1
|
Edlow BL, Boerwinkle VL, Annen J, Boly M, Gosseries O, Laureys S, Mukherjee P, Puybasset L, Stevens RD, Threlkeld ZD, Newcombe VFJ, Fernandez-Espejo D. Common Data Elements for Disorders of Consciousness: Recommendations from the Working Group on Neuroimaging. Neurocrit Care 2023; 39:611-617. [PMID: 37552410 DOI: 10.1007/s12028-023-01794-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Accepted: 06/22/2023] [Indexed: 08/09/2023]
Abstract
BACKGROUND Over the past 5 decades, advances in neuroimaging have yielded insights into the pathophysiologic mechanisms that cause disorders of consciousness (DoC) in patients with severe brain injuries. Structural, functional, metabolic, and perfusion imaging studies have revealed specific neuroanatomic regions, such as the brainstem tegmentum, thalamus, posterior cingulate cortex, medial prefrontal cortex, and occipital cortex, where lesions correlate with the current or future state of consciousness. Advanced imaging modalities, such as diffusion tensor imaging, resting-state functional magnetic resonance imaging (fMRI), and task-based fMRI, have been used to improve the accuracy of diagnosis and long-term prognosis, culminating in the endorsement of fMRI for the clinical evaluation of patients with DoC in the 2018 US (task-based fMRI) and 2020 European (task-based and resting-state fMRI) guidelines. As diverse neuroimaging techniques are increasingly used for patients with DoC in research and clinical settings, the need for a standardized approach to reporting results is clear. The success of future multicenter collaborations and international trials fundamentally depends on the implementation of a shared nomenclature and infrastructure. METHODS To address this need, the Neurocritical Care Society's Curing Coma Campaign convened an international panel of DoC neuroimaging experts to propose common data elements (CDEs) for data collection and reporting in this field. RESULTS We report the recommendations of this CDE development panel and disseminate CDEs to be used in neuroimaging studies of patients with DoC. CONCLUSIONS These CDEs will support progress in the field of DoC neuroimaging and facilitate international collaboration.
Collapse
Affiliation(s)
- Brian L Edlow
- Center for Neurotechnology and Neurorecovery, Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA.
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, USA.
| | - Varina L Boerwinkle
- Clinical Resting-State Functional Magnetic Resonance Imaging Laboratory and Service, Department of Neurology, University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | - Jitka Annen
- Coma Science Group, GIGA Consciousness, University of Liège, Liège, Belgium
- Centre de Cerveau2, University Hospital of Liège, Liège, Belgium
| | - Melanie Boly
- Department of Neurology, University of Wisconsin, Madison, WI, USA
- Department of Psychiatry, Wisconsin Institute for Sleep and Consciousness, University of Wisconsin, Madison, WI, USA
| | - Olivia Gosseries
- Coma Science Group, GIGA Consciousness, University of Liège, Liège, Belgium
- Centre de Cerveau2, University Hospital of Liège, Liège, Belgium
| | - Steven Laureys
- Coma Science Group, GIGA Consciousness, University of Liège, Liège, Belgium
- Centre de Cerveau2, University Hospital of Liège, Liège, Belgium
- CERVO Research Institute, Laval University, Quebec, Canada
| | - Pratik Mukherjee
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, USA
| | - Louis Puybasset
- Department of Anesthesiology and Intensive Care, Groupe Hospitalier Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris, Paris, France
| | - Robert D Stevens
- Departments of Anesthesiology and Critical Care Medicine, Neurology, Radiology, and Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Zachary D Threlkeld
- Department of Neurology, Stanford University School of Medicine, Stanford, CA, USA
| | | | - Davinia Fernandez-Espejo
- School of Psychology and Centre for Human Brain Health, University of Birmingham, Birmingham, UK
| |
Collapse
|
2
|
Calzolari S, Jalali R, Fernández-Espejo D. Characterising stationary and dynamic effective connectivity changes in the motor network during and after tDCS. Neuroimage 2023; 269:119915. [PMID: 36736717 DOI: 10.1016/j.neuroimage.2023.119915] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 01/26/2023] [Accepted: 01/30/2023] [Indexed: 02/04/2023] Open
Abstract
The exact mechanisms behind the effects of transcranial direct current stimulation (tDCS) at a network level are still poorly understood, with most studies to date focusing on local (cortical) effects and changes in motor-evoked potentials or BOLD signal. Here, we explored stationary and dynamic effective connectivity across the motor network at rest in two experiments where we applied tDCS over the primary motor cortex (M1-tDCS) or the cerebellum (cb-tDCS) respectively. Two cohorts of healthy volunteers (n = 21 and n = 22) received anodal, cathodal, and sham tDCS sessions (counterbalanced) during 20 min of resting-state functional magnetic resonance imaging (fMRI). We used spectral Dynamic Causal Modelling (DCM) and hierarchical Parametrical Empirical Bayes (PEB) to analyze data after (compared to a pre-tDCS baseline) and during stimulation. We also implemented a novel dynamic (sliding windows) DCM/PEB approach to model the nature of network reorganisation across time. In both experiments we found widespread effects of tDCS that extended beyond the targeted area and modulated effective connectivity between cortex, thalamus, and cerebellum. These changes were characterised by unique nonlinear temporal fingerprints across connections and polarities. Our results support growing research challenging the classic notion of anodal and cathodal tDCS as excitatory and inhibitory respectively, as well as the idea of a cumulative effect of tDCS over time. Instead, they described a rich set of changes with specific spatial and temporal patterns. Our work provides a starting point for advancing our understanding of network-level tDCS effects and may guide future work to optimise its cognitive and clinical applications.
Collapse
Affiliation(s)
- Sara Calzolari
- Centre for Human Brain Health, School of Psychology, University of Birmingham, Birmingham B15 2TT, UK; School of Psychology, University of Birmingham, Birmingham B15 2TT, UK
| | - Roya Jalali
- Centre for Human Brain Health, School of Psychology, University of Birmingham, Birmingham B15 2TT, UK; School of Psychology, University of Birmingham, Birmingham B15 2TT, UK; University Hospitals Birmingham NHS Foundation Trust, UK
| | - Davinia Fernández-Espejo
- Centre for Human Brain Health, School of Psychology, University of Birmingham, Birmingham B15 2TT, UK; School of Psychology, University of Birmingham, Birmingham B15 2TT, UK.
| |
Collapse
|
3
|
Ge Q, Wang Y, Zhuang Y, Li Q, Han R, Guo W, He J. Opioid-induced short-term consciousness improvement in patients with disorders of consciousness. Front Neurosci 2023; 17:1117655. [PMID: 36816138 PMCID: PMC9936155 DOI: 10.3389/fnins.2023.1117655] [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: 12/06/2022] [Accepted: 01/18/2023] [Indexed: 02/05/2023] Open
Abstract
Introduction Effective treatment to facilitate recovery from prolonged disorders of consciousness is a complex topic for the medical community. In clinical practice, we have found that a subset of patients has a short-term improvement of consciousness after general anesthesia. Methods To determine the clinical factors responsible for the consciousness improvement, we enrolled 50 patients with disorders of consciousness who underwent surgery from October 2021 to June 2022. Their states of consciousness were evaluated before surgery, within 48 h after surgery, and 3 months after surgery. Clinical-related factors and intraoperative anesthetic drug doses were collected and compared between patients with and without consciousness improvement. Independent associations between selected factors and postoperative improvement were assessed using multivariate logistical regression analyses. Results Postoperative short-term consciousness improvement was found in 44% (22/50) of patients, with significantly increased scores of auditory and visual subscales. Patients with traumatic etiology, a preoperative diagnosis of minimally conscious state, and higher scores in the auditory, visual, and motor subscales were more likely to have postoperative improvement. This short-term increase in consciousness after surgery correlated with patients' abilities to communicate in the long term. Furthermore, the amount of opioid analgesic used was significantly different between the improved and non-improved groups. Finally, analgesic dose, etiology, and preoperative diagnosis were independently associated with postoperative consciousness improvement. Discussion In conclusion, postoperative consciousness improvement is related to the residual consciousness of the patient and can be used to evaluate prognosis. Administration of opioids may be responsible for this short-term improvement in consciousness, providing a potential therapeutic approach for disorders of consciousness.
Collapse
Affiliation(s)
- Qianqian Ge
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Yanjun Wang
- College of Anesthesiology, Shanxi Medical University, Taiyuan, China
| | - Yutong Zhuang
- Department of Neurosurgery, The Second Clinical College of Southern Medical University, Guangzhou, China
| | - Qinghua Li
- College of Anesthesiology, Shanxi Medical University, Taiyuan, China
| | - Ruquan Han
- Department of Anesthesiology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Wenzhi Guo
- College of Anesthesiology, Shanxi Medical University, Taiyuan, China,Department of Anesthesiology, The Seventh Medical Center of PLA General Hospital, Beijing, China,Wenzhi Guo,
| | - Jianghong He
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China,*Correspondence: Jianghong He,
| |
Collapse
|
4
|
Reproducible protocol to obtain and measure first-order relay human thalamic white-matter tracts. Neuroimage 2022; 262:119558. [PMID: 35973564 DOI: 10.1016/j.neuroimage.2022.119558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2021] [Revised: 07/25/2022] [Accepted: 08/11/2022] [Indexed: 11/23/2022] Open
Abstract
The "primary" or "first-order relay" nuclei of the thalamus feed the cerebral cortex with information about ongoing activity in the environment or the subcortical motor systems. Because of the small size of these nuclei and the high specificity of their input and output pathways, new imaging protocols are required to investigate thalamocortical interactions in human perception, cognition and language. The goal of the present study was twofold: I) to develop a reconstruction protocol based on in vivo diffusion MRI to extract and measure the axonal fiber tracts that originate or terminate specifically in individual first-order relay nuclei; and, II) to test the reliability of this reconstruction protocol. In left and right hemispheres, we investigated the thalamocortical/corticothalamic axon bundles linking each of the first-order relay nuclei and their main cortical target areas, namely, the lateral geniculate nucleus (optic radiation), the medial geniculate nucleus (acoustic radiation), the ventral posterior nucleus (somatosensory radiation) and the ventral lateral nucleus (motor radiation). In addition, we examined the main subcortical input pathway to the ventral lateral posterior nucleus, which originates in the dentate nucleus of the cerebellum. Our protocol comprised three components: defining regions-of-interest; preprocessing diffusion data; and modeling white-matter tracts and tractometry. We then used computation and test-retest methods to check whether our protocol could reliably reconstruct these tracts of interest and their profiles. Our results demonstrated that the protocol had nearly perfect computational reproducibility and good-to-excellent test-retest reproducibility. This new protocol may be of interest for both basic human brain neuroscience and clinical studies and has been made publicly available to the scientific community.
Collapse
|
5
|
Aloi D, Jalali R, Tilsley P, Miall RC, Fernández-Espejo D. tDCS modulates effective connectivity during motor command following; a potential therapeutic target for disorders of consciousness. Neuroimage 2021; 247:118781. [PMID: 34879252 PMCID: PMC8803542 DOI: 10.1016/j.neuroimage.2021.118781] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 10/22/2021] [Accepted: 12/04/2021] [Indexed: 12/27/2022] Open
Abstract
Transcranial direct current stimulation (tDCS) is attracting increasing interest as a potential therapeutic route for unresponsive patients with prolonged disorders of consciousness (PDOC). However, research to date has had mixed results. Here, we propose a new direction by directly addressing the mechanisms underlying lack of responsiveness in PDOC, and using these to define our targets and the success of our intervention in the healthy brain first. We report 2 experiments that assess whether tDCS to the primary motor cortex (M1-tDCS; Experiment 1) and the cerebellum (cb-tDCS; Experiment 2) administered at rest modulate thalamo-cortical coupling in a subsequent command following task typically used to clinically assess awareness. Both experiments use sham- and polarity-controlled, randomised, double-blind, crossover designs. In Experiment 1, 22 participants received anodal, cathodal, and sham M1-tDCS sessions while in the MRI scanner. A further 22 participants received the same protocol with cb-tDCS in Experiment 2. We used Dynamic Causal Modelling of fMRI to characterise the effects of tDCS on brain activity and dynamics during simple thumb movements in response to command. We found that M1-tDCS increased thalamic excitation and that Cathodal cb-tDCS increased excitatory coupling from thalamus to M1. All these changes were polarity specific. Combined, our experiments demonstrate that tDCS can successfully modulate long range thalamo-cortical dynamics during command following via targeting of cortical regions. This suggests that M1- and cb-tDCS may allow PDOC patients to overcome the motor deficits at the root of their reduced responsiveness, improving their rehabilitation options and quality of life as a result.
Collapse
Affiliation(s)
- Davide Aloi
- School of Psychology, University of Birmingham, United Kingdom; Centre for Human Brain Health, University of Birmingham, United Kingdom
| | - Roya Jalali
- School of Psychology, University of Birmingham, United Kingdom; Centre for Human Brain Health, University of Birmingham, United Kingdom
| | - Penelope Tilsley
- School of Psychology, University of Birmingham, United Kingdom; Aix-Marseille Univ, CNRS, CRMBM, UMR 7339, Marseille, France
| | - R Chris Miall
- School of Psychology, University of Birmingham, United Kingdom; Centre for Human Brain Health, University of Birmingham, United Kingdom
| | - Davinia Fernández-Espejo
- School of Psychology, University of Birmingham, United Kingdom; Centre for Human Brain Health, University of Birmingham, United Kingdom.
| |
Collapse
|
6
|
Yu Y, Zheng W, Tan X, Li X, Zhang X, Gao J, Pan G, Wu D, Luo B. Microstructural profiles of thalamus and thalamocortical connectivity in patients with disorder of consciousness. J Neurosci Res 2021; 99:3261-3273. [PMID: 34766648 DOI: 10.1002/jnr.24921] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 06/04/2021] [Accepted: 06/24/2021] [Indexed: 01/01/2023]
Abstract
Thalamus and thalamocortical connectivity are crucial for consciousness; however, their microstructural changes in patients with a disorder of consciousness (DOC) have not yet been thoroughly characterized. In the present study, we applied the novel fixel-based analysis to comprehensively investigate the thalamus-related microstructural abnormalities in 10 patients with DOC using 7-T diffusion-weighted imaging data. We found that compared to healthy controls, patients with DOC showed reduced fiber density (FD) and fiber density and cross-section (FDC) in the mediodorsal, anterior, and ventral anterior thalamic nuclei, while fiber-bundle cross-section (FC) was not significantly altered in the thalamus. Impaired thalamocortical connectivity in the DOC cohort was mainly connected to the middle frontal gyrus, anterior cingulate gyrus, fusiform gyrus, and sensorimotor cortices, including the precentral gyrus and postcentral gyrus, with predominant microstructural abnormalities in FD and FDC. Correlation analysis showed that FC of the right mediodorsal thalamus was negatively correlated with the level of consciousness. Our results suggest that microstructural abnormalities of thalamus and thalamocortical connectivity in DOC were mainly attributed to axonal injury. In particular, the microstructural integrity of the thalamus is a vital factor in consciousness generation.
Collapse
Affiliation(s)
- Yamei Yu
- Department of Neurology and Brain Medical Centre, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Weihao Zheng
- School of Information Science and Egineering, Lanzhou University, Lanzhou, China
| | - Xufei Tan
- Department of Clinical Medicine, School of Medicine, Zhejiang University City College, Hangzhou, China
| | - Xiaoxia Li
- Department of Neurology and Brain Medical Centre, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Xiaotong Zhang
- Interdisciplinary Institute of Neuroscience and Technology, Key Laboratory for Biomedical Engineering of Ministry of Education, Zhejiang University, Hangzhou, China
| | - Jian Gao
- Hangzhou Ming Zhou Nao Kang Rehabilitation Hospital, Hangzhou, China
| | - Gang Pan
- College of Computer Science and Technology, Zhejiang University, Hangzhou, China
| | - Dan Wu
- Department of Neurology and Brain Medical Centre, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Benyan Luo
- Department of Neurology and Brain Medical Centre, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| |
Collapse
|
7
|
Coulborn S, Taylor C, Naci L, Owen AM, Fernández-Espejo D. Disruptions in Effective Connectivity within and between Default Mode Network and Anterior Forebrain Mesocircuit in Prolonged Disorders of Consciousness. Brain Sci 2021; 11:749. [PMID: 34200092 PMCID: PMC8227204 DOI: 10.3390/brainsci11060749] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 05/25/2021] [Accepted: 05/30/2021] [Indexed: 11/17/2022] Open
Abstract
Recent research indicates prolonged disorders of consciousness (PDOC) result from structural and functional impairments to key cortical and subcortical networks, including the default mode network (DMN) and the anterior forebrain mesocircuit (AFM). However, the specific mechanisms which underpin such impairments remain unknown. It is known that disruptions in the striatal-pallidal pathway can result in the over inhibition of the thalamus and lack of excitation to the cortex that characterizes PDOC. Here, we used spectral dynamic causal modelling and parametric empirical Bayes on rs-fMRI data to assess whether DMN changes in PDOC are caused by disruptions in the AFM. PDOC patients displayed overall reduced coupling within the AFM, and specifically, decreased self-inhibition of the striatum, paired with reduced coupling from striatum to thalamus. This led to loss of inhibition from AFM to DMN, mostly driven by posterior areas including the precuneus and inferior parietal cortex. In turn, the DMN showed disruptions in self-inhibition of the precuneus and medial prefrontal cortex. Our results provide support for the anterior mesocircuit model at the subcortical level but highlight an inhibitory role for the AFM over the DMN, which is disrupted in PDOC.
Collapse
Affiliation(s)
- Sean Coulborn
- Centre for Human Brain Health and School of Psychology, University of Birmingham, Birmingham B15 2TT, UK; (S.C.); (C.T.)
| | - Chris Taylor
- Centre for Human Brain Health and School of Psychology, University of Birmingham, Birmingham B15 2TT, UK; (S.C.); (C.T.)
| | - Lorina Naci
- Trinity College Institute of Neuroscience, School of Psychology, Trinity College Dublin, D02 PN40 Dublin, Ireland;
| | - Adrian M. Owen
- Brain and Mind Institute, Western University, London, ON N6A 5B7, Canada;
| | - Davinia Fernández-Espejo
- Centre for Human Brain Health and School of Psychology, University of Birmingham, Birmingham B15 2TT, UK; (S.C.); (C.T.)
| |
Collapse
|
8
|
Aloi D, della Rocchetta AI, Ditchfield A, Coulborn S, Fernández-Espejo D. Therapeutic Use of Transcranial Direct Current Stimulation in the Rehabilitation of Prolonged Disorders of Consciousness. Front Neurol 2021; 12:632572. [PMID: 33897592 PMCID: PMC8058460 DOI: 10.3389/fneur.2021.632572] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Accepted: 03/09/2021] [Indexed: 12/20/2022] Open
Abstract
Patients with Prolonged Disorders of Consciousness (PDOC) have catastrophic disabilities and very complex needs for care. Therapeutic options are very limited, and patients often show little functional improvement over time. Neuroimaging studies have demonstrated that a significant number of PDOC patients retain a high level of cognitive functioning, and in some cases even awareness, and are simply unable to show this with their external behavior - a condition known as cognitive-motor dissociation (CMD). Despite vast implications for diagnosis, the discovery of covert cognition in PDOC patients is not typically associated with a more favorable prognosis, and the majority of patients will remain in a permanent state of low responsiveness. Recently, transcranial direct current stimulation (tDCS) has attracted attention as a potential therapeutic tool in PDOC. Research to date suggests that tDCS can lead to clinical improvements in patients with a minimally conscious state (MCS), especially when administered over multiple sessions. While promising, the outcomes of these studies have been highly inconsistent, partially due to small sample sizes, heterogeneous methodologies (in terms of both tDCS parameters and outcome measures), and limitations related to electrode placement and heterogeneity of brain damage inherent to PDOC. In addition, we argue that neuroimaging and electrophysiological assessments may serve as more sensitive biomarkers to identify changes after tDCS that are not yet apparent behaviorally. Finally, given the evidence that concurrent brain stimulation and physical therapy can enhance motor rehabilitation, we argue that future studies should focus on the integration of tDCS with conventional rehabilitation programmes from the subacute phase of care onwards, to ascertain whether any synergies exist.
Collapse
Affiliation(s)
- Davide Aloi
- School of Psychology, University of Birmingham, Birmingham, United Kingdom
- Centre for Human Brain Health, University of Birmingham, Birmingham, United Kingdom
| | | | - Alice Ditchfield
- School of Psychology, University of Birmingham, Birmingham, United Kingdom
- Centre for Human Brain Health, University of Birmingham, Birmingham, United Kingdom
| | - Sean Coulborn
- School of Psychology, University of Birmingham, Birmingham, United Kingdom
- Centre for Human Brain Health, University of Birmingham, Birmingham, United Kingdom
| | - Davinia Fernández-Espejo
- School of Psychology, University of Birmingham, Birmingham, United Kingdom
- Centre for Human Brain Health, University of Birmingham, Birmingham, United Kingdom
| |
Collapse
|
9
|
Zheng W, Tan X, Liu T, Li X, Gao J, Hong L, Zhang X, Zhao Z, Yu Y, Zhang Y, Luo B, Wu D. Individualized Thalamic Parcellation Reveals Alterations in Shape and Microstructure of Thalamic Nuclei in Patients with Disorder of Consciousness. Cereb Cortex Commun 2021; 2:tgab024. [PMID: 34296169 PMCID: PMC8152869 DOI: 10.1093/texcom/tgab024] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 03/25/2021] [Accepted: 03/28/2021] [Indexed: 12/02/2022] Open
Abstract
The thalamus plays crucial roles in consciousness generation and information processing. Previous evidence suggests that disorder of consciousness (DOC) caused by severe brain injury, is potentially related to thalamic abnormalities. However, how the morphology and microstructure change in thalamic subfields and thalamocortical fiber pathways in patients with DOC, and the relationships between these changes and the consciousness status remain unclear. Here, we generated the individual-specific thalamic parcellation in 10 DOC patients and 10 healthy controls (HC) via a novel thalamic segmentation framework based on the fiber orientation distribution (FOD) derived from 7-Tesla diffusion MRI, and investigated the shape deformation of thalamic nuclei as well as the microstructural changes associated with thalamic nuclei and thalamocortical pathways in patients with DOC. Enlargement of dorsal posterior nucleus and atrophy of anterior nucleus in the right thalamus were observed in DOC cohort relative to the HCs, and the former was closely linked to the consciousness level of the patients. We also found significant reductions of fiber density, but not fiber bundle cross-section, within several thalamic nuclei and most of the thalamocortical fiber pathways, suggesting that loss of axons might take primary responsibility for the impaired thalamocortical connections in patients with DOC rather than the change in fiber-bundle morphology. Furthermore, the individual-specific thalamic parcellation achieved 80% accuracy in classifying patients at the minimally conscious state from the vegetative state, compared with ~60% accuracy based on group-level parcellations. Our findings provide the first evidence for the shape deformation of thalamic nuclei in DOC patients and the microstructural basis of the disrupted thalamocortical connections.
Collapse
Affiliation(s)
- Weihao Zheng
- Key Laboratory for Biomedical Engineering of Ministry of Education, College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou, 310027, P.R. China
| | - Xufei Tan
- Department of Clinical Medicine, School of Medicine, Zhejiang University City College, Hangzhou, 310015, P.R. China
| | - Tingting Liu
- Key Laboratory for Biomedical Engineering of Ministry of Education, College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou, 310027, P.R. China
| | - Xiaoxia Li
- Department of Neurology and Brain Medical Centre, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, 310003, P.R. China
| | - Jian Gao
- Department of Rehabilitation, Hospital of Zhejiang Armed Police Corps, Hangzhou, 310051, P.R. China
| | - Lirong Hong
- Department of Rehabilitation, Hospital of Zhejiang Armed Police Corps, Hangzhou, 310051, P.R. China
| | - Xiaotong Zhang
- Interdisciplinary Institute of Neuroscience and Technology, Qiushi Academy for Advanced Studies, Zhejiang University, Hangzhou, 310029, P.R. China
| | - Zhiyong Zhao
- Key Laboratory for Biomedical Engineering of Ministry of Education, College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou, 310027, P.R. China
| | - Yamei Yu
- Department of Neurology and Brain Medical Centre, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, 310003, P.R. China
| | - Yi Zhang
- Key Laboratory for Biomedical Engineering of Ministry of Education, College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou, 310027, P.R. China
| | - Benyan Luo
- Department of Neurology and Brain Medical Centre, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, 310003, P.R. China
| | - Dan Wu
- Key Laboratory for Biomedical Engineering of Ministry of Education, College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou, 310027, P.R. China
| |
Collapse
|
10
|
Pauli R, O'Donnell A, Cruse D. Resting-State Electroencephalography for Prognosis in Disorders of Consciousness Following Traumatic Brain Injury. Front Neurol 2020; 11:586945. [PMID: 33343491 PMCID: PMC7746866 DOI: 10.3389/fneur.2020.586945] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Accepted: 11/16/2020] [Indexed: 11/13/2022] Open
Abstract
Although the majority of patients recover consciousness after a traumatic brain injury (TBI), a minority develop a prolonged disorder of consciousness, which may never fully resolve. For these patients, accurate prognostication is essential to treatment decisions and long-term care planning. In this review, we evaluate the use of resting-state electroencephalography (EEG) as a prognostic measure in disorders of consciousness following TBI. We highlight that routine clinical EEG recordings have prognostic utility in the short to medium term. In particular, measures of alpha power and variability are indicative of relatively better functional outcomes within the first year post-TBI. This is hypothesized to reflect intact thalamocortical loops, and thus the potential for recovery of consciousness even in the apparent absence of current consciousness. However, there is a lack of research into the use of resting-state EEG for predicting longer-term recovery following TBI. We conclude that, given the potential for patients to demonstrate improvements in consciousness and functional capacity even years after TBI, a research focus on EEG-augmented prognostication in very long-term disorders of consciousness is now required.
Collapse
Affiliation(s)
- Ruth Pauli
- Centre for Human Brain Health, University of Birmingham, Birmingham, United Kingdom
| | | | | |
Collapse
|
11
|
Subcortical atrophy correlates with the perturbational complexity index in patients with disorders of consciousness. Brain Stimul 2020; 13:1426-1435. [PMID: 32717393 DOI: 10.1016/j.brs.2020.07.012] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Revised: 05/26/2020] [Accepted: 07/21/2020] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND The complexity of neurophysiological brain responses to direct cortical stimulation, referred to as the perturbational complexity index (PCI), has been shown able to discriminate between consciousness and unconsciousness in patients surviving severe brain injury as well as several other conditions (e.g., wake, dreamless sleep, sleep and ketamine dreaming, anesthesia). OBJECTIVE This study asks whether, in patients with a disorder of consciousness (DOC), the complexity of the neurophysiological response to cortical stimulation is preferentially associated with atrophy within specific brain structures. METHODS We perform a retrospective analysis of 40 DOC patients and correlate their maximal PCI to MR-based measurements of cortical thinning and subcortical atrophy. RESULTS PCI was systematically and inversely associated with the degree of local atrophy within the globus pallidus, a region previously linked to electrocortical and behavioral arousal. Conversely, we fail to detect any association between variance in cortical ribbon thickness and PCI. CONCLUSION These findings corroborate the previously reported association between pallidal atrophy and low behavioral arousal and suggest that this region's role in maintaining the overall balance of excitation and inhibition may critically affect the emergence of complex cortical interactions in chronic disorders of consciousness. This finding thus also suggests a target for potential neuromodulatory intervention in DOC patients.
Collapse
|
12
|
Clark AL, Sorg SF, Holiday K, Bigler ED, Bangen KJ, Evangelista ND, Bondi MW, Schiehser DM, Delano-Wood L. Fatigue Is Associated With Global and Regional Thalamic Morphometry in Veterans With a History of Mild Traumatic Brain Injury. J Head Trauma Rehabil 2019; 33:382-392. [PMID: 29385016 PMCID: PMC6066453 DOI: 10.1097/htr.0000000000000377] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
OBJECTIVE Fatigue is a complex, multidimensional phenomenon that commonly occurs following traumatic brain injury (TBI). The thalamus-a structure vulnerable to both primary and secondary injuries in TBI-is thought to play a pivotal role in the manifestation of fatigue. We explored how neuroimaging markers of local and global thalamic morphometry relate to the subjective experience of fatigue post-TBI. METHODS Sixty-three Veterans with a history of mild TBI underwent structural magnetic resonance imaging and completed questionnaires related to fatigue and psychiatric symptoms. FMRIB's Software (FSL) was utilized to obtain whole brain and thalamic volume estimates, as well as to perform regional thalamic morphometry analyses. RESULTS Independent of age, sex, intracranial volume, posttraumatic stress disorder, and depressive symptoms, greater levels of self-reported fatigue were significantly associated with decreased right (P = .026) and left (P = .046) thalamic volumes. Regional morphometry analyses revealed that fatigue was significantly associated with reductions in the anterior and dorsomedial aspects of the right thalamic body (P < .05). Similar trends were observed for the left thalamic body (P < .10). CONCLUSIONS Both global and regional thalamic morphometric changes are associated with the subjective experience of fatigue in Veterans with a history of mild TBI. These findings support a theory in which disruption of thalamocorticostriatal circuitry may result in the manifestation of fatigue in individuals with a history of neurotrauma.
Collapse
Affiliation(s)
- Alexandra L. Clark
- San Diego State University/University of California, San Diego
(SDSU/UCSD) Joint Doctoral Program in Clinical Psychology
- VA San Diego Healthcare System (VASDHS)
| | - Scott F. Sorg
- VA San Diego Healthcare System (VASDHS)
- University of California San Diego, School of Medicine, Department
of Psychiatry
| | - Kelsey Holiday
- San Diego State University/University of California, San Diego
(SDSU/UCSD) Joint Doctoral Program in Clinical Psychology
- VA San Diego Healthcare System (VASDHS)
| | - Erin D. Bigler
- Department of Psychology and the Neuroscience Center, Brigham and
Young University
| | - Katherine J. Bangen
- VA San Diego Healthcare System (VASDHS)
- University of California San Diego, School of Medicine, Department
of Psychiatry
| | | | - Mark W. Bondi
- VA San Diego Healthcare System (VASDHS)
- University of California San Diego, School of Medicine, Department
of Psychiatry
| | - Dawn M. Schiehser
- VA San Diego Healthcare System (VASDHS)
- Center of Excellence for Stress and Mental Health, VASDHS
- University of California San Diego, School of Medicine, Department
of Psychiatry
| | - Lisa Delano-Wood
- VA San Diego Healthcare System (VASDHS)
- Center of Excellence for Stress and Mental Health, VASDHS
- University of California San Diego, School of Medicine, Department
of Psychiatry
| |
Collapse
|
13
|
Prefrontal neural dynamics in consciousness. Neuropsychologia 2019; 131:25-41. [DOI: 10.1016/j.neuropsychologia.2019.05.018] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 05/17/2019] [Accepted: 05/20/2019] [Indexed: 12/11/2022]
|
14
|
Affiliation(s)
- Rodika Sokoliuk
- Centre for Human Brain Health / School of Psychology, University of Birmingham, Edgbaston, UK
| | - Damian Cruse
- Centre for Human Brain Health / School of Psychology, University of Birmingham, Edgbaston, UK
| |
Collapse
|
15
|
Stafford CA, Owen AM, Fernández-Espejo D. The neural basis of external responsiveness in prolonged disorders of consciousness. Neuroimage Clin 2019; 22:101791. [PMID: 30991612 PMCID: PMC6447738 DOI: 10.1016/j.nicl.2019.101791] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Revised: 02/03/2019] [Accepted: 03/24/2019] [Indexed: 01/18/2023]
Abstract
OBJECTIVE To investigate the structural integrity of fibre tracts underlying overt motor behaviour in PDOC. METHODS This cross-sectional study examined 15 PDOC patients and 22 healthy participants. Eight PDOC patients met the criteria for the vegetative state, 5 met the criteria for the minimally conscious state and 2 met the criteria for emerging from the minimally conscious state. We used fibre tractography to reconstruct the white matter fibres known to be involved in voluntary motor execution (i.e., those connecting thalamus with M1, M1 with cerebellum, and cerebellum with thalamus) and used fractional anisotropy (FA) as a measure of their integrity. RESULTS PDOC patients showed significantly reduced FA relative to controls on the fibres connecting thalamus and M1. This went above and beyond a widespread injury to the white matter and correlated with clinical severity. In a subset of patients, we also identified a similar pattern of injury in the fibres connecting M1 and cerebellum but a relative preservation of those connecting cerebellum and thalamus. CONCLUSIONS Our results suggest that structural damage to motor fibres may lead to reduced responsiveness in PDOC patients across all diagnostic sub-categories, and therefore behavioural assessments may underestimate the level of retained cognitive function and awareness across the PDOC spectrum.
Collapse
Affiliation(s)
- Clara A Stafford
- Brain and Mind Institute, Department of Psychology, The University of Western Ontario, London, Ontario N6C 5B7, Canada
| | - Adrian M Owen
- Brain and Mind Institute, Department of Psychology, The University of Western Ontario, London, Ontario N6C 5B7, Canada
| | - Davinia Fernández-Espejo
- School of Psychology, The University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom; Centre for Human Brain Health, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom.
| |
Collapse
|
16
|
Zamani A, Mychasiuk R, Semple BD. Determinants of social behavior deficits and recovery after pediatric traumatic brain injury. Exp Neurol 2019; 314:34-45. [PMID: 30653969 DOI: 10.1016/j.expneurol.2019.01.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Revised: 12/29/2018] [Accepted: 01/12/2019] [Indexed: 12/15/2022]
Abstract
Traumatic brain injury (TBI) during early childhood is associated with a particularly high risk of developing social behavior impairments, including deficits in social cognition that manifest as reduced social interactions, with profound consequences for the individuals' quality of life. A number of pre-injury, post-injury, and injury-related factors have been identified or hypothesized to determine the extent of social behavior problems after childhood TBI. These include variables associated with the individual themselves (e.g. age, genetics, the injury severity, and extent of white matter damage), proximal environmental factors (e.g. family functioning, parental mental health), and more distal environmental factors (e.g. socioeconomic status, access to resources). In this review, we synthesize the available evidence demonstrating which of these determinants influence risk versus resilience to social behavior deficits after pediatric TBI, drawing upon the available clinical and preclinical literature. Injury-related pathology in neuroanatomical regions associated with social cognition and behaviors will also be described, with a focus on findings from magnetic resonance imaging and diffusion tensor imaging. Finally, study limitations and suggested future directions are highlighted. In summary, while no single variable can alone accurately predict the manifestation of social behavior problems after TBI during early childhood, an increased understanding of how both injury and environmental factors can influence social outcomes provides a useful framework for the development of more effective rehabilitation strategies aiming to optimize recovery for young brain-injured patients.
Collapse
Affiliation(s)
- Akram Zamani
- Department of Neuroscience, Monash University, Prahran, VIC, Australia
| | - Richelle Mychasiuk
- Department of Neuroscience, Monash University, Prahran, VIC, Australia; Department of Psychology, University of Calgary, Calgary, AB, Canada
| | - Bridgette D Semple
- Department of Neuroscience, Monash University, Prahran, VIC, Australia; Department of Medicine (Royal Melbourne Hospital), The University of Melbourne, Parkville, VIC, Australia.
| |
Collapse
|
17
|
Iglesias JE, Insausti R, Lerma-Usabiaga G, Bocchetta M, Van Leemput K, Greve DN, van der Kouwe A, Fischl B, Caballero-Gaudes C, Paz-Alonso PM. A probabilistic atlas of the human thalamic nuclei combining ex vivo MRI and histology. Neuroimage 2018; 183:314-326. [PMID: 30121337 PMCID: PMC6215335 DOI: 10.1016/j.neuroimage.2018.08.012] [Citation(s) in RCA: 296] [Impact Index Per Article: 49.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Revised: 07/27/2018] [Accepted: 08/09/2018] [Indexed: 01/18/2023] Open
Abstract
The human thalamus is a brain structure that comprises numerous, highly specific nuclei. Since these nuclei are known to have different functions and to be connected to different areas of the cerebral cortex, it is of great interest for the neuroimaging community to study their volume, shape and connectivity in vivo with MRI. In this study, we present a probabilistic atlas of the thalamic nuclei built using ex vivo brain MRI scans and histological data, as well as the application of the atlas to in vivo MRI segmentation. The atlas was built using manual delineation of 26 thalamic nuclei on the serial histology of 12 whole thalami from six autopsy samples, combined with manual segmentations of the whole thalamus and surrounding structures (caudate, putamen, hippocampus, etc.) made on in vivo brain MR data from 39 subjects. The 3D structure of the histological data and corresponding manual segmentations was recovered using the ex vivo MRI as reference frame, and stacks of blockface photographs acquired during the sectioning as intermediate target. The atlas, which was encoded as an adaptive tetrahedral mesh, shows a good agreement with previous histological studies of the thalamus in terms of volumes of representative nuclei. When applied to segmentation of in vivo scans using Bayesian inference, the atlas shows excellent test-retest reliability, robustness to changes in input MRI contrast, and ability to detect differential thalamic effects in subjects with Alzheimer's disease. The probabilistic atlas and companion segmentation tool are publicly available as part of the neuroimaging package FreeSurfer.
Collapse
Affiliation(s)
- Juan Eugenio Iglesias
- Centre for Medical Image Computing (CMIC), Department of Medical Physics and Biomedical Engineering, University College London, United Kingdom; BCBL. Basque Center on Cognition, Brain and Language, Spain.
| | - Ricardo Insausti
- Human Neuroanatomy Laboratory, University of Castilla-La Mancha, Spain
| | | | - Martina Bocchetta
- Dementia Research Centre, Department of Neurodegenerative Disease, Institute of Neurology, University College London, United Kingdom
| | - Koen Van Leemput
- Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, USA; Department of Applied Mathematics and Computer Science, Technical University of Denmark, Denmark
| | - Douglas N Greve
- Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, USA
| | - Andre van der Kouwe
- Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, USA
| | - Bruce Fischl
- Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, USA; MIT Computer Science and Artificial Intelligence Laboratory, USA
| | | | | |
Collapse
|
18
|
Magrassi L, Zippo AG, Azzalin A, Bastianello S, Imberti R, Biella GEM. Single unit activities recorded in the thalamus and the overlying parietal cortex of subjects affected by disorders of consciousness. PLoS One 2018; 13:e0205967. [PMID: 30403761 PMCID: PMC6221278 DOI: 10.1371/journal.pone.0205967] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Accepted: 09/30/2018] [Indexed: 01/12/2023] Open
Abstract
The lack of direct neurophysiological recordings from the thalamus and the cortex hampers our understanding of vegetative state/unresponsive wakefulness syndrome and minimally conscious state in humans. We obtained microelectrode recordings from the thalami and the homolateral parietal cortex of two vegetative state/unresponsive wakefulness syndrome and one minimally conscious state patients during surgery for implantation of electrodes in both thalami for chronic deep brain stimulation. We found that activity of the thalamo-cortical networks differed among the two conditions. There were half the number of active neurons in the thalami of patients in vegetative state/unresponsive wakefulness syndrome than in minimally conscious state. Coupling of thalamic neuron discharge with EEG phases also differed in the two conditions and thalamo-cortical cross-frequency coupling was limited to the minimally conscious state patient. When consciousness is physiologically or pharmacologically reversibly suspended there is a significant increase in bursting activity of the thalamic neurons. By contrast, in the thalami of our patients in both conditions fewer than 17% of the recorded neurons showed bursting activity. This indicates that these conditions differ from physiological suspension of consciousness and that increased thalamic inhibition is not prominent. Our findings, albeit obtained in a limited number of patients, unveil the neurophysiology of these conditions at single unit resolution and might be relevant for inspiring novel therapeutic options.
Collapse
Affiliation(s)
- Lorenzo Magrassi
- Neurochirurgia, Dipartimento di Scienze Clinico-Chirurgiche, Diagnostiche e Pediatriche, University of Pavia—Fondazione IRCCS Policlinico S. Matteo, Pavia, Italy
- Istituto di Genetica Molecolare IGM-CNR, Pavia, Italy
- * E-mail:
| | - Antonio G. Zippo
- Istituto di Bioimmagini e Fisiologia Molecolare, CNR, LITA Bldg, Segrate, Italy
| | - Alberto Azzalin
- Neurochirurgia, Dipartimento di Scienze Clinico-Chirurgiche, Diagnostiche e Pediatriche, University of Pavia—Fondazione IRCCS Policlinico S. Matteo, Pavia, Italy
- Istituto di Genetica Molecolare IGM-CNR, Pavia, Italy
| | - Stefano Bastianello
- State University of Pavia, Dept. of Brain and Behavioral Sciences, Neuroradiology Department—C. Mondino National Neurological Institute, Pavia, Italy
| | - Roberto Imberti
- Phase I Clinical Trial Unit and Experimental Therapy, Fondazione IRCCS Policlinico S. Matteo, Pavia, Italy
| | | |
Collapse
|
19
|
Conventional Structural Magnetic Resonance Imaging in Differentiating Chronic Disorders of Consciousness. Brain Sci 2018; 8:brainsci8080144. [PMID: 30081605 PMCID: PMC6120007 DOI: 10.3390/brainsci8080144] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Revised: 07/26/2018] [Accepted: 08/03/2018] [Indexed: 01/14/2023] Open
Abstract
Differential diagnosis of unresponsive wakefulness syndrome (UWS) and minimally conscious state (MCS) is one of the most challenging problems for specialists who deal with chronic disorders of consciousness (DOC). The aim of the current study was to develop a conventional MRI-based scale and to evaluate its role in distinguishing chronic disorders of consciousness (Disorders of Consciousness MRI-based Distinguishing Scale, DOC-MRIDS). Data were acquired from 30 patients with clinically diagnosed chronic disorders of consciousness. All patients underwent conventional MRI using a Siemens Verio 3.0 T scanner, which included T2 and T1 sequences for patient assessment. Diffuse cortical atrophy, ventricular enlargement, sulcal widening, leukoaraiosis, brainstem and/or thalamus degeneration, corpus callosum degeneration, and corpus callosum lesions were assessed according to DOC-MRIDS criteria, with a total score calculation. The ROC-analysis showed that a reasonable threshold DOC-MRIDS total score was 5.5, that is, patients with DOC-MRIDS total score of 6 and above were classified as UWS and 5 and below as MCS, with sensitivity of 82.4% and specificity of 92.3%. The novel structural MRI-based scale for the assessment of typical brain lesions in patients with chronic DOC is relatively easy to apply, and provides good specificity and sensitivity values for discrimination between UWS and MCS.
Collapse
|
20
|
Kirsch M, Guldenmund P, Ali Bahri M, Demertzi A, Baquero K, Heine L, Charland-Verville V, Vanhaudenhuyse A, Bruno MA, Gosseries O, Di Perri C, Ziegler E, Brichant JF, Soddu A, Bonhomme V, Laureys S. Sedation of Patients With Disorders of Consciousness During Neuroimaging: Effects on Resting State Functional Brain Connectivity. Anesth Analg 2017; 124:588-598. [PMID: 27941576 DOI: 10.1213/ane.0000000000001721] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
BACKGROUND To reduce head movement during resting state functional magnetic resonance imaging, post-coma patients with disorders of consciousness (DOC) are frequently sedated with propofol. However, little is known about the effects of this sedation on the brain connectivity patterns in the damaged brain essential for differential diagnosis. In this study, we aimed to assess these effects. METHODS Using resting state functional magnetic resonance imaging 3T data obtained over several years of scanning patients for diagnostic and research purposes, we employed a seed-based approach to examine resting state connectivity in higher-order (default mode, bilateral external control, and salience) and lower-order (auditory, sensorimotor, and visual) resting state networks and connectivity with the thalamus, in 20 healthy unsedated controls, 8 unsedated patients with DOC, and 8 patients with DOC sedated with propofol. The DOC groups were matched for age at onset, etiology, time spent in DOC, diagnosis, standardized behavioral assessment scores, movement intensities, and pattern of structural brain injury (as assessed with T1-based voxel-based morphometry). RESULTS DOC were associated with severely impaired resting state network connectivity in all but the visual network. Thalamic connectivity to higher-order network regions was also reduced. Propofol administration to patients was associated with minor further decreases in thalamic and insular connectivity. CONCLUSIONS Our findings indicate that connectivity decreases associated with propofol sedation, involving the thalamus and insula, are relatively small compared with those already caused by DOC-associated structural brain injury. Nonetheless, given the known importance of the thalamus in brain arousal, its disruption could well reflect the diminished movement obtained in these patients. However, more research is needed on this topic to fully address the research question.
Collapse
Affiliation(s)
- Muriëlle Kirsch
- From the *Coma Science Group and §MoVeRe Group, Cyclotron Research Center, University of Liège, Liège, Belgium; †Department of Anesthesia and Intensive Care Medicine, CHU Sart Tilman Hospital, University of Liège, Liège, Belgium; ‡Computer Imaging and Medical Applications Laboratory, National University of Colombia, Bogotá, Colombia; ‖Department of Neurology, CHU Sart Tilman Hospital University of Liège, Liège, Belgium; ¶Department of Algology and Palliative Care, University Hospital of Liège, University of Liège, Liège, Belgium; #Center for Sleep and Consciousness and Postle Laboratory, Department of Psychiatry, University of Wisconsin, Madison, Wisconsin; **Department of Physics and Astronomy, Brain & Mind Institute, University of Western Ontario, London, Ontario, Canada; and ††Department of Anesthesia and Intensive Care Medicine, CHR Citadelle and CHU Liège, University of Liège, Liège, Belgium
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
21
|
Weng L, Xie Q, Zhao L, Zhang R, Ma Q, Wang J, Jiang W, He Y, Chen Y, Li C, Ni X, Xu Q, Yu R, Huang R. Abnormal structural connectivity between the basal ganglia, thalamus, and frontal cortex in patients with disorders of consciousness. Cortex 2017; 90:71-87. [PMID: 28365490 DOI: 10.1016/j.cortex.2017.02.011] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Revised: 09/28/2016] [Accepted: 02/20/2017] [Indexed: 12/17/2022]
Abstract
Consciousness loss in patients with severe brain injuries is associated with reduced functional connectivity of the default mode network (DMN), fronto-parietal network, and thalamo-cortical network. However, it is still unclear if the brain white matter connectivity between the above mentioned networks is changed in patients with disorders of consciousness (DOC). In this study, we collected diffusion tensor imaging (DTI) data from 13 patients and 17 healthy controls, constructed whole-brain white matter (WM) structural networks with probabilistic tractography. Afterward, we estimated and compared topological properties, and revealed an altered structural organization in the patients. We found a disturbance in the normal balance between segregation and integration in brain structural networks and detected significantly decreased nodal centralities primarily in the basal ganglia and thalamus in the patients. A network-based statistical analysis detected a subnetwork with uniformly significantly decreased structural connections between the basal ganglia, thalamus, and frontal cortex in the patients. Further analysis indicated that along the WM fiber tracts linking the basal ganglia, thalamus, and frontal cortex, the fractional anisotropy was decreased and the radial diffusivity was increased in the patients compared to the controls. Finally, using the receiver operating characteristic method, we found that the structural connections within the NBS-derived component that showed differences between the groups demonstrated high sensitivity and specificity (>90%). Our results suggested that major consciousness deficits in DOC patients may be related to the altered WM connections between the basal ganglia, thalamus, and frontal cortex.
Collapse
Affiliation(s)
- Ling Weng
- Center for the Study of Applied Psychology, Guangdong Key Laboratory of Mental Health and Cognitive Science, School of Psychology, Institute of Brain Science and Rehabilitation, South China Normal University, Guangzhou 510631, PR China
| | - Qiuyou Xie
- Centre for Hyperbaric Oxygen and Neurorehabilitation, Guangzhou General Hospital of Guangzhou Military Command, Guangzhou 510010, PR China
| | - Ling Zhao
- Center for the Study of Applied Psychology, Guangdong Key Laboratory of Mental Health and Cognitive Science, School of Psychology, Institute of Brain Science and Rehabilitation, South China Normal University, Guangzhou 510631, PR China
| | - Ruibin Zhang
- Department of Psychology, The University of Hong Kong, Hong Kong, PR China
| | - Qing Ma
- Centre for Hyperbaric Oxygen and Neurorehabilitation, Guangzhou General Hospital of Guangzhou Military Command, Guangzhou 510010, PR China
| | - Junjing Wang
- Center for the Study of Applied Psychology, Guangdong Key Laboratory of Mental Health and Cognitive Science, School of Psychology, Institute of Brain Science and Rehabilitation, South China Normal University, Guangzhou 510631, PR China
| | - Wenjie Jiang
- Center for the Study of Applied Psychology, Guangdong Key Laboratory of Mental Health and Cognitive Science, School of Psychology, Institute of Brain Science and Rehabilitation, South China Normal University, Guangzhou 510631, PR China
| | - Yanbin He
- Centre for Hyperbaric Oxygen and Neurorehabilitation, Guangzhou General Hospital of Guangzhou Military Command, Guangzhou 510010, PR China
| | - Yan Chen
- Centre for Hyperbaric Oxygen and Neurorehabilitation, Guangzhou General Hospital of Guangzhou Military Command, Guangzhou 510010, PR China
| | - Changhong Li
- Center for the Study of Applied Psychology, Guangdong Key Laboratory of Mental Health and Cognitive Science, School of Psychology, Institute of Brain Science and Rehabilitation, South China Normal University, Guangzhou 510631, PR China
| | - Xiaoxiao Ni
- Centre for Hyperbaric Oxygen and Neurorehabilitation, Guangzhou General Hospital of Guangzhou Military Command, Guangzhou 510010, PR China
| | - Qin Xu
- Center for the Study of Applied Psychology, Guangdong Key Laboratory of Mental Health and Cognitive Science, School of Psychology, Institute of Brain Science and Rehabilitation, South China Normal University, Guangzhou 510631, PR China
| | - Ronghao Yu
- Centre for Hyperbaric Oxygen and Neurorehabilitation, Guangzhou General Hospital of Guangzhou Military Command, Guangzhou 510010, PR China.
| | - Ruiwang Huang
- Center for the Study of Applied Psychology, Guangdong Key Laboratory of Mental Health and Cognitive Science, School of Psychology, Institute of Brain Science and Rehabilitation, South China Normal University, Guangzhou 510631, PR China.
| |
Collapse
|
22
|
Hänggi J, Bellwald D, Brugger P. Shape alterations of basal ganglia and thalamus in xenomelia. Neuroimage Clin 2016; 11:760-769. [PMID: 27330976 PMCID: PMC4909827 DOI: 10.1016/j.nicl.2016.05.015] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2016] [Revised: 05/06/2016] [Accepted: 05/27/2016] [Indexed: 12/21/2022]
Abstract
Xenomelia is a rare condition characterized by the persistent desire for the amputation of physically healthy limbs. Associations with morphological alterations such as reduced cortical thickness and surface area. Nothing is known, however, about the potential involvement of subcortical structures. The thalamus and basal ganglia process, relay, and integrate sensorimotor information and are involved in the preparation and execution of movements. Moreover, both of these structures house somatotopic representations of all body parts. We therefore investigated subcortical correlates of xenomelia by assessing basal ganglia and thalamus by means of vertex-wise shape analyses. For that purpose, we compared the shape of the thalamus, putamen, caudate nucleus, and the pallidum in 13 men suffering from xenomelia, all desiring a leg amputation, compared to 13 healthy control men. We hypothesised that the target leg is misrepresented in subcortical structures of individuals with xenomelia, especially in locations with a somatotopic representation. Shape analyses showed thinning of bilateral dorsomedial putamina, left ventromedial caudate nucleus and left medial pallidum associated with xenomelia. This was accompanied by thickening of bilateral lateral pallida and the left frontolateral thalamus. These shape differences were mainly located in sensorimotor areas of somatotopic leg representations. The present study provides strong evidence for shape differences in striatal, pallidal, and thalamic subregions housing subcortical body part representations. It adds to previously described neural correlates of a condition one can barely empathize with and invites future connectivity analyses in cortico-subcortical networks.
Collapse
Affiliation(s)
- Jürgen Hänggi
- Division Neuropsychology, Department of Psychology, University of Zurich, Switzerland.
| | - Dorian Bellwald
- Division Neuropsychology, Department of Psychology, University of Zurich, Switzerland
| | - Peter Brugger
- Neuropsychology Unit, Department of Neurology, University Hospital Zurich, Switzerland; Center for Integrative Human Physiology (ZIHP), University of Zurich, Switzerland.
| |
Collapse
|
23
|
Guldenmund P, Soddu A, Baquero K, Vanhaudenhuyse A, Bruno MA, Gosseries O, Laureys S, Gómez F. Structural brain injury in patients with disorders of consciousness: A voxel-based morphometry study. Brain Inj 2016; 30:343-52. [DOI: 10.3109/02699052.2015.1118765] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
|
24
|
Nigri A, Ferraro S, Bruzzone MG, Nava S, D'Incerti L, Bertolino N, Sattin D, Leonardi M, Lundström JN. Central olfactory processing in patients with disorders of consciousness. Eur J Neurol 2015; 23:605-12. [DOI: 10.1111/ene.12907] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Accepted: 10/01/2015] [Indexed: 02/02/2023]
Affiliation(s)
- A. Nigri
- Neuroradiology Department Foundation IRCCS Neurological Institute ‘Carlo Besta’ MilanItaly
| | - S. Ferraro
- Neuroradiology Department Foundation IRCCS Neurological Institute ‘Carlo Besta’ MilanItaly
| | - M. G. Bruzzone
- Neuroradiology Department Foundation IRCCS Neurological Institute ‘Carlo Besta’ MilanItaly
| | - S. Nava
- Neuroradiology Department Foundation IRCCS Neurological Institute ‘Carlo Besta’ MilanItaly
| | - L. D'Incerti
- Neuroradiology Department Foundation IRCCS Neurological Institute ‘Carlo Besta’ MilanItaly
| | - N. Bertolino
- Health Department Foundation IRCCS Neurological Institute ‘Carlo Besta’ MilanItaly
| | - D. Sattin
- Neurology, Public Health and Disability Unit Scientific Department Foundation IRCCS Neurological Institute ‘Carlo Besta’ Milan Italy
| | - M. Leonardi
- Neurology, Public Health and Disability Unit Scientific Department Foundation IRCCS Neurological Institute ‘Carlo Besta’ Milan Italy
| | - J. N. Lundström
- Department of Clinical Neuroscience Karolinska Institutet Stockholm Sweden
| | | |
Collapse
|
25
|
Lant ND, Gonzalez-Lara LE, Owen AM, Fernández-Espejo D. Relationship between the anterior forebrain mesocircuit and the default mode network in the structural bases of disorders of consciousness. NEUROIMAGE-CLINICAL 2015; 10:27-35. [PMID: 26693399 PMCID: PMC4660379 DOI: 10.1016/j.nicl.2015.11.004] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Revised: 10/22/2015] [Accepted: 11/07/2015] [Indexed: 12/01/2022]
Abstract
The specific neural bases of disorders of consciousness (DOC) are still not well understood. Some studies have suggested that functional and structural impairments in the default mode network may play a role in explaining these disorders. In contrast, others have proposed that dysfunctions in the anterior forebrain mesocircuit involving striatum, globus pallidus, and thalamus may be the main underlying mechanism. Here, we provide the first report of structural integrity of fiber tracts connecting the nodes of the mesocircuit and the default mode network in 8 patients with DOC. We found evidence of significant damage to subcortico-cortical and cortico-cortical fibers, which were more severe in vegetative state patients and correlated with clinical severity as determined by Coma Recovery Scale-Revised (CRS-R) scores. In contrast, fiber tracts interconnecting subcortical nodes were not significantly impaired. Lastly, we found significant damage in all fiber tracts connecting the precuneus with cortical and subcortical areas. Our results suggest a strong relationship between the default mode network - and most importantly the precuneus - and the anterior forebrain mesocircuit in the neural basis of the DOC.
Collapse
Affiliation(s)
- Nicholas D Lant
- The Brain and Mind Institute, The University of Western Ontario, London, ON N6A 5B7, Canada
| | - Laura E Gonzalez-Lara
- The Brain and Mind Institute, The University of Western Ontario, London, ON N6A 5B7, Canada
| | - Adrian M Owen
- The Brain and Mind Institute, The University of Western Ontario, London, ON N6A 5B7, Canada
| | - Davinia Fernández-Espejo
- The Brain and Mind Institute, The University of Western Ontario, London, ON N6A 5B7, Canada ; School of Psychology, University of Birmingham, Birmingham, B15 2TT, UK
| |
Collapse
|
26
|
Leeman-Markowski BA, Smart OL, Faught RE, Gross RE, Meador KJ. Cessation of gamma activity in the dorsomedial nucleus associated with loss of consciousness during focal seizures. Epilepsy Behav 2015; 51:215-20. [PMID: 26295448 DOI: 10.1016/j.yebeh.2015.07.027] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Revised: 06/20/2015] [Accepted: 07/20/2015] [Indexed: 10/23/2022]
Abstract
RATIONALE Impaired consciousness during seizures may be mediated by ictal propagation to the thalamus. Functions of individual thalamic nuclei with respect to consciousness, however, are largely unknown. The dorsomedial (DM) nucleus of the thalamus likely plays a role in arousal and cognition. We propose that alterations of firing patterns within the DM nucleus contribute to impaired arousal during focal seizures. METHODS Electroencephalograph data were collected from electrodes within the left DM thalamus and midcingulate cortex (MCC) in a patient undergoing seizure monitoring. Spectral power was computed across ictal states (preictal, ictal, and postictal) and level of consciousness (stupor/sleep vs. awake) in the DM nucleus and MCC. RESULTS Eighty-seven seizures of multifocal left frontal and temporal onsets were analyzed, characterized by loss of consciousness. At baseline, the left DM nucleus demonstrated rhythmic bursts of gamma activity, most frequently and with greatest amplitude during wakefulness. This activity ceased as ictal discharges spread to the MCC, and consciousness was impaired, and it recurred at the end of each seizure as awareness was regained. The analysis of gamma (30-40Hz) power demonstrated that when seizures occurred during wakefulness, there was lower DM ictal power (p<0.0001) and higher DM postictal power (p<0.0001) relative to the preictal epoch. This spectral pattern was not evident within the MCC or when seizures occurred during sleep. CONCLUSIONS Data revealed a characteristic pattern of DM gamma bursts during wakefulness, which disappeared during partial seizures associated with impaired consciousness. The findings are consistent with studies suggesting that the DM nucleus participates in cognition and arousal.
Collapse
Affiliation(s)
- B A Leeman-Markowski
- Department of Neurology, Emory University, 101 Woodruff Circle, Suite 6000, Atlanta, GA 30322, USA.
| | - O L Smart
- Department of Neurosurgery, Emory University, 101 Woodruff Circle, Suite 6000, Atlanta, GA 30322, USA.
| | - R E Faught
- Department of Neurology, Emory University, 101 Woodruff Circle, Suite 6000, Atlanta, GA 30322, USA.
| | - R E Gross
- Department of Neurosurgery, Emory University, 101 Woodruff Circle, Suite 6000, Atlanta, GA 30322, USA.
| | - K J Meador
- Department of Neurology and Neurological Sciences, Stanford University, 300 Pasteur Drive (Room A343), Stanford, CA 94305-5235, USA.
| |
Collapse
|
27
|
Abstract
There is growing alarm in the United States about an epidemiologically large occurrence of mild traumatic brain injury with serious long lasting consequences. Although conventional imaging has been unable to identify damage capable of explaining its organic origin or discerning patients at risk of developing long-term or permanently disabling neurological impairment, most disease models assume that diffuse axonal injury in white matter must be present but is difficult to resolve. The few histopathological investigations conducted, however, show only limited evidence of such damage, which cannot account for the stereotypical globalized nature of symptoms generally reported in patients. This review examines recent proposals that in addition to white matter, the thalamus may be another important further site of injury. Although its possible role still remains largely under-investigated, evidence from experimental human and animal models, as well as simulational and analytical representations of mild head injury and other related conditions, suggest that this strategically vital region of the brain, which has reciprocal projections to the entire cerebral cortex, could feasibly play an important role in understanding pathology and predicting outcome.
Collapse
Affiliation(s)
- Elan J Grossman
- 1 Department of Radiology, New York University School of Medicine , New York, New York.,2 Department of Physiology and Neuroscience, New York University School of Medicine , New York, New York
| | - Matilde Inglese
- 3 Department of Neurology, Radiology, and Neuroscience, Mount Sinai School of Medicine , New York, New York
| |
Collapse
|
28
|
Cruse D, Norton L, Gofton T, Young GB, Owen AM. Positive prognostication from median-nerve somatosensory evoked cortical potentials. Neurocrit Care 2015; 21:238-44. [PMID: 24865267 DOI: 10.1007/s12028-014-9982-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND The bilateral absence of the cortical N20 median-nerve somatosensory evoked potential (SSEP) is a strong predictor of poor outcome from coma. However, when N20s are present, accurate prognostication is challenging. Here, we investigated the potential for later SSEP components to help disambiguate outcome in these cases. METHODS In a retrospective review of data from two intensive care units, the amplitudes and latencies of the N20, P25, and N35 components of 28 patients in coma were quantified and related to outcome at discharge from primary care (average 1-month post-injury). Only patients who had survived primary care were included in order to avoid self-fulfilling prophecies, and to focus outcome prediction on those patients with relatively present SSEPs. RESULTS The amplitudes of the N20 and N35 components (averaged across hemispheres) significantly predicted the range of outcomes beyond death. Abnormal amplitudes of the N20 and N35--as derived from a healthy control group--were significantly associated with poor outcome. The relative latencies of the cortical components were not related to outcome. CONCLUSIONS While it is well documented that absent SSEPs are highly predictive of poor outcome, the current data indicate that the relative preservation (absolute amplitude) of "present" N20 and N35 SSEP components can also provide predictive value and thereby inform clinicians and families with decision-making in coma. Further prospective study will elucidate the relative contributions of etiology to the predictive power of these SSEP measures.
Collapse
Affiliation(s)
- Damian Cruse
- Brain and Mind Institute, Western University, Natural Sciences Centre Room 237, London, ON, N6A 5B7, Canada,
| | | | | | | | | |
Collapse
|
29
|
Lutkenhoff ES, Chiang J, Tshibanda L, Kamau E, Kirsch M, Pickard JD, Laureys S, Owen AM, Monti MM. Thalamic and extrathalamic mechanisms of consciousness after severe brain injury. Ann Neurol 2015; 78:68-76. [PMID: 25893530 DOI: 10.1002/ana.24423] [Citation(s) in RCA: 95] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2014] [Revised: 04/03/2015] [Accepted: 04/07/2015] [Indexed: 01/14/2023]
Abstract
OBJECTIVE What mechanisms underlie the loss and recovery of consciousness after severe brain injury? We sought to establish, in the largest cohort of patients with disorders of consciousness (DOC) to date, the link between gold standard clinical measures of awareness and wakefulness, and specific patterns of local brain pathology-thereby possibly providing a mechanistic framework for patient diagnosis, prognosis, and treatment development. METHODS Structural T1-weighted magnetic resonance images were collected, in a continuous sample of 143 severely brain-injured patients with DOC (and 96 volunteers), across 2 tertiary expert centers. Brain atrophy in subcortical regions (bilateral thalamus, basal ganglia, hippocampus, basal forebrain, and brainstem) was assessed across (1) healthy volunteers and patients, (2) clinical entities (eg, vegetative state, minimally conscious state), (3) clinical measures of consciousness (Coma Recovery Scale-Revised), and (4) injury etiology. RESULTS Compared to volunteers, patients exhibited significant atrophy across all structures (p < 0.05, corrected). Strikingly, we found almost no significant differences across clinical entities. Nonetheless, the clinical measures of awareness and wakefulness upon which differential diagnosis rely were systematically associated with tissue atrophy within thalamic and basal ganglia nuclei, respectively; the basal forebrain was atrophied in proportion to patients' response to sensory stimulation. In addition, nontraumatic injuries exhibited more extensive thalamic atrophy. INTERPRETATION These findings provide, for the first time, a grounding in pathology for gold standard behavior-based clinical measures of consciousness, and reframe our current models of DOC by stressing the different links tying thalamic mechanisms to willful behavior and extrathalamic mechanisms to behavioral (and electrocortical) arousal.
Collapse
Affiliation(s)
- Evan S Lutkenhoff
- Department of Psychology, University of California, Los Angeles, Los Angeles, CA
| | - Jeffrey Chiang
- Department of Psychology, University of California, Los Angeles, Los Angeles, CA
| | - Luaba Tshibanda
- Coma Science Group, Cyclotron Research Center and Neurology Department, University and University Hospital of Liège, Liège, Belgium
| | - Evelyn Kamau
- Division of Neurosurgery, University of Cambridge, Addenbrooke's Hospital, Cambridge, United Kingdom
| | - Murielle Kirsch
- Coma Science Group, Cyclotron Research Center and Neurology Department, University and University Hospital of Liège, Liège, Belgium.,Department of Anesthesia and Intensive Care Medicine, Liège University Hospital, Liège, Belgium
| | - John D Pickard
- Division of Neurosurgery, University of Cambridge, Addenbrooke's Hospital, Cambridge, United Kingdom
| | - Steven Laureys
- Coma Science Group, Cyclotron Research Center and Neurology Department, University and University Hospital of Liège, Liège, Belgium
| | - Adrian M Owen
- Brain and Mind Institute, University of Western Ontario, London, Ontario, Canada
| | - Martin M Monti
- Department of Psychology, University of California, Los Angeles, Los Angeles, CA.,Brain Injury Research Center, Department of Neurosurgery, Geffen School of Medicine at University of California, Los Angeles, Los Angeles, CA
| |
Collapse
|
30
|
Stender J, Kupers R, Rodell A, Thibaut A, Chatelle C, Bruno MA, Gejl M, Bernard C, Hustinx R, Laureys S, Gjedde A. Quantitative rates of brain glucose metabolism distinguish minimally conscious from vegetative state patients. J Cereb Blood Flow Metab 2015; 35:58-65. [PMID: 25294128 PMCID: PMC4294395 DOI: 10.1038/jcbfm.2014.169] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Revised: 08/11/2014] [Accepted: 09/03/2014] [Indexed: 12/20/2022]
Abstract
The differentiation of the vegetative or unresponsive wakefulness syndrome (VS/UWS) from the minimally conscious state (MCS) is an important clinical issue. The cerebral metabolic rate of glucose (CMRglc) declines when consciousness is lost, and may reveal the residual cognitive function of these patients. However, no quantitative comparisons of cerebral glucose metabolism in VS/UWS and MCS have yet been reported. We calculated the regional and whole-brain CMRglc of 41 patients in the states of VS/UWS (n=14), MCS (n=21) or emergence from MCS (EMCS, n=6), and healthy volunteers (n=29). Global cortical CMRglc in VS/UWS and MCS averaged 42% and 55% of normal, respectively. Differences between VS/UWS and MCS were most pronounced in the frontoparietal cortex, at 42% and 60% of normal. In brainstem and thalamus, metabolism declined equally in the two conditions. In EMCS, metabolic rates were indistinguishable from those of MCS. Ordinal logistic regression predicted that patients are likely to emerge into MCS at CMRglc above 45% of normal. Receiver-operating characteristics showed that patients in MCS and VS/UWS can be differentiated with 82% accuracy, based on cortical metabolism. Together these results reveal a significant correlation between whole-brain energy metabolism and level of consciousness, suggesting that quantitative values of CMRglc reveal consciousness in severely brain-injured patients.
Collapse
Affiliation(s)
- Johan Stender
- 1] Department of Neuroscience and Pharmacology, University of Copenhagen, Copenhagen, Denmark [2] Cyclotron Research Centre and Neurology Department, University and University Hospital of Liège, Liège, Belgium
| | - Ron Kupers
- Department of Neuroscience and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Anders Rodell
- 1] Department of Nuclear Medicine and PET Centre, Aarhus University Hospital, Aarhus, Denmark [2] Centre for Advanced Imaging, University of Queensland, Brisbane, Australia
| | - Aurore Thibaut
- Cyclotron Research Centre and Neurology Department, University and University Hospital of Liège, Liège, Belgium
| | - Camille Chatelle
- Department of Physical Medicine and Rehabilitation, Spaulding Rehabilitation Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Marie-Aurélie Bruno
- Cyclotron Research Centre and Neurology Department, University and University Hospital of Liège, Liège, Belgium
| | - Michael Gejl
- 1] Centre for Advanced Imaging, University of Queensland, Brisbane, Australia [2] Department of Biomedicine-Pharmacology, Aarhus University, Aarhus, Denmark
| | - Claire Bernard
- Department of Nuclear Medicine, University Hospital of Liège, Liège, Belgium
| | - Roland Hustinx
- Department of Nuclear Medicine, University Hospital of Liège, Liège, Belgium
| | - Steven Laureys
- Cyclotron Research Centre and Neurology Department, University and University Hospital of Liège, Liège, Belgium
| | - Albert Gjedde
- 1] Department of Neuroscience and Pharmacology, University of Copenhagen, Copenhagen, Denmark [2] Department of Neurology, McGill University, Montréal, Québec, Canada [3] Department of Radiology and Radiological Science, Johns Hopkins Medical Institutions, Baltimore, Maryland, USA
| |
Collapse
|
31
|
Matsumoto M, Sugama J, Nemoto T, Kurita T, Matsuo J, Dai M, Ueta M, Okuwa M, Nakatani T, Tabata K, Sanada H. The Nature of Sleep in 10 Bedridden Elderly Patients With Disorders of Consciousness in a Japanese Hospital. Biol Res Nurs 2014; 17:13-20. [DOI: 10.1177/1099800414523118] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
No previous study has satisfactorily clarified the nature of sleep in elderly bedridden people with disorders of consciousness (DOC). The objective of the present study was to clarify the sleep states of 10 elderly bedridden patients with DOC in a Japanese hospital to facilitate provision of evidence-based nursing care and appropriate adjustment of patients’ environments. Nocturnal polysomnography recordings were analyzed according to the standard scoring criteria, and the patients’ sleep stages and quality were investigated. Of the 10 patients, 9 showed slow wave sleep (SWS), 4 showed very high values for sleep efficiency (96–100%), and in 3 of these patients, the percentage of SWS was ≥ 20%. Furthermore, three of these four patients had 200 or more changes in sleep stage. Although the mechanism is unknown, the amount of SWS combined with the value of sleep efficiency suggests that the quality of sleep is poor in elderly bedridden patients with DOC. Further study is needed to determine better indicators of good sleep in this population.
Collapse
Affiliation(s)
- Masaru Matsumoto
- Department of Clinical Nursing, Division of Health Science, Graduate School of Medicine, Kanazawa University, Ishikawa, Japan
| | - Junko Sugama
- School of Health Sciences, College of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Ishikawa, Japan
- Wellness Promotion Science Center, College of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Ishikawa, Japan
| | - Tetsu Nemoto
- School of Health Sciences, College of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Ishikawa, Japan
| | | | - Junko Matsuo
- Faculty of Nursing, Osaka Medicine College, Osaka, Japan
| | - Misako Dai
- School of Health Sciences, College of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Ishikawa, Japan
| | - Miyuki Ueta
- Kobe City Medical Center General Hospital, Hyogo, Japan
| | - Mayumi Okuwa
- School of Health Sciences, College of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Ishikawa, Japan
| | - Toshio Nakatani
- School of Health Sciences, College of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Ishikawa, Japan
| | | | - Hiromi Sanada
- Department of Gerontological Nursing/Wound Care Management, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| |
Collapse
|
32
|
Lutkenhoff ES, McArthur DL, Hua X, Thompson PM, Vespa PM, Monti MM. Thalamic atrophy in antero-medial and dorsal nuclei correlates with six-month outcome after severe brain injury. NEUROIMAGE-CLINICAL 2013; 3:396-404. [PMID: 24273723 PMCID: PMC3815017 DOI: 10.1016/j.nicl.2013.09.010] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Revised: 09/26/2013] [Accepted: 09/27/2013] [Indexed: 11/25/2022]
Abstract
The primary and secondary damage to neural tissue inflicted by traumatic brain injury is a leading cause of death and disability. The secondary processes, in particular, are of great clinical interest because of their potential susceptibility to intervention. We address the dynamics of tissue degeneration in cortico-subcortical circuits after severe brain injury by assessing volume change in individual thalamic nuclei over the first six-months post-injury in a sample of 25 moderate to severe traumatic brain injury patients. Using tensor-based morphometry, we observed significant localized thalamic atrophy over the six-month period in antero-dorsal limbic nuclei as well as in medio-dorsal association nuclei. Importantly, the degree of atrophy in these nuclei was predictive, even after controlling for full-brain volume change, of behavioral outcome at six-months post-injury. Furthermore, employing a data-driven decision tree model, we found that physiological measures, namely the extent of atrophy in the anterior thalamic nucleus, were the most predictive variables of whether patients had regained consciousness by six-months, followed by behavioral measures. Overall, these findings suggest that the secondary non-mechanical degenerative processes triggered by severe brain injury are still ongoing after the first week post-trauma and target specifically antero-medial and dorsal thalamic nuclei. This result therefore offers a potential window of intervention, and a specific target region, in agreement with the view that specific cortico-thalamo-cortical circuits are crucial to the maintenance of large-scale network neural activity and thereby the restoration of cognitive function after severe brain injury. Performed acute and chronic structural MRI in 25 severe TBI patients Tensor brain morphometry (TBM) shows localized thalamic acute-to-chronic atrophy. Anterior, medio- and lateral-dorsal nuclei are the most significant. Atrophy in these nuclei predicts 6-month outcome scores (GOSe).
Collapse
Affiliation(s)
- Evan S Lutkenhoff
- Department of Psychology, University of California Los Angeles, Los Angeles, CA 90095, USA
| | | | | | | | | | | |
Collapse
|
33
|
León-Domínguez U, Vela-Bueno A, Froufé-Torres M, León-Carrión J. A chronometric functional sub-network in the thalamo-cortical system regulates the flow of neural information necessary for conscious cognitive processes. Neuropsychologia 2013; 51:1336-49. [DOI: 10.1016/j.neuropsychologia.2013.03.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2012] [Revised: 03/13/2013] [Accepted: 03/21/2013] [Indexed: 01/28/2023]
|
34
|
Shi C, Flanagan SR, Samadani U. Vagus nerve stimulation to augment recovery from severe traumatic brain injury impeding consciousness: a prospective pilot clinical trial. Neurol Res 2013; 35:263-76. [PMID: 23485054 PMCID: PMC4568744 DOI: 10.1179/1743132813y.0000000167] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
OBJECTIVES Traumatic brain injury (TBI) has high morbidity and mortality in both civilian and military populations. Blast and other mechanisms of TBI damage the brain by causing neurons to disconnect and atrophy. Such traumatic axonal injury can lead to persistent vegetative and minimally conscious states (VS and MCS), for which limited treatment options exist, including physical, occupational, speech, and cognitive therapies. More than 60 000 patients have received vagus nerve stimulation (VNS) for epilepsy and depression. In addition to decreased seizure frequency and severity, patients report enhanced mood, reduced daytime sleepiness independent of seizure control, increased slow wave sleep, and improved cognition, memory, and quality of life. Early stimulation of the vagus nerve accelerates the rate and extent of behavioral and cognitive recovery after fluid percussion brain injury in rats. METHODS We recently obtained Food and Drug Administration (FDA) approval for a pilot prospective randomized crossover trial to demonstrate objective improvement in clinical outcome by placement of a vagus nerve stimulator in patients who are recovering from severe TBI. Our hypothesis is that stimulation of the vagus nerve results in increased cerebral blood flow and metabolism in the forebrain, thalamus, and reticular formation, which promotes arousal and improved consciousness, thereby improving outcome after TBI resulting in MCS or VS. DISCUSSION If this study demonstrates that VNS can safely and positively impact outcome, then a larger randomized prospective crossover trial will be proposed.
Collapse
Affiliation(s)
- Chen Shi
- Department of Neurosurgery, New York University School of Medicine and NYU Langone Medical Center, 550 First Ave. New York, NY 10016
| | - Steven R. Flanagan
- Department of Rehabilitation Medicine, New York University School of Medicine and NYU Langone Medical Center, 240 E. 38 St. New York, NY 10016
| | - Uzma Samadani
- Department of Neurosurgery, New York University School of Medicine and NYU Langone Medical Center, 550 First Ave. New York, NY 10016
- Division of Neurosurgery, New York Harbor Healthcare System Manhattan Veterans Hospital, 423 E. 23 St. New York, NY 10010
| |
Collapse
|
35
|
Cologan V, Drouot X, Parapatics S, Delorme A, Gruber G, Moonen G, Laureys S. Sleep in the unresponsive wakefulness syndrome and minimally conscious state. J Neurotrauma 2013; 30:339-46. [PMID: 23121471 DOI: 10.1089/neu.2012.2654] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The goal of our study was to investigate different aspects of sleep, namely the sleep-wake cycle and sleep stages, in the vegetative state/unresponsive wakefulness syndrome (VS/UWS), and minimally conscious state (MCS). A 24-h polysomnography was performed in 20 patients who were in a UWS (n=10) or in a MCS (n=10) because of brain injury. The data were first tested for the presence of a sleep-wake cycle, and the observed sleep patterns were compared with standard scoring criteria. Sleep spindles, slow wave sleep, and rapid eye movement sleep were quantified and their clinical value was investigated. According to our results, an electrophysiological sleep-wake cycle was identified in five MCS and three VS/UWS patients. Sleep stages did not always match the standard scoring criteria, which therefore needed to be adapted. Sleep spindles were present more in patients who clinically improved within 6 months. Slow wave sleep was present in eight MCS and three VS/UWS patients but never in the ischemic etiology. Rapid eye movement sleep, and therefore dreaming that is a form of consciousness, was present in all MCS and three VS/UWS patients. In conclusion, the presence of alternating periods of eyes-open/eyes-closed cycles does not necessarily imply preserved electrophysiological sleep architecture in the UWS and MCS, contrary to previous definition. The investigation of sleep is a little studied yet simple and informative way to evaluate the integrity of residual brain function in patients with disorders of consciousness with possible clinical diagnostic and prognostic implications.
Collapse
Affiliation(s)
- Victor Cologan
- Coma Science Group, Cyclotron Research Center, University of Liège, Belgium.
| | | | | | | | | | | | | |
Collapse
|
36
|
Cruse D, Thibaut A, Demertzi A, Nantes JC, Bruno MA, Gosseries O, Vanhaudenhuyse A, Bekinschtein TA, Owen AM, Laureys S. Actigraphy assessments of circadian sleep-wake cycles in the Vegetative and Minimally Conscious States. BMC Med 2013; 11:18. [PMID: 23347467 PMCID: PMC3606428 DOI: 10.1186/1741-7015-11-18] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2012] [Accepted: 01/24/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The Vegetative and Minimally Conscious States (VS; MCS) are characterized by absent or highly disordered signs of awareness alongside preserved sleep-wake cycles. According to international diagnostic guidelines, sleep-wake cycles are assessed by means of observations of variable periods of eye-opening and eye-closure. However, there is little empirical evidence for true circadian sleep-wake cycling in these patients, and there have been no large-scale investigations of the validity of this diagnostic criterion. METHODS We measured the circadian sleep-wake rhythms of 55 VS and MCS patients by means of wrist actigraphy, an indirect method that is highly correlated with polysomnographic estimates of sleeping/waking. RESULTS Contrary to the diagnostic guidelines, a significant proportion of patients did not exhibit statistically reliable sleep-wake cycles. The circadian rhythms of VS patients were significantly more impaired than those of MCS patients, as were the circadian rhythms of patients with non-traumatic injuries relative to those with traumatic injuries. The reliability of the circadian rhythms were significantly predicted by the patients' levels of visual and motor functioning, consistent with the putative biological generators of these rhythms. CONCLUSIONS The high variability across diagnoses and etiologies highlights the need for improved guidelines for the assessment of sleep-wake cycles in VS and MCS, and advocates the use of actigraphy as an inexpensive and non-invasive alternative.
Collapse
Affiliation(s)
- Damian Cruse
- Brain and Mind Institute, University of Western Ontario, 1151 Richmond Street, London, ON N6A 3K7, Canada.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
37
|
Abstract
In a study by Cruse et al. published in BMC Medicine, patients with severe brain damage who were in the Vegetative or Minimally Conscious States (VS or MCS, respectively) from traumatic and nontraumatic etiologies had assessments of circadian rhythms using an actigraph, a device worn on a limb to evaluate circadian rhythmicity, in this population. This is a novel approach and is being used as a surrogate for polysomnography and other reference standards. Cruse et al. showed more disruption in circadian rhythms in the VS when compared to the MCS. This suggests that more brain injury occurs in the areas that control circadian rhythmicity in VS than in MCS patients. The study provides opportunities for improved prognostication and rehabilitation strategies in this patient population.
Collapse
Affiliation(s)
- Mithu Sen
- Department of Medicine, Division of Critical Care Medicine, Western University, London, Ontario N6A 5A5, Canada
| | | |
Collapse
|
38
|
Fernández-Espejo D, Soddu A, Cruse D, Palacios EM, Junque C, Vanhaudenhuyse A, Rivas E, Newcombe V, Menon DK, Pickard JD, Laureys S, Owen AM. A role for the default mode network in the bases of disorders of consciousness. Ann Neurol 2012; 72:335-43. [PMID: 23034909 DOI: 10.1002/ana.23635] [Citation(s) in RCA: 184] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
OBJECTIVE Functional connectivity in the default mode network (DMN) is known to be reduced in patients with disorders of consciousness, to a different extent depending on their clinical severity. Nevertheless, the integrity of the structural architecture supporting this network and its relation with the exhibited functional disconnections are very poorly understood. We investigated the structural connectivity and white matter integrity of the DMN in patients with disorders of consciousness of varying clinical severity. METHODS Fifty-two patients--19 in a vegetative state (VS), 27 in a minimally conscious state (MCS), and 6 emerging from a minimally conscious state (EMCS)--and 23 healthy volunteers participated in the study. Structural connectivity was assessed by means of probabilistic tractography, and the integrity of the resulting fibers was characterized by their mean fractional anisotropy values. RESULTS Patients showed significant impairments in all of the pathways connecting cortical regions within this network, as well as the pathway connecting the posterior cingulate cortex/precuneus with the thalamus, relative to the healthy volunteers. Moreover, the structural integrity of this pathway, as well as that of those connecting the posterior areas of the network, was correlated with the patients' behavioral signs for awareness, being higher in EMCS patients than those in the upper and lower ranges of the MCS patients, and lowest in VS patients. INTERPRETATION These results provide a possible neural substrate for the functional disconnection previously described in these patients, and reinforce the importance of the DMN in the genesis of awareness and the neural bases of its disorders.
Collapse
|
39
|
García-Panach J, Lull N, Lull JJ, Ferri J, Martínez C, Sopena P, Robles M, Chirivella J, Noé E. A voxel-based analysis of FDG-PET in traumatic brain injury: regional metabolism and relationship between the thalamus and cortical areas. J Neurotrauma 2012; 28:1707-17. [PMID: 21770759 DOI: 10.1089/neu.2011.1851] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The objective was to study the correlations and the differences in glucose metabolism between the thalamus and cortical structures in a sample of severe traumatic brain injury (TBI) patients with different neurological outcomes. We studied 49 patients who had suffered a severe TBI and 10 healthy control subjects using 18F-fluorodeoxyglucose positron emission tomography (18F-FDG-PET). The patients were divided into three groups: a vegetative or minimally-conscious state (MCS&VS) group (n=17), which included patients who were in a vegetative or a minimally conscious state; an In-post-traumatic amnesia (In-PTA) group (n=12), which included patients in PTA; and an Out-PTA group (n=20), which included patients who had recovered from PTA. SPM5 software was used to determine the metabolic differences between the groups. FDG-PET images were normalized and four regions of interest were generated around the thalamus, precuneus, and the frontal and temporal lobes. The groups were parameterized using Student's t-test. Principal component analysis was used to obtain an intensity-estimated-value per subject to correlate the function between the structures. Differences in glucose metabolism in all structures were related to the neurological outcome, and the most severe patients showed the most severe hypometabolism. We also found a significant correlation between the cortico-thalamo-cortical metabolism in all groups. Voxel-based analysis suggests a functional correlation between these four areas, and decreased metabolism was associated with less favorable outcomes. Higher levels of activation of the cortico-cortical connections appear to be related to better neurological condition. Differences in the thalamo-cortical correlations between patients and controls may be related to traumatic dysfunction due to focal or diffuse lesions.
Collapse
Affiliation(s)
- Javier García-Panach
- Grupo de Informática Biomédica, Instituto de Aplicaciones de las Tecnologías de la Información y de las Comunicaciones Avanzadas (ITACA), Universidad Politécnica de Valencia, Valencia, Spain
| | | | | | | | | | | | | | | | | |
Collapse
|
40
|
Abstract
Advances in imaging have made it possible to detect functional and, increasingly, structural changes in Parkinson's disease. Although imaging is not yet routinely used for diagnosis, such an application is becoming increasingly feasible. Of potentially greater interest, however, is the use of imaging as a biomarker to detect premotor disease and disease progression. Imaging also provides insights into complications of Parkinson's disease and its long-term treatment, and the role of dopamine in the normal brain. Furthermore, these techniques can be applied to animal models, to help validate these models and allow their use in the study of potential disease-modifying therapies.
Collapse
Affiliation(s)
- A Jon Stoessl
- Pacific Parkinson's Research Centre, University of British Columbia, Vancouver, BC, Canada.
| | | | | | | |
Collapse
|
41
|
Abstract
PURPOSE OF REVIEW Recent neuroimaging studies have provided novel insights on residual brain function in patients with disorders of consciousness, but also raised a number of ethical issues concerning the clinical management of these patients. RECENT FINDINGS Clinical studies have rated the Coma Recovery Scale as the most appropriate scale to accurately differentiate patients in a vegetative state from patients in a minimally conscious state. At the population level, a number of neuroimaging studies have provided evidence for more preserved brain activity patterns and cerebral tissue integrity in minimally conscious as compared to vegetative-state patients. However, the use of neuroimaging techniques to diagnose consciousness at the single-patient level remains challenging. In particular, it has been shown that whereas command-following functional MRI paradigms may sometimes detect residual awareness in patients that are behaviorally unresponsive, they can also produce negative results in patients that are communicative at the bedside. SUMMARY There is an urgent need of validation of functional MRI active paradigms on larger patient populations before they can be used in clinical routine. Further research on neural correlates of consciousness should hopefully allow using passive paradigms to assess the patients' conscious state without requiring their active collaboration.
Collapse
|
42
|
Assessment of consciousness with electrophysiological and neurological imaging techniques. Curr Opin Crit Care 2011; 17:146-51. [PMID: 21206267 DOI: 10.1097/mcc.0b013e328343476d] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE OF REVIEW Brain MRI (diffusion tensor imaging and spectroscopy) and functional neuroimaging (PET, functional MRI, EEG and evoked potential studies) are changing our understanding of patients with disorders of consciousness encountered after coma such as the 'vegetative' or minimally conscious states. RECENT FINDINGS Increasing evidence from functional neuroimaging and electrophysiology demonstrates some residual cognitive processing in a subgroup of patients who clinically fail to show any response to commands, leading to the recent proposal of 'unresponsive wakefulness syndrome' as an alternative name for patients previously coined 'vegetative' or 'apallic'. SUMMARY Consciousness can be viewed as the emergent property of the collective behavior of widespread thalamocortical frontoparietal network connectivity. Data from physiological, pharmacological and pathological alterations of consciousness provide evidence in favor of this hypothesis. Increasing our understanding of the neural correlates of consciousness is helping clinicians to do a better job in terms of diagnosis, prognosis and finally treatment and drug development for these severely brain-damaged patients. The current challenge remains to continue translating this research from the bench to the bedside. Only well controlled large multicentric neuroimaging and electrophysiology studies will enable to identify which paraclinical diagnostic or prognostic test is necessary for our routine evidence-based assessment of individuals with disorders of consciousness.
Collapse
|
43
|
Cruse D, Monti MM, Owen AM. Neuroimaging in disorders of consciousness: contributions to diagnosis and prognosis. FUTURE NEUROLOGY 2011. [DOI: 10.2217/fnl.10.87] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Conventional assessment of the level of awareness that is retained by a patient with a disorder of consciousness following a brain injury is made on the basis of exhibited behaviors. This is particularly challenging for clinicians who must decide whether a certain behavior, which might be inconsistent or incomplete, reflects a conscious or an unconscious process. These assessments are not only highly subjective, but also dependent upon the ability of the patient to produce an appropriate motor response. Recent developments in neuroimaging techniques can provide a measure of the levels of awareness that these patients may retain, and importantly, they overcome the necessity for these patients to produce detectable movements by instead relying on their adopting appropriate ‘mind-sets’ as instructed by the task. In this article, we review recent advances in this field and discuss how they may accompany behavioral assessments in future in order to provide diagnostic and prognostic information.
Collapse
Affiliation(s)
| | - Martin M Monti
- Medical Research Council, Cognition & Brain Sciences Unit, 15 Chaucer Road, Cambridge, CB2 7EF, UK
| | - Adrian M Owen
- Medical Research Council, Cognition & Brain Sciences Unit, 15 Chaucer Road, Cambridge, CB2 7EF, UK
- Centre for Brain & Mind, Natural Sciences Centre, Room 237, University of Western Ontario, London, ON N6A 5B7, Canada
| |
Collapse
|
44
|
Patenaude B, Smith SM, Kennedy DN, Jenkinson M. A Bayesian model of shape and appearance for subcortical brain segmentation. Neuroimage 2011; 56:907-22. [PMID: 21352927 DOI: 10.1016/j.neuroimage.2011.02.046] [Citation(s) in RCA: 1672] [Impact Index Per Article: 128.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2010] [Revised: 02/13/2011] [Accepted: 02/15/2011] [Indexed: 12/16/2022] Open
Abstract
Automatic segmentation of subcortical structures in human brain MR images is an important but difficult task due to poor and variable intensity contrast. Clear, well-defined intensity features are absent in many places along typical structure boundaries and so extra information is required to achieve successful segmentation. A method is proposed here that uses manually labelled image data to provide anatomical training information. It utilises the principles of the Active Shape and Appearance Models but places them within a Bayesian framework, allowing probabilistic relationships between shape and intensity to be fully exploited. The model is trained for 15 different subcortical structures using 336 manually-labelled T1-weighted MR images. Using the Bayesian approach, conditional probabilities can be calculated easily and efficiently, avoiding technical problems of ill-conditioned covariance matrices, even with weak priors, and eliminating the need for fitting extra empirical scaling parameters, as is required in standard Active Appearance Models. Furthermore, differences in boundary vertex locations provide a direct, purely local measure of geometric change in structure between groups that, unlike voxel-based morphometry, is not dependent on tissue classification methods or arbitrary smoothing. In this paper the fully-automated segmentation method is presented and assessed both quantitatively, using Leave-One-Out testing on the 336 training images, and qualitatively, using an independent clinical dataset involving Alzheimer's disease. Median Dice overlaps between 0.7 and 0.9 are obtained with this method, which is comparable or better than other automated methods. An implementation of this method, called FIRST, is currently distributed with the freely-available FSL package.
Collapse
Affiliation(s)
- Brian Patenaude
- FMRIB Centre, Department of Clinical Neurology, University of Oxford, Oxford, UK
| | | | | | | |
Collapse
|
45
|
Consciousness revealed: new insights into the vegetative and minimally conscious states. Curr Opin Neurol 2010; 23:656-60. [DOI: 10.1097/wco.0b013e32833fd4e7] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|