Electrophysiological connectivity markers of preserved language functions in post-stroke aphasia

Shah-Basak, Priyanka P.; Sivaratnam, Gayatri; Teti, Selina; Deschamps, Tiffany; Kielar, Aneta; Jokel, Regina; Meltzer, Jed A.

doi:10.1016/j.nicl.2022.103036

Cited by 9 publications

(10 citation statements)

References 63 publications

(78 reference statements)

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“…Interestingly, these cognitive functions were recently shown to be intact in PWA (Schevenels et al, 2022), leading to the speculation that protective or compensatory mechanisms might be reflected in weakened low-gamma-band network. Our results may seem in contrast with previous studies reporting either stronger connectivity (Snyder et al, 2021) or alteration in alpha- and beta-band networks (P. Shah-Basak et al, 2022) in chronic aphasia. This inconsistency is likely to be due to the chosen measure of connectivity strength, i.e., WPLI vs amplitude or power envelope correlation, and possibly the experimental paradigm, i.e.…”

Section: Discussioncontrasting

confidence: 99%

“…In the delta-band, the detected component comprised a cluster over the left temporo-parietal region, likely involving the language area, as well as frontal inter-hemispheric connectivity. Previous research reported a correlation between decrease of cortical activity and speech fluency, whilst there is still contrasting evidence from the network perspective (Fridriksson et al, 2012, 2015; P. Shah-Basak et al, 2022; Woodhead et al, 2017). A recent EEG study demonstrated an association between the delta-band activity and the perception of rhythmic properties of speech (Boucher et al, 2019).…”

Section: Discussionmentioning

confidence: 85%

“…According to resting-state M/EEG-based graph theory studies, the functional brain connectome in acute aphasia features alterations in its geometrical properties, which include reduced network segregation in delta- and theta-band networks at the acute stage compared to healthy condition (Caliandro et al, 2017), and an association between node degree of Broca area and subsequent language improvement (Nicolo et al, 2015). At the chronic stage, patients show left-hemispheric reduction of connectivity strength in alpha- and beta- bands, with an increase in a local low-gamma band subnetwork compared with healthy people (P. Shah-Basak et al, 2022; Snyder et al, 2021). Furthermore, left-hemispheric alpha and centro-frontal beta connectivity are reportedly associated with alteration of speech processing (P. Shah-Basak et al, 2022).…”

Section: Introductionmentioning

confidence: 99%

“…At the chronic stage, patients show left-hemispheric reduction of connectivity strength in alpha- and beta- bands, with an increase in a local low-gamma band subnetwork compared with healthy people (P. Shah-Basak et al, 2022; Snyder et al, 2021). Furthermore, left-hemispheric alpha and centro-frontal beta connectivity are reportedly associated with alteration of speech processing (P. Shah-Basak et al, 2022).…”

Section: Introductionmentioning

confidence: 99%

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EEG reveals brain network alterations in chronic aphasia during natural speech listening

Mehraram

Kries

Clercq

et al. 2023

Preprint

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Aphasia is a common consequence of a stroke which affects language processing. In search of an objective biomarker for aphasia, we used EEG to investigate how functional network patterns in the cortex are affected in persons with post-stroke chronic aphasia (PWA) compared to healthy controls (HC) while they are listening to a story. EEG was recorded from 22 HC and 27 PWA while they listened to a 25-min-long story. Functional connectivity between scalp regions was measured with the weighted phase lag index. The Network-Based Statistics toolbox was used to detect altered network patterns and to investigate correlations with behavioural tests within the aphasia group. Differences in network geometry were assessed by means of graph theory and a targeted node-attack approach. Group-classification accuracy was obtained with a support vector machine classifier. PWA showed stronger inter-hemispheric connectivity compared to HC in the theta-band (4.5-7 Hz), whilst a weaker subnetwork emerged in the low-gamma band (30.5-49 Hz). Two subnetworks correlated with semantic fluency in PWA respectively in delta- (1-4 Hz) and low-gamma-bands. In the theta-band network, graph alterations in PWA emerged at both local and global level, whilst only local changes were found in the low-gamma-band network. As assessed with the targeted node-attack, PWA exhibit a more scale-free network compared to HC. Network metrics effectively discriminated PWA and HC (AUC = 83%). Overall, we showed for that EEG-network metrics are effective biomarkers to assess natural speech processing in chronic aphasia. We hypothesize that the detected alterations reflect compensatory mechanisms associated with recovery.

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Section: Discussioncontrasting

confidence: 99%

Section: Discussionmentioning

confidence: 85%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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EEG reveals brain network alterations in chronic aphasia during natural speech listening

Mehraram

Kries

Clercq

et al. 2023

Preprint

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“…Across the range of PPA subtypes, anodal electrode placement has been examined in temporoparietal regions ( Hung et al, 2017 ; Roncero et al, 2017 ; Shah-Basak et al, 2022 ), dorsolateral prefrontal cortex ( Cotelli et al, 2014 , 2016 ), and the inferior frontal lobe ( Ficek et al, 2018 ; Tsapkini et al, 2018 ; de Aguiar et al, 2022 ). In the context of lvPPA, treatment may logically be directed toward strengthening weakened phonological processes associated with temporoparietal atrophy.…”

Section: Introductionmentioning

confidence: 99%

Positive changes to written language following phonological treatment in logopenic variant primary progressive aphasia: Case report

Nickels

Beeson

Rising

et al. 2023

Front. Hum. Neurosci.

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Phonological impairment contributes to deficits in repetition and spoken naming in logopenic variant Primary Progressive Aphasia (lvPPA), but weakened phonology can also affect written language skills. In this experimental case report, we demonstrate phonological text agraphia in a 71-year-old woman in the early stages of lvPPA that undermined her ability to write meaningful, grammatical sentences. We investigated the therapeutic value of a rigorous treatment protocol to strengthen phonological manipulation skills coupled with transcranial direct current stimulation (tDCS). Intervention took place 5 days a week for 2 weeks with active tDCS, followed by a 2-month rest period, and then a second period of phonological treatment with sham tDCS. Over the course of treatment, our participant demonstrated improved phonological transcoding and manipulation skills as well as marked improvement in the proportion of grammatically well-formed, meaningful written narratives. Improvements in spelling and letter selection were also observed. Treatment gains were documented during phonological intervention in both active tDCS and sham treatment phases and were maintained 2 months after the conclusion of intervention. Importantly, improvements were observed in the context of a progressive disorder. These data present compelling evidence regarding the impairment-based approach that targets compromised phonological skills, presenting opportunity for improving functional written communication skills relevant to the everyday lives of individuals with lvPPA.

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Functional and Effective Connectivity Underlying Semantic Verbal Fluency

Arrigo,

da Silva,

Leoni

2024

Brain Topogr

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Electrophysiological connectivity markers of preserved language functions in post-stroke aphasia

Cited by 9 publications

References 63 publications

EEG reveals brain network alterations in chronic aphasia during natural speech listening

EEG reveals brain network alterations in chronic aphasia during natural speech listening

Positive changes to written language following phonological treatment in logopenic variant primary progressive aphasia: Case report

Functional and Effective Connectivity Underlying Semantic Verbal Fluency

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