Efficient and effective assessment of deficits and their neural bases in stroke aphasia

Halai, Ajay D.; Pérez, Blanca De Dios; Stefaniak, James D.; Ralph, Matthew A. Lambon

doi:10.1016/j.cortex.2022.07.014

Cited by 16 publications

(5 citation statements)

References 51 publications

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“…This understanding could inform future steps such as improving tests for neuropsychological assessment and reducing the length of test batteries. 48 However, a subsequent challenge that emerged was the difficulty associated with interpreting changes along all six PCs in parallel. We therefore complemented PCA with strengths of advanced neighbour embedding methods, namely UMAP.…”

Section: Discussionmentioning

confidence: 99%

Mapping the multidimensional geometric landscape of graded phenotypic variation and progression in neurodegenerative syndromes

Ramanan,

Akarca,

Henderson

et al. 2023

Preprint

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Clinical variants of Alzheimers disease (AD) and frontotemporal lobar degeneration (FTLD) display a spectrum of cognitive-behavioural changes varying between individuals and over time. Understanding the landscape of these graded individual-/group-level longitudinal variations is critical for precise phenotyping; however, this remains challenging to model. Addressing this challenge, we leverage the National Alzheimers Coordinating Center database to derive a unified geometric framework of graded AD/FTLD longitudinal phenotypic variation. Using three time-point, cognitive-behavioural and clinical data from 390 typical, atypical and intermediate AD/FTLD variants, we apply advanced data-science approaches to derive low-dimensional geometric spaces capturing core features underpinning AD/FTLD clinical progression. Importantly, these geometries enable the assimilation and inter-relation of paradigmatic and mixed cases, capturing dynamic individual trajectories, and linking syndromic variability to neuropathology and key clinical end-points such as survival. This resultant mapping of dynamics underlying cognitive-behavioural evolution potentially holds paradigm-changing implications to predicting phenotypic diversification and phenotype-neurobiological mapping in AD/FTLD.

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Section: Discussionmentioning

confidence: 99%

Mapping the multidimensional geometric landscape of graded phenotypic variation and progression in neurodegenerative syndromes

Ramanan,

Akarca,

Henderson

et al. 2023

Preprint

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“…There is still a dearth of longitudinal (acute to chronic) data in stroke aphasia to formally investigate prognosis using structural 16 , 35 , 74 and/or functional (see recent meta-analysis 75 ) neuroimaging. There are critical practical issues associated with collecting longitudinal data that limit our ability to explore prognosis: (i) samples tend to dominated by moderate to mild cases who continue to become mild or recovered in the chronic stage, whereas a typical cross-sectional chronic sample tends to span a broader range of severities 76 , 77 ; (ii) the times at which patients are tested acutely vary, at least for functional imaging it is rare to find populations tested within 6 months 75 ; (iii) behavioural testing is often limited in the variety and depth of data 78 ; and (iv) the overall sample size in longitudinal studies is generally smaller than chronic-only studies. These issues highlight the importance of open science and international collaboration to build large and sensitive datasets to tackle these problems.…”

Section: Discussionmentioning

confidence: 99%

Using in vivo functional and structural connectivity to predict chronic stroke aphasia deficits

Zhao

Cox

Ralph

et al. 2022

Brain

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Focal brain damage caused by stroke can result in aphasia and advances in cognitive neuroscience suggest that impairment may be associated with network-level disorder rather than just circumscribed cortical damage. A number of studies have shown meaningful relationships between brain-behaviour using lesions; however only a handful of studies have incorporated in-vivo structural and functional connectivity. Patients with chronic post-stroke aphasia were assessed with structural (N = 68) and functional (N = 39) MRI to assess whether predicting performance can be improved with multiple modalities and if additional variance can be explained compared to lesion models alone. These neural measurements were used to construct models to predict four key language-cognitive factors: 1) phonology, 2) semantics, 3) executive function, and 4) fluency. Our results showed that each factor (except executive ability) could be significantly related to each neural measurement alone; however, structural and functional connectivity models did not explain additional variance above the lesion models. We did find evidence that the structural and functional predictors may be linked to the core lesion sites. First, the predictive functional connectivity features were found to be located within functional resting state networks identified in healthy controls, suggesting that the result might reflect functionally-specific reorganisation (damage to a node within a network can result in disruption to the entire network). Second, predictive structural connectivity features were located within core lesion sites, suggesting that multi-modal information may be redundant in prediction modelling. In addition, we observed that the optimum sparsity within the regularised regression models differed for each behavioural component and across different imaging features, suggesting that future studies should consider optimising hyperparameters related to sparsity per target. Together, the results indicate that the observed network-level disruption was predicted by the lesion alone and does not significantly improve model performance in predicting the profile of language impairment.

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“…General semantic memory was assessed using a battery of receptive and expressive tasks, comprising the modified picture-version of Camel and Cactus semantic association test (mCCT) (69, 70), a synonym judgement task (71, 72), the Cambridge Naming (70, 72) and Boston Naming (72, 73) tests and a word-to-picture matching task. For all patients ( N =33), a principal component analysis (PCA) was conducted on the mCCT, synonym judgement task and word-to-picture matching task scores.…”

Section: Methodsmentioning

confidence: 99%

The impact of bilateral versus unilateral anterior temporal lobe damage on face recognition, person knowledge and semantic memory

Rouse,

Ramanan,

Halai

et al. 2024

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In recent years, the functional importance of the anterior temporal lobes (ATLs) has come to prominence in two active, albeit unconnected branches of the literature. In one branch, neuropsychology and functional neuroimaging evidence emphasises the role of the ATLs in face recognition and linking faces to biographical knowledge. In the other, cognitive and clinical neuroscience investigations have shown that the ATLs are critical to all forms of semantic memory. To draw these literatures together and generate a unified account of ATL function, we test the predictions arising from each literature and examine the effects of bilateral versus unilateral ATL damage on face recognition, person knowledge and semantic memory. Sixteen people with bilateral ATL atrophy from semantic dementia (SD), 17 people with unilateral ATL resection for temporal lobe epilepsy (TLE; left=10, right=7), and 14 controls completed a test battery encompassing general semantic processing, person knowledge and perceptual face matching. SD patients were severely impaired across all semantic tasks, including person knowledge. Despite commensurate total ATL damage, unilateral resection generated mild impairments, with minimal differences between left- and right-ATL resection. Face matching performance was largely preserved but slightly reduced in SD and right TLE. All groups displayed the classic familiarity effect in face matching; however, this benefit was reduced in SD and right TLE groups and was aligned with the level of item-specific semantic knowledge in all participants. We propose a unified neurocognitive framework whereby the ATLs underpin a resilient bilateral representation system that supports semantic memory, person knowledge and face recognition.

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Efficient and effective assessment of deficits and their neural bases in stroke aphasia

Cited by 16 publications

References 51 publications

Mapping the multidimensional geometric landscape of graded phenotypic variation and progression in neurodegenerative syndromes

Mapping the multidimensional geometric landscape of graded phenotypic variation and progression in neurodegenerative syndromes

Using in vivo functional and structural connectivity to predict chronic stroke aphasia deficits

The impact of bilateral versus unilateral anterior temporal lobe damage on face recognition, person knowledge and semantic memory

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