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Riccardi N, Zhao X, den Ouden DB, Fridriksson J, Desai RH, Wang Y. Network-based statistics distinguish anomic and Broca's aphasia. Brain Struct Funct 2023:10.1007/s00429-023-02738-4. [PMID: 38160205 DOI: 10.1007/s00429-023-02738-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Accepted: 11/21/2023] [Indexed: 01/03/2024]
Abstract
INTRODUCTION Aphasia is a speech-language impairment commonly caused by damage to the left hemisphere. The neural mechanisms that underpin different types of aphasia and their symptoms are still not fully understood. This study aims to identify differences in resting-state functional connectivity between anomic and Broca's aphasia measured through resting-state functional magnetic resonance imaging (rs-fMRI). METHODS We used the network-based statistic (NBS) method, as well as voxel- and connectome-based lesion symptom mapping (V-, CLSM), to identify distinct neural correlates of the anomic and Broca's groups. To control for lesion effect, we included lesion volume as a covariate in both the NBS method and LSM. RESULTS NBS identified a subnetwork located in the dorsal language stream bilaterally, including supramarginal gyrus, primary sensory, motor, and auditory cortices, and insula. The connections in the subnetwork were weaker in the Broca's group than the anomic group. The properties of the subnetwork were examined through complex network measures, which indicated that regions in right inferior frontal sulcus, right paracentral lobule, and bilateral superior temporal gyrus exhibit intensive interaction. Left superior temporal gyrus, right postcentral gyrus, and left supramarginal gyrus play an important role in information flow and overall communication efficiency. Disruption of this network underlies the constellation of symptoms associated with Broca's aphasia. Whole-brain CLSM did not detect any significant connections, suggesting an advantage of NBS when thousands of connections are considered. However, CLSM identified connections that differentiated Broca's from anomic aphasia when analysis was restricted to a hypothesized network of interest. DISCUSSION We identified novel signatures of resting-state brain network differences between groups of individuals with anomic and Broca's aphasia. We identified a subnetwork of connections that statistically differentiated the resting-state brain networks of the two groups, in comparison with standard CLSM results that yielded isolated connections. Network-level analyses are useful tools for the investigation of the neural correlates of language deficits post-stroke.
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Affiliation(s)
- Nicholas Riccardi
- Department of Psychology, University of South Carolina, Columbia, SC, USA
| | - Xingpei Zhao
- Department of Epidemiology and Biostatistics, University of South Carolina, Columbia, SC, USA
| | - Dirk-Bart den Ouden
- Department of Communication Sciences and Disorders, University of South Carolina, Columbia, SC, USA
| | - Julius Fridriksson
- Department of Communication Sciences and Disorders, University of South Carolina, Columbia, SC, USA
| | - Rutvik H Desai
- Department of Psychology, University of South Carolina, Columbia, SC, USA
| | - Yuan Wang
- Department of Epidemiology and Biostatistics, University of South Carolina, Columbia, SC, USA.
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2
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Zhao X, Riccardi N, den Ouden DB, Desai RH, Fridriksson J, Wang Y. Network-based statistics distinguish anomic and Broca aphasia. ARXIV 2023:arXiv:2302.03250v2. [PMID: 36798458 PMCID: PMC9934734] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Abstract
Aphasia is a speech-language impairment commonly caused by damage to the left hemisphere. Due to the complexity of speech-language processing, the neural mechanisms that underpin various symptoms between different types of aphasia are still not fully understood. We used the network-based statistic method to identify distinct subnetwork(s) of connections differentiating the resting-state functional networks of the anomic and Broca groups. We identified one such subnetwork that mainly involved the brain regions in the premotor, primary motor, primary auditory, and primary sensory cortices in both hemispheres. The majority of connections in the subnetwork were weaker in the Broca group than the anomic group. The network properties of the subnetwork were examined through complex network measures, which indicated that the regions in the superior temporal gyrus and auditory cortex bilaterally exhibit intensive interaction, and primary motor, premotor and primary sensory cortices in the left hemisphere play an important role in information flow and overall communication efficiency. These findings underlied articulatory difficulties and reduced repetition performance in Broca aphasia, which are rarely observed in anomic aphasia. This research provides novel findings into the resting-state brain network differences between groups of individuals with anomic and Broca aphasia. We identified a subnetwork of, rather than isolated, connections that statistically differentiate the resting-state brain networks of the two groups, in comparison with standard lesion symptom mapping results that yield isolated connections.
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Affiliation(s)
- Xingpei Zhao
- Department of Epidemiology and Biostatistics, University of South Carolina
| | | | - Dirk-Bart den Ouden
- Department of Communication Sciences and Disorders, University of South Carolina
| | | | - Julius Fridriksson
- Department of Communication Sciences and Disorders, University of South Carolina
| | - Yuan Wang
- Department of Epidemiology and Biostatistics, University of South Carolina
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3
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Altered Spontaneous Brain Activity in Poststroke Aphasia: A Resting-State fMRI Study. Brain Sci 2023; 13:brainsci13020300. [PMID: 36831843 PMCID: PMC9954170 DOI: 10.3390/brainsci13020300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2022] [Revised: 02/04/2023] [Accepted: 02/09/2023] [Indexed: 02/12/2023] Open
Abstract
PURPOSE Brain areas frequently implicated in language recovery after stroke comprise perilesional sites in the left hemisphere and homotopic regions in the right hemisphere. However, the neuronal mechanisms underlying language restoration are still largely unclear. METHODS AND MATERIALS In the present study, we investigated the brain function in 15 patients with poststroke aphasia and 30 matched control subjects by combining the regional homogeneity (ReHo) and amplitudes of low-frequency fluctuation (ALFF) analysis methods based on resting-state fMRI. RESULTS Compared to the control subjects, the patients with aphasia exhibited increased ReHo and ALFF values in the ipsilateral perilesional areas and increased ReHo in the contralesional right middle frontal gyrus. CONCLUSIONS The increased spontaneous brain activity in patients with poststroke aphasia during the recovery period, specifically in the ipsilateral perilesional regions and the homologous language regions of the right hemisphere, has potential implications for the treatment of patients with aphasia.
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Xie X, Zhang T, Bai T, Chen C, Ji GJ, Tian Y, Yang J, Wang K. Resting-State Neural-Activity Alterations in Subacute Aphasia after Stroke. Brain Sci 2022; 12:brainsci12050678. [PMID: 35625064 PMCID: PMC9139890 DOI: 10.3390/brainsci12050678] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2022] [Revised: 05/06/2022] [Accepted: 05/20/2022] [Indexed: 11/16/2022] Open
Abstract
Linguistic deficits are frequent symptoms among stroke survivors. The neural mechanism of post-stroke aphasia (PSA) was incompletely understood. Recently, resting-state functional magnetic resonance imaging (rs-fMRI) was widely used among several neuropsychological disorders. However, previous rs-fMRI studies of PSA were limited to very small sample size and the absence of reproducibility with different neuroimaging indexes. The present study performed comparisons with static and dynamic amplitude of low-frequency fluctuations (ALFF) and functional connectivity (FC) based on modest sample size (40 PSA and 37 healthy controls). Compared with controls, PSA showed significantly increased static ALFF predominantly in the bilateral supplementary motor area (SMA) and right hippocampus-parahippocampus (R HIP-ParaHip) and decreased static ALFF in right cerebellum. The increased dynamic ALFF in SMA and decreased dynamic ALFF in right cerebellum were also found in PSA. The static and dynamic ALFF in right cerebellum was positively correlated with spontaneous speech. The FC between the SMA and R HIP-ParaHip was significantly stronger in patients than controls and positively correlated with ALFF in bilateral SMA. In addition, the FC between the R HIP-ParaHip and the right temporal was also enhanced in patients and negatively correlated with repetition, naming, and comprehension score. These findings revealed consistently abnormal intrinsic neural activity in SMA and cerebellum, which may underlie linguistic deficits in PSA.
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Affiliation(s)
- Xiaohui Xie
- Department of Neurology, The First Affiliated Hospital of Anhui Medical University, Anhui Medical University, Hefei 230032, China; (X.X.); (T.Z.); (T.B.); (C.C.); (Y.T.)
- Anhui Province Key Laboratory of Cognition and Neuropsychiatric Disorders, Hefei 230032, China;
- Collaborative Innovation Center of Neuropsychiatric Disorders and Mental Health, Hefei 230032, China
| | - Ting Zhang
- Department of Neurology, The First Affiliated Hospital of Anhui Medical University, Anhui Medical University, Hefei 230032, China; (X.X.); (T.Z.); (T.B.); (C.C.); (Y.T.)
- Anhui Province Key Laboratory of Cognition and Neuropsychiatric Disorders, Hefei 230032, China;
- Collaborative Innovation Center of Neuropsychiatric Disorders and Mental Health, Hefei 230032, China
| | - Tongjian Bai
- Department of Neurology, The First Affiliated Hospital of Anhui Medical University, Anhui Medical University, Hefei 230032, China; (X.X.); (T.Z.); (T.B.); (C.C.); (Y.T.)
- Anhui Province Key Laboratory of Cognition and Neuropsychiatric Disorders, Hefei 230032, China;
- Collaborative Innovation Center of Neuropsychiatric Disorders and Mental Health, Hefei 230032, China
| | - Chen Chen
- Department of Neurology, The First Affiliated Hospital of Anhui Medical University, Anhui Medical University, Hefei 230032, China; (X.X.); (T.Z.); (T.B.); (C.C.); (Y.T.)
- Anhui Province Key Laboratory of Cognition and Neuropsychiatric Disorders, Hefei 230032, China;
- Collaborative Innovation Center of Neuropsychiatric Disorders and Mental Health, Hefei 230032, China
| | - Gong-Jun Ji
- Anhui Province Key Laboratory of Cognition and Neuropsychiatric Disorders, Hefei 230032, China;
- Collaborative Innovation Center of Neuropsychiatric Disorders and Mental Health, Hefei 230032, China
- The School of Mental Health and Psychological Sciences, Anhui Medical University, Hefei 230032, China
| | - Yanghua Tian
- Department of Neurology, The First Affiliated Hospital of Anhui Medical University, Anhui Medical University, Hefei 230032, China; (X.X.); (T.Z.); (T.B.); (C.C.); (Y.T.)
- Anhui Province Key Laboratory of Cognition and Neuropsychiatric Disorders, Hefei 230032, China;
- Collaborative Innovation Center of Neuropsychiatric Disorders and Mental Health, Hefei 230032, China
| | - Jinying Yang
- Laboratory Center for Information Science, University of Science and Technology of China, Hefei 230026, China;
| | - Kai Wang
- Department of Neurology, The First Affiliated Hospital of Anhui Medical University, Anhui Medical University, Hefei 230032, China; (X.X.); (T.Z.); (T.B.); (C.C.); (Y.T.)
- Anhui Province Key Laboratory of Cognition and Neuropsychiatric Disorders, Hefei 230032, China;
- Collaborative Innovation Center of Neuropsychiatric Disorders and Mental Health, Hefei 230032, China
- The School of Mental Health and Psychological Sciences, Anhui Medical University, Hefei 230032, China
- Institute of Artificial Intelligence, Hefei Comprehensive National Science Center, Hefei 231299, China
- Correspondence: ; Tel.: +86-0551-62923704
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5
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Meier EL. The role of disrupted functional connectivity in aphasia. HANDBOOK OF CLINICAL NEUROLOGY 2022; 185:99-119. [PMID: 35078613 DOI: 10.1016/b978-0-12-823384-9.00005-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Language is one of the most complex and specialized higher cognitive processes. Brain damage to the distributed, primarily left-lateralized language network can result in aphasia, a neurologic disorder characterized by receptive and/or expressive deficits in spoken and/or written language. Most often, aphasia is the consequence of stroke-termed poststroke aphasia (PSA)-yet, aphasia can also manifest due to neurodegenerative disease, specifically, a disorder called primary progressive aphasia (PPA). In recent years, functional connectivity neuroimaging studies have provided emerging evidence supporting theories regarding the relationships between language impairments, structural brain damage, and functional network properties in these two disorders. This chapter reviews the current evidence for the "network phenotype of stroke injury" hypothesis (Siegel et al., 2016) as it pertains to PSA and the "network degeneration hypothesis" (Seeley et al., 2009) as it pertains to PPA. Methodologic considerations for functional connectivity studies, limitations of the current functional connectivity literature in aphasia, and future directions are also discussed.
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Affiliation(s)
- Erin L Meier
- Department of Communication Sciences and Disorders, Northeastern University, Boston, MA, United States.
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Dai M, Qiao J, Wei X, Chen H, Shi Z, Dou Z. Increased cortical-medulla functional connectivity is correlated with swallowing in dysphagia patients with subacute infratentorial stroke. NEUROIMAGE: CLINICAL 2022; 35:103104. [PMID: 35792418 PMCID: PMC9421453 DOI: 10.1016/j.nicl.2022.103104] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Revised: 05/29/2022] [Accepted: 06/28/2022] [Indexed: 11/19/2022] Open
Abstract
Patients with infratentorial stroke showed increased cortex-medulla connectivity. The cortex-medulla functional connectivities were related to swallowing function. The identified regions may be candidates for non-invasive strategies for dysphagia. FC mapping using the medulla as a seed is useful in swallowing network research.
Patients with infratentorial stroke (IS) exhibit more severe dysphagia and a higher risk of aspiration than patients with supratentorial stroke. Nevertheless, a large proportion of patients with IS regain swallowing function within 6 months; however, the neural mechanism for this recovery remains unclear. We aimed to investigate possible neuroplastic changes involved using functional magnetic resonance imaging (fMRI) and their relation to swallowing function. We assessed 21 patients with IS (mean age: 59.9 ± 11.1 years) exhibiting dysphagia in the subacute phase and 21 healthy controls (mean age: 57.1 ± 7.8 years). Patient evaluations were based on the functional oral intake scale (FOIS), videofluoroscopic swallow study (VFSS), and fMRI. Temporal swallowing measures and the penetration-aspiration scale (PAS) were obtained using VFSS. Whole-brain–medulla resting-state functional connectivity (rsFC) was calculated and compared between patients and healthy controls. The rsFCs were also correlated with functional measures within the patient group. In patients with IS, whole-brain–medulla rsFCs were significantly higher in the precuneus, the left and right precentral gyrus, and the right supplementary motor area compared to those in healthy controls (P < 0.001, family-wise error-corrected cluster-level P < 0.05). The rsFCs to the medulla for the left (r = −0.507, P = 0.027) and right side (r = −0.503, P = 0.028) precentral gyrus were negatively correlated with the PAS. The rsFC between the left (r = 0.470, P = 0.042) and right (r = 0.459, P = 0.048) precentral gyrus to the medulla was positively correlated with upper esophageal sphincter opening durations (UOD). In addition, PAS was also correlated with UOD (r = −0.638, P = 0.003) whereas the laryngeal closure duration was correlated with the hyoid bone movement duration (r = 0.550, P = 0.015). Patients with IS exhibited overall modulation of cortical-medulla connectivity during the subacute phase. Patients with higher connectivities showed better swallowing performance. These findings support that there is cortical involvement in swallowing regulation after IS and can aid in determining potential treatment targets for dysphagia.
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Affiliation(s)
- Meng Dai
- Department of Rehabilitation Medicine, The Third Affiliated Hospital of Sun Yat-sen University, 600 Tianhe Road, Guangzhou 510630, Guangdong Province, People's Republic of China
| | - Jia Qiao
- Department of Rehabilitation Medicine, The Third Affiliated Hospital of Sun Yat-sen University, 600 Tianhe Road, Guangzhou 510630, Guangdong Province, People's Republic of China
| | - Xiaomei Wei
- Department of Rehabilitation Medicine, The Third Affiliated Hospital of Sun Yat-sen University, 600 Tianhe Road, Guangzhou 510630, Guangdong Province, People's Republic of China
| | - Huayu Chen
- Department of Rehabilitation Medicine, The Third Affiliated Hospital of Sun Yat-sen University, 600 Tianhe Road, Guangzhou 510630, Guangdong Province, People's Republic of China
| | - Zhonghui Shi
- Department of Rehabilitation Medicine, The Third Affiliated Hospital of Sun Yat-sen University, 600 Tianhe Road, Guangzhou 510630, Guangdong Province, People's Republic of China
| | - Zulin Dou
- Department of Rehabilitation Medicine, The Third Affiliated Hospital of Sun Yat-sen University, 600 Tianhe Road, Guangzhou 510630, Guangdong Province, People's Republic of China.
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7
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Zhang N, Yuan B, Yan J, Cheng J, Lu J, Wu J. Multivariate machine learning-based language mapping in glioma patients based on lesion topography. Brain Imaging Behav 2021; 15:2552-2562. [PMID: 33619646 DOI: 10.1007/s11682-021-00457-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2019] [Revised: 12/11/2020] [Accepted: 01/21/2021] [Indexed: 12/21/2022]
Abstract
Diffusive and progressive tumor infiltration within language-related areas of the brain induces functional reorganization. However, the macrostructural basis of subsequent language deficits is less clear. To address this issue, lesion topography data from 137 preoperative patients with left cerebral language-network gliomas (81 low-grade gliomas and 56 high-grade gliomas), were adopted for multivariate machine-learning-based lesion-language mapping analysis. We found that tumor location in the left posterior middle temporal gyrus-a bottleneck where both dorsal and ventral language pathways travel-predicted deficits of spontaneous speech (cluster size = 1356 mm3, false discovery rate corrected P < 0.05) and naming scores (cluster size = 1491 mm3, false discovery rate corrected P < 0.05) in the high-grade glioma group. In contrast, no significant lesion-language mapping results were observed in the low-grade glioma group, suggesting a large functional reorganization. These findings suggest that in patients with gliomas, the macrostructural plasticity mechanisms that modulate brain-behavior relationships depend on glioma grade.
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Affiliation(s)
- Nan Zhang
- Department of Neurosurgery, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Anhui, Hefei, China.,Glioma Surgery Division, Neurologic Surgery Department, Huashan Hospital, Fudan University, Shanghai, China
| | - Binke Yuan
- Institute for Brain Research and Rehabilitation, South China Normal University, Guangzhou, China.,Key Laboratory of Brain, Cognition and Education Sciences (South China Normal University), Ministry of Education, Guangzhou, China.,Center for Language and Brain, Shenzhen Institute of Neuroscience, Shenzhen, China
| | - Jing Yan
- Department of MRI , The First Affiliated Hospital of Zhengzhou University , Zhengzhou, China
| | - Jingliang Cheng
- Department of MRI , The First Affiliated Hospital of Zhengzhou University , Zhengzhou, China
| | - Junfeng Lu
- Glioma Surgery Division, Neurologic Surgery Department, Huashan Hospital, Fudan University, Shanghai, China.
| | - Jinsong Wu
- Glioma Surgery Division, Neurologic Surgery Department, Huashan Hospital, Fudan University, Shanghai, China.,Institute of Brain-Intelligence Technology , Zhangjiang Lab, Shanghai, China
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8
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Ingram RU, Halai AD, Pobric G, Sajjadi S, Patterson K, Lambon Ralph MA. Graded, multidimensional intra- and intergroup variations in primary progressive aphasia and post-stroke aphasia. Brain 2021; 143:3121-3135. [PMID: 32940648 PMCID: PMC7586084 DOI: 10.1093/brain/awaa245] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Revised: 05/30/2020] [Accepted: 06/17/2020] [Indexed: 12/14/2022] Open
Abstract
Language impairments caused by stroke (post-stroke aphasia, PSA) and neurodegeneration (primary progressive aphasia, PPA) have overlapping symptomatology, nomenclature and are classically divided into categorical subtypes. Surprisingly, PPA and PSA have rarely been directly compared in detail. Rather, previous studies have compared certain subtypes (e.g. semantic variants) or have focused on a specific cognitive/linguistic task (e.g. reading). This study assessed a large range of linguistic and cognitive tasks across the full spectra of PSA and PPA. We applied varimax-rotated principal component analysis to explore the underlying structure of the variance in the assessment scores. Similar phonological, semantic and fluency-related components were found for PSA and PPA. A combined principal component analysis across the two aetiologies revealed graded intra- and intergroup variations on all four extracted components. Classification analysis was used to test, formally, whether there were any categorical boundaries for any subtypes of PPA or PSA. Semantic dementia formed a true diagnostic category (i.e. within group homogeneity and distinct between-group differences), whereas there was considerable overlap and graded variations within and between other subtypes of PPA and PSA. These results suggest that (i) a multidimensional rather than categorical classification system may be a better conceptualization of aphasia from both causes; and (ii) despite the very different types of pathology, these broad classes of aphasia have considerable features in common.
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Affiliation(s)
- Ruth U Ingram
- Division of Neuroscience and Experimental Psychology, School of Biological Sciences, University of Manchester, UK
| | - Ajay D Halai
- MRC Cognition and Brain Sciences Unit, University of Cambridge, Cambridge, UK
| | - Gorana Pobric
- Division of Neuroscience and Experimental Psychology, School of Biological Sciences, University of Manchester, UK
| | - Seyed Sajjadi
- Department of Neurology, University of California, Irvine, Irvine, USA
| | - Karalyn Patterson
- MRC Cognition and Brain Sciences Unit, University of Cambridge, Cambridge, UK.,Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
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9
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Liu D, Chen J, Hu X, Hu G, Liu Y, Yang K, Xiao C, Zou Y, Liu H. Contralesional homotopic functional plasticity in patients with temporal glioma. J Neurosurg 2020; 134:417-425. [PMID: 31923896 DOI: 10.3171/2019.11.jns191982] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Accepted: 11/05/2019] [Indexed: 11/06/2022]
Abstract
OBJECTIVE This study aimed to explore the contralesional homotopic functional plasticity in the brain of patients with unilateral temporal glioma. METHODS Demographic, neurocognitive, and resting-state functional MRI data were collected from 17 patients with temporal glioma (10 in the right lobe and 7 in the left lobe), along with 14 age- and sex-matched healthy controls. The amplitude of low-frequency fluctuation (ALFF) of the contralesional homotopic region and 2 control regions was examined. The region-of-interest-based analysis was used to determine the altered functional connectivity (FC) of the contralesional homotopic region, showing significantly different intrinsic regional brain activity between patients and controls. Partial correlation analysis was conducted to determine the association between the altered neural activity and behavioral characteristics. RESULTS Compared with controls, patients with right temporal glioma exhibited significantly increased ALFF in the contralesional homotopic hippocampus and parahippocampal region. In addition, the intrinsic regional activity in these regions was negatively correlated with the visuospatial score (r = -0.718, p = 0.045). Whole-brain FC analysis revealed significantly increased FC between the left hippocampus and parahippocampal regions and the left inferior temporal gyrus, and decreased FC between the left hippocampus and parahippocampal regions and the left inferior frontal gyrus. No significant changes were found in the 2 control regions. CONCLUSIONS Contralesional homotopic regions are instrumental in the process of neural plasticity and functional compensation observed in patients with unilateral temporal glioma. The observed findings might be used to help preoperative evaluation or rehabilitation of postsurgical patients.
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Affiliation(s)
- Dongming Liu
- 1Department of Neurosurgery, The Affiliated Brain Hospital of Nanjing Medical University, Nanjing, Jiangsu
| | - Jiu Chen
- 2Institute of Neuropsychiatry, The Affiliated Brain Hospital of Nanjing Medical University, Fourth Clinical College of Nanjing Medical University, Nanjing, Jiangsu
- 3Institute of Brain Functional Imaging, Nanjing Medical University, Nanjing, Jiangsu; and
| | - Xinhua Hu
- 1Department of Neurosurgery, The Affiliated Brain Hospital of Nanjing Medical University, Nanjing, Jiangsu
- 3Institute of Brain Functional Imaging, Nanjing Medical University, Nanjing, Jiangsu; and
| | - Guanjie Hu
- 1Department of Neurosurgery, The Affiliated Brain Hospital of Nanjing Medical University, Nanjing, Jiangsu
| | - Yong Liu
- 1Department of Neurosurgery, The Affiliated Brain Hospital of Nanjing Medical University, Nanjing, Jiangsu
| | - Kun Yang
- 1Department of Neurosurgery, The Affiliated Brain Hospital of Nanjing Medical University, Nanjing, Jiangsu
| | - Chaoyong Xiao
- 3Institute of Brain Functional Imaging, Nanjing Medical University, Nanjing, Jiangsu; and
- 4Department of Radiology, The Affiliated Brain Hospital of Nanjing Medical University, Nanjing, Jiangsu, China
| | - Yuanjie Zou
- 1Department of Neurosurgery, The Affiliated Brain Hospital of Nanjing Medical University, Nanjing, Jiangsu
- 3Institute of Brain Functional Imaging, Nanjing Medical University, Nanjing, Jiangsu; and
| | - Hongyi Liu
- 1Department of Neurosurgery, The Affiliated Brain Hospital of Nanjing Medical University, Nanjing, Jiangsu
- 3Institute of Brain Functional Imaging, Nanjing Medical University, Nanjing, Jiangsu; and
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10
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Guo J, Biswal BB, Han S, Li J, Yang S, Yang M, Chen H. Altered dynamics of brain segregation and integration in poststroke aphasia. Hum Brain Mapp 2019; 40:3398-3409. [PMID: 31016854 DOI: 10.1002/hbm.24605] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Revised: 03/30/2019] [Accepted: 04/08/2019] [Indexed: 01/06/2023] Open
Abstract
Poststroke aphasia (PSA) results from direct effect of focal lesions and dysfunction of distributed language networks. However, how flexible the activity at specific nodes control global dynamics is currently unknown. In this study, we demonstrate that alterations in the regional activity may cause imbalances between segregation and integration in temporo-spatial pattern, and the transient dynamics are disrupted in PSA patients. Specifically, we applied dynamic framework to eyes-closed resting-state functional MRI data from PSA patients (n = 17), and age-, gender-, and education-matched healthy controls (HCs, n = 20). Subsequently, we calculated two basis brain organizational principles: "dynamic segregation," obtained from dynamic amplitude of low-frequency fluctuations (dALFF), which represent the specialized processing within interconnected brain regions; and "dynamic integration," obtained from dynamic functional connectivity, which measures the efficient communication between interconnected brain regions. We found that both measures were decreased in the PSA patients within the left frontal and temporal subregions compared to the HCs. PSA patients displayed increased flexibility of interaction between left temporo-frontal subregions and right temporo-parieto-frontal subnetworks. Furthermore, we found that dALFF in the pars triangularis of left inferior frontal gyrus was associated with aphasia quotient. These findings suggest that the reduced temporal flexibility of regional activity in language-relevant cortical regions in PSA is related to the disrupted organization of intrahemispheric networks, leading to a loss of the corresponding functions. By using dynamic framework, our results offer valuable information about the alterations in segregation and integration of spatiotemporal information across networks and illuminate how dysfunction in flexible activity may underlie language deficits in PSA.
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Affiliation(s)
- Jing Guo
- The Clinical Hospital of Chengdu Brain Science Institute, MOE Key Lab for Neuroinformation, University of Electronic Science and Technology of China, Chengdu, China.,School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Bharat B Biswal
- The Clinical Hospital of Chengdu Brain Science Institute, MOE Key Lab for Neuroinformation, University of Electronic Science and Technology of China, Chengdu, China.,Department of Biomedical Engineering, New Jersey Institute of Technology, Newark, New Jersey
| | - Shaoqiang Han
- The Clinical Hospital of Chengdu Brain Science Institute, MOE Key Lab for Neuroinformation, University of Electronic Science and Technology of China, Chengdu, China.,School of Life Science and Technology, Center for Information in Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Jiao Li
- The Clinical Hospital of Chengdu Brain Science Institute, MOE Key Lab for Neuroinformation, University of Electronic Science and Technology of China, Chengdu, China.,School of Life Science and Technology, Center for Information in Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Siqi Yang
- The Clinical Hospital of Chengdu Brain Science Institute, MOE Key Lab for Neuroinformation, University of Electronic Science and Technology of China, Chengdu, China.,School of Life Science and Technology, Center for Information in Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Mi Yang
- The Clinical Hospital of Chengdu Brain Science Institute, MOE Key Lab for Neuroinformation, University of Electronic Science and Technology of China, Chengdu, China
| | - Huafu Chen
- The Clinical Hospital of Chengdu Brain Science Institute, MOE Key Lab for Neuroinformation, University of Electronic Science and Technology of China, Chengdu, China.,School of Life Science and Technology, Center for Information in Medicine, University of Electronic Science and Technology of China, Chengdu, China
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11
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Vinehout K, Schmit BD, Schindler-Ivens S. Lower Limb Task-Based Functional Connectivity Is Altered in Stroke. Brain Connect 2019; 9:365-377. [PMID: 30799641 DOI: 10.1089/brain.2018.0640] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The goal of this work was to examine task-dependent functional connectivity of the brain in people with stroke. The work was motivated by prior observations indicating that, during pedaling, cortical activation volume is lower in people with stroke than controls. During paretic foot tapping, activation volume tends to be higher in people with stroke than controls. This study asked whether these differences could be explained by altered network function of the brain. Functional magnetic resonance imaging was used to examine local and global network function of the brain during tapping and pedaling in 15 stroke and 8 control participants. Independent component analysis was used to identify six task regions of interest (ROIs) in the primary sensorimotor cortex (M1S1), anterior lobe of cerebellum (AlCb), and secondary sensory cortex (S2) on the lesioned and non-lesioned sides of the brain (left, right for controls). Global connectivity was calculated as the correlation between mean time series for each ROI. Local connectivity was calculated as the mean correlation between voxels within each ROI. Local efficiency, weighted sum, and clustering coefficient were also calculated. Results suggested that local and global networks of the brain were altered in stroke, but not in the same direction. Detection of both global and local network changes was task-dependent. We found that global network function of the brain was reduced in stroke participants as compared with controls. This effect was detected during pedaling and nonparetic tapping, but not during paretic tapping. Local network function of the brain was elevated in stroke participants during paretic tapping and reduced during pedaling. No between-group differences in local connectivity were seen during nonparetic tapping. Connections involving S2, M1S1, and AlCb were significantly affected. Reduced global connectivity of the brain might contribute to reduced brain activation volume during pedaling poststroke.
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Affiliation(s)
- Kaleb Vinehout
- 1 Department of Biomedical Engineering, Marquette University and the Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Brian D Schmit
- 1 Department of Biomedical Engineering, Marquette University and the Medical College of Wisconsin, Milwaukee, Wisconsin
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12
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De Bruyn N, Meyer S, Kessner SS, Essers B, Cheng B, Thomalla G, Peeters A, Sunaert S, Duprez T, Thijs V, Feys H, Alaerts K, Verheyden G. Functional network connectivity is altered in patients with upper limb somatosensory impairments in the acute phase post stroke: A cross-sectional study. PLoS One 2018; 13:e0205693. [PMID: 30312350 PMCID: PMC6185852 DOI: 10.1371/journal.pone.0205693] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Accepted: 09/28/2018] [Indexed: 11/19/2022] Open
Abstract
Background Aberrant functional connectivity in brain networks associated with motor impairment after stroke is well described, but little is known about the association with somatosensory impairments. Aim The objective of this cross-sectional observational study was to investigate the relationship between brain functional connectivity and severity of somatosensory impairments in the upper limb in the acute phase post stroke. Methods Nineteen first-ever stroke patients underwent resting-state functional magnetic resonance imaging (rs-fMRI) and a standardized clinical somatosensory profile assessment (exteroception and higher cortical somatosensation) in the first week post stroke. Integrity of inter- and intrahemispheric (ipsilesional and contralesional) functional connectivity of the somatosensory network was assessed between patients with severe (Em-NSA< 13/32) and mild to moderate (Em-NSA> 13/32) somatosensory impairments. Results Patients with severe somatosensory impairments displayed significantly lower functional connectivity indices in terms of interhemispheric (p = 0.001) and ipsilesional intrahemispheric (p = 0.035) connectivity compared to mildly to moderately impaired patients. Significant associations were found between the perceptual threshold of touch assessment and interhemispheric (r = -0.63) and ipsilesional (r = -0.51) network indices. Additional significant associations were found between the index of interhemispheric connectivity and light touch (r = 0.55) and stereognosis (r = 0.64) evaluation. Conclusion Patients with more severe somatosensory impairments have lower inter- and ipsilesional intrahemispheric connectivity of the somatosensory network. Lower connectivity indices are related to more impaired exteroception and higher cortical somatosensation. This study highlights the importance of network integrity in terms of inter- and ipsilesional intrahemispheric connectivity for somatosensory function. Further research is needed investigating the effect of therapy on the re-establishment of these networks.
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Affiliation(s)
- Nele De Bruyn
- KU Leuven—University of Leuven, Department of Rehabilitation Sciences, Leuven, Belgium
- * E-mail:
| | - Sarah Meyer
- KU Leuven—University of Leuven, Department of Rehabilitation Sciences, Leuven, Belgium
| | - Simon S. Kessner
- University Medical Center Hamburg-Eppendorf, Department of Neurology, Hamburg, Germany
| | - Bea Essers
- KU Leuven—University of Leuven, Department of Rehabilitation Sciences, Leuven, Belgium
| | - Bastian Cheng
- University Medical Center Hamburg-Eppendorf, Department of Neurology, Hamburg, Germany
| | - Götz Thomalla
- University Medical Center Hamburg-Eppendorf, Department of Neurology, Hamburg, Germany
| | - Andre Peeters
- Cliniques Universitaires Saint-Luc, Department of Neurology, Brussels, Belgium
| | - Stefan Sunaert
- KU Leuven—University of Leuven, Department of Imaging and Pathology, Leuven, Belgium
- University Hospitals Leuven, Department of Radiology, Leuven, Belgium
| | - Thierry Duprez
- Cliniques Universitaires Saint-Luc, Department of Radiology, Brussels, Belgium
| | - Vincent Thijs
- University of Melbourne, Florey Institute of Neuroscience and Mental Health, Victoria, Australia
- University of Melbourne, Department of Neurology, Austin Health, Victoria, Australia
| | - Hilde Feys
- KU Leuven—University of Leuven, Department of Rehabilitation Sciences, Leuven, Belgium
| | - Kaat Alaerts
- KU Leuven—University of Leuven, Department of Rehabilitation Sciences, Leuven, Belgium
| | - Geert Verheyden
- KU Leuven—University of Leuven, Department of Rehabilitation Sciences, Leuven, Belgium
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13
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Abnormal Functional Connectivity Density in Post-Stroke Aphasia. Brain Topogr 2018; 32:271-282. [DOI: 10.1007/s10548-018-0681-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Accepted: 10/03/2018] [Indexed: 12/17/2022]
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14
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Functional Connectivity Alterations in Children with Spastic and Dyskinetic Cerebral Palsy. Neural Plast 2018; 2018:7058953. [PMID: 30186320 PMCID: PMC6114065 DOI: 10.1155/2018/7058953] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Revised: 06/01/2018] [Accepted: 06/06/2018] [Indexed: 01/28/2023] Open
Abstract
Cerebral palsy (CP) has long been investigated to be associated with a range of motor and cognitive dysfunction. As the two most common CP subtypes, spastic cerebral palsy (SCP) and dyskinetic cerebral palsy (DCP) may share common and distinct elements in their pathophysiology. However, the common and distinct dysfunctional characteristics between SCP and DCP on the brain network level are less known. This study aims to detect the alteration of brain functional connectivity in children with SCP and DCP based on resting-state functional MRI (fMRI). Resting-state networks (RSNs) were established based on the independent component analysis (ICA), and the functional network connectivity (FNC) was performed on the fMRI data from 16 DCP, 18 bilateral SCP, and 18 healthy children. Compared with healthy controls, altered functional connectivity within the cerebellum network, sensorimotor network (SMN), left frontoparietal network (LFPN), and salience network (SN) were found in DCP and SCP groups. Furthermore, the disconnections of the FNC consistently focused on the visual pathway; covariance of the default mode network (DMN) with other networks was observed both in DCP and SCP groups, while the DCP group had a distinct connectivity abnormality in motor pathway and self-referential processing-related connections. Correlations between the functional disconnection and the motor-related clinical measurement in children with CP were also found. These findings indicate functional connectivity impairment and altered integration widely exist in children with CP, suggesting that the abnormal functional connectivity is a pathophysiological mechanism of motor and cognitive dysfunction of CP.
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15
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Zhang N, Xia M, Qiu T, Wang X, Lin CP, Guo Q, Lu J, Wu Q, Zhuang D, Yu Z, Gong F, Farrukh Hameed NU, He Y, Wu J, Zhou L. Reorganization of cerebro-cerebellar circuit in patients with left hemispheric gliomas involving language network: A combined structural and resting-state functional MRI study. Hum Brain Mapp 2018; 39:4802-4819. [PMID: 30052314 DOI: 10.1002/hbm.24324] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Revised: 06/13/2018] [Accepted: 07/11/2018] [Indexed: 12/16/2022] Open
Abstract
The role of cerebellum and cerebro-cerebellar system in neural plasticity induced by cerebral gliomas involving language network has long been ignored. Moreover, whether or not the process of reorganization is different in glioma patients with different growth kinetics remains largely unknown. To address this issue, we utilized preoperative structural and resting-state functional MRI data of 78 patients with left cerebral gliomas involving language network areas, including 46 patients with low-grade glioma (LGG, WHO grade II), 32 with high-grade glioma (HGG, WHO grade III/IV), and 44 healthy controls. Spontaneous brain activity, resting-state functional connectivity and gray matter volume alterations of the cerebellum were examined. We found that both LGG and HGG patients exhibited bidirectional alteration of brain activity in language-related cerebellar areas. Brain activity in areas with increased alteration was significantly correlated with the language and MMSE scores. Structurally, LGG patients exhibited greater gray matter volume in regions with increased brain activity, suggesting a structure-function coupled alteration in cerebellum. Furthermore, we observed that cerebellar regions with decreased brain activity exhibited increased functional connectivity with contralesional cerebro-cerebellar system in LGG patients. Together, our findings provide empirical evidence for a vital role of cerebellum and cerebro-cerebellar circuit in neural plasticity following lesional damage to cerebral language network. Moreover, we highlight the possible different reorganizational mechanisms of brain functional connectivity underlying different levels of behavioral impairments in LGG and HGG patients.
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Affiliation(s)
- Nan Zhang
- Glioma Surgery Division, Department of Neurosurgery, Huashan Hospital, Fudan University, Shanghai, China
| | - Mingrui Xia
- State Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University, Beijing, China
- Beijing Key Laboratory of Brain Imaging and Connectomics, Beijing Normal University, Beijing, China
- IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing, China
| | - Tianming Qiu
- Glioma Surgery Division, Department of Neurosurgery, Huashan Hospital, Fudan University, Shanghai, China
| | - Xindi Wang
- State Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University, Beijing, China
- Beijing Key Laboratory of Brain Imaging and Connectomics, Beijing Normal University, Beijing, China
- IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing, China
| | - Ching-Po Lin
- Institute of Science and Technology for Brain-Inspired Intelligence, Fudan University, Shanghai, China
- Institute of Neuroscience, National Yang-Ming University, Taipei, Taiwan
- Brain Research Center, National Yang-Ming University, Taipei, Taiwan
| | - Qihao Guo
- Department of Neurology, Huashan Hospital, Fudan University, Shanghai, China
| | - Junfeng Lu
- Glioma Surgery Division, Department of Neurosurgery, Huashan Hospital, Fudan University, Shanghai, China
| | - Qizhu Wu
- Sinorad Medical Electronics Co., Ltd, Shenzhen, China
| | - Dongxiao Zhuang
- Glioma Surgery Division, Department of Neurosurgery, Huashan Hospital, Fudan University, Shanghai, China
| | - Zhengda Yu
- Glioma Surgery Division, Department of Neurosurgery, Huashan Hospital, Fudan University, Shanghai, China
| | - Fangyuan Gong
- Glioma Surgery Division, Department of Neurosurgery, Huashan Hospital, Fudan University, Shanghai, China
| | - N U Farrukh Hameed
- Glioma Surgery Division, Department of Neurosurgery, Huashan Hospital, Fudan University, Shanghai, China
| | - Yong He
- State Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University, Beijing, China
- Beijing Key Laboratory of Brain Imaging and Connectomics, Beijing Normal University, Beijing, China
- IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing, China
| | - Jinsong Wu
- Glioma Surgery Division, Department of Neurosurgery, Huashan Hospital, Fudan University, Shanghai, China
- Shanghai Key Laboratory of Medical Image Computing and Computer Assisted Intervention, Shanghai, China
| | - Liangfu Zhou
- Glioma Surgery Division, Department of Neurosurgery, Huashan Hospital, Fudan University, Shanghai, China
- Shanghai Key Laboratory of Medical Image Computing and Computer Assisted Intervention, Shanghai, China
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Zhao N, Zhang J, Qiu M, Wang C, Xiang Y, Wang H, Xie J, Liu S, Wu J. Scalp acupuncture plus low-frequency rTMS promotes repair of brain white matter tracts in stroke patients: A DTI study. J Integr Neurosci 2018. [DOI: 10.3233/jin-170043] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Affiliation(s)
- Ning Zhao
- Department of Rehabilitation Medicine, Shenzhen Nanshan Hospital, Shenzhen University, Shenzhen, 518052, China
- Department of Rehabilitation Medicine, Shenzhen Nanshan District People’s Hospital, Shenzhen, 518052, China
| | - Jingna Zhang
- College of Biomedical Engineering, Third Military Medical University, Chongqing, 400038, China
| | - Mingguo Qiu
- College of Biomedical Engineering, Third Military Medical University, Chongqing, 400038, China
| | - Chunrong Wang
- Department of Radiology, Shenzhen Nanshan District People’s Hospital, Shenzhen, 518052, China
| | - Yun Xiang
- Department of Rehabilitation Medicine, Shenzhen Nanshan Hospital, Shenzhen University, Shenzhen, 518052, China
- Department of Rehabilitation Medicine, Shenzhen Nanshan District People’s Hospital, Shenzhen, 518052, China
| | - Hui Wang
- Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China
| | - Jingwen Xie
- Department of Radiology, Shenzhen Nanshan District People’s Hospital, Shenzhen, 518052, China
| | - Shu Liu
- Hunan University of Chinese Medicine, Changsha, 410007, China
| | - Jing Wu
- Hunan University of Chinese Medicine, Changsha, 410007, China
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17
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Sebastian R, Breining BL. Contributions of Neuroimaging to Understanding Language Deficits in Acute Stroke. Semin Speech Lang 2018; 39:66-78. [PMID: 29359306 PMCID: PMC5840876 DOI: 10.1055/s-0037-1608854] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Advances in structural and functional imaging techniques have provided new insights into our understanding of brain and language relationships. In this article, we review the various structural and functional imaging methods currently used to study language deficits in acute stroke. We also discuss the advantages and the limitations of each imaging modality and the applications of each modality in the clinical and research settings in the study of language deficits.
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Affiliation(s)
- Rajani Sebastian
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Bonnie L Breining
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland
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18
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Liu W, Hu X, An D, Gong Q, Zhou D. Disrupted intrinsic and remote functional connectivity in heterotopia-related epilepsy. Acta Neurol Scand 2018; 137:109-116. [PMID: 28875535 DOI: 10.1111/ane.12831] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/17/2017] [Indexed: 02/05/2023]
Abstract
OBJECTIVES Several neuroimaging studies have examined neural interactions in patients with periventricular nodular heterotopia (PNH). However, features of the underlying functional network remain poorly understood. In this study, we examined alterations in the local (regional) and remote (interregional) cerebral networks in this disorder. METHODS Twenty-eight subjects all having suffered from PNH with epilepsy, as well as 28 age- and sex- matched healthy controls, were enrolled in this study. Amplitude of low-frequency fluctuation (ALFF) and seed-based functional connectivity (FC) were calculated to detect regional neural function and functional network integration, respectively. RESULTS Compared with healthy controls, patients with PNH-related epilepsy showed decreased ALFF in the ventromedial prefrontal cortex (vmPFC) and precuneus areas. ALFF values in both areas were negative correlated with epilepsy duration (P < .05, Bonferroni-corrected). Furthermore, patients with PNH-related epilepsy had increased remote interregional FC mainly in bilateral prefrontal and parietal cortices, supramarginal gyrus, dorsal cingulate gyrus, and right insula; lower FC was found in posterior brain regions including bilateral parahippocampal gyrus and inferior temporal gyrus. CONCLUSIONS Focal spontaneous hypofunction, as assessed by ALFF, correlates with epilepsy duration in patients with PNH-related epilepsy. Abnormalities existed both within the default-mode network and then across the whole brain, demonstrating that intrinsic brain dysfunction may be related to specific network interactions. Our findings provide novel understanding of the connectivity-based pathophysiological mechanisms of PNH.
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Affiliation(s)
- W. Liu
- Departments of Neurology; West China Hospital; Sichuan University; Chengdu China
| | - X. Hu
- Departments of Radiology; Huaxi MR Research Center (HMRRC); West China Hospital; Sichuan University; Chengdu China
| | - D. An
- Departments of Neurology; West China Hospital; Sichuan University; Chengdu China
| | - Q. Gong
- Departments of Radiology; Huaxi MR Research Center (HMRRC); West China Hospital; Sichuan University; Chengdu China
| | - D. Zhou
- Departments of Neurology; West China Hospital; Sichuan University; Chengdu China
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19
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Yang M, Li J, Li Z, Yao D, Liao W, Chen H. Whole-brain functional connectome-based multivariate classification of post-stroke aphasia. Neurocomputing 2017. [DOI: 10.1016/j.neucom.2016.10.094] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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20
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Fu CH, Li KS, Ning YZ, Tan ZJ, Zhang Y, Liu HW, Han X, Zou YH. Altered effective connectivity of resting state networks by acupuncture stimulation in stroke patients with left hemiplegia: A multivariate granger analysis. Medicine (Baltimore) 2017; 96:e8897. [PMID: 29382021 PMCID: PMC5709020 DOI: 10.1097/md.0000000000008897] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The aim of this study was to explore the response feature of resting-state networks (RSNs) of stroke patients with left hemiplegia by acupuncture stimulation.Nineteen stroke patients with left hemiplegia and 17 controls were recruited in this study. Resting-state functional magnetic resonance imaging data before and after acupuncture were acquired using magnetic scanning. The independent component analysis (ICA) was employed to extract RSNs related to motion, sensation, cognition, and execution, including sensorimotor network (SMN), left and right frontoparietal network (LFPN and RFPN), anterior and posterior default mode network (aDMN, pDMN), visual network (VN), and salience network (SN). Granger causality method was used to explore how acupuncture stimulation affects the causality between intrinsic RSNs in stroke patients. Compared with healthy subjects, stroke patients presented the more complex effective connectivity. Before acupuncture stimulation, LFPN inputted most information from other networks while DMN outputted most information to other networks; however, the above results were reversal by acupuncture. In addition, we found aDMN reside in between SMN and LFPN after acupuncture.The finding suggested that acupuncture probably integrated the effective connectivity internetwork by modulating multiple networks and transferring information between LFPN and SMN by DMN as the relay station.
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Affiliation(s)
- Cai-Hong Fu
- Department of Neurology and Stroke Center, Dongzhimen Hospital, the First Affiliated Hospital of Beijing University of Chinese Medicine, Beijing, China
- Shunyi Hospital Affiliated to Beijing Hospital of Traditional Chinese Medicine
| | - Kuang-Shi Li
- Department of Emergency, Beijing GuLou Hospital of Traditional Chinese Medicine
| | - Yan-Zhe Ning
- The National Clinical Research Center for Mental Disorders & Beijing Key Laboratory of Mental Disorders, Beijing Anding Hospital, Capital Medical University
| | - Zhong-Jian Tan
- Department of Radiology, Dongzhimen Hospital, the First Affiliated Hospital of Beijing University of Chinese Medicine, Beijing, China
| | - Yong Zhang
- Department of Neurology and Stroke Center, Dongzhimen Hospital, the First Affiliated Hospital of Beijing University of Chinese Medicine, Beijing, China
| | - Hong-Wei Liu
- Department of Neurology and Stroke Center, Dongzhimen Hospital, the First Affiliated Hospital of Beijing University of Chinese Medicine, Beijing, China
- Shunyi Hospital Affiliated to Beijing Hospital of Traditional Chinese Medicine
| | - Xiao Han
- Department of Neurology and Stroke Center, Dongzhimen Hospital, the First Affiliated Hospital of Beijing University of Chinese Medicine, Beijing, China
| | - Yi-Huai Zou
- Department of Neurology and Stroke Center, Dongzhimen Hospital, the First Affiliated Hospital of Beijing University of Chinese Medicine, Beijing, China
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What Do Language Disorders Reveal about Brain-Language Relationships? From Classic Models to Network Approaches. J Int Neuropsychol Soc 2017; 23:741-754. [PMID: 29198286 PMCID: PMC6606454 DOI: 10.1017/s1355617717001126] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Studies of language disorders have shaped our understanding of brain-language relationships over the last two centuries. This article provides a review of this research and how our thinking has changed over the years regarding how the brain processes language. In the 19th century, a series of famous case studies linked distinct speech and language functions to specific portions of the left hemisphere of the brain, regions that later came to be known as Broca's and Wernicke's areas. One hundred years later, the emergence of new brain imaging tools allowed for the visualization of brain injuries in vivo that ushered in a new era of brain-behavior research and greatly expanded our understanding of the neural processes of language. Toward the end of the 20th century, sophisticated neuroimaging approaches allowed for the visualization of both structural and functional brain activity associated with language processing in both healthy individuals and in those with language disturbance. More recently, language is thought to be mediated by a much broader expanse of neural networks that covers a large number of cortical and subcortical regions and their interconnecting fiber pathways. Injury to both grey and white matter has been seen to affect the complexities of language in unique ways that have altered how we think about brain-language relationships. The findings that support this paradigm shift are described here along with the methodologies that helped to discover them, with some final thoughts on future directions, techniques, and treatment interventions for those with communication impairments. (JINS, 2017, 23, 741-754).
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Yang M, Yang P, Fan YS, Li J, Yao D, Liao W, Chen H. Altered Structure and Intrinsic Functional Connectivity in Post-stroke Aphasia. Brain Topogr 2017; 31:300-310. [PMID: 28921389 DOI: 10.1007/s10548-017-0594-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Accepted: 09/13/2017] [Indexed: 01/19/2023]
Abstract
Previous studies have demonstrated that alterations of gray matter exist in post-stroke aphasia (PSA) patients. However, so far, few studies combined structural alterations of gray matter volume (GMV) and intrinsic functional connectivity (iFC) imbalances of resting-state functional MRI to investigate the mechanism underlying PSA. The present study investigated specific regions with GMV abnormality in patients with PSA (n = 17) and age- and sex- matched healthy controls (HCs, n = 20) using voxel-based morphometry. In addition, we examined whether there is a link between abnormal gray matter and altered iFC. Furthermore, we explored the correlations between abnormal iFC and clinical scores in aphasic patients. We found significantly increased GMV in the right superior temporal gyrus, right inferior parietal lobule (IPL)/supramarginal gyrus (SMG), and left middle occipital gyrus. Decreased GMV was found in the right caudate gyrus, bilateral thalami in PSA patients. Patients showed increased remote interregional FC between the right IPL/SMG and right precuneus, right angular gyrus, right superior occipital gyrus; while reduced FC in the right caudate gyrus and supplementary motor area, dorsolateral superior frontal gyrus. Moreover, iFC strength between the left middle occipital gyrus and the left orbital middle frontal gyrus was positively correlated with the performance quotient. We suggest that GMV abnormality contributes to interregional FC in PSA. These results may provide useful information to understand the pathogenesis of post-stroke aphasia.
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Affiliation(s)
- Mi Yang
- Key Laboratory for NeuroInformation of Ministry of Education, Center for Information in BioMedicine, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, 610054, People's Republic of China
- Department of Stomatology, the Fourth People's Hospital of Chengdu, Chengdu, 610036, People's Republic of China
| | - Pu Yang
- Key Laboratory for NeuroInformation of Ministry of Education, Center for Information in BioMedicine, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, 610054, People's Republic of China
| | - Yun-Shuang Fan
- Key Laboratory for NeuroInformation of Ministry of Education, Center for Information in BioMedicine, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, 610054, People's Republic of China
| | - Jiao Li
- Key Laboratory for NeuroInformation of Ministry of Education, Center for Information in BioMedicine, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, 610054, People's Republic of China
| | - Dezhong Yao
- Key Laboratory for NeuroInformation of Ministry of Education, Center for Information in BioMedicine, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, 610054, People's Republic of China
| | - Wei Liao
- Key Laboratory for NeuroInformation of Ministry of Education, Center for Information in BioMedicine, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, 610054, People's Republic of China.
| | - Huafu Chen
- Key Laboratory for NeuroInformation of Ministry of Education, Center for Information in BioMedicine, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, 610054, People's Republic of China.
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Zhang J, Zhang Y, Wang L, Sang L, Yang J, Yan R, Li P, Wang J, Qiu M. Disrupted structural and functional connectivity networks in ischemic stroke patients. Neuroscience 2017; 364:212-225. [PMID: 28918259 DOI: 10.1016/j.neuroscience.2017.09.009] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Revised: 09/04/2017] [Accepted: 09/05/2017] [Indexed: 01/10/2023]
Abstract
Local lesions caused by stroke may result in extensive structural and functional reorganization in the brain. Previous studies of this phenomenon have focused on specific brain networks. Here, we aimed to discover abnormalities in whole-brain networks and to explore the decoupling between structural and functional connectivity in patients with stroke. Fifteen ischemic stroke patients and 23 normal controls (NCs) were recruited in this study. A graph theoretical analysis was employed to investigate the abnormal topological properties of structural and functional brain networks in patients with stroke. Both patients with stroke and NCs exhibited small-world organization in brain networks. However, compared to NCs, patients with stroke exhibited abnormal global properties characterized by a higher characteristic path length and lower global efficiency. Furthermore, patients with stroke showed altered nodal characteristics, primarily in certain motor- and cognition-related regions. Positive correlations between the nodal degree of the inferior parietal lobule and the Fugl-Meyer Assessment (FMA) score and between the nodal betweenness centrality of the posterior cingulate gyrus (PCG) and immediate recall were observed in patients with stroke. Most importantly, the strength of the structural-functional connectivity network coupling was decreased, and the coupling degree was related to the FMA score of patients, suggesting that decoupling may provide a novel biomarker for the assessment of motor impairment in patients with stroke. Thus, the topological organization of brain networks is altered in patients with stroke, and our results provide insights into the structural and functional organization of the brain after stroke from the viewpoint of network topology.
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Affiliation(s)
- Jingna Zhang
- Department of Medical Imaging, College of Biomedical Engineering, Third Military Medical University, 30 Gaotanyan Road, Chongqing 40038, China
| | - Ye Zhang
- Department of Medical Imaging, College of Biomedical Engineering, Third Military Medical University, 30 Gaotanyan Road, Chongqing 40038, China
| | - Li Wang
- Department of Medical Imaging, College of Biomedical Engineering, Third Military Medical University, 30 Gaotanyan Road, Chongqing 40038, China
| | - Linqiong Sang
- Department of Medical Imaging, College of Biomedical Engineering, Third Military Medical University, 30 Gaotanyan Road, Chongqing 40038, China
| | - Jun Yang
- Department of Radiology, Southwest Hospital, Third Military Medical University, 30 Gaotanyan Road, Chongqing 400038, China
| | - Rubing Yan
- Department of Rehabilitation, Southwest Hospital, Third Military Medical University, Chongqing 400038, China
| | - Pengyue Li
- Department of Medical Imaging, College of Biomedical Engineering, Third Military Medical University, 30 Gaotanyan Road, Chongqing 40038, China
| | - Jian Wang
- Department of Radiology, Southwest Hospital, Third Military Medical University, 30 Gaotanyan Road, Chongqing 400038, China.
| | - Mingguo Qiu
- Department of Medical Imaging, College of Biomedical Engineering, Third Military Medical University, 30 Gaotanyan Road, Chongqing 40038, China.
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Smitha KA, Arun KM, Rajesh PG, Thomas B, Kesavadas C. Resting-State Seed-Based Analysis: An Alternative to Task-Based Language fMRI and Its Laterality Index. AJNR Am J Neuroradiol 2017; 38:1187-1192. [PMID: 28428208 DOI: 10.3174/ajnr.a5169] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2016] [Accepted: 02/02/2017] [Indexed: 02/05/2023]
Abstract
BACKGROUND AND PURPOSE Language is a cardinal function that makes human unique. Preservation of language function poses a great challenge for surgeons during resection. The aim of the study was to assess the efficacy of resting-state fMRI in the lateralization of language function in healthy subjects to permit its further testing in patients who are unable to perform task-based fMRI. MATERIALS AND METHODS Eighteen healthy right-handed volunteers were prospectively evaluated with resting-state fMRI and task-based fMRI to assess language networks. The laterality indices of Broca and Wernicke areas were calculated by using task-based fMRI via a voxel-value approach. We adopted seed-based resting-state fMRI connectivity analysis together with parameters such as amplitude of low-frequency fluctuation and fractional amplitude of low-frequency fluctuation (fALFF). Resting-state fMRI connectivity maps for language networks were obtained from Broca and Wernicke areas in both hemispheres. We performed correlation analysis between the laterality index and the z scores of functional connectivity, amplitude of low-frequency fluctuation, and fALFF. RESULTS Pearson correlation analysis between signals obtained from the z score of fALFF and the laterality index yielded a correlation coefficient of 0.849 (P < .05). Regression analysis of the fALFF with the laterality index yielded an R2 value of 0.721, indicating that 72.1% of the variance in the laterality index of task-based fMRI could be predicted from the fALFF of resting-state fMRI. CONCLUSIONS The present study demonstrates that fALFF can be used as an alternative to task-based fMRI for assessing language laterality. There was a strong positive correlation between the fALFF of the Broca area of resting-state fMRI with the laterality index of task-based fMRI. Furthermore, we demonstrated the efficacy of fALFF for predicting the laterality of task-based fMRI.
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Affiliation(s)
- K A Smitha
- From the Departments of Imaging Sciences and Interventional Radiology (K.A.S., K.M.A., B.T., C.K.)
| | - K M Arun
- From the Departments of Imaging Sciences and Interventional Radiology (K.A.S., K.M.A., B.T., C.K.)
| | - P G Rajesh
- Neurology (P.G.R.), Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, Kerala, India
| | - B Thomas
- From the Departments of Imaging Sciences and Interventional Radiology (K.A.S., K.M.A., B.T., C.K.)
| | - C Kesavadas
- From the Departments of Imaging Sciences and Interventional Radiology (K.A.S., K.M.A., B.T., C.K.)
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25
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Sandberg CW. Hypoconnectivity of Resting-State Networks in Persons with Aphasia Compared with Healthy Age-Matched Adults. Front Hum Neurosci 2017; 11:91. [PMID: 28293185 PMCID: PMC5329062 DOI: 10.3389/fnhum.2017.00091] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Accepted: 02/14/2017] [Indexed: 01/21/2023] Open
Abstract
Aphasia is a language disorder affecting more than one million people in the US. While language function has traditionally been the focus of neuroimaging research, other cognitive functions are affected in this population, which has implications not only for those specific processes but also for the interaction of language and other cognitive functions. Resting state fMRI (rs-fMRI) is a practical and informative way to explore and characterize general cognitive engagement and/or health in this population, but it is currently underutilized. The aim of this study was to explore the functional connectivity in resting state networks (RSNs) and in the semantic network in seven persons with aphasia (PWA) who were at least 6 months post onset compared with 11 neurologically healthy adults (NHA) in order to gain a more comprehensive understanding of general cognitive engagement in aphasia. These preliminary results show that PWA exhibit hypoconnectivity in the semantic network and all RSNs except the visual network. Compared with NHA, PWA appear to have fewer cross- and left-hemispheric connections. However, PWA exhibit some stronger connections than NHA within the semantic network, which could indicate compensatory mechanisms. Importantly, connectivity for RSNs appear to increase with decreasing aphasia severity and decrease with increasing lesion size. This knowledge has the potential to improve aphasia therapy by furthering the understanding of lesion effects on the cognitive system as a whole, which can guide treatment target selection and promotion of favorable neural reorganization for optimal recovery of function.
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Affiliation(s)
- Chaleece W Sandberg
- Adult Neuroplasticity Laboratory, Department of Communication Sciences and Disorders, Penn State University University Park, PA, USA
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26
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Norise C, Hamilton RH. Non-invasive Brain Stimulation in the Treatment of Post-stroke and Neurodegenerative Aphasia: Parallels, Differences, and Lessons Learned. Front Hum Neurosci 2017; 10:675. [PMID: 28167904 PMCID: PMC5253356 DOI: 10.3389/fnhum.2016.00675] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Accepted: 12/19/2016] [Indexed: 11/22/2022] Open
Abstract
Numerous studies over the span of more than a decade have shown that non-invasive brain stimulation (NIBS) techniques, namely transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS), can facilitate language recovery for patients who have suffered from aphasia due to stroke. While stroke is the most common etiology of aphasia, neurodegenerative causes of language impairment—collectively termed primary progressive aphasia (PPA)—are increasingly being recognized as important clinical phenotypes in dementia. Very limited data now suggest that (NIBS) may have some benefit in treating PPAs. However, before applying the same approaches to patients with PPA as have previously been pursued in patients with post-stroke aphasia, it will be important for investigators to consider key similarities and differences between these aphasia etiologies that is likely to inform successful approaches to stimulation. While both post-stroke aphasia and the PPAs have clear overlaps in their clinical phenomenology, the mechanisms of injury and theorized neuroplastic changes associated with the two etiologies are notably different. Importantly, theories of plasticity in post-stroke aphasia are largely predicated on the notion that regions of the brain that had previously been uninvolved in language processing may take on new compensatory roles. PPAs, however, are characterized by slow distributed degeneration of cellular units within the language system; compensatory recruitment of brain regions to subserve language is not currently understood to be an important aspect of the condition. This review will survey differences in the mechanisms of language representation between the two etiologies of aphasia and evaluate properties that may define and limit the success of different neuromodulation approaches for these two disorders.
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Affiliation(s)
- Catherine Norise
- Laboratory for Cognition and Neural Stimulation, Department of Neurology, University of Pennsylvania Philadelphia, PA, USA
| | - Roy H Hamilton
- Laboratory for Cognition and Neural Stimulation, Department of Neurology, University of Pennsylvania Philadelphia, PA, USA
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27
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Li J, Du D, Gao W, Sun X, Xie H, Zhang G, Li J, Li H, Li K. The regional neuronal activity in left posterior middle temporal gyrus is correlated with the severity of chronic aphasia. Neuropsychiatr Dis Treat 2017; 13:1937-1945. [PMID: 28790829 PMCID: PMC5530067 DOI: 10.2147/ndt.s140091] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
BACKGROUND Aphasia is one of the most disabling cognitive deficits affecting >2 million people in the USA. The neuroimaging characteristics of chronic aphasic patients (>6 months post onset) remain largely unknown. OBJECTIVE The objective of this study was to investigate the regional signal changes of spontaneous neuronal activity of brain and the inter-regional connectivity in chronic aphasia. MATERIALS AND METHODS Resting-state blood oxygenation level-dependent functional magnetic resonance imaging (fMRI) was used to obtain fMRI data from 17 chronic aphasic patients and 20 healthy control subjects in a Siemens Verio 3.0T MR Scanner. The amplitude of low-frequency fluctuation (ALFF) was determined, which directly reflects the regional neuronal activity. The functional connectivity (FC) of fMRI was assessed using a seed voxel linear correlation approach. The severity of aphasia was evaluated by aphasia quotient (AQ) scores obtained from Western Aphasia Battery test. RESULTS Compared with normal subjects, aphasic patients showed decreased ALFF values in the regions of left posterior middle temporal gyrus (PMTG), left medial prefrontal gyrus, and right cerebellum. The ALFF values in left PMTG showed strong positive correlation with the AQ score (coefficient r=0.79, P<0.05). There was a positive FC in chronic aphasia between left PMTG and left inferior temporal gyrus (BA20), fusiform gyrus (BA37), and inferior frontal gyrus (BA47\45\44). CONCLUSION Left PMTG might play an important role in language dysfunction of chronic aphasia, and ALFF value might be a promising indicator to evaluate the severity of aphasia.
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Affiliation(s)
- Jianlin Li
- Department of Radiology, Yantai Yuhuangding Hospital
| | - Dunren Du
- Department of Radiology, Yantai Laishan Branch Hospital of Yuhuangding Hospital, Medical College of Qingdao University
| | - Wei Gao
- Department of Radiology, Yantai Yuhuangding Hospital
| | - Xichun Sun
- Department of Radiology, Yantai Hospital of Traditional Chinese Medicine, Yantai, China
| | - Haizhu Xie
- Department of Radiology, Yantai Yuhuangding Hospital
| | - Gang Zhang
- Department of Radiology, Yantai Yuhuangding Hospital
| | - Jian Li
- Department of Radiology, Yantai Yuhuangding Hospital
| | - Honglun Li
- Department of Radiology, Yantai Yuhuangding Hospital
| | - Kefeng Li
- School of Medicine, University of California, San Diego, CA, USA
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Baldassarre A, Ramsey LE, Siegel JS, Shulman GL, Corbetta M. Brain connectivity and neurological disorders after stroke. Curr Opin Neurol 2016; 29:706-713. [PMID: 27749394 PMCID: PMC5682022 DOI: 10.1097/wco.0000000000000396] [Citation(s) in RCA: 77] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
PURPOSE OF REVIEW An important challenge in neurology is identifying the neural mechanisms underlying behavioral deficits after brain injury. Here, we review recent advances in understanding the effects of focal brain lesions on brain networks and behavior. RECENT FINDINGS Neuroimaging studies indicate that the human brain is organized in large-scale resting state networks (RSNs) defined via functional connectivity, that is the temporal correlation of spontaneous activity between different areas. Prior studies showed that focal brain lesion induced behaviorally relevant changes of functional connectivity beyond the site of damage. Recent work indicates that across domains, functional connectivity changes largely conform to two patterns: a reduction in interhemispheric functional connectivity and an increase in intrahemispheric functional connectivity between networks that are normally anticorrelated, for example dorsal attention and default networks. Abnormal functional connectivity can exhibit a high degree of behavioral specificity such that deficits in a given behavioral domain are selectively related to functional connectivity of the corresponding RSN, but some functional connectivity changes allow prediction across domains. Finally, as behavioral recovery proceeds, the prestroke pattern of functional connectivity is restored. SUMMARY Investigating changes in RSNs may shed light on the neural mechanisms underlying brain dysfunction after stroke. Therefore, resting state functional connectivity may represent an important tool for clinical diagnosis, tracking recovery and rehabilitation.
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Affiliation(s)
| | | | - Joshua S. Siegel
- Department of Neurology, School of Medicine, Washington University in Saint Louis, Saint Louis, USA
| | - Gordon L. Shulman
- Department of Neurology, School of Medicine, Washington University in Saint Louis, Saint Louis, USA
| | - Maurizio Corbetta
- Department of Neurology, School of Medicine, Washington University in Saint Louis, Saint Louis, USA
- Department of Radiology, School of Medicine, Washington University in Saint Louis, Saint Louis, USA
- Department of Neuroscience, School of Medicine, Washington University in Saint Louis, Saint Louis, USA
- Department of Bioengineering, School of Medicine, Washington University in Saint Louis, Saint Louis, USA
- Department of Neuroscience, University of Padua, Padua, Italy
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29
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Beyond the Arcuate Fasciculus: Damage to Ventral and Dorsal Language Pathways in Aphasia. Brain Topogr 2016; 30:249-256. [DOI: 10.1007/s10548-016-0503-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Accepted: 06/13/2016] [Indexed: 12/16/2022]
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