@article{PatilHanneBurchertetal.2016,
  author    = {Patil, Umesh and Hanne, Sandra and Burchert, Frank and De Bleser, Ria and Vasishth, Shravan},
  title     = {A Computational Evaluation of Sentence Processing Deficits in Aphasia},
  series = {Cognitive science : a multidisciplinary journal of anthropology, artificial intelligence, education, linguistics, neuroscience, philosophy, psychology ; journal of the Cognitive Science Society},
  volume    = {40},
  journal   = {Cognitive science : a multidisciplinary journal of anthropology, artificial intelligence, education, linguistics, neuroscience, philosophy, psychology ; journal of the Cognitive Science Society},
  publisher = {Wiley-Blackwell},
  address   = {Hoboken},
  issn      = {0364-0213},
  doi       = {10.1111/cogs.12250},
  pages     = {5 -- 50},
  year      = {2016},
  abstract  = {Individuals with agrammatic Broca's aphasia experience difficulty when processing reversible non-canonical sentences. Different accounts have been proposed to explain this phenomenon. The Trace Deletion account (Grodzinsky, 1995, 2000, 2006) attributes this deficit to an impairment in syntactic representations, whereas others (e.g., Caplan, Waters, Dede, Michaud, \& Reddy, 2007; Haarmann, Just, \& Carpenter, 1997) propose that the underlying structural representations are unimpaired, but sentence comprehension is affected by processing deficits, such as slow lexical activation, reduction in memory resources, slowed processing and/or intermittent deficiency, among others. We test the claims of two processing accounts, slowed processing and intermittent deficiency, and two versions of the Trace Deletion Hypothesis (TDH), in a computational framework for sentence processing (Lewis \& Vasishth, 2005) implemented in ACT-R (Anderson, Byrne, Douglass, Lebiere, \& Qin, 2004). The assumption of slowed processing is operationalized as slow procedural memory, so that each processing action is performed slower than normal, and intermittent deficiency as extra noise in the procedural memory, so that the parsing steps are more noisy than normal. We operationalize the TDH as an absence of trace information in the parse tree. To test the predictions of the models implementing these theories, we use the data from a German sentence—picture matching study reported in Hanne, Sekerina, Vasishth, Burchert, and De Bleser (2011). The data consist of offline (sentence-picture matching accuracies and response times) and online (eye fixation proportions) measures. From among the models considered, the model assuming that both slowed processing and intermittent deficiency are present emerges as the best model of sentence processing difficulty in aphasia. The modeling of individual differences suggests that, if we assume that patients have both slowed processing and intermittent deficiency, they have them in differing degrees.},
  language  = {en}
}
@article{HanneBurchertDeBleseretal.2015,
  author    = {Hanne, Sandra and Burchert, Frank and De Bleser, Ria and Vasishth, Shravan},
  title     = {Sentence comprehension and morphological cues in aphasia: What eye-tracking reveals about integration and prediction},
  series = {Journal of neurolinguistics : an international journal for the study of brain function in language behavior and experience},
  volume    = {34},
  journal   = {Journal of neurolinguistics : an international journal for the study of brain function in language behavior and experience},
  publisher = {Elsevier},
  address   = {Oxford},
  issn      = {0911-6044},
  doi       = {10.1016/j.jneuroling.2014.12.003},
  pages     = {83 -- 111},
  year      = {2015},
  abstract  = {Comprehension of non-canonical sentences can be difficult for individuals with aphasia (IWA). It is still unclear to which extent morphological cues like case marking or verb inflection may influence IWA's performance or even help to override deficits in sentence comprehension. Until now, studies have mainly used offline methods to draw inferences about syntactic deficits and, so far, only a few studies have looked at online syntactic processing in aphasia. We investigated sentence processing in German-speaking IWA by combining an offline (sentence-picture matching) and an online (eye-tracking in the visual-world paradigm) method. Our goal was to determine whether IWA are capable of using inflectional morphology (number-agreement markers on verbs and case markers in noun phrases) as a cue to sentence interpretation. We report results of two visual-world experiments using German reversible SVO and OVS sentences. In each study, there were eight IWA and 20 age-matched controls. Experiment 1 targeted the role of unambiguous case morphology, while Experiment 2 looked at processing of number-agreement cues at the verb in caseambiguous sentences. IWA showed deficits in using both types of morphological markers as a cue to non-canonical sentence interpretation and the results indicate that in aphasia, processing of case-marking cues is more vulnerable as compared to verbagreement morphology. We ascribe this finding to the higher cue reliability of agreement cues, which renders them more resistant against impairments in aphasia. However, the online data revealed that IWA are in principle capable of successfully computing morphological cues, but the integration of morphological information is delayed as compared to age-matched controls. Furthermore, we found striking differences between controls and IWA regarding subject-before-object parsing predictions. While in case-unambiguous sentences IWA showed evidence for early subjectbefore-object parsing commitments, they exhibited no straightforward subject-first prediction in case-ambiguous sentences, although controls did so for ambiguous structures. IWA delayed their parsing decisions in case-ambiguous sentences until unambiguous morphological information, such as a subject-verbnumber-agreement cue, was available. We attribute the results for IWA to deficits in predictive processes based on morphosyntactic cues during sentence comprehension. The results indicate that IWA adopt a wait-and-see strategy and initiate prediction of upcoming syntactic structure only when unambiguous case or agreement cues are available. (C) 2015 Elsevier Ltd. All rights reserved.},
  language  = {en}
}
@article{BosHanneWartenburgeretal.2014,
  author    = {Bos, Laura S. and Hanne, Sandra and Wartenburger, Isabell and Bastiaanse, Roelien},
  title     = {Losing track of time? Processing of time reference inflection in agrammatic and healthy speakers of German},
  series = {Neuropsychologia : an international journal in behavioural and cognitive neuroscience},
  volume    = {65},
  journal   = {Neuropsychologia : an international journal in behavioural and cognitive neuroscience},
  publisher = {Elsevier},
  address   = {Oxford},
  issn      = {0028-3932},
  doi       = {10.1016/j.neuropsychologia.2014.10.026},
  pages     = {180 -- 190},
  year      = {2014},
  abstract  = {Background: Individuals with agrammatic aphasia (IWAs) have problems with grammatical decoding of tense inflection. However, these difficulties depend on the time frame that the tense refers to. Verb morphology with reference to the past is more difficult than with reference to the non-past, because a link needs to be made to the past event in discourse, as captured in the PAst Discourse Linking Hypothesis (PADILIH; Bastiaanse, R., Bamyaci, E., Hsu, C., Lee, J., Yarbay Duman, T., Thompson, C. K., 2011. Time reference in agrammatic aphasia: A cross-linguistic study. J. Neurolinguist. 24, 652-673). With respect to reference to the (non-discourse-linked) future, data so far indicate that IWAs experience less difficulties as compared to past time reference (Bastiaanse, R., Bamyaci, E., Hsu, C., Lee, J., Yarbay Duman, T., Thompson, C. K., 2011. Time reference in agrammatic aphasia: A cross-linguistic study. J. Neurolinguist. 24, 652-673), supporting the assumptions of the PADILIH. Previous online studies of time reference in aphasia used methods such as reaction times analysis (e.g., Faroqi-Shah, Y., Dickey, M. W., 2009. On-line processing of tense and temporality in agrammatic aphasia. Brain Lang. 108, 97-111). So far, no such study used eye-tracking, even though this technique can bring additional insights (Burchert, F., Hanne, S., Vasishth, S., 2013. Sentence comprehension disorders in aphasia: the concept of chance performance revisited. Aphasiology 27, 112-125, doi:10.1080/02687038.2012.730603). Aims: This study investigated (1) whether processing of future and past time reference inflection differs between non-brain-damaged individuals (NBDs) and IWAs, and (2) underlying mechanisms of time reference comprehension failure by IWAs. Results and discussion: NBDs scored at ceiling and significantly higher than the IWAs. IWAs had below-ceiling performance on the future condition, and both participant groups were faster to respond to the past than to the future condition. These differences are attributed to a pre-existing preference to look at a past picture, which has to be overcome. Eye movement patterns suggest that both groups interpret future time reference similarly, while IWAs show a delay relative to NBDs in interpreting past time reference inflection. The eye tracking results support the PADILIH, because processing reference to the past in discourse syntax requires additional resources and thus, is problematic and delayed for people with aphasia. (C) 2014 Elsevier Ltd. All rights reserved.},
  language  = {en}
}