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Kries J, De Clercq P, Gillis M, Vanthornhout J, Lemmens R, Francart T, Vandermosten M. Exploring neural tracking of acoustic and linguistic speech representations in individuals with post-stroke aphasia. Hum Brain Mapp 2024; 45:e26676. [PMID: 38798131 PMCID: PMC11128780 DOI: 10.1002/hbm.26676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Revised: 03/04/2024] [Accepted: 03/21/2024] [Indexed: 05/29/2024] Open
Abstract
Aphasia is a communication disorder that affects processing of language at different levels (e.g., acoustic, phonological, semantic). Recording brain activity via Electroencephalography while people listen to a continuous story allows to analyze brain responses to acoustic and linguistic properties of speech. When the neural activity aligns with these speech properties, it is referred to as neural tracking. Even though measuring neural tracking of speech may present an interesting approach to studying aphasia in an ecologically valid way, it has not yet been investigated in individuals with stroke-induced aphasia. Here, we explored processing of acoustic and linguistic speech representations in individuals with aphasia in the chronic phase after stroke and age-matched healthy controls. We found decreased neural tracking of acoustic speech representations (envelope and envelope onsets) in individuals with aphasia. In addition, word surprisal displayed decreased amplitudes in individuals with aphasia around 195 ms over frontal electrodes, although this effect was not corrected for multiple comparisons. These results show that there is potential to capture language processing impairments in individuals with aphasia by measuring neural tracking of continuous speech. However, more research is needed to validate these results. Nonetheless, this exploratory study shows that neural tracking of naturalistic, continuous speech presents a powerful approach to studying aphasia.
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Affiliation(s)
- Jill Kries
- Experimental Oto‐Rhino‐Laryngology, Department of Neurosciences, Leuven Brain InstituteKU LeuvenLeuvenBelgium
- Department of PsychologyStanford UniversityStanfordCaliforniaUSA
| | - Pieter De Clercq
- Experimental Oto‐Rhino‐Laryngology, Department of Neurosciences, Leuven Brain InstituteKU LeuvenLeuvenBelgium
| | - Marlies Gillis
- Experimental Oto‐Rhino‐Laryngology, Department of Neurosciences, Leuven Brain InstituteKU LeuvenLeuvenBelgium
| | - Jonas Vanthornhout
- Experimental Oto‐Rhino‐Laryngology, Department of Neurosciences, Leuven Brain InstituteKU LeuvenLeuvenBelgium
| | - Robin Lemmens
- Experimental Neurology, Department of NeurosciencesKU LeuvenLeuvenBelgium
- Laboratory of Neurobiology, VIB‐KU Leuven Center for Brain and Disease ResearchLeuvenBelgium
- Department of NeurologyUniversity Hospitals LeuvenLeuvenBelgium
| | - Tom Francart
- Experimental Oto‐Rhino‐Laryngology, Department of Neurosciences, Leuven Brain InstituteKU LeuvenLeuvenBelgium
| | - Maaike Vandermosten
- Experimental Oto‐Rhino‐Laryngology, Department of Neurosciences, Leuven Brain InstituteKU LeuvenLeuvenBelgium
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Graessner A, Duchow C, Zaccarella E, Friederici AD, Obrig H, Hartwigsen G. Electrophysiological correlates of basic semantic composition in people with aphasia. Neuroimage Clin 2023; 40:103516. [PMID: 37769366 PMCID: PMC10540050 DOI: 10.1016/j.nicl.2023.103516] [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: 05/02/2023] [Revised: 09/21/2023] [Accepted: 09/22/2023] [Indexed: 09/30/2023]
Abstract
The neuroanatomical correlates of basic semantic composition have been investigated in previous neuroimaging and lesion studies, but research on the electrophysiology of the involved processes is scarce. A large literature on sentence-level event-related potentials (ERPs) during semantic processing has identified at least two relevant components - the N400 and the P600. Other studies demonstrated that these components are reduced and/or delayed in people with aphasia (PWA). However, it remains to be shown if these findings generalize beyond the sentence level. Specifically, it is an open question if an alteration in ERP responses in PWA can also be observed during basic semantic composition, providing a potential future diagnostic tool. The present study aimed to elucidate the electrophysiological dynamics of basic semantic composition in a group of post-stroke PWA. We included 20 PWA and 20 age-matched controls (mean age 58 years) and measured ERP responses while they performed a plausibility judgment task on two-word phrases that were either meaningful ("anxious horse"), anomalous ("anxious wood") or had the noun replaced by a pseudoword ("anxious gufel"). The N400 effect for anomalous versus meaningful phrases was similar in both groups. In contrast, unlike the control group, PWA did not show an N400 effect between pseudoword and meaningful phrases. Moreover, both groups exhibited a parietal P600 effect towards pseudoword phrases, while PWA showed an additional P600 over frontal electrodes. Finally, PWA showed an inverse correlation between the magnitude of the N400 and P600 effects: PWA exhibiting no or even reversed N400 effects towards anomalous and pseudoword phrases showed a stronger P600 effect. These results may reflect a compensatory mechanism which allows PWA to arrive at the correct interpretation of the phrase. When compositional processing capacities are impaired in the early N400 time-window, PWA may make use of a more elaborate re-analysis process reflected in the P600.
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Affiliation(s)
- Astrid Graessner
- Wilhelm Wundt Institute for Psychology, Leipzig University, Germany; Lise-Meitner Research Group Cognition and Plasticity, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany.
| | - Caroline Duchow
- Lise-Meitner Research Group Cognition and Plasticity, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
| | - Emiliano Zaccarella
- Department of Neuropsychology, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
| | - Angela D Friederici
- Department of Neuropsychology, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
| | - Hellmuth Obrig
- Clinic for Cognitive Neurology, University Hospital Leipzig, Germany; Department of Neurology, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
| | - Gesa Hartwigsen
- Wilhelm Wundt Institute for Psychology, Leipzig University, Germany; Lise-Meitner Research Group Cognition and Plasticity, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
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3
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Johnson LP, Fridriksson J. Electrophysiologic evidence of reorganization in poststroke aphasia. HANDBOOK OF CLINICAL NEUROLOGY 2022; 185:167-174. [PMID: 35078597 DOI: 10.1016/b978-0-12-823384-9.00020-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Electrophysiologic methods have been used to investigate neural changes in individuals with poststroke aphasia. The major types of electrophysiologic measures include the event-related potential (ERP) and spectral power, and aspects of both (including amplitude, topography, and power) have been shown to differ in people with aphasia. Not only that, these measures are sensitive to spontaneous and treatment-induced language change. The purpose of this chapter is to review evidence of poststroke reorganization in the language network that has been identified in the acute and chronic phases of poststroke aphasia. The chapter will begin with a brief introduction to electrophysiologic methods and then focus on evidence from the most commonly studied ERPs and spectral bands in aphasia.
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Affiliation(s)
- Lorelei Phillip Johnson
- Department of Communication Sciences and Disorders, University of South Carolina, Columbia, SC, United States.
| | - Julius Fridriksson
- Department of Communication Sciences and Disorders, University of South Carolina, Columbia, SC, United States
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Silkes JP, Anjum J. The role and use of event-related potentials in aphasia: A scoping review. BRAIN AND LANGUAGE 2021; 219:104966. [PMID: 34044294 DOI: 10.1016/j.bandl.2021.104966] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 04/30/2021] [Accepted: 05/04/2021] [Indexed: 06/12/2023]
Abstract
Event-related potentials (ERPs) can provide important insights into underlying language processes in both unimpaired and neurologically impaired populations and may be particularly useful in aphasia. This scoping review was conducted to provide a comprehensive summary of how ERPs have been used with people with aphasia (PWA), with the goal of exploring the potential clinical application of ERPs in aphasia assessment and treatment. We identified 117 studies that met inclusionary criteria, reflecting six thematic domains of inquiry that relate to understanding both unimpaired and aphasic language processing and the use of ERPs with PWA. In these studies, a wide variety of ERP components were reported. Inconsistencies in reporting of participant characteristics and study protocols limit our ability to generalize beyond the individual studies and understand implications for clinical applicability. We discuss the potential roles of ERPs in aphasia management and make recommendations for further developing ERPs for clinical utility in PWA.
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Affiliation(s)
- JoAnn P Silkes
- School of Speech, Language, and Hearing Sciences, San Diego State University, 5500 Campanile Rd, SLHS-1518, San Diego, CA 92182-1518, USA.
| | - Javad Anjum
- Speech-Language Pathology, Saint Gianna School of Health Sciences, University of Mary, 7500 University Dr. Bismarck, ND 58504, USA.
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Brain plasticity in aphasic patients: intra- and inter-hemispheric reorganisation of the whole linguistic network probed by N150 and N350 components. Sci Rep 2015. [PMID: 26217919 PMCID: PMC4649892 DOI: 10.1038/srep12541] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
The present study examined linguistic plastic reorganization of language through Evoked Potentials in a group of 17 non-fluent aphasic patients who had suffered left perisylvian focal lesions, and showed a good linguistic recovery. Language reorganisation was probed with three linguistic tasks (Phonological, Semantic, Orthographic), the early word recognition potential (N150) and the later phonological-related component (N350). Results showed the typical left-lateralised posterior N150 in healthy controls (source: left Fusiform Gyrus), that was bilateral (Semantic) or right sided (Phonological task) in patients (sources: right Inferior/Middle Temporal and Fusiform Gyri). As regards N350, controls revealed different intra- and inter-hemispheric linguistic activation across linguistic tasks, whereas patients exhibited greater activity in left intact sites, anterior and posterior to the damaged area, in all tasks (sources: Superior Frontal Gyri). A comprehensive neurofunctional model is presented, describing how complete intra- and inter-hemispheric reorganisation of the linguistic networks occurs after aphasic damage in the strategically dominant left perisylvian linguistic centres.
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Barbancho MA, Berthier ML, Navas-Sánchez P, Dávila G, Green-Heredia C, García-Alberca JM, Ruiz-Cruces R, López-González MV, Dawid-Milner MS, Pulvermüller F, Lara JP. Bilateral brain reorganization with memantine and constraint-induced aphasia therapy in chronic post-stroke aphasia: An ERP study. BRAIN AND LANGUAGE 2015; 145-146:1-10. [PMID: 25932618 DOI: 10.1016/j.bandl.2015.04.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Revised: 02/06/2015] [Accepted: 04/11/2015] [Indexed: 06/04/2023]
Abstract
Changes in ERP (P100 and N400) and root mean square (RMS) were obtained during a silent reading task in 28 patients with chronic post-stroke aphasia in a randomized, double-blind, placebo-controlled trial of both memantine and constraint-induced aphasia therapy (CIAT). Participants received memantine/placebo alone (weeks 0-16), followed by drug treatment combined with CIAT (weeks 16-18), and then memantine/placebo alone (weeks 18-20). ERP/RMS values (week 16) decreased more in the memantine group than in the placebo group. During CIAT application (weeks 16-18), improvements in aphasia severity and ERP/RMS values were amplified by memantine and changes remained stable thereafter (weeks 18-20). Changes in ERP/RMS occurred in left and right hemispheres and correlated with gains in language performance. No changes in ERP/RMS were found in a healthy group in two separated evaluations. Our results show that aphasia recovery induced by both memantine alone and in combination with CIAT is indexed by bilateral cortical potentials.
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Affiliation(s)
- Miguel A Barbancho
- Universidad de Málaga, Andalucía TECH-IBIMA, Unidad de Neurofisiología Cognitiva, Centro de Investigaciones Médico-Sanitarias (CIMES), Marqués de Beccaria, 3, 29010 Málaga, Spain
| | - Marcelo L Berthier
- Universidad de Málaga, Andalucía TECH-IBIMA, Unidad de Afasia y Neurología Cognitiva, Centro de Investigaciones Médico-Sanitarias (CIMES) y Cátedra Fundación Morera y Vallejo de Afasia, Marqués de Beccaria, 3, 29010 Málaga, Spain
| | - Patricia Navas-Sánchez
- Universidad de Málaga, Andalucía TECH-IBIMA, Unidad de Neurofisiología Cognitiva, Centro de Investigaciones Médico-Sanitarias (CIMES), Marqués de Beccaria, 3, 29010 Málaga, Spain
| | - Guadalupe Dávila
- Universidad de Málaga, Andalucía TECH-IBIMA, Unidad de Afasia y Neurología Cognitiva, Centro de Investigaciones Médico-Sanitarias (CIMES) y Cátedra Fundación Morera y Vallejo de Afasia, Marqués de Beccaria, 3, 29010 Málaga, Spain
| | - Cristina Green-Heredia
- Departamento de Neurociencia, Hospital Quirón, Av. Imperio Argentina, 1, 29004 Málaga, Spain
| | | | - Rafael Ruiz-Cruces
- Universidad de Málaga, Andalucía TECH-IBIMA, Unidad de Neurofisiología Cognitiva, Centro de Investigaciones Médico-Sanitarias (CIMES), Marqués de Beccaria, 3, 29010 Málaga, Spain
| | - Manuel V López-González
- Universidad de Málaga, Andalucía TECH-IBIMA, Unidad de Neurofisiología Cognitiva, Centro de Investigaciones Médico-Sanitarias (CIMES), Marqués de Beccaria, 3, 29010 Málaga, Spain
| | - Marc S Dawid-Milner
- Universidad de Málaga, Andalucía TECH-IBIMA, Unidad de Neurofisiología Cognitiva, Centro de Investigaciones Médico-Sanitarias (CIMES), Marqués de Beccaria, 3, 29010 Málaga, Spain
| | - Friedemann Pulvermüller
- Brain Language Laboratory, Freie Universität Berlin, Germany; Medical Research Council, Cognition and Brain Sciences Unit, Cambridge, United Kingdom
| | - J Pablo Lara
- Universidad de Málaga, Andalucía TECH-IBIMA, Unidad de Neurofisiología Cognitiva, Centro de Investigaciones Médico-Sanitarias (CIMES), Marqués de Beccaria, 3, 29010 Málaga, Spain.
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Wilson KR, O'Rourke H, Wozniak LA, Kostopoulos E, Marchand Y, Newman AJ. Changes in N400 topography following intensive speech language therapy for individuals with aphasia. BRAIN AND LANGUAGE 2012; 123:94-103. [PMID: 22944529 DOI: 10.1016/j.bandl.2012.06.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2011] [Revised: 06/18/2012] [Accepted: 06/23/2012] [Indexed: 06/01/2023]
Abstract
Our goal was to characterize the effects of intensive aphasia therapy on the N400, an electrophysiological index of lexical-semantic processing. Immediately before and after 4 weeks of intensive speech-language therapy, people with aphasia performed a task in which they had to determine whether spoken words were a 'match' or a 'mismatch' to pictures of objects. Pre-therapy, people with aphasia exhibited an N400 mismatch effect that started over right hemisphere electrodes. Post-therapy, gains were seen in clinical measures of language ability, and the onset of the N400 was left-lateralized. No changes in the scalp distribution of the N400 were observed in healthy controls tested twice over the same 4 week interval. Since the distribution of the N400 after aphasia therapy differed from that of healthy controls, we conclude that it reflects the engagement of compensatory neural mechanisms for language processing rather than a return to a "normal" pattern of brain activation.
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Affiliation(s)
- K Ryan Wilson
- Department of Psychology and Neuroscience, Dalhousie University, Halifax, NS B3H 4R2, Canada
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8
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Font effects of Chinese characters and pseudo-characters on the N400: Evidence for an orthographic processing view. Brain Cogn 2012; 80:96-103. [DOI: 10.1016/j.bandc.2012.05.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2011] [Revised: 04/18/2012] [Accepted: 05/02/2012] [Indexed: 11/20/2022]
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Gillespie DC, Bowen A, Foster JK. The Assessment of Premorbid Intellectual Ability Following Right-Hemisphere Stroke: Reliability of a Lexical Decision Task. APPLIED NEUROPSYCHOLOGY-ADULT 2012; 19:32-7. [DOI: 10.1080/09084282.2011.643937] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
- David C. Gillespie
- a Department of Clinical Psychology (NHS Lothian) , Astley Ainslie Hospital , Edinburgh , United Kingdom
| | - Audrey Bowen
- b Human Communication and Deafness , University of Manchester , Manchester , United Kingdom
| | - Jonathan K. Foster
- c School of Psychology and Speech Pathology , Curtin University , Bentley , Perth , Australia
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Spironelli C, Galfano G, Umiltà C, Angrilli A. Word position affects stimulus recognition: Evidence for early ERP short-term plastic modulation. Int J Psychophysiol 2011; 82:217-24. [DOI: 10.1016/j.ijpsycho.2011.08.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2011] [Revised: 08/29/2011] [Accepted: 08/30/2011] [Indexed: 10/17/2022]
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Laganaro M, Morand S, Michel CM, Spinelli L, Schnider A. ERP Correlates of Word Production before and after Stroke in an Aphasic Patient. J Cogn Neurosci 2011; 23:374-81. [DOI: 10.1162/jocn.2010.21412] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Abstract
Changes in brain activity characterizing impaired speech production after brain damage have usually been investigated by comparing aphasic speakers with healthy subjects because prestroke data are normally not available. However, when interpreting the results of studies of stroke patients versus healthy controls, there is an inherent difficulty in disentangling the contribution of neuropathology from other sources of between-subject variability. In the present work, we had an unusual opportunity to study an aphasic patient with severe anomia who had incidentally performed a picture naming task in an ERP study as a control subject one year before suffering a left hemisphere stroke. The fortuitous recording of this patient's brain activity before his stroke allows direct comparison of his pre- and poststroke brain activity in the same language production task. The subject did not differ from other healthy subjects before his stroke, but presented major electrophysiological differences after stroke, both in comparison to himself before stroke and to the control group. ERP changes consistently appeared after stroke in a specific time window starting about 250 msec after picture onset, characterized by a single divergent but stable topographic configuration of the scalp electric field associated with a cortical generator abnormally limited to left temporal posterior perilesional areas. The patient's pattern of anomia revealed a severe lexical–phonological impairment and his ERP responses diverged from those of healthy controls in the time window that has previously been associated with lexical–phonological processes during picture naming. Given that his prestroke ERPs were indistinguishable from those of healthy controls, it seems highly likely that the change in his poststroke ERPs is due to changes in language production processes as a consequence of stroke. The patient's neurolinguistic deficits, combined with the ERPs results, provide unique evidence for the role of left temporal cortex in lexical–phonological processing from about 250 to 450 msec during word production.
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Affiliation(s)
- Marina Laganaro
- 1University Hospital and University of Geneva, Switzerland
- 2University of Neuchâtel, Switzerland
| | - Stéphanie Morand
- 1University Hospital and University of Geneva, Switzerland
- 4University of Glasgow, UK
| | | | | | - Armin Schnider
- 1University Hospital and University of Geneva, Switzerland
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Laufer I, Negishi M, Constable RT. Comparator and non-comparator mechanisms of change detection in the context of speech--an ERP study. Neuroimage 2009; 44:546-62. [PMID: 18938250 PMCID: PMC2643129 DOI: 10.1016/j.neuroimage.2008.09.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2008] [Revised: 08/11/2008] [Accepted: 09/09/2008] [Indexed: 11/25/2022] Open
Abstract
Automatic change detection reflects a cognitive memory-based comparison mechanism as well as a sensorial non-comparator mechanism based on differential states of refractoriness. The purpose of this study was to examine whether the comparator mechanism of the mismatch negativity component (MMN) is differentially affected by the lexical status of the deviant. Event-related potential (ERP) data was collected during an "oddball" paradigm designed to elicit the MMN from 15 healthy subjects that were involved in a counting task. Topography pattern analysis and source estimation were utilized to examine the deviance (deviants vs. standards), cognitive (deviants vs. control counterparts) and refractoriness (standards vs. control counterparts) effects elicited by standard-deviant pairs ("deh-day"; "day-deh"; "teh-tay") embedded within "oddball" blocks. Our results showed that when the change was salient regardless of lexical status (i.e., the /e:/ to /eI/ transition) the response tapped the comparator based-mechanism of the MMN which was located in the cuneus/posterior cingulate, reflected sensitivity to the novelty of the auditory object, appeared in the P2 latency range and mainly involved topography modulations. In contrast, when the novelty was low (i.e., the /eI/ to /e:/ transition) an acoustic change complex was elicited which involved strength modulations over the P1/N1 range and implicated the middle temporal gyrus. This result pattern also resembled the one displayed by the non-comparator mechanism. These findings suggest spatially and temporally distinct brain activities of comparator mechanisms of change detection in the context of speech.
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Affiliation(s)
- Ilan Laufer
- Department of Diagnostic Radiology, Yale University School of Medicine, The Anlyan Center, New Haven, CT 06520-8043, USA.
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The problem of aphasia in the assessment of consciousness in brain-damaged patients. PROGRESS IN BRAIN RESEARCH 2009; 177:49-61. [PMID: 19818894 DOI: 10.1016/s0079-6123(09)17705-1] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The assessment of the level and content of consciousness in brain-damaged patients relies to a large extent on behavioral assessment techniques. The limited behavioral repertoire displayed by vegetative and minimally conscious states requires the use of highly sensitive and reliable behavioral assessment methods, allowing the detection of subtle changes in behavior and associated level of consciousness. This situation is further complicated when patients with such disorders of consciousness have underlying deficits in the domain of communication functions, such as aphasia. The present paper examines the consequences of receptive and/or productive aphasia on the already limited behavioral repertoire presented in these patients and discusses a number of behavioral and neuroimaging assessment procedures designed to: (1) detect the presence of aphasia in patients with disorders of consciousness, and (2) reliably assess the level of consciousness of brain-damaged patients while taking into account the existence of receptive and/or expressive language deficits. The combined use of behavioral and neuroimaging assessment techniques appears to be particularly promising for disentangling impaired consciousness and aphasia.
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Language plasticity in aphasics after recovery: Evidence from slow evoked potentials. Neuroimage 2008; 40:912-922. [DOI: 10.1016/j.neuroimage.2007.12.012] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2007] [Revised: 12/05/2007] [Accepted: 12/09/2007] [Indexed: 11/22/2022] Open
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Carretié L, Hinojosa JA, Albert J, López-Martín S, De La Gándara BS, Igoa JM, Sotillo M. Modulation of ongoing cognitive processes by emotionally intense words. Psychophysiology 2008; 45:188-96. [DOI: 10.1111/j.1469-8986.2007.00617.x] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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17
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Yuan W, Szaflarski JP, Schmithorst VJ, Schapiro M, Byars AW, Strawsburg RH, Holland SK. fMRI shows atypical language lateralization in pediatric epilepsy patients. Epilepsia 2006; 47:593-600. [PMID: 16529628 PMCID: PMC1402337 DOI: 10.1111/j.1528-1167.2006.00474.x] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
PURPOSE The goal of this study was to compare language lateralization between pediatric epilepsy patients and healthy children. METHODS Two groups of subjects were evaluated with functional magnetic resonance imaging (fMRI) by using a silent verb-generation task. The first group included 18 pediatric epilepsy patients, whereas the control group consisted of 18 age/gender/handedness-matched healthy subjects. RESULTS A significant difference in hemispheric lateralization index (LI) was found between children with epilepsy (mean LI =-0.038) and the age/gender/handedness-matched healthy control subjects (mean LI=0.257; t=6.490, p<0.0001). A dramatic difference also was observed in the percentage of children with epilepsy (77.78%) who had atypical LI (right-hemispheric or bilateral, LI<0.1) when compared with the age/gender/handedness-matched group (11.11%; chi(2)=16.02, p<0.001). A linear regression analysis showed a trend toward increasing language lateralization with age in healthy controls (R(2)=0.152; p=0.108). This association was not observed in pediatric epilepsy subjects (R(2)=0.004, p=0.80). A significant association between language LI and epilepsy duration also was found (R(2)=0.234, p<0.05). CONCLUSIONS This study shows that epilepsy during childhood is associated with neuroplasticity and reorganization of language function.
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Affiliation(s)
- Weihong Yuan
- Cincinnati Children’s Hospital Medical Center, Imaging Research Center, Cincinnati, OH, USA
- Corresponding Author Name: Weihong Yuan, Address: Cincinnati Children’s Hospital Medical Center Imaging Research Center ML 5031 3333 Burnet Ave., Cincinnati, OH 45229 Phone: 513-636-2862, Fax: 513-636-3754, E-mail:
| | | | - Vincent J. Schmithorst
- Cincinnati Children’s Hospital Medical Center, Imaging Research Center, Cincinnati, OH, USA
| | - Mark Schapiro
- Cincinnati Children’s Hospital Medical Center, Division of Neurology, Cincinnati, OH, USA
| | - Anna W. Byars
- Cincinnati Children’s Hospital Medical Center, Division of Neurology, Cincinnati, OH, USA
| | | | - Scott K. Holland
- Cincinnati Children’s Hospital Medical Center, Imaging Research Center, Cincinnati, OH, USA
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Pulvermüller F, Hauk O, Zohsel K, Neininger B, Mohr B. Therapy-related reorganization of language in both hemispheres of patients with chronic aphasia. Neuroimage 2005; 28:481-9. [PMID: 16099176 DOI: 10.1016/j.neuroimage.2005.06.038] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2005] [Revised: 05/18/2005] [Accepted: 06/10/2005] [Indexed: 10/25/2022] Open
Abstract
The brain processes of language recovery after stroke are poorly understood, partly because past research did not allow to differentiate the effects of spontaneous restitution processes from those of learning-related cortical reorganization. Here, we use a new approach offered by recently developed intense neuropsychological therapy methods, which allow for improving language functions within a short time period. Stroke patients with chronic aphasia received intense language therapy for 2 weeks and, over this period, improved their language performance as assessed using clinical tests. Neurophysiological activity elicited by words and pseudowords was measured before and after treatment. Over the therapy interval, early word evoked potentials (latency 250-300 ms) became significantly stronger whereas pseudoword responses did not change. Word-specific changes were documented by analyses of ERP amplitudes and root mean square values, which revealed interactions of the factors Assessment time (before vs. after therapy) and Wordness (word vs. pseudoword). Source localization using Minimum Norm Current Estimates showed that bilateral cortical sources activated by word stimuli contributed to the change, suggesting that neuronal networks distributed over both hemispheres are the substrate of cortical reorganization of language processing in intense aphasia therapy. Word-evoked differences in source strengths were significantly correlated with performance on a clinical language test, demonstrating a link between behavioral and neurophysiological changes. We suggest that the early word-evoked negativity might represent an index of reorganization of language after stroke and thus an aphasia recovery potential.
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Affiliation(s)
- Friedemann Pulvermüller
- Medical Research Council, Cognition and Brain Sciences Unit, 15 Chaucer Road, Cambridge CB2 2EF, UK.
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