
• Anomic aphasics and normal controls named actions more proficiently than objects.
• This contrasts with the performance of agrammatic patients.

Conclusions:

• The action naming impairment supports a lexical deficit hypothesis for verb omission in agrammatism.
• Agrammatism is a heterogeneous disorder affecting both lexical and syntactic mechanisms.