The role of syntactic complexity in training wh-movement structures in agrammatic aphasia: Optimal order for promoting generalization

This study examined the postulate that training production of syntactically complex sentences results in generalization to less complex sentences that have processes in common with treated structures. Three agrammatic aphasic patients were trained to produce wh-movement structures, object clefts and /or object extracted who-questions, while generalization between these stru ctures was tested. One NP-movement structure, passive sentences, also was t ested for control purposes. Wh-movement occurs from the direct object posit ion to specifier position in the complementizer phrase [SPEC, CP] for both wk-movement structures. In who-questions movement occurs in the matrix sent ence, whereas, in object clefts movement occurs within an embedded relative clause, rendering them the most complex. Results showed robust generalizat ion effects from object clefts to matrix wile-question for I participant (D .L.); however, no generalization was noted from who-questions to object cle fts for another (EP.), and 1 participant (C.H.) showed acquisition of who-q uestions, but not object clefts, during the baseline condition without dire ct treatment. As expected, none of the participants showed improved product ion of passives. These findings supported those derived from our previous s tudies, indicating that generalization is enhanced not only when target str uctures are related along dimensions articulated by linguistic theory, but also when the direction of treatment is from more to less complex structure s. The present findings also support proposals that projections of higher l evels in the syntactic treatment are dependent on successful projection of lower levels. For our participants, training movement within CP in a lower (embedded) clause resulted in their ability to project to CP at higher leve ls.