COMPREHENSION OF WH-QUESTIONS IN 2 BROCA APHASICS

This study investigated comprehension of wh-questions in two Broca's a phasics. Patients were presented for comprehension with two types of w h-questions: questions headed by which and questions headed by who, Th ese two types were chosen because according to recent syntactic analys es they give rise to different types of syntactic ''chains.'' These qu estions were presented in both subject gap versions (e.g., which car c hased the dog?) and object gap versions (e.g., which cat did the dog c hase?). Comprehension of which questions was asymmetric, with subject gap versions comprehended significantly better than object gap version s, the latter yielding chance-level performance. This finding is consi stent with previous reports of subject-object asymmetries in comprehen sion of relative clauses and clefts, as well as active-passive compreh ension asymmetries. In contrast, comprehension of who questions was sy mmetrical over subject gap and object gap versions: Both patients perf ormed equally well (significantly better than chance) on subject gap a nd object gap who questions. These findings rue inconsistent with curr ent formulations of ''chain'' or ''trace''-based theories of agrammati c comprehension which assume a deficit that affects both types of synt actic chains. We suggest that linguistic descriptions of agrammatic co mprehension should be limited to deficits involving only one type of c hain. We also suggest that there are processing differences underlying the syntactic distinctions between which-type and who-type questions and that this may for different patterns of comprehension on these and other constructions. (C) 1995 Academic Press, Inc.