Complexity in the comprehension of wh-movement structures in agrammatic Broca’s aphasia: Evidence from eyetracking Cynthia K. Thompson, a,b,c Michael Walsh Dickey, a,b,* and JungWon Janet Choy a,b a Aphasia and Neurolinguistics Research Laboratory, Northwestern University, USA b Department of Communication Sciences and Disorders, Northwestern University, 2240 Campus Drive, Evanston, IL 60208-3540, USA c Department of Neurology, Northwestern University, USA Available online 22 July 2004 Background and rationale Individuals with agrammatic Broca’s aphasia have problems comprehending complex sentences like (1a–b). (1) a. Who i did the boy kiss t i today at school? b. It was the girl I who i the boy kissed t I today at school. Both these structures involve wh-movement (Chomsky, 1986). The wh-question word ‘‘who’’ in (1a) and the wh-operator ‘‘who’’ in (1b) have moved to their non-canonical surface positions, with a trace (t) occupying their basic position following the verb ‘‘kiss(ed).’’ Recent work (Dickey & Thompson, 2004) has found that some agrammatic aphasic patients show success in comprehending such sentences on- line, and that linguistically motivated treatment (TUF; Thompson, 2001) improves their real-time comprehension of movement. The current study further examines the comprehension of wh- movement structures by agrammatic aphasic individuals using eyetracking. It also examines the role that syntactic complexity plays in the on-line comprehension of these structures, comparing the compre- hension of more simple non-canonical wh-questions (1a) and complex object clefts (1b). In Thompson, Shapiro, Kiran, and Sobecks’ (2003) Complexity Account of Treatment Efficacy (CATE), the complexity of linguistic stimuli in addition to their grammatical form plays a crucial role in recovery and generalization in aphasia. Under this complexity- based account, syntactically more complex sentences involving wh- movement should evince greater comprehension difficulty than simple ones, even if two sentence types share the syntactic structure (wh- movement) which is problematic for agrammatic aphasic patients. Such a difference is unexpected under simple grammar-only accounts of aphasic language deficits (Grodzinky, 2000; Mauner, Fromkin, & Cor- nell, 1993). Methods Participants Four individuals with agrammatic Broca’s aphasia (2 female) and four healthy age matched individuals (3 female) served as participants. The agrammatic participants were all mildly to moderately impaired, as assessed by the Western Aphasia Battery (Kertesz, 1982). Their WAB AQs ranged from 55.4 to 82.3; they were between 9 and 13 years post-onset and between 52 and 68 years of age at the time of testing. All four showed asyntactic comprehension patterns and agrammatic, nonfluent production. The control participants were between 54 and 62 years of age. All subjects were premorbidly right-handed, well edu- cated, native monolingual speakers of English and demonstrated good visual and hearing acuity. Materials and procedures Participants listened to brief stories like (2) below over a loud- speaker. Each story ended with a beep and was followed by either a simple wh-question (2a), a more complex object cleft (2b), or a yes-no question (2c). (2) This story is about a girl and a boy. One day, they were playing at school. The girl was pretty, so the boy kissed the girl. They were both embarrassed after the kiss. a. Who did the boy kiss that day at school? b. It was the girl that the boy kissed that day at school. c. Did the boy kiss the girl at school that day? Each story was accompanied by a visual display with pictures de- picting the critical sentence’s subject (the boy in (2)), object (the girl), location (the school), and an inanimate distractor not mentioned in the story (a door). Participants were instructed to respond aloud to the final sentence, either answering the question (for wh- and yes–no questions) or judging the sentence true or false (for object clefts). Participants heard 30 experimental stories like (2) and 20 fillers while their eye movements were recorded by an ASL model 504 remote eyetracker. The position of each participant’s gaze was sampled once every 16 ms. Responses to com- prehension question were recorded by hand. Results Mean accuracy of yes–no and wh-question comprehension was high for both participant groups, with yes/no comprehension at 85% for aphasic participants and 95% for controls and wh-question com- prehension at 100% correct for controls and 92.5% correct for agrammatics (above chance for all four agrammatic participants, ps < .05, Sign test). In addition, in the wh-question condition, both the aphasic and the control participants looked to the object picture sig- nificantly more often than the subject (Fig. 1) during the verb/gap Brain and Language 91 (2004) 124–125 www.elsevier.com/locate/b&l * Corresponding author. E-mail address: m-dickey@northwestern.edu (M.W. Dickey). 0093-934X/$ - see front matter Ó 2004 Elsevier Inc. All rights reserved. doi: 10.1016/j.bandl.2004.06.064