Comprehension Of Non-canonical Sentences Research Articles

The Wernicke conundrum revisited: evidence from connectome-based lesion-symptom mapping.

Wernicke's area has been assumed since the 1800s to be the primary region supporting word and sentence comprehension. However, in 2015 and 2019, Mesulam and colleagues raised what they termed the 'Wernicke conundrum', noting widespread variability in the anatomical definition of this area and presenting data from primary progressive aphasia that challenged this classical assumption. To resolve the conundrum, they posited a 'double disconnection' hypothesis: that word and sentence comprehension deficits in stroke-based aphasia result from disconnection of anterior temporal and inferior frontal regions from other parts of the brain due to white matter damage, rather than dysfunction of Wernicke's area itself. To test this hypothesis, we performed lesion-deficit correlations, including connectome-based lesion-symptom mapping, in four large, partially overlapping groups of English-speaking chronic left hemisphere stroke survivors. After removing variance due to object recognition and associative semantic processing, the same middle and posterior temporal lobe regions were implicated in both word comprehension deficits and complex non-canonical sentence comprehension deficits. Connectome lesion-symptom mapping revealed similar temporal-occipital white matter disconnections for impaired word and non-canonical sentence comprehension, including the temporal pole. We found an additional significant temporal-parietal disconnection for non-canonical sentence comprehension deficits, which may indicate a role for phonological working memory in processing complex syntax, but no significant frontal disconnections. Moreover, damage to these middle-posterior temporal lobe regions was associated with both word and non-canonical sentence comprehension deficits even when accounting for variance due to the strongest anterior temporal and inferior frontal white matter disconnections, respectively. Our results largely agree with the classical notion that Wernicke's area, defined here as middle superior temporal gyrus and middle-posterior superior temporal sulcus, supports both word and sentence comprehension, suggest a supporting role for temporal pole in both word and sentence comprehension, and speak against the hypothesis that comprehension deficits in Wernicke's aphasia result from double disconnection.

Effects of prosody on the cognitive and neural resources supporting sentence comprehension: A behavioral and lesion-symptom mapping study

Non-canonical sentence comprehension impairments are well-documented in aphasia. Studies of neurotypical controls indicate that prosody can aid comprehension by facilitating attention towards critical pitch inflections and phrase boundaries. However, no studies have examined how prosody may engage specific cognitive and neural resources during non-canonical sentence comprehension in persons with left hemisphere damage. Experiment 1 examines the relationship between comprehension of non-canonical sentences spoken with typical and atypical prosody and several cognitive measures in 25 persons with chronic left hemisphere stroke and 20 matched controls. Experiment 2 explores the neural resources critical for non-canonical sentence comprehension with each prosody type using region-of-interest-based multiple regressions. Lower orienting attention abilities and greater inferior frontal and parietal damage predicted lower comprehension, but only for sentences with typical prosody. Our results suggest that typical sentence prosody may engage attention resources to support non-canonical sentence comprehension, and this relationship may be disrupted following left hemisphere stroke.

The effects of prosody on sentence comprehension: evidence from a neurotypical control group and seven cases of chronic stroke

ABSTRACTBoth prosody and sentence structure (e.g., canonical versus non-canonical) affect sentence comprehension. However, few previous studies have examined a possible interaction between prosody and sentence structure. In adult controls we found a significant interaction: typical sentence prosody, versus list prosody, facilitated comprehension of only some sentence structures. In seven stroke patients, impaired attentional control was related to impaired comprehension with sentence prosody but not list prosody; impaired working memory was related to impaired comprehension with list prosody, but not sentence prosody. Thus, non-canonical sentence comprehension impairments in stroke patients may be modulated by prosody, based on a patient’s cognitive abilities.

Neurocognitive disorders and language: The impact of cognitive decline and neuropsychiatric symptoms on the language performance

A growing body of literature supports a key role of fronto-striatal circuits in language perception. It is now known that the striatum plays a role in engaging attentional resources and linguistic rule computation while also serving phonological short-term memory capabilities. The ventral semantic and the dorsal phonological stream dichotomy assumed for spoken language processing also seems to play a role in cortico-striatal perception. Based on recent studies that correlate deep Broca-striatal pathways with complex syntax performance, we used a previously developed computational model of frontal-striatal syntax circuits and hypothesized that different parallel language pathways may contribute to canonical and non-canonical sentence comprehension separately. We modified and further analyzed a thematic role assignment task and corresponding reservoir computing model of language circuits, as previously developed by Dominey and coworkers. We examined the models performance under various parameter regimes, by influencing how fast the presented language input decays and altering the temporal dynamics of activated word representations. This enabled us to quantify canonical and non-canonical sentence comprehension abilities. The modeling results suggest that separate cortico-cortical and cortico-striatal circuits may be recruited differently for processing syntactically more difficult and less complicated sentences. Alternatively, a single circuit would need to dynamically and adaptively adjust to syntactic complexity.

Comprehension of Complex Sentences in the Persian-Speaking Patients With Aphasia.

Introduction:To study sentence comprehension in Persian-speaking Patients with Aphasia considering the factors of complexity.Methods:In this cross-sectional study, the performance of 6 non-fluent aphasic patients were tested and their performance was compared to 15 matched control group. Comprehension of semantically reversible sentences was assessed using a binary sentence-picture matching task. The stimuli were as follows: clefts; subject clefts and object clefts, also relative clauses; subject relatives and object relatives. All of them were types of movement-derived structures and also simple declarative sentences as the control task.Results:The best performance of aphasic patients were seen in the comprehension of subject clefts, although prior to this result we assumed that simple declarative sentences (in which there is no structural factor of complexity) can be understood easily. They showed the highest difficulty in the comprehension of object relatives. Furthermore, the performance of patients in the comprehension of relative clauses was significantly weaker than understanding the clefts.Conclusion:The outcomes of this study suggest that the sentence comprehension deficits of aphasic patients, in contrast to the specific deficit models, may not be related to linguistic disabilities. Moreover, the problems in the comprehension of non-canonical sentences may be related to failure in the allocation of attention. Finally, our results support the claims that neural characterization of the cognitive resources (e.g. working memory) is disrupted in sentence comprehension deficits.

The Effect of Frontal Lobe Traumatic Brain Injury on Sentence Comprehension and Working Memory

Background: This study was conducted to examine the sentence comprehension and working memory in individuals with mild and moderate frontal lobe traumatic brain injury (TBI) and determine the relationship between them. Methods: Participants included 18 patients with mild TBI, 17 patients with moderate TBI and 18 non-TBI individuals. The digit span subtest of the Wechsler intelligence scale-IV (WISC-IV) and a N-back test were used to evaluate working memory. Moreover, the syntactic comprehension subtest of Bilingual Aphasia Test (BAT) was used for sentence comprehension assessment. Results: The results showed that patients withmild and moderate TBI had a lower performance in comprehension of non-canonical sentences and working memory compared to the non-TBI group. There was also a significant correlation between sentence comprehension and working memory in the TBI groups. Conclusions: Sentence comprehension and working memory in TBI patients with frontal lobe damage are significantly lower than that of the non-TBI group, which may lead to some daily communication problems in these individuals.

What happens when they think they are right? Error awareness analysis of sentence comprehension deficits in aphasia

ABSTRACTBackground: Comprehension of non-canonical sentences is frequently characterised by chance level performance in people with aphasia (PWA). Chance level performance has been interpreted as guessing, but online data does not support this rendering. It is still not clear whether the incorrect sentence processing is guided by the compensatory strategies that PWA might employ to overcome linguistic difficulties.Aims: We aim to study to what extent people with non-fluent aphasia are aware of their sentence comprehension deficits.Methods & Procedures: This study combined offline and online data to investigate the effect of word order and error-awareness on sentence comprehension in a group of PWA and non-brain damaged (NBD) participants. The offline tasks involved auditory sentence picture-matching immediately followed by a confidence rating (CR). Participants were asked to judge the perceived correctness of their previous answer. Online data consisted of eye-tracking.Outcomes & Results: Replicating previous findings, PWA had significantly worse comprehension of Theme-Agent order compared to Agent-Theme order sentences. Controls showed ceiling level sentence comprehension. CR was a poor predictor of response accuracy in PWA, but moderate-good in NBD. A total of 6.8% of judgements were classified as “guessing” by PWA. Post hoc gaze data analysis indicated that CR was a predictor of the fixation pattern during the presentation of the linguistic stimuli.Conclusions: Results suggest that PWA were mostly unaware of their sentence comprehension errors and did not consciously employ strategies to compensate for their difficulties.

Neurocognitive sequela of non-canonical sentence comprehension in chronic agrammatic aphasia: eye movement and fMRI correlates of behavioral recovery

Neurocognitive sequela of non-canonical sentence comprehension in chronic agrammatic aphasia: eye movement and fMRI correlates of behavioral recovery

A Comparison of Two Treatment Approaches for Agrammatic Broca's Aphasia: Script Therapy vs. Verb Network Strengthening Treatment

A Comparison of Two Treatment Approaches for Agrammatic Broca's Aphasia: Script Therapy vs. Verb Network Strengthening Treatment

Meta-analysis of Treatment of Underlying Forms: dosage-related and person-level predictors of acquisition and generalization response

Meta-analysis of Treatment of Underlying Forms: dosage-related and person-level predictors of acquisition and generalization response

"Whatdunit?" Sentence Comprehension Abilities of Children With SLI: Sensitivity to Word Order in Canonical and Noncanonical Structures.

With Aim 1, we compared the comprehension of and sensitivity to canonical and noncanonical word order structures in school-age children with specific language impairment (SLI) and same-age typically developing (TD) children. Aim 2 centered on the developmental improvement of sentence comprehension in the groups. With Aim 3, we compared the comprehension error patterns of the groups. Using a "Whatdunit" agent selection task, 117 children with SLI and 117 TD children (ages 7:0-11:11, years:months) propensity matched on age, gender, mother's education, and family income pointed to the picture that best represented the agent in semantically implausible canonical structures (subject-verb-object, subject relative) and noncanonical structures (passive, object relative). The SLI group performed worse than the TD group across sentence types. TD children demonstrated developmental improvement across each sentence type, but children with SLI showed improvement only for canonical sentences. Both groups chose the object noun as agent significantly more often than the noun appearing in a prepositional phrase. In the absence of semantic-pragmatic cues, comprehension of canonical and noncanonical sentences by children with SLI is limited, with noncanonical sentence comprehension being disproportionately limited. The children's ability to make proper semantic role assignments to the noun arguments in sentences, especially noncanonical, is significantly hindered.

Cortico-striatal language pathways dynamically adjust for syntactic complexity: A computational study

A growing body of literature supports a key role of fronto-striatal circuits in language perception. It is now known that the striatum plays a role in engaging attentional resources and linguistic rule computation while also serving phonological short-term memory capabilities. The ventral semantic and the dorsal phonological stream dichotomy assumed for spoken language processing also seems to play a role in cortico-striatal perception. Based on recent studies that correlate deep Broca-striatal pathways with complex syntax performance, we used a previously developed computational model of frontal-striatal syntax circuits and hypothesized that different parallel language pathways may contribute to canonical and non-canonical sentence comprehension separately. We modified and further analyzed a thematic role assignment task and corresponding reservoir computing model of language circuits, as previously developed by Dominey and coworkers. We examined the models performance under various parameter regimes, by influencing how fast the presented language input decays and altering the temporal dynamics of activated word representations. This enabled us to quantify canonical and non-canonical sentence comprehension abilities. The modeling results suggest that separate cortico-cortical and cortico-striatal circuits may be recruited differently for processing syntactically more difficult and less complicated sentences. Alternatively, a single circuit would need to dynamically and adaptively adjust to syntactic complexity.

Sentence comprehension and morphological cues in aphasia: What eye-tracking reveals about integration and prediction

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 case-ambiguous 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 verb-agreement 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 subject-before-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-verb-number-agreement cue, was available. We attribute the results for IWA to deficits in predictive processes based on morpho-syntactic 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.

Chance in agrammatic sentence comprehension: What does it really mean? Evidence from eye movements of German agrammatic aphasic patients

Background: In addition to the canonical subject-verb-object (SVO) word order, German also allows for non-canonical order (OVS), and the case-marking system supports thematic role interpretation. Previous eye-tracking studies (Kamide et al., 2003; Knoeferle, 2007) have shown that unambiguous case information in non-canonical sentences is processed incrementally. For individuals with agrammatic aphasia, comprehension of non-canonical sentences is at chance level (Burchert et al., 2003). The trace deletion hypothesis (Grodzinsky 1995, 2000) claims that this is due to structural impairments in syntactic representations, which force the individual with aphasia (IWA) to apply a guessing strategy. However, recent studies investigating online sentence processing in aphasia (Caplan et al., 2007; Dickey et al., 2007) found that divergences exist in IWAs' sentence-processing routines depending on whether they comprehended non-canonical sentences correctly or not, pointing rather to a processing deficit explanation. Aims: The aim of the current study was to investigate agrammatic IWAs' online and offline sentence comprehension simultaneously in order to reveal what online sentence-processing strategies they rely on and how these differ from controls' processing routines. We further asked whether IWAs' offline chance performance for non-canonical sentences does indeed result from guessing. Methods & Procedures: We used the visual-world paradigm and measured eye movements (as an index of online sentence processing) of controls (N = 8) and individuals with aphasia (N = 7) during a sentence–picture matching task. Additional offline measures were accuracy and reaction times. Outcomes & Results: While the offline accuracy results corresponded to the pattern predicted by the TDH, IWAs' eye movements revealed systematic differences depending on the response accuracy. Conclusions: These findings constitute evidence against attributing IWAs' chance performance for non-canonical structures to mere guessing. Instead, our results support processing deficit explanations and characterise the agrammatic parser as deterministic and inefficient: it is slowed down, affected by intermittent deficiencies in performing syntactic operations, and fails to compute reanalysis even when one is detected.

Agrammatic comprehension caused by a glioma in the left frontal cortex

It has been known that lesions in the left inferior frontal gyrus (L. IFG) do not always cause Broca’s aphasia, casting doubt upon the specificity of this region. We have previously devised a picture–sentence matching task for a functional magnetic resonance imaging (fMRI) study, and observed that both pars triangularis (L. F3t) of L. IFG (extending to pars opercularis (L. F3op)) and the left lateral premotor cortex (L. LPMC) are selectively involved in syntactic processing. The present study with lesion-symptoms mapping was conducted to examine whether the function of these regions is indeed critical for syntactic comprehension. Using the same picture–sentence matching task, we examined 21 patients with a glioma in the left frontal cortex but with no apparent disability in verbal/written communication or intelligence quotient. This task included three main conditions of sentence types: canonical/subject-initial active sentences, non-canonical/subject-initial passive sentences, and non-canonical/object-initial scrambled sentences. The patients preoperatively underwent a high-resolution 3D-MRI, and voxel-based lesion-symptom mapping was employed for the error rates data. We found that the patients with a lesion in L. F3op/F3t or L. LPMC showed differential patterns of condition-selective deficits in the comprehension of sentences. More specifically, the L. F3op/F3t-damaged patients had more profound deficits in the comprehension of non-canonical sentences, whereas the L. LPMC-damaged patients had more profound deficits in the comprehension of object-initial scrambled sentences. These results establish that a lesion in L. F3op/F3t or L. LPMC is sufficient to cause agrammatic comprehension.

The speed of lexical activation is altered in Parkinson's disease

Disturbed comprehension of complex noncanonical sentences in Parkinson's disease (PD) has been linked to dopamine depletion and delayed lexical retrieval. The aim of the present study was to replicate findings of delayed lexical activation in PD patients with noncanonical sentence processing difficulties, and investigate the influence of dopamine depletion on these changes to lexical access. In the first experiment, 20 patients with PD (tested whilst ‘on’ dopaminergic medication) and 23 controls participated in a list priming experiment. In this paradigm, stimuli are presented as a continuous list of words/nonwords, and semantic priming effects were measured across inter-stimulus intervals (ISIs) of 500 ms, 1000 ms and 1500 ms, with data analyzed using multivariate analyses of variance. The results revealed longer delays in lexical activation for PD patients with poor comprehension of noncanonical sentences, suggesting that the speed of lexical access may be compromised in PD, and that this feature may contribute to certain sentencecomprehension difficulties. In the second experiment, 7 patients with PD who participated in the first experiment, performed the same lexical decision task while ‘off’ their dopaminergic medication. Semantic priming effects were measured across ISIs of 500 ms and 1500 ms. Within group comparisons revealed a different pattern of semantic priming for the PD patients when ‘on’ compared to ‘off’ medication, providing further support for a dopaminergic influence on the speed of information processing and lexical activation.

Agrammatism: A Cross-Linguistic Clinical Perspective

Agrammatism: A Cross-Linguistic Clinical Perspective

Cross-modal generalization effects of training noncanonical sentence comprehension and production in agrammatic aphasia.

The cross-modal generalization effects of training complex sentence comprehension and complex sentence production were examined in 4 individuals with agrammatic Broca's aphasia who showed difficulty comprehending and producing complex, noncanonical sentences. Object-cleft and passive sentences were selected for treatment because the two are linguistically distinct, relying on wh-and NP movement, respectively (Chomsky, 1986). Two participants received comprehension training, and 2 received production training using linguistic specific treatment (LST). LST takes participants through a series of steps that emphasize the verb and verb argument structure, as well as the linguistic movement required to derive target sentences. A single-subject multiple-baseline design across behaviors was used to measure acquisition and generalization within and across sentence types, as well as cross-modal generalization (i.e., from comprehension to production and vice versa) and generalization to discourse. Results indicated that both treatment methods were effective for training comprehension and production of target sentences and that comprehension treatment resulted in generalization to spoken and written sentence production. Sentence production treatment generalized to written sentence production only; generalization to comprehension did not occur. Across sentence types generalization also did not occur, as predicted, and the effects of treatment on discourse were inconsistent across participants. These data are discussed with regard to models of normal sentence comprehension and production.