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Lee S, Faroqi-Shah Y. A Meta-Analysis of Anomia Treatment in Bilingual Aphasia: Within- and Cross-Language Generalization and Predictors of the Treatment Outcomes. JOURNAL OF SPEECH, LANGUAGE, AND HEARING RESEARCH : JSLHR 2024; 67:1558-1600. [PMID: 38629966 PMCID: PMC11087086 DOI: 10.1044/2024_jslhr-23-00026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Revised: 09/15/2023] [Accepted: 01/14/2024] [Indexed: 05/09/2024]
Abstract
PURPOSE The present meta-analysis investigated the efficacy of anomia treatment in bilingual and multilingual persons with aphasia (BPWAs) by assessing the magnitudes of six anomia treatment outcomes. Three of the treatment outcomes pertained to the "trained language": improvement of trained words (treatment effect [TE]), within-language generalization of semantically related untrained words (WLG-Related), and within-language generalization of unrelated words (WLG-Unrelated). Three treatment outcomes were for the "untrained language": improvement of translations of the trained words (cross-language generalization of trained words [CLG-Tx]), cross-language generalization of semantically related untrained words (CLG-Related), and cross-language generalization of unrelated untrained words (CLG-Unrelated). This study also examined participant- and treatment-related predictors of these treatment outcomes. METHOD This study is registered in the International Prospective Register of Systematic Reviews (PROSPERO) under the number CRD42023418147. Nine electronic databases were searched to identify word retrieval treatment studies of poststroke BPWAs of at least 6 months postonset. Pre- and posttreatment single-word naming scores were extracted for each eligible participant and used to calculate effect sizes (within-case Cohen's d) of the six treatment outcomes. Random-effects meta-analyses were conducted to assess weighted mean effect sizes of the treatment outcomes across studies. Multiple linear regression analyses were used to examine the effects of participant-related variables (pretreatment single-word naming and comprehension representing poststroke lexical processing abilities) and treatment-related variables (type, language, and duration). The methodological quality of eligible studies and the risk of bias in this meta-analysis were assessed. RESULTS A total of 17 published studies with 39 BPWAs were included in the meta-analysis. The methodological quality of the included studies ranged from fair (n = 4) to good (n = 13). Anomia treatment produced a medium effect size for TE (M = 8.36) and marginally small effect sizes for WLG-Related (M = 1.63), WLG-Unrelated (M = 0.68), and CLG-Tx (M = 1.56). Effect sizes were nonsignificant for CLG-Related and CLG-Unrelated. TE was significantly larger than the other five types of treatment outcomes. TE and WLG-Related effect sizes were larger for BPWAs with milder comprehension or naming impairments and for treatments of longer duration. WLG-Unrelated was larger when BPWAs received phonological treatment than semantic and mixed treatments. The overall risk of bias in the meta-analysis was low with a potential risk of bias present in the study identification process. CONCLUSIONS Current anomia treatment practices for bilingual speakers are efficacious in improving trained items but produce marginally small within-language generalization and cross-language generalization to translations of the trained items. These results highlight the need to provide treatment in each language of BPWAs and/or investigate other approaches to promote cross-language generalization. Furthermore, anomia treatment outcomes are influenced by BPWAs' poststroke single-word naming and comprehension abilities as well as treatment duration and the provision of phonological treatment. SUPPLEMENTAL MATERIAL https://doi.org/10.23641/asha.25595712.
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Affiliation(s)
- Seongsil Lee
- Department of Hearing and Speech Sciences, University of Maryland, College Park
| | - Yasmeen Faroqi-Shah
- Department of Hearing and Speech Sciences, University of Maryland, College Park
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Gnedykh D, Tsvetova D, Mkrtychian N, Blagovechtchenski E, Kostromina S, Shtyrov Y. tDCS of right-hemispheric Wernicke's area homologue affects contextual learning of novel lexicon. Neurobiol Learn Mem 2024; 210:107905. [PMID: 38403010 DOI: 10.1016/j.nlm.2024.107905] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2023] [Revised: 11/01/2023] [Accepted: 02/21/2024] [Indexed: 02/27/2024]
Abstract
Numerous studies have shown robust evidence of the right hemisphere's involvement in the language function, for instance in the processing of intonation, grammar, word meanings, metaphors, etc. However, its role in lexicon acquisition remains obscure. We applied transcranial direct current stimulation (tDCS) over the right-hemispheric homologue of Wernicke's area to assess its putative involvement in the processing of different types of novel semantics. After receiving 15 min of anodal, cathodal, or sham (placebo) tDCS, three groups of healthy participants learnt novel concrete and abstract words in the context of short stories. Learning outcomes were assessed using a battery of tests immediately after this contextual learning session and 24 h later. As a result, an inhibitory effect of cathodal tDCS and a facilitatory effect of anodal tDCS were found for abstract word acquisition only. We also found a significant drop in task performance on the second day of the assessment for both word types in all the stimulation groups, suggesting no significant influence of tDCS on the post-learning consolidation of new memory traces. The results suggest an involvement of Wernicke's right-hemispheric counterpart in initial encoding (but not consolidation) of abstract semantics, which may be explained either by the right hemispheres direct role in processing lexical semantics or by an indirect impact of tDCS on contralateral (left-hemispheric) cortical areas through cross-callosal connections.
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Affiliation(s)
- Daria Gnedykh
- Laboratory of Behavioural Neurodynamics, St. Petersburg State University, 199034 St. Petersburg, Russia; Department of Psychology, St. Petersburg State University, 199034 St. Petersburg, Russia.
| | - Diana Tsvetova
- Laboratory of Behavioural Neurodynamics, St. Petersburg State University, 199034 St. Petersburg, Russia
| | - Nadezhda Mkrtychian
- Laboratory of Behavioural Neurodynamics, St. Petersburg State University, 199034 St. Petersburg, Russia
| | - Evgeny Blagovechtchenski
- Laboratory of Behavioural Neurodynamics, St. Petersburg State University, 199034 St. Petersburg, Russia; Department of Psychology, St. Petersburg State University, 199034 St. Petersburg, Russia
| | - Svetlana Kostromina
- Laboratory of Behavioural Neurodynamics, St. Petersburg State University, 199034 St. Petersburg, Russia; Department of Psychology, St. Petersburg State University, 199034 St. Petersburg, Russia
| | - Yury Shtyrov
- Center of Functionally Integrative Neuroscience (CFIN), Department of Clinical Medicine, Aarhus University, 8000 Aarhus, Denmark
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Varkanitsa M, Kiran S. Insights gained over 60 years on factors shaping post-stroke aphasia recovery: A commentary on Vignolo (1964). Cortex 2024; 170:90-100. [PMID: 38123405 PMCID: PMC10962385 DOI: 10.1016/j.cortex.2023.12.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 12/01/2023] [Accepted: 12/04/2023] [Indexed: 12/23/2023]
Abstract
Aphasia is an acquired language disorder resulting from brain injury, including strokes which is the most common etiology, neurodegenerative diseases, tumors, traumatic brain injury, and resective surgery. Aphasia affects a significant portion of stroke survivors, with approximately one third experiencing its debilitating effects in the long term. Despite its challenges, there is growing evidence that recovery from aphasia is possible, even in the chronic phase of stroke. Sixty years ago, Vignolo (1964) outlined the primary challenges confronted by researchers in this field. These challenges encompassed the absence of an objective evaluation of language difficulties, the scarcity of evidence regarding spontaneous aphasia recovery, and the presence of numerous variables that could potentially influence the process of aphasia recovery. In this paper, we discuss the remarkable progress that has been made in the assessment of language and communication in aphasia as well as in understanding the factors influencing post-stroke aphasia recovery.
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Affiliation(s)
| | - Swathi Kiran
- Center for Brain Recovery, Boston University, USA
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Simic T, Desjardins MÈ, Courson M, Bedetti C, Houzé B, Brambati SM. Treatment-induced neuroplasticity after anomia therapy in post-stroke aphasia: A systematic review of neuroimaging studies. BRAIN AND LANGUAGE 2023; 244:105300. [PMID: 37633250 DOI: 10.1016/j.bandl.2023.105300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Revised: 05/02/2023] [Accepted: 06/21/2023] [Indexed: 08/28/2023]
Abstract
We systematically reviewed the literature on neural changes following anomia treatment post-stroke. We conducted electronic searches of CINAHL, Cochrane Trials, Embase, Ovid MEDLINE, MEDLINE-in-Process and PsycINFO databases; two independent raters assessed all abstracts and full texts. Accepted studies reported original data on adults with post-stroke aphasia, who received behavioural treatment for anomia, and magnetic resonance brain imaging (MRI) pre- and post-treatment. Search results yielded 2481 citations; 33 studies were accepted. Most studies employed functional MRI and the quality of reporting neuroimaging methodology was variable, particularly for pre-processing steps and statistical analyses. The most methodologically robust data were synthesized, focusing on pre- versus post-treatment contrasts. Studies more commonly reported increases (versus decreases) in activation following naming therapy, primarily in the left supramarginal gyrus, and left/bilateral precunei. Our findings highlight the methodological heterogeneity across MRI studies, and the paucity of robust evidence demonstrating direct links between brain and behaviour in anomia rehabilitation.
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Affiliation(s)
- Tijana Simic
- Centre de Recherche de l'Institut Universitaire de Gériatrie de Montréal (CRIUGM), 4545 Queen Mary R.d., Montréal, QC H3W 1W4, Canada; Département de Psychologie, Université de Montréal, 90 Vincent-d'Indy Avenue, Montréal, QC H2V 2S9, Canada; Hôpital du Sacré-Cœur de Montréal (HSCM), 5400 Boul Gouin O, Montréal, QC H4J 1C5, Canada.
| | - Marie-Ève Desjardins
- Centre de Recherche de l'Institut Universitaire de Gériatrie de Montréal (CRIUGM), 4545 Queen Mary R.d., Montréal, QC H3W 1W4, Canada; Département de Psychologie, Université de Montréal, 90 Vincent-d'Indy Avenue, Montréal, QC H2V 2S9, Canada; Hôpital du Sacré-Cœur de Montréal (HSCM), 5400 Boul Gouin O, Montréal, QC H4J 1C5, Canada
| | - Melody Courson
- Centre de Recherche de l'Institut Universitaire de Gériatrie de Montréal (CRIUGM), 4545 Queen Mary R.d., Montréal, QC H3W 1W4, Canada; Département de Psychologie, Université de Montréal, 90 Vincent-d'Indy Avenue, Montréal, QC H2V 2S9, Canada
| | - Christophe Bedetti
- Centre de Recherche de l'Institut Universitaire de Gériatrie de Montréal (CRIUGM), 4545 Queen Mary R.d., Montréal, QC H3W 1W4, Canada
| | - Bérengère Houzé
- Centre de Recherche de l'Institut Universitaire de Gériatrie de Montréal (CRIUGM), 4545 Queen Mary R.d., Montréal, QC H3W 1W4, Canada; Département de Psychologie, Université de Montréal, 90 Vincent-d'Indy Avenue, Montréal, QC H2V 2S9, Canada
| | - Simona Maria Brambati
- Centre de Recherche de l'Institut Universitaire de Gériatrie de Montréal (CRIUGM), 4545 Queen Mary R.d., Montréal, QC H3W 1W4, Canada; Département de Psychologie, Université de Montréal, 90 Vincent-d'Indy Avenue, Montréal, QC H2V 2S9, Canada; Hôpital du Sacré-Cœur de Montréal (HSCM), 5400 Boul Gouin O, Montréal, QC H4J 1C5, Canada
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Meier EL. The role of disrupted functional connectivity in aphasia. HANDBOOK OF CLINICAL NEUROLOGY 2022; 185:99-119. [PMID: 35078613 DOI: 10.1016/b978-0-12-823384-9.00005-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Language is one of the most complex and specialized higher cognitive processes. Brain damage to the distributed, primarily left-lateralized language network can result in aphasia, a neurologic disorder characterized by receptive and/or expressive deficits in spoken and/or written language. Most often, aphasia is the consequence of stroke-termed poststroke aphasia (PSA)-yet, aphasia can also manifest due to neurodegenerative disease, specifically, a disorder called primary progressive aphasia (PPA). In recent years, functional connectivity neuroimaging studies have provided emerging evidence supporting theories regarding the relationships between language impairments, structural brain damage, and functional network properties in these two disorders. This chapter reviews the current evidence for the "network phenotype of stroke injury" hypothesis (Siegel et al., 2016) as it pertains to PSA and the "network degeneration hypothesis" (Seeley et al., 2009) as it pertains to PPA. Methodologic considerations for functional connectivity studies, limitations of the current functional connectivity literature in aphasia, and future directions are also discussed.
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Affiliation(s)
- Erin L Meier
- Department of Communication Sciences and Disorders, Northeastern University, Boston, MA, United States.
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Schevenels K, Price CJ, Zink I, De Smedt B, Vandermosten M. A Review on Treatment-Related Brain Changes in Aphasia. NEUROBIOLOGY OF LANGUAGE (CAMBRIDGE, MASS.) 2020; 1:402-433. [PMID: 37215585 PMCID: PMC10158631 DOI: 10.1162/nol_a_00019] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Accepted: 06/29/2020] [Indexed: 05/24/2023]
Abstract
Numerous studies have investigated brain changes associated with interventions targeting a range of language problems in patients with aphasia. We strive to integrate the results of these studies to examine (1) whether the focus of the intervention (i.e., phonology, semantics, orthography, syntax, or rhythmic-melodic) determines in which brain regions changes occur; and (2a) whether the most consistent changes occur within the language network or outside, and (2b) whether these are related to individual differences in language outcomes. The results of 32 studies with 204 unique patients were considered. Concerning (1), the location of treatment-related changes does not clearly depend on the type of language processing targeted. However, there is some support that rhythmic-melodic training has more impact on the right hemisphere than linguistic training. Concerning (2), we observed that language recovery is not only associated with changes in traditional language-related structures in the left hemisphere and homolog regions in the right hemisphere, but also with more medial and subcortical changes (e.g., precuneus and basal ganglia). Although it is difficult to draw strong conclusions, because there is a lack of systematic large-scale studies on this topic, this review highlights the need for an integrated approach to investigate how language interventions impact on the brain. Future studies need to focus on larger samples preserving subject-specific information (e.g., lesion effects) to cope with the inherent heterogeneity of stroke-induced aphasia. In addition, recovery-related changes in whole-brain connectivity patterns need more investigation to provide a comprehensive neural account of treatment-related brain plasticity and language recovery.
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Affiliation(s)
- Klara Schevenels
- Experimental Oto-Rhino-Laryngology, Department of Neurosciences, KU Leuven, Leuven, Belgium
| | - Cathy J. Price
- Welcome Centre for Human Neuroimaging, Institute of Neurology, University College London, UK
| | - Inge Zink
- Experimental Oto-Rhino-Laryngology, Department of Neurosciences, KU Leuven, Leuven, Belgium
| | - Bert De Smedt
- Parenting and Special Education Research Unit, Faculty of Psychology and Educational Sciences, KU Leuven, Leuven, Belgium
| | - Maaike Vandermosten
- Experimental Oto-Rhino-Laryngology, Department of Neurosciences, KU Leuven, Leuven, Belgium
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Kiran S, Meier EL, Johnson JP. Neuroplasticity in Aphasia: A Proposed Framework of Language Recovery. JOURNAL OF SPEECH, LANGUAGE, AND HEARING RESEARCH : JSLHR 2019; 62:3973-3985. [PMID: 31756154 PMCID: PMC7203519 DOI: 10.1044/2019_jslhr-l-rsnp-19-0054] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Revised: 06/21/2019] [Accepted: 08/27/2019] [Indexed: 05/20/2023]
Abstract
Purpose Despite a tremendous amount of research in this topic, the precise neural mechanisms underlying language recovery remain unclear. Much of the evidence suggests that activation of remaining left-hemisphere tissue, including perilesional areas, is linked to the best treatment outcomes, yet recruitment of the right hemisphere for various language tasks has also been linked to favorable behavioral outcomes. In this review article, we propose a framework of language recovery that incorporates a network-based view of the brain regions involved in recovery. Method We review evidence from the extant literature and work from our own laboratory to identify findings consistent with our proposed framework and identify gaps in our current knowledge. Results Expanding on Heiss and Thiel's (2006) hierarchy of language recovery, we identify 4 emerging themes: (a) Several bilateral regions constitute a network engaged in language recovery; (b) spared left-hemisphere regions are important components of the network engaged in language recovery; (c) as damage increases in the left hemisphere, activation expands to the right hemisphere and domain-general regions; and (d) patients with efficient, control-like network topology show greater improvement than patients with abnormal topology. We propose a mechanistic model of language recovery that accounts for individual differences in behavior, network topology, and treatment responsiveness. Conclusion Continued work in this topic will lead us to a better understanding of the mechanisms underlying language recovery, biomarkers that influence recovery, and, consequently, more personalized treatment options for individual patients. Presentation Video https://doi.org/10.23641/asha.10257590.
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Affiliation(s)
- Swathi Kiran
- Department of Speech, Language & Hearing Sciences, College of Health & Rehabilitation Sciences: Sargent College, Boston University, MA
| | - Erin L. Meier
- Department of Neurology, School of Medicine, Johns Hopkins University, Baltimore, MD
| | - Jeffrey P. Johnson
- Geriatric Research Education and Clinical Center, VA Pittsburgh Healthcare System, PA
- Audiology and Speech Pathology Program, VA Pittsburgh Healthcare System, PA
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Meier EL, Johnson JP, Pan Y, Kiran S. A lesion and connectivity-based hierarchical model of chronic aphasia recovery dissociates patients and healthy controls. NEUROIMAGE-CLINICAL 2019; 23:101919. [PMID: 31491828 PMCID: PMC6702239 DOI: 10.1016/j.nicl.2019.101919] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/20/2018] [Revised: 06/05/2019] [Accepted: 06/30/2019] [Indexed: 12/28/2022]
Abstract
Traditional models of left hemisphere stroke recovery propose that reactivation of remaining ipsilesional tissue is optimal for language processing whereas reliance on contralesional right hemisphere homologues is less beneficial or possibly maladaptive in the chronic recovery stage. However, neuroimaging evidence for this proposal is mixed. This study aimed to elucidate patterns of effective connectivity in patients with chronic aphasia in light of healthy control connectivity patterns and in relation to damaged tissue within left hemisphere regions of interest and according to performance on a semantic decision task. Using fMRI and dynamic causal modeling, biologically-plausible models within four model families were created to correspond to potential neural recovery patterns, including Family A: Left-lateralized connectivity (i.e., no/minimal damage), Family B: Bilateral anterior-weighted connectivity (i.e., posterior damage), Family C: Bilateral posterior-weighted connectivity (i.e., anterior damage) and Family D: Right-lateralized connectivity (i.e., extensive damage). Controls exhibited a strong preference for left-lateralized network models (Family A) whereas patients demonstrated a split preference for Families A and C. At the level of connections, controls exhibited stronger left intrahemispheric task-modulated connections than did patients. Within the patient group, damage to left superior frontal structures resulted in greater right intrahemispheric connectivity whereas damage to left ventral structures resulted in heightened modulation of left frontal regions. Lesion metrics best predicted accuracy on the fMRI task and aphasia severity whereas left intrahemispheric connectivity predicted fMRI task reaction times. These results are discussed within the context of the hierarchical recovery model of chronic aphasia. The semantic network in neurologically-intact, healthy controls was characterized by left-lateralized connectivity. Patient connectivity was split between left-lateralized and bilateral, posterior-weighted (i.e., anterior damage) models. Controls solely recruited LITG-driven connections whereas patients recruited a distributed network of connections. Within the patient group, intra- and inter-hemispheric connections were related to lesion site and/or size. Lesion size predicted aphasia severity and fMRI task accuracy, and effective connectivity predicted task reaction times.
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Affiliation(s)
- Erin L Meier
- Department of Speech, Language, & Hearing Sciences, Sargent College of Health and Rehabilitation Sciences, Boston University, 635 Commonwealth Avenue, Room 326, Boston, MA 02215, United States of America.
| | - Jeffrey P Johnson
- Department of Speech, Language, & Hearing Sciences, Sargent College of Health and Rehabilitation Sciences, Boston University, 635 Commonwealth Avenue, Room 326, Boston, MA 02215, United States of America
| | - Yue Pan
- Department of Speech, Language, & Hearing Sciences, Sargent College of Health and Rehabilitation Sciences, Boston University, 635 Commonwealth Avenue, Room 326, Boston, MA 02215, United States of America
| | - Swathi Kiran
- Department of Speech, Language, & Hearing Sciences, Sargent College of Health and Rehabilitation Sciences, Boston University, 635 Commonwealth Avenue, Room 326, Boston, MA 02215, United States of America
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Kiran S, Thompson CK. Neuroplasticity of Language Networks in Aphasia: Advances, Updates, and Future Challenges. Front Neurol 2019; 10:295. [PMID: 31001187 PMCID: PMC6454116 DOI: 10.3389/fneur.2019.00295] [Citation(s) in RCA: 116] [Impact Index Per Article: 23.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Accepted: 03/06/2019] [Indexed: 11/13/2022] Open
Abstract
Researchers have sought to understand how language is processed in the brain, how brain damage affects language abilities, and what can be expected during the recovery period since the early 19th century. In this review, we first discuss mechanisms of damage and plasticity in the post-stroke brain, both in the acute and the chronic phase of recovery. We then review factors that are associated with recovery. First, we review organism intrinsic variables such as age, lesion volume and location and structural integrity that influence language recovery. Next, we review organism extrinsic factors such as treatment that influence language recovery. Here, we discuss recent advances in our understanding of language recovery and highlight recent work that emphasizes a network perspective of language recovery. Finally, we propose our interpretation of the principles of neuroplasticity, originally proposed by Kleim and Jones (1) in the context of extant literature in aphasia recovery and rehabilitation. Ultimately, we encourage researchers to propose sophisticated intervention studies that bring us closer to the goal of providing precision treatment for patients with aphasia and a better understanding of the neural mechanisms that underlie successful neuroplasticity.
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Affiliation(s)
- Swathi Kiran
- Sargent College of Health and Rehabilitation Sciences, Boston University, Boston, MA, United States
| | - Cynthia K. Thompson
- Department of Communication Sciences and Disorders, Northwestern University, Evanston, IL, United States
- Department of Neurology, The Cognitive Neurology and Alzheimer's Disease Center, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
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Hartwigsen G, Saur D. Neuroimaging of stroke recovery from aphasia - Insights into plasticity of the human language network. Neuroimage 2017; 190:14-31. [PMID: 29175498 DOI: 10.1016/j.neuroimage.2017.11.056] [Citation(s) in RCA: 147] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Revised: 11/02/2017] [Accepted: 11/22/2017] [Indexed: 12/15/2022] Open
Abstract
The role of left and right hemisphere brain regions in language recovery after stroke-induced aphasia remains controversial. Here, we summarize how neuroimaging studies increase the current understanding of functional interactions, reorganization and plasticity in the language network. We first discuss the temporal dynamics across the time course of language recovery, with a main focus on longitudinal studies from the acute to the chronic phase after stroke. These studies show that the functional contribution of perilesional and spared left hemisphere as well as contralesional right hemisphere regions to language recovery changes over time. The second section introduces critical variables and recent advances on early prediction of subsequent outcome. In the third section, we outline how multi-method approaches that combine neuroimaging techniques with non-invasive brain stimulation elucidate mechanisms of plasticity and reorganization in the language network. These approaches provide novel insights into general mechanisms of plasticity in the language network and might ultimately support recovery processes during speech and language therapy. Finally, the neurobiological correlates of therapy-induced plasticity are discussed. We argue that future studies should integrate individualized approaches that might vary the combination of language therapy with specific non-invasive brain stimulation protocols across the time course of recovery. The way forward will include the combination of such approaches with large data sets obtained from multicentre studies.
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Affiliation(s)
- Gesa Hartwigsen
- Research Group Modulation of Language Networks, Department of Neuropsychology, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany.
| | - Dorothee Saur
- Language & Aphasia Laboratory, Department of Neurology, University of Leipzig, Germany.
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Gow DW, Ahlfors SP. Tracking reorganization of large-scale effective connectivity in aphasia following right hemisphere stroke. BRAIN AND LANGUAGE 2017; 170:12-17. [PMID: 28364641 PMCID: PMC5472378 DOI: 10.1016/j.bandl.2017.03.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Revised: 12/22/2016] [Accepted: 03/15/2017] [Indexed: 06/07/2023]
Abstract
In this paper we demonstrate the application of new effective connectivity analyses to characterize changing patterns of task-related directed interaction in large (25-55 node) cortical networks following the onset of aphasia. The subject was a left-handed woman who became aphasic following a right-hemisphere stroke. She was tested on an auditory word-picture verification task administered one and seven months after the onset of aphasia. MEG/EEG and anatomical MRI data were used to create high spatiotemporal resolution estimates of task-related cortical activity. Effective connectivity analyses of those data showed a reduction of bilateral network influences on preserved right-hemisphere structures, and an increase in intra-hemispheric left-hemisphere influences. She developed a connectivity pattern that was more left lateralized than that of right-handed control subjects. Her emergent left hemisphere network showed a combination of increased functional subdivision of perisylvian language areas and recruitment of medial structures.
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Affiliation(s)
- David W Gow
- Neuropsychology Laboratory, Massachusetts General Hospital, 175 Cambridge St., CPZ S340, Boston, MA 02114, United States; Department of Psychology, Salem State University, 352 Lafayette St., Salem, MA 01970, United States; Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, 149 Thirteenth St., S2301, Charlestown, MA 02129, United States; Harvard-MIT Division of Health Sciences and Technology, 77 Massachusetts Ave., E25-519, Cambridge, MA 02139, United States.
| | - Seppo P Ahlfors
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, 149 Thirteenth St., S2301, Charlestown, MA 02129, United States
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Sandberg CW, Bohland JW, Kiran S. Changes in functional connectivity related to direct training and generalization effects of a word finding treatment in chronic aphasia. BRAIN AND LANGUAGE 2015; 150:103-16. [PMID: 26398158 PMCID: PMC4663144 DOI: 10.1016/j.bandl.2015.09.002] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2014] [Revised: 07/30/2015] [Accepted: 09/01/2015] [Indexed: 05/03/2023]
Abstract
The neural mechanisms that underlie generalization of treatment-induced improvements in word finding in persons with aphasia (PWA) are currently poorly understood. This study aimed to shed light on changes in functional network connectivity underlying generalization in aphasia. To this end, we used fMRI and graph theoretic analyses to examine changes in functional connectivity after a theoretically-based word-finding treatment in which abstract words were used as training items with the goal of promoting generalization to concrete words. Ten right-handed native English-speaking PWA (7 male, 3 female) ranging in age from 47 to 75 (mean=59) participated in this study. Direct training effects coincided with increased functional connectivity for regions involved in abstract word processing. Generalization effects coincided with increased functional connectivity for regions involved in concrete word processing. Importantly, similarities between training and generalization effects were noted as were differences between participants who generalized and those who did not.
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Affiliation(s)
- Chaleece W Sandberg
- Boston University, Department of Speech and Hearing Sciences, 635 Commonwealth Ave., Boston, MA 02215, USA.
| | - Jason W Bohland
- Boston University, Department of Speech and Hearing Sciences, 635 Commonwealth Ave., Boston, MA 02215, USA
| | - Swathi Kiran
- Boston University, Department of Speech and Hearing Sciences, 635 Commonwealth Ave., Boston, MA 02215, USA
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Kiran S, Meier EL, Kapse KJ, Glynn PA. Changes in task-based effective connectivity in language networks following rehabilitation in post-stroke patients with aphasia. Front Hum Neurosci 2015; 9:316. [PMID: 26106314 PMCID: PMC4460429 DOI: 10.3389/fnhum.2015.00316] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2014] [Accepted: 05/18/2015] [Indexed: 11/19/2022] Open
Abstract
In this study, we examined regions in the left and right hemisphere language network that were altered in terms of the underlying neural activation and effective connectivity subsequent to language rehabilitation. Eight persons with chronic post-stroke aphasia and eight normal controls participated in the current study. Patients received a 10 week semantic feature-based rehabilitation program to improve their skills. Therapy was provided on atypical examples of one trained category while two control categories were monitored; the categories were counterbalanced across patients. In each fMRI session, two experimental tasks were conducted: (a) picture naming and (b) semantic feature verification of trained and untrained categories. Analysis of treatment effect sizes revealed that all patients showed greater improvements on the trained category relative to untrained categories. Results from this study show remarkable patterns of consistency despite the inherent variability in lesion size and activation patterns across patients. Across patients, activation that emerged as a function of rehabilitation on the trained category included bilateral IFG, bilateral SFG, LMFG, and LPCG for picture naming; and bilateral IFG, bilateral MFG, LSFG, and bilateral MTG for semantic feature verification. Analysis of effective connectivity using Dynamic Causal Modeling (DCM) indicated that LIFG was the consistently significantly modulated region after rehabilitation across participants. These results indicate that language networks in patients with aphasia resemble normal language control networks and that this similarity is accentuated by rehabilitation.
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Affiliation(s)
- Swathi Kiran
- Aphasia Research Laboratory, Speech Language and Hearing Sciences, Sargent College, Boston University Boston MA, USA
| | - Erin L Meier
- Aphasia Research Laboratory, Speech Language and Hearing Sciences, Sargent College, Boston University Boston MA, USA
| | - Kushal J Kapse
- Aphasia Research Laboratory, Speech Language and Hearing Sciences, Sargent College, Boston University Boston MA, USA
| | - Peter A Glynn
- Feinberg School of Medicine, Northwestern University Chicago IL, USA
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Guàrdia-Olmos J, Peró-Cebollero M, Zarabozo-Hurtado D, González-Garrido AA, Gudayol-Ferré E. Effective connectivity of visual word recognition and homophone orthographic errors. Front Psychol 2015; 6:640. [PMID: 26042070 PMCID: PMC4438596 DOI: 10.3389/fpsyg.2015.00640] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Accepted: 05/01/2015] [Indexed: 11/13/2022] Open
Abstract
The study of orthographic errors in a transparent language like Spanish is an important topic in relation to writing acquisition. The development of neuroimaging techniques, particularly functional magnetic resonance imaging (fMRI), has enabled the study of such relationships between brain areas. The main objective of the present study was to explore the patterns of effective connectivity by processing pseudohomophone orthographic errors among subjects with high and low spelling skills. Two groups of 12 Mexican subjects each, matched by age, were formed based on their results in a series of ad hoc spelling-related out-scanner tests: a high spelling skills (HSSs) group and a low spelling skills (LSSs) group. During the f MRI session, two experimental tasks were applied (spelling recognition task and visuoperceptual recognition task). Regions of Interest and their signal values were obtained for both tasks. Based on these values, structural equation models (SEMs) were obtained for each group of spelling competence (HSS and LSS) and task through maximum likelihood estimation, and the model with the best fit was chosen in each case. Likewise, dynamic causal models (DCMs) were estimated for all the conditions across tasks and groups. The HSS group's SEM results suggest that, in the spelling recognition task, the right middle temporal gyrus, and, to a lesser extent, the left parahippocampal gyrus receive most of the significant effects, whereas the DCM results in the visuoperceptual recognition task show less complex effects, but still congruent with the previous results, with an important role in several areas. In general, these results are consistent with the major findings in partial studies about linguistic activities but they are the first analyses of statistical effective brain connectivity in transparent languages.
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Affiliation(s)
- Joan Guàrdia-Olmos
- Facultat de Psicologia, Institut de Recerca en Cognició, Cervell i Conducta, Universitat de BarcelonaBarcelona, Spain
- Department of Methodology of Behavioral Sciences, School of Psychology, University of BarcelonaBarcelona, Spain
| | - Maribel Peró-Cebollero
- Facultat de Psicologia, Institut de Recerca en Cognició, Cervell i Conducta, Universitat de BarcelonaBarcelona, Spain
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Meinzer M, Beeson PM, Cappa S, Crinion J, Kiran S, Saur D, Parrish T, Crosson B, Thompson CK. Neuroimaging in aphasia treatment research: consensus and practical guidelines for data analysis. Neuroimage 2013; 73:215-24. [PMID: 22387474 PMCID: PMC3416913 DOI: 10.1016/j.neuroimage.2012.02.058] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2012] [Accepted: 02/19/2012] [Indexed: 11/19/2022] Open
Abstract
Functional magnetic resonance imaging is the most widely used imaging technique to study treatment-induced recovery in post-stroke aphasia. The longitudinal design of such studies adds to the challenges researchers face when studying patient populations with brain damage in cross-sectional settings. The present review focuses on issues specifically relevant to neuroimaging data analysis in aphasia treatment research identified in discussions among international researchers at the Neuroimaging in Aphasia Treatment Research Workshop held at Northwestern University (Evanston, Illinois, USA). In particular, we aim to provide the reader with a critical review of unique problems related to the pre-processing, statistical modeling and interpretation of such data sets. Despite the fact that data analysis procedures critically depend on specific design features of a given study, we aim to discuss and communicate a basic set of practical guidelines that should be applicable to a wide range of studies and useful as a reference for researchers pursuing this line of research.
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Affiliation(s)
- Marcus Meinzer
- Charite Universitätsmedizin, Department of Neurology, Center for Stroke Research Berlin & Cluster of Excellence NeuroCure, Berlin, Germany.
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Kiran S. What is the nature of poststroke language recovery and reorganization? ISRN NEUROLOGY 2012; 2012:786872. [PMID: 23320190 PMCID: PMC3540797 DOI: 10.5402/2012/786872] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/09/2012] [Accepted: 11/05/2012] [Indexed: 12/16/2022]
Abstract
This review focuses on three main topics related to the nature of poststroke language recovery and reorganization. The first topic pertains to the nature of anatomical and physiological substrates in the infarcted hemisphere in poststroke aphasia, including the nature of the hemodynamic response in patients with poststroke aphasia, the nature of the peri-infarct tissue, and the neuronal plasticity potential in the infarcted hemisphere. The second section of the paper reviews the current neuroimaging evidence for language recovery in the acute, subacute, and chronic stages of recovery. The third and final section examines changes in connectivity as a function of recovery in poststroke aphasia, specifically in terms of changes in white matter connectivity, changes in functional effective connectivity, and changes in resting state connectivity after stroke. While much progress has been made in our understanding of language recovery, more work needs to be done. Future studies will need to examine whether reorganization of language in poststroke aphasia corresponds to a tighter, more coherent, and efficient network of residual and new regions in the brain. Answering these questions will go a long way towards being able to predict which patients are likely to recover and may benefit from future rehabilitation.
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Affiliation(s)
- Swathi Kiran
- Department of Speech, Language, and Hearing Sciences, Sargent College of Health & Rehabilitation Sciences, Boston University, 635 Commonwealth Avenue, Boston, MA 02215, USA ; Massachusetts General Hospital, Boston, MA, USA
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17
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Cappa SF. The neural basis of aphasia rehabilitation: Evidence from neuroimaging and neurostimulation. Neuropsychol Rehabil 2011; 21:742-54. [DOI: 10.1080/09602011.2011.614724] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
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Meinzer M, Harnish S, Conway T, Crosson B. Recent developments in functional and structural imaging of aphasia recovery after stroke. APHASIOLOGY 2011; 25:271-290. [PMID: 21532927 PMCID: PMC3083028 DOI: 10.1080/02687038.2010.530672] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
BACKGROUND: Functional and structural neuroimaging techniques can increase our knowledge about the neural processes underlying recovery from post-stroke language impairments (aphasia). AIMS: In the present review we highlight recent developments in neuroimaging research of aphasia recovery. MAIN CONTRIBUTION: We review (a) cross-sectional findings in aphasia with regard to local brain functions and functional connectivity, (b) structural and functional imaging findings using longitudinal (intervention) paradigms, (c) new adjunct treatments that are guided by functional imaging techniques (e.g., electrical brain stimulation) and (d) studies related to the prognosis of language recovery and treatment responsiveness after stroke. CONCLUSIONS: More recent developments in data acquisition and analysis foster better understanding and more realistic modelling of the neural substrates of language recovery after stroke. Moreover, the combination of different neuroimaging protocols can provide converging evidence for neuroplastic brain remodelling during spontaneous and treatment-induced recovery. Researchers are also beginning to use sophisticated imaging analyses to improve accuracy of prognosis, which may eventually improve patient care by allowing for more efficient treatment planning. Brain stimulation techniques offer a new and exciting way to improve the recovery potential after stroke.
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Affiliation(s)
- Marcus Meinzer
- Department of Neurology, Center for Stroke Research Berlin & Cluster of Excellence NeuroCure, Charite, Universitätsmedizin Berlin, Berlin, Germany
- Department of Clinical & Health Psychology, University of Florida, Gainesville, FL, USA
| | - Stacy Harnish
- Brain Rehabilitation Research Center, Malcom Randall VA Medical Center, Gainesville, FL, USA
- Department of Neurology, University of Florida, Gainesville, FL, USA
| | - Tim Conway
- Department of Clinical & Health Psychology, University of Florida, Gainesville, FL, USA
- Brain Rehabilitation Research Center, Malcom Randall VA Medical Center, Gainesville, FL, USA
| | - Bruce Crosson
- Department of Clinical & Health Psychology, University of Florida, Gainesville, FL, USA
- Brain Rehabilitation Research Center, Malcom Randall VA Medical Center, Gainesville, FL, USA
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