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Campos B, Choi H, DeMarco AT, Seydell-Greenwald A, Hussain SJ, Joy MT, Turkeltaub PE, Zeiger W. Rethinking Remapping: Circuit Mechanisms of Recovery after Stroke. J Neurosci 2023; 43:7489-7500. [PMID: 37940595 PMCID: PMC10634578 DOI: 10.1523/jneurosci.1425-23.2023] [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: 07/27/2023] [Revised: 08/21/2023] [Accepted: 08/21/2023] [Indexed: 11/10/2023] Open
Abstract
Stroke is one of the most common causes of disability, and there are few treatments that can improve recovery after stroke. Therapeutic development has been hindered because of a lack of understanding of precisely how neural circuits are affected by stroke, and how these circuits change to mediate recovery. Indeed, some of the hypotheses for how the CNS changes to mediate recovery, including remapping, redundancy, and diaschisis, date to more than a century ago. Recent technological advances have enabled the interrogation of neural circuits with ever greater temporal and spatial resolution. These techniques are increasingly being applied across animal models of stroke and to human stroke survivors, and are shedding light on the molecular, structural, and functional changes that neural circuits undergo after stroke. Here we review these studies and highlight important mechanisms that underlie impairment and recovery after stroke. We begin by summarizing knowledge about changes in neural activity that occur in the peri-infarct cortex, specifically considering evidence for the functional remapping hypothesis of recovery. Next, we describe the importance of neural population dynamics, disruptions in these dynamics after stroke, and how allocation of neurons into spared circuits can restore functionality. On a more global scale, we then discuss how effects on long-range pathways, including interhemispheric interactions and corticospinal tract transmission, contribute to post-stroke impairments. Finally, we look forward and consider how a deeper understanding of neural circuit mechanisms of recovery may lead to novel treatments to reduce disability and improve recovery after stroke.
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Affiliation(s)
- Baruc Campos
- Department of Neurology, David Geffen School of Medicine, University of California-Los Angeles, Los Angeles, California 90095
| | - Hoseok Choi
- Department of Neurology, Weill Institute for Neuroscience, University of California-San Francisco, San Francisco, California 94158
| | - Andrew T DeMarco
- Center for Brain Plasticity and Recovery, Georgetown University Medical Center, Georgetown University, Washington, DC 20057
- Department of Rehabilitation Medicine, Georgetown University Medical Center, Georgetown University, Washington, DC 20057
| | - Anna Seydell-Greenwald
- Center for Brain Plasticity and Recovery, Georgetown University Medical Center, Georgetown University, Washington, DC 20057
- MedStar National Rehabilitation Hospital, Washington, DC 20010
| | - Sara J Hussain
- Movement and Cognitive Rehabilitation Science Program, Department of Kinesiology and Health Education, University of Texas at Austin, Austin, Texas 78712
| | - Mary T Joy
- The Jackson Laboratory, Bar Harbor, Maine 04609
| | - Peter E Turkeltaub
- Center for Brain Plasticity and Recovery, Georgetown University Medical Center, Georgetown University, Washington, DC 20057
- MedStar National Rehabilitation Hospital, Washington, DC 20010
| | - William Zeiger
- Department of Neurology, David Geffen School of Medicine, University of California-Los Angeles, Los Angeles, California 90095
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Low TA, Lindland K, Kirton A, Carlson HL, Harris AD, Goodyear BG, Monchi O, Hill MD, Dukelow SP. Repetitive transcranial magnetic stimulation (rTMS) combined with multi-modality aphasia therapy for chronic post-stroke non-fluent aphasia: A pilot randomized sham-controlled trial. BRAIN AND LANGUAGE 2023; 236:105216. [PMID: 36525719 DOI: 10.1016/j.bandl.2022.105216] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2021] [Revised: 10/22/2022] [Accepted: 12/03/2022] [Indexed: 06/17/2023]
Abstract
Repetitive transcranial magnetic stimulation (rTMS) shows promise in improving speech production in post-stroke aphasia. Limited evidence suggests pairing rTMS with speech therapy may result in greater improvements. Twenty stroke survivors (>6 months post-stroke) were randomized to receive either sham rTMS plus multi-modality aphasia therapy (M-MAT) or rTMS plus M-MAT. For the first time, we demonstrate that rTMS combined with M-MAT is feasible, with zero adverse events and minimal attrition. Both groups improved significantly over time on all speech and language outcomes. However, improvements did not differ between rTMS or sham. We found that rTMS and sham groups differed in lesion location, which may explain speech and language outcomes as well as unique patterns of BOLD signal change within each group. We offer practical considerations for future studies and conclude that while combination therapy of rTMS plus M-MAT in chronic post-stroke aphasia is safe and feasible, personalized intervention may be necessary.
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Affiliation(s)
- Trevor A Low
- Department of Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Kevin Lindland
- Department of Allied Health, Alberta Health Services, Calgary, Alberta, Canada
| | - Adam Kirton
- Department of Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada; Department of Pediatrics, Cummings School of Medicine, University of Calgary, Calgary, Alberta, Canada; Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada; Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Alberta, Canada
| | - Helen L Carlson
- Department of Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada; Department of Pediatrics, Cummings School of Medicine, University of Calgary, Calgary, Alberta, Canada; Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada; Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Alberta, Canada
| | - Ashley D Harris
- Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada; Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Alberta, Canada; Department of Radiology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Bradley G Goodyear
- Department of Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada; Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada; Department of Radiology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Oury Monchi
- Department of Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada; Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada; Department of Radiology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Michael D Hill
- Department of Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada; Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada; Department of Radiology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Sean P Dukelow
- Department of Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada; Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada; Division of Physical Medicine and Rehabilitation, University of Calgary, Calgary, Alberta, Canada.
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Diffusion Tensor Tractography Studies on Recovery Mechanisms of Aphasia in Stroke Patients: A Narrative Mini-Review. Healthcare (Basel) 2022; 10:healthcare10101927. [PMID: 36292374 PMCID: PMC9601675 DOI: 10.3390/healthcare10101927] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Revised: 09/18/2022] [Accepted: 09/22/2022] [Indexed: 11/04/2022] Open
Abstract
Aphasia is a common and serious clinical feature of stroke. Various neural tracts are known to be involved in language processing. Diffusion tensor tractography (DTT) appears to be an appropriate imaging technique for the elucidation of the recovery mechanisms of aphasia in the language-related neural tracts in stroke patients. In this article, twelve previous DTT-based studies on the recovery mechanisms of aphasia in stroke were reviewed. We classified the twelve studies into the following three categories according to the recovery mechanisms: recovery via the neural tracts in the dominant hemisphere (eight studies), via transcallosal fibers (two studies), and via the neural tracts in the non-dominant hemisphere (two studies). Although there are various neural tracts for language processing, eight of the ten studies focused only on the role of the arcuate fasciculus (AF) in the recovery process. Consequently, it appears from the studies that only one recovery mechanism of aphasia via the restoration of the integrity of the injured AF in the dominant hemisphere was clearly demonstrated. However, because various neural tracts are involved in language processing, there could be other mechanisms that have not yet been elucidated. Therefore, further original studies involving a larger number of patients with aphasia in stroke should be encouraged forthwith. Further studies involving various lesion locations and severity levels of injuries to the language-related neural tracts are also necessary because the recovery mechanisms of aphasia in stroke could be dependent on these factors.
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Xie H, Jing J, Ma Y, Song Y, Yin J, Xu G, Li X, Li Z, Wang Y. Effects of simultaneous use of m-NMES and language training on brain functional connectivity in stroke patients with aphasia: A randomized controlled clinical trial. Front Aging Neurosci 2022; 14:965486. [PMID: 36158562 PMCID: PMC9489908 DOI: 10.3389/fnagi.2022.965486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Accepted: 08/18/2022] [Indexed: 11/13/2022] Open
Abstract
Introduction The m-NMES had been demonstrated to redistribute brain resources and induce plastic changes in the stroke patients. However, the physiological mechanism and clinical efficacy of m-NMES combination with existing clinical rehabilitation programs remains unclear in patients with aphasia after stroke. This study aimed to investigate the effects of simultaneous use of m-NMES and language training (m-NMES-LT) with on cerebral oscillations and brain connection, as well as the effect on clinical efficacy. Materials and methods Total 21 right–handed adult patients with aphasia were randomly assigned to language training (LT) group and m-NMES-LT group, and tissue concentration of oxyhemoglobin and deoxyhemoglobin oscillations were measured by functional near-infrared spectroscopy in resting and treatment state during three consecutive weeks. Five characteristic frequency signals (I, 0.6–2 Hz; II, 0.145–0.6 Hz; III, 0.052–0.145 Hz; IV, 0.021–0.052 Hz; and V, 0.0095–0.021 Hz) were identified using the wavelet method. The wavelet amplitude (WA) and wavelet phase coherence (WPCO) were calculated to describe the frequency-specific cortical activities. Results The m-NMES-LT induced significantly higher WA values in contralesional PFC in intervals I, II, and V, and ipsilesional MC in intervals I-V than the resting state. The WPCO values between ipsilesional PFC-MC in interval III-IV, and between bilateral MC in interval III-IV were significantly higher than resting state. In addition, there was a significant positive correlation between WPCO and Western Aphasia Battery in m-NMES-LT group. Conclusion The language training combined with neuromuscular electrical stimulation on median nerve could improve and achieve higher clinical efficacy for aphasia. This is attributed to the m-NMES-LT could enhance cortical activation and brain functional connectivity in patients with aphasia, which was derived from myogenic, neurogenic, and endothelial cell metabolic activities.
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Affiliation(s)
- Hui Xie
- Rehabilitation Center, Qilu Hospital of Shandong University, Jinan, Shandong, China
- Beijing Key Laboratory of Rehabilitation Technical Aids for Old-Age Disability, National Research Center for Rehabilitation Technical Aids, Beijing, China
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| | - Jing Jing
- Rehabilitation Center, Qilu Hospital of Shandong University, Jinan, Shandong, China
| | - Yanping Ma
- Rehabilitation Center, Qilu Hospital of Shandong University, Jinan, Shandong, China
| | - Ying Song
- Rehabilitation Center, Qilu Hospital of Shandong University, Jinan, Shandong, China
| | - Jiahui Yin
- Beijing Key Laboratory of Rehabilitation Technical Aids for Old-Age Disability, National Research Center for Rehabilitation Technical Aids, Beijing, China
| | - Gongcheng Xu
- Beijing Key Laboratory of Rehabilitation Technical Aids for Old-Age Disability, National Research Center for Rehabilitation Technical Aids, Beijing, China
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| | - Xinglou Li
- Rehabilitation Center, Qilu Hospital of Shandong University, Jinan, Shandong, China
| | - Zengyong Li
- Beijing Key Laboratory of Rehabilitation Technical Aids for Old-Age Disability, National Research Center for Rehabilitation Technical Aids, Beijing, China
- Key Laboratory of Rehabilitation Aids Technology and System of the Ministry of Civil Affairs, Beijing, China
- Zengyong Li,
| | - Yonghui Wang
- Rehabilitation Center, Qilu Hospital of Shandong University, Jinan, Shandong, China
- *Correspondence: Yonghui Wang,
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Schneider HR, Wawrzyniak M, Stockert A, Klingbeil J, Saur D. fMRI informed voxel-based lesion analysis to identify lesions associated with right-hemispheric activation in aphasia recovery. Neuroimage Clin 2022; 36:103169. [PMID: 36037659 PMCID: PMC9440420 DOI: 10.1016/j.nicl.2022.103169] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 08/01/2022] [Accepted: 08/22/2022] [Indexed: 12/14/2022]
Abstract
Several mechanisms have been attributed to post-stroke loss and recovery of language functions. However, the significance and timing of domain-general and homotopic right-hemispheric activation is controversial. We aimed to examine the effect of left-hemispheric lesion location and time post-stroke on right-hemispheric activation. Voxel-based lesion analyses were informed by auditory language-related fMRI activation of 71 patients with left middle cerebral artery stroke examined longitudinally in the acute, subacute and early chronic phase. Language activation was determined in several right-hemispheric regions of interest and served as regressor of interest for voxel-based lesion analyses. We found that an acute to chronic increase of language activation in the right supplementary motor area was associated with lesions to the left extreme capsule as part of the ventral language pathway. Importantly, this activation increase correlated significantly with improvement of out-of-scanner comprehension abilities. We interpret our findings in terms of successful domain-general compensation in patients with critical left frontotemporal disconnection due to damage to the ventral language pathway but relatively spared cortical language areas.
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Affiliation(s)
| | - Max Wawrzyniak
- Corresponding author at: Klinik und Poliklinik für Neurologie, Universitätsklinikum Leipzig AöR, Liebigstraße 20, 04103 Leipzig, Germany.
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Tang H, Fan S, Niu X, Li Z, Xiao P, Zeng J, Xing S. Remote cortical atrophy and language outcomes after chronic left subcortical stroke with aphasia. Front Neurosci 2022; 16:853169. [PMID: 35992910 PMCID: PMC9381815 DOI: 10.3389/fnins.2022.853169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Accepted: 07/18/2022] [Indexed: 11/25/2022] Open
Abstract
Objective Subcortical stroke can cause a variety of language deficits. However, the neural mechanisms underlying subcortical aphasia after stroke remain incompletely elucidated. We aimed to determine the effects of distant cortical structures on aphasia outcomes and examine the correlation of cortical thickness measures with connecting tracts integrity after chronic left subcortical stroke. Methods Thirty-two patients and 30 healthy control subjects underwent MRI scanning and language assessment with the Western Aphasia Battery-Revised (WAB-R) subtests. Among patients, the cortical thickness in brain regions that related to language performance were assessed by the FreeSurfer software. Fiber tracts connecting the identified cortical regions to stroke lesions were reconstructed to determine its correlations with the cortical thickness measures across individual patient. Results Cortical thickness in different parts of the left fronto-temporo-parietal (FTP) regions were positively related to auditory-verbal comprehension, spontaneous speech and naming/word finding abilities when controlling for key demographic variables and lesion size. Cortical thickness decline in the identified cortical regions was positively correlated with integrity loss of fiber tracts connected to stroke lesions. Additionally, no significant difference in cortical thickness was found across the left hemisphere between the subgroup of patients with hypoperfusion (HP) and those without HP at stroke onset. Conclusions These findings suggest that remote cortical atrophy independently predicts language outcomes in patients with chronic left subcortical stroke and aphasia and that cortical thinning in these regions might relate to integrity loss of fiber tracts connected to stroke lesions.
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Affiliation(s)
- Huijia Tang
- Department of Neurology and Stroke Center, Guangdong Provincial Key Laboratory of Diagnosis and Treatment of Major Neurological Diseases, National Key Clinical Department and Key Discipline of Neurology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Shuhan Fan
- Department of Neurology and Stroke Center, Guangdong Provincial Key Laboratory of Diagnosis and Treatment of Major Neurological Diseases, National Key Clinical Department and Key Discipline of Neurology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Xingyang Niu
- Department of Neurology and Stroke Center, Guangdong Provincial Key Laboratory of Diagnosis and Treatment of Major Neurological Diseases, National Key Clinical Department and Key Discipline of Neurology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Zhuhao Li
- Department of Radiology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Peiyi Xiao
- Department of Neurology and Stroke Center, Guangdong Provincial Key Laboratory of Diagnosis and Treatment of Major Neurological Diseases, National Key Clinical Department and Key Discipline of Neurology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Jinsheng Zeng
- Department of Neurology and Stroke Center, Guangdong Provincial Key Laboratory of Diagnosis and Treatment of Major Neurological Diseases, National Key Clinical Department and Key Discipline of Neurology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Shihui Xing
- Department of Neurology and Stroke Center, Guangdong Provincial Key Laboratory of Diagnosis and Treatment of Major Neurological Diseases, National Key Clinical Department and Key Discipline of Neurology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
- *Correspondence: Shihui Xing,
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DeMarco AT, van der Stelt C, Paul S, Dvorak E, Lacey E, Snider S, Turkeltaub PE. Absence of Perilesional Neuroplastic Recruitment in Chronic Poststroke Aphasia. Neurology 2022; 99:e119-e128. [PMID: 35508398 PMCID: PMC9280993 DOI: 10.1212/wnl.0000000000200382] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Accepted: 02/25/2022] [Indexed: 01/27/2023] Open
Abstract
BACKGROUND AND OBJECTIVES A prominent theory proposes that neuroplastic recruitment of perilesional tissue supports aphasia recovery, especially when language-capable cortex is spared by smaller lesions. This theory has rarely been tested directly and findings have been inconclusive. We tested the perilesional plasticity hypothesis using 2 fMRI tasks in 2 groups of patients with previous aphasia diagnosis. METHODS Two cohorts totaling 82 patients with chronic left-hemisphere stroke with previous aphasia diagnosis and 82 control participants underwent fMRI using either a naming task or a reliable semantic decision task. Individualized perilesional tissue was defined by dilating anatomical lesions and language regions were defined using meta-analyses. Mixed modeling examined differences in activity between groups. Relationships with lesion size and aphasia severity were examined. RESULTS Patients exhibited reduced activity in perilesional language tissue relative to controls in both tasks. Although a few cortical regions exhibited greater activity irrespective of distance from the lesion, or only when distant from the lesion, no regions exhibited increased activity only when near the lesion. Larger lesions were associated with reduced language activity irrespective of distance from the lesion. Using the reliable fMRI task, reduced language activity was related to aphasia severity independent of lesion size. DISCUSSION We found no evidence for neuroplastic recruitment of perilesional tissue in aphasia beyond its typical role in language. Rather, our findings are consistent with alternative hypotheses that changes in left-hemisphere activation during recovery relate to normalization of language network dysfunction and possibly recruitment of alternate cortical processors. These findings clarify left-hemisphere neuroplastic mechanisms supporting language recovery after stroke.
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Affiliation(s)
- Andrew Tesla DeMarco
- From the Departments of Rehabilitation Medicine (A.T.D., P.E.T.) and Neurology (A.T.D., C.v.d.S., S.P., E.D., E.L., S.S., P.E.T.), Georgetown University; and MedStar National Rehabilitation Hospital (E.L., P.E.T.), Washington, DC
| | - Candace van der Stelt
- From the Departments of Rehabilitation Medicine (A.T.D., P.E.T.) and Neurology (A.T.D., C.v.d.S., S.P., E.D., E.L., S.S., P.E.T.), Georgetown University; and MedStar National Rehabilitation Hospital (E.L., P.E.T.), Washington, DC
| | - Sachi Paul
- From the Departments of Rehabilitation Medicine (A.T.D., P.E.T.) and Neurology (A.T.D., C.v.d.S., S.P., E.D., E.L., S.S., P.E.T.), Georgetown University; and MedStar National Rehabilitation Hospital (E.L., P.E.T.), Washington, DC
| | - Elizabeth Dvorak
- From the Departments of Rehabilitation Medicine (A.T.D., P.E.T.) and Neurology (A.T.D., C.v.d.S., S.P., E.D., E.L., S.S., P.E.T.), Georgetown University; and MedStar National Rehabilitation Hospital (E.L., P.E.T.), Washington, DC
| | - Elizabeth Lacey
- From the Departments of Rehabilitation Medicine (A.T.D., P.E.T.) and Neurology (A.T.D., C.v.d.S., S.P., E.D., E.L., S.S., P.E.T.), Georgetown University; and MedStar National Rehabilitation Hospital (E.L., P.E.T.), Washington, DC
| | - Sarah Snider
- From the Departments of Rehabilitation Medicine (A.T.D., P.E.T.) and Neurology (A.T.D., C.v.d.S., S.P., E.D., E.L., S.S., P.E.T.), Georgetown University; and MedStar National Rehabilitation Hospital (E.L., P.E.T.), Washington, DC
| | - Peter E Turkeltaub
- From the Departments of Rehabilitation Medicine (A.T.D., P.E.T.) and Neurology (A.T.D., C.v.d.S., S.P., E.D., E.L., S.S., P.E.T.), Georgetown University; and MedStar National Rehabilitation Hospital (E.L., P.E.T.), Washington, DC.
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Li R, Mukadam N, Kiran S. Functional MRI evidence for reorganization of language networks after stroke. HANDBOOK OF CLINICAL NEUROLOGY 2022; 185:131-150. [PMID: 35078595 DOI: 10.1016/b978-0-12-823384-9.00007-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
In this chapter, we review fMRI evidence for language reorganization in individuals with poststroke aphasia. Several studies in the current literature have utilized fMRI as a tool to understand patterns of functional reorganization in poststroke aphasia. Consistent with previous models that have been proposed to explain the trajectory of language recovery, differential patterns of language processing and language recovery have been identified across individuals with poststroke aphasia in different stages of recovery. Overall, a global network breakdown typically occurs in the early stages of aphasia recovery, followed by normalization in "traditional" left hemisphere language networks. Depending on individual characteristics, right hemisphere regions and bilateral domain-general regions may be further recruited. The main takeaway of this chapter is that poststroke aphasia recovery does not depend on individual neural regions, but rather involves a complex interaction among regions in larger networks. Many of the unresolved issues and contrastive findings in the literature warrant further research with larger groups of participants and standard protocols of fMRI implementation.
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Affiliation(s)
- Ran Li
- Department of Speech, Language and Hearing Sciences, Boston University, Boston, MA, United States
| | - Nishaat Mukadam
- Department of Speech, Language and Hearing Sciences, Boston University, Boston, MA, United States
| | - Swathi Kiran
- Department of Speech, Language and Hearing Sciences, Boston University, Boston, MA, United States.
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9
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Szaflarski JP, Nenert R, Allendorfer JB, Martin AN, Amara AW, Griffis JC, Dietz A, Mark VW, Sung VW, Walker HC, Zhou X, Lindsell CJ. Intermittent Theta Burst Stimulation (iTBS) for Treatment of Chronic Post-Stroke Aphasia: Results of a Pilot Randomized, Double-Blind, Sham-Controlled Trial. Med Sci Monit 2021; 27:e931468. [PMID: 34183640 PMCID: PMC8254416 DOI: 10.12659/msm.931468] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Background Research indicates intermittent theta burst stimulation (iTBS) is a potential treatment of post-stroke aphasia. Material/Methods In this double-blind, sham-controlled trial (NCT 01512264) participants were randomized to receive 3 weeks of sham (G0), 1 week of iTBS/2 weeks of sham (G1), 2 weeks of iTBS/1 week of sham (G2), or 3 weeks of iTBS (G3). FMRI localized residual language function in the left hemisphere; iTBS was applied to the maximum fMRI activation in the residual language cortex in the left frontal lobe. FMRI and aphasia testing were conducted pre-treatment, at ≤1 week after completing treatment, and at 3 months follow-up. Results 27/36 participants completed the trial. We compared G0 to each of the individual treatment group and to all iTBS treatment groups combined (G1–3). In individual groups, participants gained (of moderate or large effect sizes; some significant at P<0.05) on the Boston Naming Test (BNT), the Semantic Fluency Test (SFT), and the Aphasia Quotient of the Western Aphasia Battery-Revised (WAB-R AQ). In G1–3, BNT, and SFT improved immediately after treatment, while the WAB-R AQ improved at 3 months. Compared to G0, the other groups showed greater fMRI activation in both hemispheres and non-significant increases in language lateralization to the left hemisphere. Changes in IFG connectivity were noted with iTBS, showing differences between time-points, with some of them correlating with the behavioral measures. Conclusions The results of this pilot trial support the hypothesis that iTBS applied to the ipsilesional hemisphere can improve aphasia and result in cortical plasticity.
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Affiliation(s)
- Jerzy P Szaflarski
- Department of Neurology, University of Alabama at Birmingham, Birmingham, AL, USA.,Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Rodolphe Nenert
- Department of Neurology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Jane B Allendorfer
- Department of Neurology, University of Alabama at Birmingham, Birmingham, AL, USA.,Center for Exercise Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Amber N Martin
- Department of Neurology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Amy W Amara
- Department of Neurology, University of Alabama at Birmingham, Birmingham, AL, USA.,Center for Exercise Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Joseph C Griffis
- Department of Neurology, University of Alabama at Birmingham, Birmingham, AL, USA.,Department of Psychology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Aimee Dietz
- Department of Communication Sciences and Disorders, University of Cincinnati, Cincinnati, OH, USA
| | - Victor W Mark
- Department of Neurology, University of Alabama at Birmingham, Birmingham, AL, USA.,Department of Psychology, University of Alabama at Birmingham, Birmingham, AL, USA.,Department of Physical Medicine and Rehabilitation, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Victor W Sung
- Department of Neurology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Harrison C Walker
- Department of Neurology, University of Alabama at Birmingham, Birmingham, AL, USA.,Department of Physical Medicine and Rehabilitation, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Xiaohua Zhou
- Department of Physical Medicine and Rehabilitation, University of Alabama at Birmingham, Birmingham, AL, USA
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10
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Krishna S, Kakaizada S, Almeida N, Brang D, Hervey-Jumper S. Central Nervous System Plasticity Influences Language and Cognitive Recovery in Adult Glioma. Neurosurgery 2021; 89:539-548. [PMID: 33476391 DOI: 10.1093/neuros/nyaa456] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Accepted: 08/05/2020] [Indexed: 01/01/2023] Open
Abstract
Gliomas exist within the framework of complex neuronal circuitry in which network dynamics influence both tumor biology and cognition. The generalized impairment of cognition or loss of language function is a common occurrence for glioma patients. The interface between intrinsic brain tumors such as gliomas and functional cognitive networks are poorly understood. The ability to communicate effectively is critically important for receiving oncological therapies and maintaining a high quality of life. Although the propensity of gliomas to infiltrate cortical and subcortical structures and disrupt key anatomic language pathways is well documented, there is new evidence offering insight into the network and cellular mechanisms underpinning glioma-related aphasia and aphasia recovery. In this review, we will outline the current understanding of the mechanisms of cognitive dysfunction and recovery, using aphasia as an illustrative model.
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Affiliation(s)
- Saritha Krishna
- Department of Neurological Surgery, University of California, San Francisco, San Francisco, California
| | - Sofia Kakaizada
- Department of Neurological Surgery, University of California, San Francisco, San Francisco, California
| | - Nyle Almeida
- Department of Neurological Surgery, University of California, San Francisco, San Francisco, California
| | - David Brang
- Department of Psychology, University of Michigan, Ann Arbor, Michigan
| | - Shawn Hervey-Jumper
- Department of Neurological Surgery, University of California, San Francisco, San Francisco, California
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11
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Goodman AM, Diggs MD, Balachandran N, Kakulamarri PS, Oster RA, Allendorfer JB, Szaflarski JP. Repeatability of Neural and Autonomic Responses to Acute Psychosocial Stress. Front Neurosci 2020; 14:585509. [PMID: 33328855 PMCID: PMC7732671 DOI: 10.3389/fnins.2020.585509] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Accepted: 11/05/2020] [Indexed: 11/13/2022] Open
Abstract
FMRI Montreal Imaging Stress Tasks (MIST) have been shown to activate endocrine and autonomic stress responses that are mediated by a prefrontal cortex (PFC)-hippocampus-amygdala circuit. However, the stability of the neurobehavioral responses over time and the ability to monitor response to clinical interventions has yet to be validated. The objective of this study was to compare the fMRI and physiologic responses to acute psychosocial stress in healthy volunteers during initial and follow-up visits approximately 13 weeks later, simulating a typical duration of clinical intervention. We hypothesized that responses to stress would remain highly conserved across the 2 visits in the absence of an intervention. 15 healthy volunteers completed a variant of control math task (CMT) and stress math task (SMT) conditions based on MIST. Neural responses were modeled using an event-related design with estimates for math performance and auditory feedback for each task condition. For each visit, measures of stress reactivity included differential fMRI and heart rate (SMT-CMT), as well as salivary alpha-amylase before and after scanning sessions. The results revealed that differential fMRI, as well as increased heart rate and salivary alpha-amylase from before and after scanning remained similar between visits. Intraclass correlation coefficient (ICC) values revealed areas of reliable task-dependent BOLD fMRI signal response across visits for peaks of clusters for the main effect of condition (SMT vs CMT) within dorsal anterior cingulate cortex (ACC), insula, and hippocampus regions during math performance and within subgenual ACC, posterior cingulate cortex, dorsolateral PFC regions during auditory feedback. Given that the neurobehavioral response to acute stress remained highly conserved across visits in the absence of an intervention, this study confirms the utility for MIST for assessing longitudinal changes in controlled trials that can identify underlying neurobiological mechanisms involved in mediating the efficacy of stress-reduction interventions.
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Affiliation(s)
- Adam M Goodman
- Department of Neurology, University of Alabama at Birmingham (UAB) Epilepsy Center, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Michael David Diggs
- Department of Neurology, University of Alabama at Birmingham (UAB) Epilepsy Center, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Neha Balachandran
- Department of Neurology, University of Alabama at Birmingham (UAB) Epilepsy Center, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Pranav S Kakulamarri
- Department of Neurology, University of Alabama at Birmingham (UAB) Epilepsy Center, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Robert A Oster
- Department of Medicine, University of Alabama at Birmingham (UAB), Birmingham, AL, United States
| | - Jane B Allendorfer
- Department of Neurology, University of Alabama at Birmingham (UAB) Epilepsy Center, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Jerzy P Szaflarski
- Department of Neurology, University of Alabama at Birmingham (UAB) Epilepsy Center, University of Alabama at Birmingham, Birmingham, AL, United States
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12
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A unified neurocomputational bilateral model of spoken language production in healthy participants and recovery in poststroke aphasia. Proc Natl Acad Sci U S A 2020; 117:32779-32790. [PMID: 33273118 PMCID: PMC7768768 DOI: 10.1073/pnas.2010193117] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Studies of healthy and impaired language have generated many verbally described hypotheses. While these verbal descriptions have advanced our understanding of language processing, some explanations are mutually incompatible, and it is unclear how they work mechanistically. We constructed a neurocomputational bilateral model of spoken language production to simulate a range of phenomena in healthy participants and patients with aphasia simultaneously, including language lateralization, impaired performance after left but not right damage, and hemispheric involvement in plasticity-dependent recovery. The model demonstrates how seemly contradictory findings can be simulated within a single framework. This provides a coherent mechanistic account of language lateralization and recovery from poststroke aphasia. Understanding the processes underlying normal, impaired, and recovered language performance has been a long-standing goal for cognitive and clinical neuroscience. Many verbally described hypotheses about language lateralization and recovery have been generated. However, they have not been considered within a single, unified, and implemented computational framework, and the literatures on healthy participants and patients are largely separated. These investigations also span different types of data, including behavioral results and functional MRI brain activations, which augment the challenge for any unified theory. Consequently, many key issues, apparent contradictions, and puzzles remain to be solved. We developed a neurocomputational, bilateral pathway model of spoken language production, designed to provide a unified framework to simulate different types of data from healthy participants and aphasic patients. The model encapsulates key computational principles (differential computational capacity, emergent division of labor across pathways, experience-dependent plasticity-related recovery) and provides an explanation for the bilateral yet asymmetric lateralization of language in healthy participants, chronic aphasia after left rather than right hemisphere lesions, and the basis of partial recovery in patients. The model provides a formal basis for understanding the relationship between behavioral performance and brain activation. The unified model is consistent with the degeneracy and variable neurodisplacement theories of language recovery, and adds computational insights to these hypotheses regarding the neural machinery underlying language processing and plasticity-related recovery following damage.
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13
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14
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Jones LM, Ginier E, Debbs J, Eaton JL, Renner C, Hawkins J, Rios-Spicer R, Tang E, Schertzing C, Giordani B. Exploring Representation of Diverse Samples in fMRI Studies Conducted in Patients With Cardiac-Related Chronic Illness: A Focused Systematic Review. Front Hum Neurosci 2020; 14:108. [PMID: 32477079 PMCID: PMC7240043 DOI: 10.3389/fnhum.2020.00108] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Accepted: 03/11/2020] [Indexed: 01/14/2023] Open
Abstract
Introduction/Purpose: Cardiovascular disease (CVD) is the leading cause of death worldwide, and in the United States alone, CVD causes nearly 840,000 deaths annually. Using functional magnetic resonance imaging (fMRI), a tool to assess brain activity, researchers have identified some brain-behavior connections and predicted several self-management behaviors. The purpose of this study was to examine the sample characteristics of individuals with CVD who participated in fMRI studies. Methods: A literature search was conducted in PubMed, CINAHL, and Scopus. No date or language restrictions were applied and research methodology filters were used. In October 2017, 1659 titles and abstracts were identified. Inclusion criteria were: (1) utilized an empirical study design, (2) used fMRI to assess brain activity, and (3) focused on patients with CVD-related chronic illness. Articles were excluded if they: were theory or opinion articles, focused on mental or neuropathic illness, included non-human samples, or were not written in English. After duplicates were removed (230), 1,429 titles and abstracts were reviewed based on inclusion criteria; 1,243 abstracts were then excluded. A total of 186 studies were reviewed in their entirety; after additional review, 142 were further excluded for not meeting the inclusion criteria. Forty-four articles met criteria and were included in the final review. An evidence table was created to capture the demographics of each study sample. Results: Ninety eight percent of the studies did not report the racial or ethnic composition of their sample. Most studies (66%) contained more men than women. Mean age ranged from 38 to 78 years; 77% reported mean age ≥50 years. The most frequently studied CVD was stroke (86%), while hypertension was studied the least (2%). Conclusion: Understanding brain-behavior relationships can help researchers and practitioners tailor interventions to meet specific patient needs. These findings suggest that additional studies are needed that focus on populations historically underrepresented in fMRI research. Researchers should thoughtfully consider diversity and purposefully sample groups by including individuals that are: women, from diverse backgrounds, younger, and diagnosed with a variety of CVD-related illnesses. Identifying and addressing these gaps by studying more representative samples will help healthcare providers reduce disparities and tailor interventions for all CVD populations.
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Affiliation(s)
- Lenette M. Jones
- School of Nursing, University of Michigan, Ann Arbor, MI, United States
| | - Emily Ginier
- Taubman Health Sciences Library, University of Michigan, Ann Arbor, MI, United States
| | - Joseph Debbs
- School of Nursing, University of Michigan, Ann Arbor, MI, United States
| | - Jarrod L. Eaton
- School of Nursing, University of Michigan, Ann Arbor, MI, United States
| | - Catherine Renner
- School of Nursing, University of Michigan, Ann Arbor, MI, United States
| | - Jaclynn Hawkins
- School of Social Work, University of Michigan, Ann Arbor, MI, United States
| | | | - Emily Tang
- School of Nursing, University of Michigan, Ann Arbor, MI, United States
| | | | - Bruno Giordani
- Psychiatry, Neurology, Psychology, and Nursing, University of Michigan, Ann Arbor, MI, United States
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15
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Higgins J, Barbieri E, Wang X, Mack J, Caplan D, Kiran S, Rapp B, Thompson C, Zinbarg R, Parrish T. Reliability of BOLD signals in chronic stroke-induced aphasia. Eur J Neurosci 2020; 52:3963-3978. [PMID: 32282965 DOI: 10.1111/ejn.14739] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 04/01/2020] [Accepted: 04/02/2020] [Indexed: 11/30/2022]
Abstract
Investigating the neurobiology of language impairment and treatment in chronic stroke aphasia using fMRI requires an understanding of measurement variability within and between participants. In this multicenter study, we evaluated the scan-rescan reliability of an auditory and visual (written) story comprehension paradigm in stroke participants with aphasia (N = 65) and healthy controls (N = 22). The multi-modal task was conducted twice (~1 week apart) on separate visits upon study enrolment and twice again at completion three months later. A non-language visuomotor task was studied in the aphasia group only, which was conducted once per time point (3 months apart). While participants were asked to make responses during the comprehension task, these in-scanner responses were not recorded. Reliability was assessed using intraclass correlation coefficient (ICC) at both group and individual participant levels. The visual story comprehension condition had higher reliability than the auditory condition in both groups, with participants with aphasia exhibiting lower reliability than controls in both conditions (stroke ICC = .43, healthy ICC = .81). Differences in reliability within the group of participants with aphasia were found to be partially explained by overall language impairment as well as greater head motion. In the participants with aphasia, the visuomotor paradigm was found to have greater reliability than the story comprehension task at equivalent interscan intervals (visuomotor = 0.50, comprehension = 0.34), and its reliability was not associated with language impairment. This work highlights the importance of considering the reliability of fMRI tasks in aphasia research, provides strategies to improve reliability and has potential implications for the field of clinical neuroimaging in general.
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Affiliation(s)
- James Higgins
- Center for the Neurobiology of Language Recovery, Northwestern University, Evanston, IL, USA.,Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Elena Barbieri
- Center for the Neurobiology of Language Recovery, Northwestern University, Evanston, IL, USA.,Department of Communication Sciences and Disorders, School of Communication, Northwestern University, Evanston, IL, USA
| | - Xue Wang
- Center for the Neurobiology of Language Recovery, Northwestern University, Evanston, IL, USA.,Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Jennifer Mack
- Center for the Neurobiology of Language Recovery, Northwestern University, Evanston, IL, USA.,Department of Communication Sciences and Disorders, School of Communication, Northwestern University, Evanston, IL, USA
| | - David Caplan
- Center for the Neurobiology of Language Recovery, Northwestern University, Evanston, IL, USA.,Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Swathi Kiran
- Center for the Neurobiology of Language Recovery, Northwestern University, Evanston, IL, USA.,Department of Speech, Language, and Hearing, College of Health & Rehabilitation, Boston University, Boston, MA, USA
| | - Brenda Rapp
- Center for the Neurobiology of Language Recovery, Northwestern University, Evanston, IL, USA.,Department of Cognitive Science, Krieger School of Arts & Sciences, Johns Hopkins University, Baltimore, MD, USA
| | - Cynthia Thompson
- Center for the Neurobiology of Language Recovery, Northwestern University, Evanston, IL, USA.,Department of Communication Sciences and Disorders, School of Communication, Northwestern University, Evanston, IL, USA.,Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Richard Zinbarg
- Center for the Neurobiology of Language Recovery, Northwestern University, Evanston, IL, USA.,Department of Psychology, Weinberg College of Arts and Sciences, Northwestern University, Evanston, IL, USA.,The Family Institute at Northwestern University, Evanston, IL, USA
| | - Todd Parrish
- Center for the Neurobiology of Language Recovery, Northwestern University, Evanston, IL, USA.,Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
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16
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The neural and neurocomputational bases of recovery from post-stroke aphasia. Nat Rev Neurol 2019; 16:43-55. [DOI: 10.1038/s41582-019-0282-1] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/14/2019] [Indexed: 12/15/2022]
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17
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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: 30] [Impact Index Per Article: 6.0] [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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18
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Mogensen J, Overgaard M. Reorganization of the connectivity between elementary functions as a common mechanism of phenomenal consciousness and working memory: from functions to strategies. Philos Trans R Soc Lond B Biol Sci 2019; 373:rstb.2017.0346. [PMID: 30061460 DOI: 10.1098/rstb.2017.0346] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/08/2018] [Indexed: 02/07/2023] Open
Abstract
In the present communication, phenomenal consciousness, access consciousness and the closely related concept of working memory are presented in the context of a neurocognitive model-the REF (reorganization of elementary functions) framework. The REF framework is based on connectionist networks within which the 'units' are advanced processing modules called elementary functions (EFs). In this framework, the focus is on dynamically changeable 'strategies'-based on reorganizations of the connectivity between EFs-rather than on the more traditional 'cognitive functions'. The background for the REF framework and especially how the neural correlate of consciousness is understood within these models is summarized. According to the REF framework, phenomenal consciousness cannot 'overflow' availability of information for action. Phenomenal consciousness may, however, overflow working memory because working memory in the present context is seen as a surface phenomenon reflecting underlying dynamic strategies-influenced by both experience and situational factors.This article is part of the theme issue 'Perceptual consciousness and cognitive access'.
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Affiliation(s)
- Jesper Mogensen
- The Unit for Cognitive Neuroscience (UCN), Department of Psychology, University of Copenhagen, Oester Farimagsgade 2A, 1353 Copenhagen K, Denmark
| | - Morten Overgaard
- CNRU, CFIN, MindLab, Aarhus University, Nørrebrogade 44, Building 10 G, 8000 Aarhus C, Denmark
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19
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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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20
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Dietz A, Vannest J, Maloney T, Altaye M, Holland S, Szaflarski JP. The feasibility of improving discourse in people with aphasia through AAC: Clinical and functional MRI correlates. APHASIOLOGY 2018; 32:693-719. [PMID: 32999522 PMCID: PMC7523709 DOI: 10.1080/02687038.2018.1447641] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
AIMS The purpose of this study is twofold: (1) to examine the feasibility of providing high-tech augmentative and alternative communication (AAC) treatment to people with chronic aphasia, with the goal of evoking changes in spoken language; and (2) to identify evidence of AAC-induced changes in brain activation. METHOD & PROCEDURES We employed a pre- post-treatment design with a control (usual care) group to observe the impact of an AAC treatment on aphasia severity and spoken discourse. Further, we used functional magnetic resonance imaging (fMRI) to examine associated neural reorganization. OUTCOMES & RESULTS Compared to the usual care group, the AAC intervention trended toward larger treatment effects and resulted in a higher number of responders on behavioral outcomes. Both groups demonstrated a trend toward greater leftward lateralization of language functions via fMRI. Secondary analyses of responders to treatment revealed increased activation in visual processing regions, primarily for the AAC group. CONCLUSIONS This study provides preliminary guidance regarding how to implement AAC treatment in a manner that simultaneously facilitates language recovery across a variety of aphasia types and severity levels while compensating for residual deficits in people with chronic aphasia. Further, this work motivates continued efforts to unveil the role of AAC-based interventions in the aphasia recovery process and provides insight regarding the neurobiological mechanisms supporting AAC-induced language changes.
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21
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Shuster LI. Considerations for the Use of Neuroimaging Technologies for Predicting Recovery of Speech and Language in Aphasia. AMERICAN JOURNAL OF SPEECH-LANGUAGE PATHOLOGY 2018; 27:291-305. [PMID: 29497745 DOI: 10.1044/2018_ajslp-16-0180] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Accepted: 01/16/2018] [Indexed: 06/08/2023]
Abstract
PURPOSE The number of research articles aimed at identifying neuroimaging biomarkers for predicting recovery from aphasia continues to grow. Although the clinical use of these biomarkers to determine prognosis has been proposed, there has been little discussion of how this would be accomplished. This is an important issue because the best translational science occurs when translation is considered early in the research process. The purpose of this clinical focus article is to present a framework to guide the discussion of how neuroimaging biomarkers for recovery from aphasia could be implemented clinically. METHOD The genomics literature reveals that implementing genetic testing in the real-world poses both opportunities and challenges. There is much similarity between these opportunities and challenges and those related to implementing neuroimaging testing to predict recovery in aphasia. Therefore, the Center for Disease Control's model list of questions aimed at guiding the review of genetic testing has been adapted to guide the discussion of using neuroimaging biomarkers as predictors of recovery in aphasia. CONCLUSION The adapted model list presented here is a first and useful step toward initiating a discussion of how neuroimaging biomarkers of recovery could be employed clinically to provide improved quality of care for individuals with aphasia.
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Affiliation(s)
- Linda I Shuster
- Department of Speech, Language, and Hearing Sciences, Western Michigan University, Kalamazoo
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22
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Zhang H, Chen Y, Hu R, Yang L, Wang M, Zhang J, Lu H, Wu Y, Du X. rTMS treatments combined with speech training for a conduction aphasia patient: A case report with MRI study. Medicine (Baltimore) 2017; 96:e7399. [PMID: 28796033 PMCID: PMC5556199 DOI: 10.1097/md.0000000000007399] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
RATIONALE To date, little is known regarding the neural mechanisms of the functional recovery of language after repetitive transcranial magnetic stimulation (rTMS) in aphasia. Our aim was to investigate the mechanism that underlies rTMS and speech training in a case report. PATIENT CONCERNS AND DIAGNOSES We report the case of a 39-year-old woman who was initially diagnosed with conduction aphasia following a left hemisphere stroke. INTERVENTIONS The rTMS location comprised the left Broca area, and a frequency of 5 Hz for 20 min/d for 10 days during a 2-week period was used. She had received speech rehabilitation training 1 month after stroke. Functional magnetic resonance imaging (fMRI) and diffusion tensor imaging were used to investigate the functional and microstructural changes before and after rTMS treatment. OUTCOMES The results demonstrated that the Western Aphasia Battery scores significantly improved for language ability at 2 weeks post-treatment, and the gains were steadily increased at 2.5 months post-treatment. The fMRI results indicated a more focused activation pattern and showed significant activation in the left dominant hemisphere relative to the right hemisphere, especially in the perilesional areas, post-treatment during 2 language tasks compared with pretreatment. Moreover, the fractional anisotropy increased in the left superior temporal gyrus, which comprises an important area that is involved in language processing. LESSONS Our findings suggest that rTMS combined with speech training improved the speech-language ability of this chronic conduction aphasia patient and enhanced the cerebral functional and microstructural reorganization.
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Affiliation(s)
- Hui Zhang
- Shanghai Key Laboratory of Magnetic Resonance and Department of Physics, School of Physics and Materials Science, East China Normal University
| | - Ying Chen
- Department of Rehabilitation Medicine, Huashan Hospital
| | - Ruiping Hu
- Department of Rehabilitation Medicine, Huashan Hospital
- Department of Rehabilitation Medicine, Shanghai Third Rehabilitation Hospital
| | | | - Mengxing Wang
- Shanghai Key Laboratory of Magnetic Resonance and Department of Physics, School of Physics and Materials Science, East China Normal University
| | - Jilei Zhang
- Shanghai Key Laboratory of Magnetic Resonance and Department of Physics, School of Physics and Materials Science, East China Normal University
| | - Haifeng Lu
- Shanghai Key Laboratory of Magnetic Resonance and Department of Physics, School of Physics and Materials Science, East China Normal University
| | - Yi Wu
- Department of Rehabilitation Medicine, Huashan Hospital
- Department of Sports Medicine and Rehabilitation, Huashan Hospital
- State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China
| | - Xiaoxia Du
- Shanghai Key Laboratory of Magnetic Resonance and Department of Physics, School of Physics and Materials Science, East China Normal University
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23
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Alferova VV, Mayorova LA, Ivanova EG, Guekht AB, Shklovskij VM. [Functional neuroimaging of the brain structures associated with language in healthy individuals and patients with post-stroke aphasia]. Zh Nevrol Psikhiatr Im S S Korsakova 2017; 117:71-78. [PMID: 28665373 DOI: 10.17116/jnevro20171173271-78] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The introduction of non-invasive functional neuroimaging techniques such as functional magnetic resonance imaging (fMRI), in the practice of scientific and clinical research can increase our knowledge about the organization of cognitive processes, including language, in normal and reorganization of these cognitive functions in post-stroke aphasia. The article discusses the results of fMRI studies of functional organization of the cortex of a healthy adult's brain in the processing of various voice information as well as the main types of speech reorganization after post-stroke aphasia in different stroke periods. The concepts of 'effective' and 'ineffective' brain plasticity in post-stroke aphasia were considered. It was concluded that there was an urgent need for further comprehensive studies, including neuropsychological testing and several complementary methods of functional neuroimaging, to develop a phased treatment plan and neurorehabilitation of patients with post-stroke aphasia.
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Affiliation(s)
- V V Alferova
- Center for Speech Pathology and Neurorehabilitation, Moscow, Russia; Pirogov Russian National Research Medical University, Moscow, Russia
| | - L A Mayorova
- Center for Speech Pathology and Neurorehabilitation, Moscow, Russia; Institute of Higher Nervous Activity of RAS, Moscow, Russia
| | - E G Ivanova
- Center for Speech Pathology and Neurorehabilitation, Moscow, Russia; Pirogov Russian National Research Medical University, Moscow, Russia
| | - A B Guekht
- Pirogov Russian National Research Medical University, Moscow, Russia; The Solovyov Scientific and Practical Centre of neuropsychiatric, Moscow, Russia
| | - V M Shklovskij
- Center for Speech Pathology and Neurorehabilitation, Moscow, Russia; The Serbsky State Scientific Center for Psychiatry and Narcology, Moscow, Russia
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24
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Mogensen J, Overgaard M. Reorganization of the Connectivity between Elementary Functions - A Model Relating Conscious States to Neural Connections. Front Psychol 2017; 8:625. [PMID: 28473797 PMCID: PMC5397468 DOI: 10.3389/fpsyg.2017.00625] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2016] [Accepted: 04/04/2017] [Indexed: 01/08/2023] Open
Abstract
In the present paper it is argued that the "neural correlate of consciousness" (NCC) does not appear to be a separate "module" - but an aspect of information processing within the neural substrate of various cognitive processes. Consequently, NCC can only be addressed adequately within frameworks that model the general relationship between neural processes and mental states - and take into account the dynamic connectivity of the brain. We presently offer the REFGEN (general reorganization of elementary functions) model as such a framework. This model builds upon and expands the REF (reorganization of elementary functions) and REFCON (of elementary functions and consciousness) models. All three models integrate the relationship between the neural and mental layers of description via the construction of an intermediate level dealing with computational states. The importance of experience based organization of neural and cognitive processes is stressed. The models assume that the mechanisms of consciousness are in principle the same as the basic mechanisms of all aspects of cognition - when information is processed to a sufficiently "high level" it becomes available to conscious experience. The NCC is within the REFGEN model seen as aspects of the dynamic and experience driven reorganizations of the synaptic connectivity between the neurocognitive "building blocks" of the model - the elementary functions.
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Affiliation(s)
- Jesper Mogensen
- The Unit for Cognitive Neuroscience, Department of Psychology, University of CopenhagenCopenhagen, Denmark
| | - Morten Overgaard
- Cognitive Neuroscience Research Unit, Center of Functionally Integrative Neuroscience, MindLab, Aarhus UniversityAarhus, Denmark
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Qiu WH, Wu HX, Yang QL, Kang Z, Chen ZC, Li K, Qiu GR, Xie CQ, Wan GF, Chen SQ. Evidence of cortical reorganization of language networks after stroke with subacute Broca's aphasia: a blood oxygenation level dependent-functional magnetic resonance imaging study. Neural Regen Res 2017; 12:109-117. [PMID: 28250756 PMCID: PMC5319215 DOI: 10.4103/1673-5374.198996] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Aphasia is an acquired language disorder that is a common consequence of stroke. The pathogenesis of the disease is not fully understood, and as a result, current treatment options are not satisfactory. Here, we used blood oxygenation level-dependent functional magnetic resonance imaging to evaluate the activation of bilateral cortices in patients with Broca's aphasia 1 to 3 months after stroke. Our results showed that language expression was associated with multiple brain regions in which the right hemisphere participated in the generation of language. The activation areas in the left hemisphere of aphasia patients were significantly smaller compared with those in healthy adults. The activation frequency, volumes, and intensity in the regions related to language, such as the left inferior frontal gyrus (Broca's area), the left superior temporal gyrus, and the right inferior frontal gyrus (the mirror region of Broca's area), were lower in patients compared with healthy adults. In contrast, activation in the right superior temporal gyrus, the bilateral superior parietal lobule, and the left inferior temporal gyrus was stronger in patients compared with healthy controls. These results suggest that the right inferior frontal gyrus plays a role in the recovery of language function in the subacute stage of stroke-related aphasia by increasing the engagement of related brain areas.
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Affiliation(s)
- Wei-Hong Qiu
- Department of Rehabilitation Medicine, the Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong Province, China
| | - Hui-Xiang Wu
- Department of Rehabilitation Medicine, the Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong Province, China
| | - Qing-Lu Yang
- Department of Rehabilitation Medicine, the Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong Province, China
| | - Zhuang Kang
- Department of Radiology, the Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong Province, China
| | - Zhao-Cong Chen
- Department of Rehabilitation Medicine, the Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong Province, China
| | - Kui Li
- Department of Rehabilitation Medicine, the Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong Province, China
| | - Guo-Rong Qiu
- Department of Rehabilitation Medicine, the Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong Province, China
| | - Chun-Qing Xie
- Department of Rehabilitation Medicine, the Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong Province, China
| | - Gui-Fang Wan
- Department of Rehabilitation Medicine, the Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong Province, China
| | - Shao-Qiong Chen
- Department of Radiology, the Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong Province, China
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Lee YS, Zreik JT, Hamilton RH. Patterns of neural activity predict picture-naming performance of a patient with chronic aphasia. Neuropsychologia 2016; 94:52-60. [PMID: 27864027 DOI: 10.1016/j.neuropsychologia.2016.11.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Revised: 10/06/2016] [Accepted: 11/13/2016] [Indexed: 10/20/2022]
Abstract
Naming objects represents a substantial challenge for patients with chronic aphasia. This could be in part because the reorganized compensatory language networks of persons with aphasia may be less stable than the intact language systems of healthy individuals. Here, we hypothesized that the degree of stability would be instantiated by spatially differential neural patterns rather than either increased or diminished amplitudes of neural activity within a putative compensatory language system. We recruited a chronic aphasic patient (KL; 66 year-old male) who exhibited a semantic deficit (e.g., often said "milk" for "cow" and "pillow" for "blanket"). Over the course of four behavioral sessions involving a naming task performed in a mock scanner, we identified visual objects that yielded an approximately 50% success rate. We then conducted two fMRI sessions in which the patient performed a naming task for multiple exemplars of those objects. Multivoxel pattern analysis (MVPA) searchlight revealed differential activity patterns associated with correct and incorrect trials throughout intact brain regions. The most robust and largest cluster was found in the right occipito-temporal cortex encompassing fusiform cortex, lateral occipital cortex (LOC), and middle occipital cortex, which may account for the patient's propensity for semantic naming errors. None of these areas were found by a conventional univariate analysis. By using an alternative approach, we extend current evidence for compensatory naming processes that operate through spatially differential patterns within the reorganized language system.
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Affiliation(s)
- Yune Sang Lee
- Department of Speech and Hearing Science, The Ohio State University, Columbus, OH, USA.
| | - Jihad T Zreik
- Department of Neurology, University of Pennsylvania, Philadelphia, PA, USA
| | - Roy H Hamilton
- Department of Neurology, University of Pennsylvania, Philadelphia, PA, USA.
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Overgaard M, Mogensen J. Visual perception from the perspective of a representational, non-reductionistic, level-dependent account of perception and conscious awareness. Philos Trans R Soc Lond B Biol Sci 2014; 369:20130209. [PMID: 24639581 PMCID: PMC3965164 DOI: 10.1098/rstb.2013.0209] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
This article proposes a new model to interpret seemingly conflicting evidence concerning the correlation of consciousness and neural processes. Based on an analysis of research of blindsight and subliminal perception, the reorganization of elementary functions and consciousness framework suggests that mental representations consist of functions at several different levels of analysis, including truly localized perceptual elementary functions and perceptual algorithmic modules, which are interconnections of the elementary functions. We suggest that conscious content relates to the 'top level' of analysis in a 'situational algorithmic strategy' that reflects the general state of an individual. We argue that conscious experience is intrinsically related to representations that are available to guide behaviour. From this perspective, we find that blindsight and subliminal perception can be explained partly by too coarse-grained methodology, and partly by top-down enhancing of representations that normally would not be relevant to action.
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Affiliation(s)
- Morten Overgaard
- CNRU, CFIN, MindLab, Aarhus University, Noerrebrogade 44, Building 10G, DK-8000 Aarhus, Denmark
- CCN, Department of Psychology and Communication, Aalborg University, Aalborg, Denmark
| | - Jesper Mogensen
- Unit for Cognitive Neuroscience (UCN), Department of Psychology, University of Copenhagen, Copenhagen, Denmark
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Mattioli F, Ambrosi C, Mascaro L, Scarpazza C, Pasquali P, Frugoni M, Magoni M, Biagi L, Gasparotti R. Early Aphasia Rehabilitation Is Associated With Functional Reactivation of the Left Inferior Frontal Gyrus. Stroke 2014; 45:545-52. [DOI: 10.1161/strokeaha.113.003192] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Flavia Mattioli
- From Neuropsychology Unit (F.M., C.S., P.P., M.F.), Department of Diagnostic Imaging, Medical Physics Unit (L.M.), and Stroke Unit (M.M.), Spedali Civili di Brescia, Brescia, Italy; Department of Diagnostic Imaging, Neuroradiology Unit, University of Brescia, Brescia, Italy (C.A., R.G.); and IRCCS Stella Maris Foundation, Pisa, Italy (L.B.)
| | - Claudia Ambrosi
- From Neuropsychology Unit (F.M., C.S., P.P., M.F.), Department of Diagnostic Imaging, Medical Physics Unit (L.M.), and Stroke Unit (M.M.), Spedali Civili di Brescia, Brescia, Italy; Department of Diagnostic Imaging, Neuroradiology Unit, University of Brescia, Brescia, Italy (C.A., R.G.); and IRCCS Stella Maris Foundation, Pisa, Italy (L.B.)
| | - Lorella Mascaro
- From Neuropsychology Unit (F.M., C.S., P.P., M.F.), Department of Diagnostic Imaging, Medical Physics Unit (L.M.), and Stroke Unit (M.M.), Spedali Civili di Brescia, Brescia, Italy; Department of Diagnostic Imaging, Neuroradiology Unit, University of Brescia, Brescia, Italy (C.A., R.G.); and IRCCS Stella Maris Foundation, Pisa, Italy (L.B.)
| | - Cristina Scarpazza
- From Neuropsychology Unit (F.M., C.S., P.P., M.F.), Department of Diagnostic Imaging, Medical Physics Unit (L.M.), and Stroke Unit (M.M.), Spedali Civili di Brescia, Brescia, Italy; Department of Diagnostic Imaging, Neuroradiology Unit, University of Brescia, Brescia, Italy (C.A., R.G.); and IRCCS Stella Maris Foundation, Pisa, Italy (L.B.)
| | - Patrizia Pasquali
- From Neuropsychology Unit (F.M., C.S., P.P., M.F.), Department of Diagnostic Imaging, Medical Physics Unit (L.M.), and Stroke Unit (M.M.), Spedali Civili di Brescia, Brescia, Italy; Department of Diagnostic Imaging, Neuroradiology Unit, University of Brescia, Brescia, Italy (C.A., R.G.); and IRCCS Stella Maris Foundation, Pisa, Italy (L.B.)
| | - Marina Frugoni
- From Neuropsychology Unit (F.M., C.S., P.P., M.F.), Department of Diagnostic Imaging, Medical Physics Unit (L.M.), and Stroke Unit (M.M.), Spedali Civili di Brescia, Brescia, Italy; Department of Diagnostic Imaging, Neuroradiology Unit, University of Brescia, Brescia, Italy (C.A., R.G.); and IRCCS Stella Maris Foundation, Pisa, Italy (L.B.)
| | - Mauro Magoni
- From Neuropsychology Unit (F.M., C.S., P.P., M.F.), Department of Diagnostic Imaging, Medical Physics Unit (L.M.), and Stroke Unit (M.M.), Spedali Civili di Brescia, Brescia, Italy; Department of Diagnostic Imaging, Neuroradiology Unit, University of Brescia, Brescia, Italy (C.A., R.G.); and IRCCS Stella Maris Foundation, Pisa, Italy (L.B.)
| | - Laura Biagi
- From Neuropsychology Unit (F.M., C.S., P.P., M.F.), Department of Diagnostic Imaging, Medical Physics Unit (L.M.), and Stroke Unit (M.M.), Spedali Civili di Brescia, Brescia, Italy; Department of Diagnostic Imaging, Neuroradiology Unit, University of Brescia, Brescia, Italy (C.A., R.G.); and IRCCS Stella Maris Foundation, Pisa, Italy (L.B.)
| | - Roberto Gasparotti
- From Neuropsychology Unit (F.M., C.S., P.P., M.F.), Department of Diagnostic Imaging, Medical Physics Unit (L.M.), and Stroke Unit (M.M.), Spedali Civili di Brescia, Brescia, Italy; Department of Diagnostic Imaging, Neuroradiology Unit, University of Brescia, Brescia, Italy (C.A., R.G.); and IRCCS Stella Maris Foundation, Pisa, Italy (L.B.)
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Shah PP, Szaflarski JP, Allendorfer J, Hamilton RH. Induction of neuroplasticity and recovery in post-stroke aphasia by non-invasive brain stimulation. Front Hum Neurosci 2013; 7:888. [PMID: 24399952 PMCID: PMC3870921 DOI: 10.3389/fnhum.2013.00888] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2013] [Accepted: 12/05/2013] [Indexed: 11/13/2022] Open
Abstract
Stroke victims tend to prioritize speaking, writing, and walking as the three most important rehabilitation goals. Of note is that two of these goals involve communication. This underscores the significance of developing successful approaches to aphasia treatment for the several hundred thousand new aphasia patients each year and over 1 million stroke survivors with chronic aphasia in the U.S. alone. After several years of growth as a research tool, non-invasive brain stimulation (NBS) is gradually entering the arena of clinical aphasiology. In this review, we first examine the current state of knowledge of post-stroke language recovery including the contributions from the dominant and non-dominant hemispheres. Next, we briefly discuss the methods and the physiologic basis of the use of inhibitory and excitatory repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS) as research tools in patients who experience post-stroke aphasia. Finally, we provide a critical review of the most influential evidence behind the potential use of these two brain stimulation methods as clinical rehabilitative tools.
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Affiliation(s)
- Priyanka P Shah
- Department of Neurology, University of Pennsylvania Philadelphia, PA, USA ; Laboratory for Cognition and Neural Stimulation, Center for Cognitive Neuroscience, University of Pennsylvania Philadelphia, PA, USA
| | - Jerzy P Szaflarski
- Department of Neurology, University of Alabama at Birmingham Birmingham, AL, USA
| | - Jane Allendorfer
- Department of Neurology, University of Alabama at Birmingham Birmingham, AL, USA
| | - Roy H Hamilton
- Department of Neurology, University of Pennsylvania Philadelphia, PA, USA ; Laboratory for Cognition and Neural Stimulation, Center for Cognitive Neuroscience, University of Pennsylvania Philadelphia, PA, USA
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Training in rapid auditory processing ameliorates auditory comprehension in aphasic patients: a randomized controlled pilot study. J Neurol Sci 2013; 338:77-86. [PMID: 24388435 DOI: 10.1016/j.jns.2013.12.020] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2013] [Revised: 12/10/2013] [Accepted: 12/10/2013] [Indexed: 11/23/2022]
Abstract
Experimental studies have often reported close associations between rapid auditory processing and language competency. The present study was aimed at improving auditory comprehension in aphasic patients following specific training in the perception of temporal order (TO) of events. We tested 18 aphasic patients showing both comprehension and TO perception deficits. Auditory comprehension was assessed by the Token Test, phonemic awareness and Voice-Onset-Time Test. The TO perception was assessed using auditory Temporal-Order-Threshold, defined as the shortest interval between two consecutive stimuli, necessary to report correctly their before-after relation. Aphasic patients participated in eight 45-minute sessions of either specific temporal training (TT, n=11) aimed to improve sequencing abilities, or control non-temporal training (NT, n=7) focussed on volume discrimination. The TT yielded improved TO perception; moreover, a transfer of improvement was observed from the time domain to the language domain, which was untrained during the training. The NT did not improve either the TO perception or comprehension in any language test. These results are in agreement with previous literature studies which proved ameliorated language competency following the TT in language-learning-impaired or dyslexic children. Our results indicated for the first time such benefits also in aphasic patients.
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Tokgoz S, Demirkaya S, Bek S, Kasıkcı T, Odabasi Z, Genc G, Yucel M. Clinical Properties of Regional Thalamic Hemorrhages. J Stroke Cerebrovasc Dis 2013; 22:1006-12. [DOI: 10.1016/j.jstrokecerebrovasdis.2012.02.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2012] [Revised: 02/05/2012] [Accepted: 02/17/2012] [Indexed: 12/01/2022] Open
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Abstract
Despite advances in the acute management of stroke, a large proportion of stroke patients are left with significant impairments. Over the coming decades the prevalence of stroke-related disability is expected to increase worldwide and this will impact greatly on families, healthcare systems and economies. Effective neuro-rehabilitation is a key factor in reducing disability after stroke. In this review, we discuss the effects of stroke, principles of stroke rehabilitative care and predictors of recovery. We also discuss novel therapies in stroke rehabilitation, including non-invasive brain stimulation, robotics and pharmacological augmentation. Many trials are currently underway, which, in time, may impact on future rehabilitative practice.
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Affiliation(s)
- L Brewer
- Department of Stroke and Geriatric Medicine, Royal College of Surgeons in Ireland, Dublin, Ireland.
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Szaflarski JP, Allendorfer JB, Banks C, Vannest J, Holland SK. Recovered vs. not-recovered from post-stroke aphasia: the contributions from the dominant and non-dominant hemispheres. Restor Neurol Neurosci 2013; 31:347-60. [PMID: 23482065 PMCID: PMC3701454 DOI: 10.3233/rnn-120267] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
PURPOSE Several adult studies have documented the importance of the peri-stroke areas to aphasia recovery. But, studies examining the differences in patterns of cortical participation in language comprehension in patients who have (LMCA-R) or have not recovered (LMCA-NR) from left middle cerebral artery infarction have not been performed up to date. METHODS In this study, we compare cortical correlates of language comprehension using fMRI and semantic decision/tone decision task in 9 LMCA-R and 18 LMCA-NR patients matched at the time of stroke for age and handedness. We examine the cortical correlates of language performance by correlating intra- and extra-scanner measures of linguistic performance with fMRI activation and stroke volumes. RESULTS Our analyses show that LMCA-R at least 1 year after stroke show a return to typical fMRI language activation patterns and that there is a compensatory reorganization of language function in LMCA-NR patients with shifts to the right hemispheric brain regions. Further, with increasing strength of the left-hemispheric fMRI signal shift there are associated improvements in performance as tested with standardized linguistic measures. A negative correlation between the size of the stroke and performance on some of the linguistic tests is also observed. CONCLUSIONS This right-hemispheric shift as a mechanism of post-stroke recovery in adults appears to be an ineffective mode of language function recovery with increasing right-hemispheric shift associated with lower language performance. Thus, normalization of the post-stroke language activation patterns is needed for better language performance while shifts of the activation patterns to the non-dominant (right) hemisphere and/or large stroke size are associated with decreased linguistic abilities after stroke.
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Affiliation(s)
- Jerzy P. Szaflarski
- Department of Neurology, University of Alabama at Birmingham, Birmingham, AL, USA
- Department of Neurology, University of Cincinnati Academic Health Center, Cincinnati, OH, USA
| | - Jane B. Allendorfer
- Department of Neurology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Christi Banks
- Department of Neurology, University of Cincinnati Academic Health Center, Cincinnati, OH, USA
| | - Jennifer Vannest
- Department of Neurology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, USA
- Pediatric Neuroimaging Research Consortium, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, USA
| | - Scott K. Holland
- Department of Neurology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, USA
- Department of Radiology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, USA
- Pediatric Neuroimaging Research Consortium, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, USA
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Allendorfer JB, Kissela BM, Holland SK, Szaflarski JP. Different patterns of language activation in post-stroke aphasia are detected by overt and covert versions of the verb generation fMRI task. Med Sci Monit 2012; 18:CR135-7. [PMID: 22367124 PMCID: PMC3319663 DOI: 10.12659/msm.882518] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Background Post-stroke language functions depend on the relative contributions of the dominant and non-dominant hemispheres. Thus, we aimed to identify the neural correlates of overt and covert verb generation in adult post-stroke aphasia. Material/Methods Sixteen aphasic LMCA stroke patients (SPs) and 32 healthy controls (HCs) underwent language testing followed by fMRI while performing an overt event-related verb generation task (ER-VGT) isolating activations related to noun-verb semantic processing or to articulation and auditory processing, and a covert block design verb generation task (BD-VGT). Results BD-VGT activation patterns were consistent with previous studies, while ER-VGT showed different patterns in SPs relative to HCs including less left-hemispheric involvement during semantic processing and predominantly right-sided activation related to articulation and auditory processing. ER-VGT intra-scanner performance was positively associated with activation during semantic associations in the left middle temporal gyrus for HCs (p=0.031) and left middle frontal gyrus for SPs (p=0.042). Increased activation in superior frontal/cingulate gyri was associated with better intra-scanner performance (p=0.020). Lesion size negatively impacted verbal fluency tested with Controlled Oral Word Association Test (p=0.0092) and the Semantic Fluency Test (p=0.033) and trended towards a negative association with verb generation performance on the event-related verb generation task (p=0.081). Conclusions Greater retention of pre-stroke language skills is associated with greater involvement of the left hemisphere with different cortical recruitment patterns observed in SPs versus HCs. Post-stroke verbal fluency may depend more upon the structural and functional integrity of the dominant left hemisphere language network rather than the shift to contralateral homologues.
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Affiliation(s)
- Jane B Allendorfer
- Department of Neurology, University of Cincinnati Academic Health Center, Cincinnati, OH 45267-0525, USA.
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Neurobiology of Language Recovery After Stroke: Lessons From Neuroimaging Studies. Arch Phys Med Rehabil 2012; 93:S15-25. [PMID: 22202187 DOI: 10.1016/j.apmr.2011.03.036] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2011] [Revised: 03/22/2011] [Accepted: 03/22/2011] [Indexed: 11/24/2022]
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Szaflarski JP, Vannest J, Wu SW, DiFrancesco MW, Banks C, Gilbert DL. Excitatory repetitive transcranial magnetic stimulation induces improvements in chronic post-stroke aphasia. Med Sci Monit 2011; 17:CR132-9. [PMID: 21358599 PMCID: PMC3057942 DOI: 10.12659/msm.881446] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND Aphasia affects 1/3 of stroke patients with improvements noted only in some of them. The goal of this exploratory study was to provide preliminary evidence regarding safety and efficacy of fMRI-guided excitatory repetitive transcranial magnetic stimulation (rTMS) applied to the residual left-hemispheric Broca's area for chronic aphasia treatment. MATERIAL/METHODS We enrolled 8 patients with moderate or severe aphasia >1 year after LMCA stroke. Linguistic battery was administered pre-/post-rTMS; a semantic decision/tone decision (SDTD) fMRI task was used to localize left-hemispheric Broca's area. RTMS protocol consisted of 10 daily treatments of 200 seconds each using an excitatory stimulation protocol called intermittent theta burst stimulation (iTBS). Coil placement was targeted individually to the left Broca's. RESULTS 6/8 patients showed significant pre-/post-rTMS improvements in semantic fluency (p=0.028); they were able to generate more appropriate words when prompted with a semantic category. Pre-/post-rTMS fMRI maps showed increases in left fronto-temporo-parietal language networks with a significant left-hemispheric shift in the left frontal (p=0.025), left temporo-parietal (p=0.038) regions and global language LI (p=0.018). Patients tended to report subjective improvement on Communicative Activities Log (mini-CAL; p=0.075). None of the subjects reported ill effects of rTMS. CONCLUSIONS FMRI-guided, excitatory rTMS applied to the affected Broca's area improved language skills in patients with chronic post-stroke aphasia; these improvements correlated with increased language lateralization to the left hemisphere. This rTMS protocol appears to be safe and should be further tested in blinded studies assessing its short- and long-term safety/efficacy for post-stroke aphasia rehabilitation.
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Affiliation(s)
- Jerzy P Szaflarski
- Department of Neurology, University of Cincinnati Academic Health Center, Cincinnati, OH 45267-0525, USA.
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Mogensen J. Reorganization of the injured brain: implications for studies of the neural substrate of cognition. Front Psychol 2011; 2:7. [PMID: 21713186 PMCID: PMC3111425 DOI: 10.3389/fpsyg.2011.00007] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2010] [Accepted: 01/05/2011] [Indexed: 01/16/2023] Open
Abstract
In the search for a neural substrate of cognitive processes, a frequently utilized method is the scrutiny of post-traumatic symptoms exhibited by individuals suffering focal injury to the brain. For instance, the presence or absence of conscious awareness within a particular domain may, combined with knowledge of which regions of the brain have been injured, provide important data in the search for neural correlates of consciousness. Like all studies addressing the consequences of brain injury, however, such research has to face the fact that in most cases, post-traumatic impairments are accompanied by a "functional recovery" during which symptoms are reduced or eliminated. The apparent contradiction between localization and recovery, respectively, of functions constitutes a problem to almost all aspects of cognitive neuroscience. Several lines of investigation indicate that although the brain remains highly plastic throughout life, the post-traumatic plasticity does not recreate a copy of the neural mechanisms lost to injury. Instead, the uninjured parts of the brain are functionally reorganized in a manner which - in spite of not recreating the basic information processing lost to injury - is able to allow a more or less complete return of the surface phenomena (including manifestations of consciousness) originally impaired by the trauma. A novel model [the Reorganization of Elementary Functions-model] of these processes is presented - and some of its implications discussed relative to studies of the neural substrates of cognition and consciousness.
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Affiliation(s)
- Jesper Mogensen
- The Unit for Cognitive Neuroscience, Department of Psychology, University of CopenhagenCopenhagen, Denmark
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