Recovering two languages with the right hemisphere

Marini, Andrea; Galetto, Valentina; Tatu, Karina; Duca, Sergio; Geminiani, Giuliano; Sacco, Katiuscia; Zettin, Marina

doi:10.1016/j.bandl.2016.05.014

Cited by 10 publications

(7 citation statements)

References 72 publications

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“…Attention to right hemisphere atrophy is consistent with contemporary models of aphasia recovery, which tend to emphasize worsening aphasia severity as damage spills out of core language regions and into non-language left hemisphere regions, and finally into right hemisphere regions 12 , 86 , 87 . This view offers a potential reconciliation of conflicting evidence about the contribution of the right hemisphere during language recovery as measured by functional neuroimaging studies 88 by proposing that worse outcomes are the consequence of more extensive left hemisphere damage that necessitates atypical involvement of the intact regions, which happen to be in the right hemisphere.…”

Section: Discussionsupporting

confidence: 79%

Distinct brain morphometry patterns revealed by deep learning improve prediction of aphasia severity

Teghipco

Newman‐Norlund

Fridriksson

et al. 2023

Preprint

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Emerging evidence suggests that post-stroke aphasia severity depends on the integrity of the brain beyond the stroke lesion. While measures of lesion anatomy and brain integrity combine synergistically to explain aphasic symptoms, significant interindividual variability remains unaccounted for. A possible explanatory factor may be the spatial distribution of brain atrophy beyond the lesion. This includes not just the specific brain areas showing atrophy, but also distinct three-dimensional patterns of atrophy. Here, we tested whether deep learning with Convolutional Neural Networks (CNN) on whole brain morphometry (i.e., segmented tissue volumes) and lesion anatomy can better predict which individuals with chronic stroke (N=231) have severe aphasia, and whether encoding spatial dependencies in the data might be capable of improving predictions by identifying unique individualized spatial patterns. We observed that CNN achieves significantly higher accuracy and F1 scores than Support Vector Machine (SVM), even when the SVM is nonlinear or integrates linear and nonlinear dimensionality reduction techniques. Performance parity was only achieved when the SVM was directly trained on the latent features learned by the CNN. Saliency maps demonstrated that the CNN leveraged widely distributed patterns of brain atrophy predictive of aphasia severity, whereas the SVM focused almost exclusively on the area around the lesion. Ensemble clustering of CNN saliency maps revealed distinct morphometry patterns that were unrelated to lesion size, highly consistent across individuals, and implicated unique brain networks associated with different cognitive processes as measured by the wider neuroimaging literature. Individualized predictions of severity depended on both ipsilateral and contralateral features outside of the location of stroke. Our findings illustrate that three-dimensional network distributions of atrophy in individuals with aphasia are directly associated with aphasia severity, underscoring the potential for deep learning to improve prognostication of behavioral outcomes from neuroimaging data, and highlighting the prospective benefits of interrogating spatial dependence at different scales in multivariate feature space.

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Section: Discussionsupporting

confidence: 79%

Distinct brain morphometry patterns revealed by deep learning improve prediction of aphasia severity

Teghipco

Newman‐Norlund

Fridriksson

et al. 2023

Preprint

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“…Finally, there were nine studies that investigated shifting ability in bPWA. Six studies, including 15 participants, found it to be impaired (Adrover-Roig et al, 2011; Kohnert, 2004; Kong et al, 2014; Lee et al, 2016; Marini et al, 2016; Penn et al, 2017), and three studies, including four participants, report unimpaired shifting abilities (Aglioti, Beltramello, Girardi & Fabbro, 1996; Mariën et al, 2017; Penn et al, 2010).…”

Section: Resultsmentioning

confidence: 99%

“…Evaluating the influence of aphasia severity proved to be difficult, as this is operationalized differently across studies. But at first sight, it appears that all studies that included patients with (moderate to) severe aphasia also report deficits in EC (Keane & Kiran, 2015; Kohnert, 2004; Kong et al, 2014; Lee et al, 2016; Leemann et al, 2007; Marini et al, 2016; Penn et al, 2017; Van der Linden et al, 2018a).…”

Section: Discussionmentioning

confidence: 99%

Executive control in bilingual aphasia: a systematic review

et al. 2021

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Much research has been dedicated to the effects of bilingualism on executive control (EC). For bilinguals with aphasia, the interplay with EC is complex. In this systematic review, we synthesize research on this topic and provide an overview of the current state of the field. First, we examine the evidence for EC deficits in bilingual persons with aphasia (bPWA). We then discuss the domain generality of bilingual language control impairments. Finally, we evaluate the bilingual advantage hypothesis in bPWA. We conclude that (1) EC impairments in bPWA are frequently observed, (2) experimental results on the relationship between linguistic and domain-general control are mixed, (3) bPWA with language control problems in everyday communication have domain-general EC problems, and (4) there are indications for EC advantages in bPWA. We end with directions for experimental work that could provide better insight into the intricate relationship between EC and bilingual aphasia.

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“…However, there is also some evidence to suggest that patients who managed to achieve a full language recovery and exclusively showed an activity in the homologous language areas of the right hemisphere ( Thompson and den Ouden, 2008 ; Marini et al, 2016 ). It is believed that this has a greater chance of occurring in case of more severe left hemisphere damage leaving little to no perilesional tissue left ( Marini et al, 2016 ). In these cases, the inhibitory signal toward the healthy hemisphere would be missing and the right hemisphere would consequently be hyperactive ( Thompson and den Ouden, 2008 ).…”

Section: Patientsmentioning

confidence: 99%

Transcranial Direct-Current Stimulation and Behavioral Training, a Promising Tool for a Tailor-Made Post-stroke Aphasia Rehabilitation: A Review

Zettin

Bondesan

Nada

et al. 2021

Front. Hum. Neurosci.

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Aphasia is an acquired language disorder resulting from damage to portions of the brain which are responsible for language comprehension and formulation. This disorder can involve different levels of language processing with impairments in both oral and written comprehension and production. Over the last years, different rehabilitation and therapeutic interventions have been developed, especially non-invasive brain stimulation (NIBS) techniques. One of the most used NIBS techniques in aphasia rehabilitation is the Transcranial Direct-Current Stimulation (tDCS). It has been proven to be effective in promoting a successful recovery both in the short and the long term after a brain injury. The main strength of tDCS is its feasibility associated with relatively minor side effects, if safely and properly administered. TDCS requires two electrodes, an anode and a cathode, which are generally placed on the scalp. The electrode montage can be either unipolar or bipolar. The main aim of this review is to give an overview of the state of the art of tDCS for the treatment of aphasia. The studies described included patients with different types of language impairments, especially with non-fluent aphasia and in several cases anomia. The effects of tDCS are variable and depend on several factors, such as electrode size and montage, duration of the stimulation, current density and characteristics of the brain tissue underneath the electrodes. Generally, tDCS has led to promising results in rehabilitating patients with acquired aphasia, especially if combined with different language and communication therapies. The selection of the appropriate approach depends on the patients treated and their impaired language function. When used in combination with treatments such as Speech and Language Therapy, Constraint Induced Aphasia Therapy or Intensive Action Treatment, tDCS has generally promoted a better recovery of the impaired functions. In addition to these rehabilitation protocols, Action Observation Therapy, such as IMITAF, appeared to contribute to the reduction of post-stroke anomia. The potential of combining such techniques with tDCS would would therefore be a possibility for further improvement, also providing the clinician with a new action and intervention tool. The association of a tDCS protocol with a dedicated rehabilitation training would favor a generalized long-term improvement of the different components of language.

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Recovering two languages with the right hemisphere

Cited by 10 publications

References 72 publications

Distinct brain morphometry patterns revealed by deep learning improve prediction of aphasia severity

Distinct brain morphometry patterns revealed by deep learning improve prediction of aphasia severity

Executive control in bilingual aphasia: a systematic review

Transcranial Direct-Current Stimulation and Behavioral Training, a Promising Tool for a Tailor-Made Post-stroke Aphasia Rehabilitation: A Review

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