Varieties of semantic ‘access’ deficit in Wernicke’s aphasia and semantic aphasia

Thompson, Hannah E.; Robson, Holly; Ralph, Matthew A. Lambon; Jefferies, Elizabeth

doi:10.1093/brain/awv281

Cited by 53 publications

(63 citation statements)

References 104 publications

(193 reference statements)

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“…We contrasted the DYS group with performance in 24 SA patients, most of whom had participated in our previous investigations of semantic control deficits (see Table 2; Almaghyuli, Thompson, Lambon Ralph, & Jefferies, 2012;Thompson, Henshall, & Jefferies, 2016;Thompson et al, 2015). SA patients had a cerebrovascular accident at least a year previously.…”

Section: Sa Groupmentioning

confidence: 99%

“…The term 'semantic aphasia' transcends classical 'Boston' aphasia classifications, and patients can present different aphasia profiles as their spoken language skills are variable. SA patients have left-hemisphere damage focused on inferior frontal gyrus (IFG) and posterior middle temporal gyrus (pMTG) (Gardner et al, 2012;Noonan, Jefferies, Corbett, & Lambon Ralph, 2010;Thompson, Robson, Lambon Ralph, & Jefferies, 2015), and deficits affecting the comprehension of words, objects, environmental sounds, and actions (Corbett, Jefferies, Ehsan, et al, 2009;Gardner et al, 2012;. Similar brain regions have been implicated in the control of semantic processing by neuroimaging and neurostimulation studies (Badre, Poldrack, Par e-Blagoev, Insler, & Wagner, 2005;Davey, Cornelissen, et al, 2015;Davey, Rueschemeyer, et al, 2015;Davey, Thompson, et al, 2016;Krieger-Redwood, Teige, Davey, Hymers, & Jefferies, 2015;Noonan et al, 2013;Thompson-Schill, D'Esposito, Aguirre, & Farah, 1997;Whitney, Kirk, O'Sullivan, Lambon Ralph, & Jefferies, 2011).…”

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confidence: 99%

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The contribution of executive control to semantic cognition: Convergent evidence from semantic aphasia and executive dysfunction

Thompson

Almaghyuli

Noonan

et al. 2018

Journal of Neuropsychology

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Semantic cognition, as described by the controlled semantic cognition (CSC) framework (Rogers et al., 2015, Neuropsychologia, 76, 220), involves two key components: activation of coherent, generalizable concepts within a heteromodal 'hub' in combination with modality-specific features (spokes), and a constraining mechanism that manipulates and gates this knowledge to generate time-and task-appropriate behaviour. Executivesemantic goal representations, largely supported by executive regions such as frontal and parietal cortex, are thought to allow the generation of non-dominant aspects of knowledge when these are appropriate for the task or context. Semantic aphasia (SA) patients have executive-semantic deficits, and these are correlated with general executive impairment. If the CSC proposal is correct, patients with executive impairment should not only exhibit impaired semantic cognition, but should also show characteristics that align with those observed in SA. This possibility remains largely untested, as patients selected on the basis that they show executive impairment (i.e., with 'dysexecutive syndrome') have not been extensively tested on tasks tapping semantic control and have not been previously compared with SA cases. We explored conceptual processing in 12 patients showing symptoms consistent with dysexecutive syndrome (DYS) and 24 SA patients, using a range of multimodal semantic assessments which manipulated control demands. Patients with executive impairments, despite not being selected to show semantic impairments, nevertheless showed parallel patterns to SA cases. They showed strong effects of distractor strength, cues and miscues, and probe-target distance, plus minimal effects of word frequency on comprehension (unlike semantic dementia patients with degradation of conceptual knowledge). This supports a component process account of semantic cognition in which retrieval is shaped by control processes, and confirms that deficits in SA patients reflect difficulty controlling semantic retrieval.This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. Successful retrieval of semantic knowledge in a context-specific and timely manner depends on the interaction of multiple processes, including (1) the conversion of sensory input into meaning (Sharp, Scott, & Wise, 2004), (2) generalizable conceptual representations (Lambon Ralph, Sage, Jones, & Mayberry, 2010;Patterson, Nestor, & Rogers, 2007), and (3) flexible control over the retrieval of knowledge, such that semantic processing focuses on information appropriate to the context even when this is not necessarily the dominant feature or association ). An interaction between these components is envisaged within the controlled semantic cognition ( , 2010). However, the mechanisms underpinning semantic control are underspecified; in particular, it is unclear the extent to which this capacity draws on domain-gene...

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Section: Sa Groupmentioning

confidence: 99%

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confidence: 99%

The contribution of executive control to semantic cognition: Convergent evidence from semantic aphasia and executive dysfunction

Thompson

Almaghyuli

Noonan

et al. 2018

Journal of Neuropsychology

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“…Clinically, semantic variant PPA shares some features with Wernicke's aphasia in that it is characterized by impairments in naming and single-word comprehension (Hodges and Patterson, 2007; Gorno-Tempini et al, 2011; Thompson et al, 2015). However, a notable difference between the two clinical presentations is that while repetition is impaired in Wernicke's aphasia, it can be relatively spared in the semantic variant of PPA (Hodges and Patterson, 2007; Gorno-Tempini et al, 2011; Thompson et al, 2015).…”

Section: Comparing Causes and Consequences Of Aphasiamentioning

confidence: 99%

“…However, a notable difference between the two clinical presentations is that while repetition is impaired in Wernicke's aphasia, it can be relatively spared in the semantic variant of PPA (Hodges and Patterson, 2007; Gorno-Tempini et al, 2011; Thompson et al, 2015). Patterns of neural injury also differ between the two, in that the semantic variant of PPA features atrophy predominantly affecting the anterior, ventral, and lateral aspects temporal lobes.…”

Section: Comparing Causes and Consequences Of Aphasiamentioning

confidence: 99%

Non-invasive Brain Stimulation in the Treatment of Post-stroke and Neurodegenerative Aphasia: Parallels, Differences, and Lessons Learned

Norise

Hamilton

2017

Front. Hum. Neurosci.

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Numerous studies over the span of more than a decade have shown that non-invasive brain stimulation (NIBS) techniques, namely transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS), can facilitate language recovery for patients who have suffered from aphasia due to stroke. While stroke is the most common etiology of aphasia, neurodegenerative causes of language impairment—collectively termed primary progressive aphasia (PPA)—are increasingly being recognized as important clinical phenotypes in dementia. Very limited data now suggest that (NIBS) may have some benefit in treating PPAs. However, before applying the same approaches to patients with PPA as have previously been pursued in patients with post-stroke aphasia, it will be important for investigators to consider key similarities and differences between these aphasia etiologies that is likely to inform successful approaches to stimulation. While both post-stroke aphasia and the PPAs have clear overlaps in their clinical phenomenology, the mechanisms of injury and theorized neuroplastic changes associated with the two etiologies are notably different. Importantly, theories of plasticity in post-stroke aphasia are largely predicated on the notion that regions of the brain that had previously been uninvolved in language processing may take on new compensatory roles. PPAs, however, are characterized by slow distributed degeneration of cellular units within the language system; compensatory recruitment of brain regions to subserve language is not currently understood to be an important aspect of the condition. This review will survey differences in the mechanisms of language representation between the two etiologies of aphasia and evaluate properties that may define and limit the success of different neuromodulation approaches for these two disorders.

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“…Semantic interference, observed in the LASSI-L, taps into control mechanisms (a component of executive function), and is observed on cycling naming tasks (e.g., naming a picture while ignoring semantically related or unrelated words) in healthy and aphasic patients (Schnur & Martin, 2012; Thompson, Robson, Lambon Ralph, & Jefferies, 2015). However, it is unknown whether semantic interference has the same effect on a bilingual’s languages.…”

Section: Discussionmentioning

confidence: 99%

Effects of Bilingualism on Verbal and Nonverbal Memory Measures in Mild Cognitive Impairment

Rosselli

Loewenstein²,

Curiel³

et al. 2018

J Int Neuropsychol Soc

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Objective: Maintaining two active languages may increase cognitive and brain reserve among bilingual individuals. We explored whether such a neuroprotective effect was manifested in the performance of memory tests for participants with amnestic Mild Cognitive Impairment (aMCI). Method: We compared 42 bilinguals to 25 monolinguals on verbal and nonverbal memory tests. We employed: a) the Loewenstein-Acevedo Scales for Semantic Interference and Learning (LASSI-L), a sensitive test that taps into proactive, retroactive, and recovery from proactive semantic interference (verbal memory), and b) the Benson Figure delayed recall (nonverbal memory). A subsample had volumetric MRI scans. Results: The bilingual group significantly outperformed the monolingual group on two LASSI-L cued recall measures (Cued A2 and Cued B2). A measure of maximum learning (Cued A2) showed a correlation with the volume of the left hippocampus in the bilingual group only. Cued B2 recall (sensitive to recovery from proactive semantic interference) was correlated with the volume of the hippocampus and the entorhinal cortex of both cerebral hemispheres in the bilingual group, as well as with the left and right hippocampus in the monolingual group. The memory advantage in bilinguals on these measures was associated with higher inhibitory control as measured by the Stroop Color-Word test. Conclusion: Our results demonstrated a superior performance of aMCI bilinguals over aMCI monolinguals on selected verbal memory tasks. This advantage was not observed in nonverbal memory. Superior memory performance of bilinguals over monolinguals suggests that bilinguals develop a different and perhaps more efficient semantic association system that influences verbal recall.

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Varieties of semantic ‘access’ deficit in Wernicke’s aphasia and semantic aphasia

Cited by 53 publications

References 104 publications

The contribution of executive control to semantic cognition: Convergent evidence from semantic aphasia and executive dysfunction

The contribution of executive control to semantic cognition: Convergent evidence from semantic aphasia and executive dysfunction

Non-invasive Brain Stimulation in the Treatment of Post-stroke and Neurodegenerative Aphasia: Parallels, Differences, and Lessons Learned

Effects of Bilingualism on Verbal and Nonverbal Memory Measures in Mild Cognitive Impairment

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