Dataset Information

Sentence Context Prevails Over Word Association in Aphasia Patients with Spared Comprehension: Evidence from N400 Event-Related Potential.

ABSTRACT: Behavioral and event-related potential (ERP) studies on aphasia patients showed that lexical information is not lost but rather its integration into the working context is hampered. Studies have been conducted on the processing of sentence-level information (meaningful versus meaningless) and of word-level information (related versus unrelated) in aphasia patients, but we are not aware of any study that assesses the relationship between the two. In healthy subjects the processing of a single word in a sentence context has been studied using the N400 ERP. It was shown that, even when there is only a weak expectation of a final word in a sentence, this expectation will dominate word relatedness. In order to study the effect of semantic relatedness between words in sentence processing in aphasia patients, we conducted a crossed-design ERP study, crossing the factors of word relatedness and sentence congruity. We tested aphasia patients with mild to minimum comprehension deficit and healthy young and older (age-matched with our patients) controls on a semantic anomaly judgment task when simultaneously recording EEG. Our results show that our aphasia patient's N400 amplitudes in response to the sentences of our crossed-design study were similar to those of our age-matched healthy subjects. However, we detected an increase in the N400 ERP latency in those patients, indicating a delay in the integration of the new word into the working context. Additionally, we observed a positive correlation between comprehension level of those patients and N400 effect in response to meaningful sentences without word relatedness contrasted to meaningless sentences without word relatedness.

SUBMITTER: Khachatryan E

PROVIDER: S-EPMC5223168 | biostudies-literature | 2016

REPOSITORIES: biostudies-literature

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Sentence Context Prevails Over Word Association in Aphasia Patients with Spared Comprehension: Evidence from N400 Event-Related Potential.

Khachatryan Elvira E De Letter Miet M Vanhoof Gertie G Goeleven Ann A Van Hulle Marc M MM

Frontiers in human neuroscience 20170110

Behavioral and event-related potential (ERP) studies on aphasia patients showed that lexical information is not lost but rather its integration into the working context is hampered. Studies have been conducted on the processing of sentence-level information (meaningful versus meaningless) and of word-level information (related versus unrelated) in aphasia patients, but we are not aware of any study that assesses the relationship between the two. In healthy subjects the processing of a single wor ...[more]

PMID: 28119590

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Project description:BackgroundA subset of patients with the nonfluent variant of primary progressive aphasia (PPA) exhibit concomitant single-word comprehension problems, constituting a 'mixed variant' phenotype. This phenotype is rare and currently not fully characterized. The aim of this study was twofold: to assess the prevalence and nature of single-word comprehension problems in the nonfluent variant and to study multimodal imaging characteristics of atrophy, tau, and amyloid burden associated with this mixed phenotype.MethodsA consecutive memory-clinic recruited series of 20 PPA patients (12 nonfluent, five semantic, and three logopenic variants) were studied on neurolinguistic and neuropsychological domains relative to 64 cognitively intact healthy older control subjects. The neuroimaging battery included high-resolution volumetric magnetic resonance imaging processed with voxel-based morphometry, and positron emission tomography with the tau-tracer [18F]-THK5351 and amyloid-tracer [11C]-Pittsburgh Compound B.ResultsSeven out of 12 subjects who had been classified a priori with nonfluent variant PPA showed deficits on conventional single-word comprehension tasks along with speech apraxia and agrammatism, corresponding to a mixed variant phenotype. These mixed variant cases included three females and four males, with a mean age at onset of 65 years (range 44-77 years). Object knowledge and object recognition were additionally affected, although less severely compared with the semantic variant. The mixed variant was characterized by a distributed atrophy pattern in frontal and temporoparietal regions. A more focal pattern of elevated [18F]-THK5351 binding was present in the supplementary motor area, the left premotor cortex, midbrain, and basal ganglia. This pattern was closely similar to that seen in pure nonfluent variant PPA. At the individual patient level, elevated [18F]-THK5351 binding in the supplementary motor area and premotor cortex was present in six out of seven mixed variant cases and in five and four of these cases, respectively, in the thalamus and midbrain. Amyloid biomarker positivity was present in two out of seven mixed variant cases, compared with none of the five pure nonfluent cases.ConclusionsA substantial proportion of PPA patients with speech apraxia and agrammatism also have single-word comprehension deficits. At the neurobiological level, the mixed variant shows a high degree of similarity with the pure nonfluent variant of PPA.Trial registrationEudraCT, 2014-002976-10 . Registered on 13-01-2015.

Project description:BackgroundThe application of videoconferencing to the assessment and treatment of aphasia has been rapidly increasing; however, there is a need to develop treatments targeting sentence production in persons with aphasia (PWA) that can be delivered through videoconferencing. Structural priming has received recent attention as a potential training method for PWA. We investigated the feasibility and efficacy of a collaborative structural priming task delivered via the internet, TelePriming, in facilitating sentence production in PWA and healthy adults.MethodIn Study 1, young adults (YA), older adults (OA), and PWA participated in a collaborative dialogue-like priming task through videoconferencing, taking turns with an interlocutor (experimenter) to describe transitive action pictures with the goal of finding matching pictures. We measured whether participants produced more passive sentences to describe their picture after hearing their interlocutor produce passive compared to active sentences (primes). In Study 2, we compared the data from the OA and PWA of Study 1 (TelePriming) to different groups of OA and PWA, who completed the same priming task in person.ResultsAll three groups showed robust priming effects in Study 1, producing more passive sentences to describe target pictures after hearing the experimenter produce passive versus active sentences. In Study 2, when controlling for demographic information (age, education) and aphasia severity, TelePriming resulted in larger priming effects for OA and PWA, compared to the in-person priming task. Survey results revealed that both OA and PWA experienced increased comfort and satisfaction with using technology following the task.ConclusionInteractive message-structure alignment processes remain largely intact in PWA, and the positive effects of structural priming in a collaborative communicative task are not diminished by remote delivery. The findings demonstrate the feasibility and validity of TelePriming in OA and PWA, laying experimental groundwork for future use of TelePriming in the assessment and treatment of clinical populations with limited access to face-to-face sessions.

Dataset Information

Sentence Context Prevails Over Word Association in Aphasia Patients with Spared Comprehension: Evidence from N400 Event-Related Potential.

Publications

Sentence Context Prevails Over Word Association in Aphasia Patients with Spared Comprehension: Evidence from N400 Event-Related Potential.

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