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Complexity in the comprehension of wh-movement structures in agrammatic Broca's aphasia: Evidence from eyetracking
Brain and Language 91 (2004) 124–125 www.elsevier.com/locate/b&l
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 Choya,b a Aphasia and Neurolinguistics Research Laboratory, Northwestern University, USA Department of Communication Sciences and Disorders, Northwestern University, 2240 Campus Drive, Evanston, IL 60208-3540, USA c Department of Neurology, Northwestern University, USA
b
Available online 22 July 2004
Background and rationale Individuals with agrammatic Broca’s aphasia have problems comprehending complex sentences like (1a–b). (1) a. Whoi did the boy kiss ti today at school? b. It was the girlI whoi the boy kissed tI 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 online, and that linguistically motivated treatment (TUF; Thompson, 2001) improves their real-time comprehension of movement. The current study further examines the comprehension of whmovement 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 comprehension 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 complexitybased account, syntactically more complex sentences involving whmovement should evince greater comprehension difficulty than simple ones, even if two sentence types share the syntactic structure (whmovement) 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, & Cornell, 1993).
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 educated, 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 loudspeaker. 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 depicting 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 comprehension question were recorded by hand.
Methods Participants
Results
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
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 comprehension 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 significantly more often than the subject (Fig. 1) during the verb/gap
* Corresponding author. E-mail address: [email protected] (M.W. Dickey).
0093-934X/$ - see front matter Ó 2004 Elsevier Inc. All rights reserved. doi: 10.1016/j.bandl.2004.06.064
Abstract / Brain and Language 91 (2004) 124–125
125
Further, the results show that not all wh-movement structures are equally impaired among agrammatic aphasic individuals. This dissociation supports the predictions of the complexity-based account (Thompson et al., 2003) for the impairment and recovery of whmovement structures. However, it is surprising under purely grammatical accounts of agrammatic comprehension (Grodzinsky, 2000; Mauner et al., 1993). Under such accounts, all sentences with non-canonical wh-movement should be equally impaired, regardless of their complexity.
References Fig. 1. Mean proportion of looks, wh-question. region (i.e., the trace site), defined as the period from the offset of the verb to the onset of the location PP (ps < .05 for both regions, onetailed t test). It is in the temporal region of the verb/gap that the whelement is reactivated during sentence processing; the eye-movement data thus indicate the expected pattern of gap-filling. This result is parallel to findings for the comprehension of wh-questions by young, unimpaired listeners (Sussman & Sedivy, 2003). The agrammatic participants, however, showed impaired comprehension of object cleft structures, with a mean accuracy of 52.5% compared to 95% for controls. They also did not look to the object more often than the subject at the position of the trace. That is, they showed no visual evidence of reactivating the antecedent of the trace for the more complex object clefts.
Discussion These results demonstrate a tight link between on-line performance in eyetracking tasks and off-line sentence comprehension, even in disordered populations. This suggests that eyetracking can be useful as an on-line measure of linguistic deficits and recovery.
Chomsky, N. (1986). Barriers. Cambridge, MA: MIT Press. Dickey, M. W., & Thompson, C. K. (2004). The resolution and recovery of filler-gap dependencies in aphasia: Evidence from online anomaly detection. Brain and Language, 88, 108–127. Sussman, R. S., & Sedivy, J. C. (2003). The time-course of processing syntactic dependencies: Evidence from eye movements. Language and Cognitive Processes, 18, 143–161. Kertesz, A. (1982). Western Aphasia Battery. New York: Grune & Stratton. Grodzinsky, Y. (2000). The neurology of syntax: Language use without Broca’s area. Behavioral and Brain Sciences, 23, 1–71. Mauner, G., Fromkin, V., & Cornell, T. (1993). Comprehension and acceptability judgments in agrammatism: Disruptions in the syntax of referential dependency. Brain and Language, 45, 340– 370. Thompson, C. K. (2001). Treatment of underlying forms: A linguistic specific approach for sentence production deficits in agrammatic aphasia. In R. Chapey (Ed.), Language intervention strategies in adult aphasia. Baltimore: Williams & Wilkins. Thompson, C. K, Shapiro, L. P, Kiran, S., & Sobecks, J. (2003). The role of syntactic complexity in treatment of sentence deficits in agrammatic aphasia: The complexity account of treatment efficacy (CATE). Journal of Speech Language and Hearing Research, 46, 591–607.
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 Choya,b a Aphasia and Neurolinguistics Research Laboratory, Northwestern University, USA Department of Communication Sciences and Disorders, Northwestern University, 2240 Campus Drive, Evanston, IL 60208-3540, USA c Department of Neurology, Northwestern University, USA
b
Available online 22 July 2004
Background and rationale Individuals with agrammatic Broca’s aphasia have problems comprehending complex sentences like (1a–b). (1) a. Whoi did the boy kiss ti today at school? b. It was the girlI whoi the boy kissed tI 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 online, and that linguistically motivated treatment (TUF; Thompson, 2001) improves their real-time comprehension of movement. The current study further examines the comprehension of whmovement 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 comprehension 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 complexitybased account, syntactically more complex sentences involving whmovement should evince greater comprehension difficulty than simple ones, even if two sentence types share the syntactic structure (whmovement) 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, & Cornell, 1993).
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 educated, 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 loudspeaker. 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 depicting 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 comprehension question were recorded by hand.
Methods Participants
Results
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
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 comprehension 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 significantly more often than the subject (Fig. 1) during the verb/gap
* Corresponding author. E-mail address: [email protected] (M.W. Dickey).
0093-934X/$ - see front matter Ó 2004 Elsevier Inc. All rights reserved. doi: 10.1016/j.bandl.2004.06.064
Abstract / Brain and Language 91 (2004) 124–125
125
Further, the results show that not all wh-movement structures are equally impaired among agrammatic aphasic individuals. This dissociation supports the predictions of the complexity-based account (Thompson et al., 2003) for the impairment and recovery of whmovement structures. However, it is surprising under purely grammatical accounts of agrammatic comprehension (Grodzinsky, 2000; Mauner et al., 1993). Under such accounts, all sentences with non-canonical wh-movement should be equally impaired, regardless of their complexity.
References Fig. 1. Mean proportion of looks, wh-question. region (i.e., the trace site), defined as the period from the offset of the verb to the onset of the location PP (ps < .05 for both regions, onetailed t test). It is in the temporal region of the verb/gap that the whelement is reactivated during sentence processing; the eye-movement data thus indicate the expected pattern of gap-filling. This result is parallel to findings for the comprehension of wh-questions by young, unimpaired listeners (Sussman & Sedivy, 2003). The agrammatic participants, however, showed impaired comprehension of object cleft structures, with a mean accuracy of 52.5% compared to 95% for controls. They also did not look to the object more often than the subject at the position of the trace. That is, they showed no visual evidence of reactivating the antecedent of the trace for the more complex object clefts.
Discussion These results demonstrate a tight link between on-line performance in eyetracking tasks and off-line sentence comprehension, even in disordered populations. This suggests that eyetracking can be useful as an on-line measure of linguistic deficits and recovery.
Chomsky, N. (1986). Barriers. Cambridge, MA: MIT Press. Dickey, M. W., & Thompson, C. K. (2004). The resolution and recovery of filler-gap dependencies in aphasia: Evidence from online anomaly detection. Brain and Language, 88, 108–127. Sussman, R. S., & Sedivy, J. C. (2003). The time-course of processing syntactic dependencies: Evidence from eye movements. Language and Cognitive Processes, 18, 143–161. Kertesz, A. (1982). Western Aphasia Battery. New York: Grune & Stratton. Grodzinsky, Y. (2000). The neurology of syntax: Language use without Broca’s area. Behavioral and Brain Sciences, 23, 1–71. Mauner, G., Fromkin, V., & Cornell, T. (1993). Comprehension and acceptability judgments in agrammatism: Disruptions in the syntax of referential dependency. Brain and Language, 45, 340– 370. Thompson, C. K. (2001). Treatment of underlying forms: A linguistic specific approach for sentence production deficits in agrammatic aphasia. In R. Chapey (Ed.), Language intervention strategies in adult aphasia. Baltimore: Williams & Wilkins. Thompson, C. K, Shapiro, L. P, Kiran, S., & Sobecks, J. (2003). The role of syntactic complexity in treatment of sentence deficits in agrammatic aphasia: The complexity account of treatment efficacy (CATE). Journal of Speech Language and Hearing Research, 46, 591–607.