scholarly journals Using principal component analysis to capture individual differences within a unified neuropsychological model of chronic post-stroke aphasia: Revealing the unique neural correlates of speech fluency, phonology and semantics

Cortex ◽  
2017 ◽  
Vol 86 ◽  
pp. 275-289 ◽  
Author(s):  
Ajay D. Halai ◽  
Anna M. Woollams ◽  
Matthew A. Lambon Ralph
Keyword(s):  
Principal Component Analysis ◽  
Individual Differences ◽  
Principal Component ◽  
Component Analysis ◽  
Neural Correlates ◽  
Speech Fluency ◽  
Post Stroke

scholarly journals Evaluating the granularity and statistical structure of lesions and behaviour in post-stroke aphasia

2020 ◽  
Vol 2 (2) ◽  
Author(s):  
Ying Zhao ◽  
Ajay D Halai ◽  
Matthew A Lambon Ralph
Keyword(s):  
Principal Component Analysis ◽  
Middle Cerebral Artery ◽  
Cerebral Artery ◽  
Principal Component ◽  
Component Analysis ◽  
Vascular Supply ◽  
Angular Gyrus ◽  
Statistical Structure ◽  
Speech Fluency ◽  
Post Stroke

Abstract The pursuit of relating the location of neural damage to the pattern of acquired language and general cognitive deficits post-stroke stems back to the 19th century behavioural neurology. While spatial specificity has improved dramatically over time, from the large areas of damage specified by post-mortem investigation to the millimetre precision of modern MRI, there is an underlying issue that is rarely addressed, which relates to the fact that damage to a given area of the brain is not random but constrained by the brain’s vasculature. Accordingly, the aim of this study was to uncover the statistical structure underlying the lesion profile in chronic aphasia post-stroke. By applying varimax-rotated principal component analysis to the lesions of 70 patients with chronic post-stroke aphasia, we identified 17 interpretable clusters, largely reflecting the vascular supply of middle cerebral artery sub-branches and other sources of individual variation in vascular supply as shown in classical angiography studies. This vascular parcellation produced smaller displacement error in simulated lesion–symptom analysis compared with individual voxels and Brodmann regions. A second principal component analysis of the patients’ detailed neuropsychological data revealed a four-factor solution reflecting phonological, semantic, executive-demand and speech fluency abilities. As a preliminary exploration, stepwise regression was used to relate behavioural factor scores to the lesion principal components. Phonological ability was related to two components, which covered the posterior temporal region including the posterior segment of the arcuate fasciculus, and the inferior frontal gyrus. Three components were linked to semantic ability and were located in the white matter underlying the anterior temporal lobe, the supramarginal gyrus and angular gyrus. Executive-demand related to two components covering the dorsal edge of the middle cerebral artery territory, while speech fluency was linked to two components that were located in the middle frontal gyrus, precentral gyrus and subcortical regions (putamen and thalamus). Future studies can explore in formal terms the utility of these principal component analysis-derived lesion components for relating post-stroke lesions and symptoms.

scholarly journals Evaluating the granularity and statistical structure of lesions and behaviour in post-stroke aphasia

2019 ◽  
Author(s):  
Ying Zhao ◽  
Ajay D. Halai ◽  
Matthew A. Lambon Ralph
Keyword(s):  
Principal Component Analysis ◽  
Middle Cerebral Artery ◽  
Cerebral Artery ◽  
Principal Component ◽  
Component Analysis ◽  
Vascular Supply ◽  
Angular Gyrus ◽  
Statistical Structure ◽  
Speech Fluency ◽  
Post Stroke

AbstractThe pursuit of relating the location of neural damage to the pattern of acquired language and general cognitive deficits post-stroke stems back to 19th century behavioural neurology. Whilst spatial specificity has improved dramatically over time, from the large areas of damage specified by post-mortem investigation to the millimetre precision of modern MRI, there is an underlying issue that is rarely addressed, which relates to the fact that damage to a given area of the brain is not random but constrained by the brain’s vasculature. Accordingly, the aim of this study was to uncover the statistical structure underlying the lesion profile in chronic aphasia post-stroke. By applying varimax-rotated principal component analysis to the lesions of 70 patients with chronic post-stroke aphasia, we identified 17 interpretable clusters, largely reflecting the vascular supply of middle cerebral artery sub-branches and other sources of individual variation in vascular supply as shown in classical angiography studies. This vascular parcellation produced smaller displacement error in simulated lesion-symptom analysis compared with individual voxels and Brodmann regions. A second principal component analysis of the patients’ detailed neuropsychological data revealed a four factor solution reflecting phonological, semantic, executive-demand and speech fluency abilities. As a preliminary exploration, stepwise regression was used to relate behavioural factor scores to the lesion principal components. Phonological ability was related to two components, which covered the posterior temporal region including the posterior segment of the arcuate fasciculus, and the inferior frontal gyrus. Three components were linked to semantic ability and were located in the white matter underlying the anterior temporal lobe, the supramarginal gyrus and angular gyrus. Executive-demand related to two components covering the dorsal edge of the middle cerebral artery territory, while speech fluency was linked to two components that were located in the middle frontal gyrus, precentral gyrus, and subcortical regions (putamen and thalamus). Future studies can explore in formal terms the utility of these PCA-derived lesion components for relating post-stroke lesions and symptoms.

scholarly journals A new methodology based on functional principal component analysis to study postural stability post-stroke

2018 ◽  
Vol 56 ◽  
pp. 18-26 ◽  
Author(s):  
M. Luz Sánchez-Sánchez ◽  
Juan-Manuel Belda-Lois ◽  
Silvia Mena-del Horno ◽  
Enrique Viosca-Herrero ◽  
Celedonia Igual-Camacho ◽  
...  
Keyword(s):  
Principal Component Analysis ◽  
Postural Stability ◽  
Principal Component ◽  
Component Analysis ◽  
Functional Principal Component Analysis ◽  
Post Stroke ◽  
Functional Principal Component

scholarly journals A unified model of post-stroke language deficits including discourse production and their neural correlates

Brain ◽  
2020 ◽  
Vol 143 (5) ◽  
pp. 1541-1554 ◽  
Author(s):  
Reem S W Alyahya ◽  
Ajay D Halai ◽  
Paul Conroy ◽  
Matthew A Lambon Ralph
Keyword(s):  
Principal Component Analysis ◽  
White Matter ◽  
Speech Production ◽  
Principal Component ◽  
Neural Correlates ◽  
Unified Model ◽  
Connected Speech ◽  
Lexical Diversity ◽  
Post Stroke ◽  
Procedural Discourse

Abstract The clinical profiles of individuals with post-stroke aphasia demonstrate considerable variation in the presentation of symptoms. Recent aphasiological studies have attempted to account for this individual variability using a multivariate data-driven approach (principal component analysis) on an extensive neuropsychological and aphasiological battery, to identify fundamental domains of post-stroke aphasia. These domains mainly reflect phonology, semantics and fluency; however, these studies did not account for variability in response to different forms of connected speech, i.e. discourse genres. In the current study, we initially examined differences in the quantity, diversity and informativeness between three different discourse genres, including a simple descriptive genre and two naturalistic forms of connected speech (storytelling narrative, and procedural discourse). Subsequently, we provided the first quantitative investigation on the multidimensionality of connected speech production at both behavioural and neural levels. Connected speech samples across descriptive, narrative, and procedural discourse genres were collected from 46 patients with chronic post-stroke aphasia and 20 neurotypical adults. Content analyses conducted on all connected speech samples indicated that performance differed across discourse genres and between groups. Specifically, storytelling narratives provided higher quantities of content words and lexical diversity compared to composite picture description and procedural discourse. The analyses further revealed that, relative to neurotypical adults, patients with aphasia, both fluent and non-fluent, showed reduction in the quantity of verbal production, lexical diversity, and informativeness across all discourses. Given the differences across the discourses, we submitted the connected speech metrics to principal component analysis alongside an extensive neuropsychological/aphasiological battery that assesses a wide range of language and cognitive skills. In contrast to previous research, three unique orthogonal connected speech components were extracted in a unified model, reflecting verbal quantity, verbal quality, and motor speech, alongside four core language and cognitive components: phonological production, semantic processing, phonological recognition, and executive functions. Voxel-wise lesion-symptom mapping using these components provided evidence on the involvement of widespread cortical regions and their white matter connections. Specifically, left frontal regions and their underlying white matter tracts corresponding to the frontal aslant tract and the anterior segment of the arcuate fasciculus were particularly engaged with the quantity and quality of fluent connected speech production while controlling for other co-factors. The neural correlates associated with the other language domains align with existing models on the ventral and dorsal pathways for language processing.

scholarly journals Dissecting individual differences in responses to naturalistic stimuli in functional MRI: effects of development and gender

2020 ◽  
Author(s):  
Xin Di ◽  
Bharat B. Biswal
Keyword(s):  
Principal Component Analysis ◽  
Individual Differences ◽  
Functional Mri ◽  
Principal Component ◽  
Component Analysis ◽  
Gender Effects ◽  
Delayed Response ◽  
List Type ◽  
And Gender ◽  
The Individual

AbstractFunctional MRI (fMRI) study of naturalistic conditions, e.g. movie watching, usually focuses on shared responses across subjects. However, individual differences in the responses have been attracting increasing attention in search of group differences or associations with behavioral outcomes. The individual differences have been studied by directly modeling the cross-subject correlation matrix or projecting the relations into a 1-D space. We contend that it is critical to examine whether there are single or multiple consistent components of responses underlying the whole population, because multiple components may undermine the individual relations using the previous methods. We use principal component analysis (PCA) to examine the heterogeneity of brain responses across subjects in terms of the eigenvalues of the covariance matrix, and utilize this approach to study developmental trajectories and gender effects in a movie watching dataset. We identified several brain networks in the parietal cortex that showed a significant second principal component (PC) of regional responses, which were mainly represented the younger children. The second PCs in some networks, i.e. the supramarginal network, resembled a delayed version of the first PCs for 4 seconds (2 TR), indicating delayed responses in the younger children than the older children and adults. However, no apparent gender effects were found in the first and second PCs. The analyses highlight the importance of identifying multiple consistent responses underlying individual differences in responses to naturalistic stimuli. And the PCA-based approach could be complementary to the commonly used intersubject correlation analysis.HighlightsThere may be multiple consistent responses among subjects during movie watchingPrincipal component analysis can be used to identify the multiple consistent responsesMany brain regions showed two principal components that were separated by ageYounger children showed delayed response in the supramarginal gyrus and precuneus

scholarly journals Neural correlates of impaired vocal emotion perception: New insights from principal component analysis

2015 ◽  
Vol 9 ◽  
Author(s):  
Kershaw Kelly ◽  
Rushby Jacqueline ◽  
McDonald Skye ◽  
De Blasio Frances ◽  
Sufani Christopher ◽  
...  
Keyword(s):  
Principal Component Analysis ◽  
Emotion Perception ◽  
Principal Component ◽  
Component Analysis ◽  
Neural Correlates ◽  
Vocal Emotion

Types and variables: towards a congenial procedure for handling personality data

2002 ◽  
Vol 16 (1_suppl) ◽  
pp. S89-S96 ◽  
Author(s):  
Willem K. B. Hofstee
Keyword(s):  
Principal Component Analysis ◽  
Individual Differences ◽  
Personality Assessment ◽  
Principal Component ◽  
Component Analysis ◽  
Cross Product ◽  
Standard Procedures ◽  
Individual Comparison

Standard procedures for processing and interpreting data in personality assessment run the risk of losing their audience. Most notably, relative scaling of data, whether through interindividual or intra‐individual comparison, leads to losing either the persons or the variables from view. I set out an alternative, more congenial procedure for handling personality data, consisting of (i) translating assessments to a bipolar bounded scale running from − 1 to + 1, (ii) adopting the uncorrected average cross‐product (ACP) as the index of association or correspondence between variables and between individuals, and (iii) applying raw‐scores principal component analysis to find factors and types. The ACP index appears eminently fit for handling individual (N = 1) cases. Adoption of the congenial procedure would imply a substantive correction of one's views of individual differences in personality and their structure. Copyright © 2002 John Wiley & Sons, Ltd.

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