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BACKGROUND: Patients with brain injury who are unresponsive to commands may perform cognitive tasks that are detected on functional magnetic resonance imaging (fMRI) and electroencephalography (EEG). This phenomenon, known as cognitive motor dissociation, has not been systematically studied in a large cohort of persons with disorders of consciousness. METHODS: In this prospective cohort study conducted at six international centers, we collected clinical, behavioral, and task-based fMRI and EEG data from a convenience sample of 353 adults with disorders of consciousness. We assessed the response to commands on task-based fMRI or EEG in participants without an observable response to verbal commands (i.e., those with a behavioral diagnosis of coma, vegetative state, or minimally conscious state-minus) and in participants with an observable response to verbal commands. The presence or absence of an observable response to commands was assessed with the use of the Coma Recovery Scale-Revised (CRS-R). RESULTS: Data from fMRI only or EEG only were available for 65% of the participants, and data from both fMRI and EEG were available for 35%. The median age of the participants was 37.9 years, the median time between brain injury and assessment with the CRS-R was 7.9 months (25% of the participants were assessed with the CRS-R within 28 days after injury), and brain trauma was an etiologic factor in 50%. We detected cognitive motor dissociation in 60 of the 241 participants (25%) without an observable response to commands, of whom 11 had been assessed with the use of fMRI only, 13 with the use of EEG only, and 36 with the use of both techniques. Cognitive motor dissociation was associated with younger age, longer time since injury, and brain trauma as an etiologic factor. In contrast, responses on task-based fMRI or EEG occurred in 43 of 112 participants (38%) with an observable response to verbal commands. CONCLUSIONS: Approximately one in four participants without an observable response to commands performed a cognitive task on fMRI or EEG as compared with one in three participants with an observable response to commands. (Funded by the James S. McDonnell Foundation and others.).
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Transtornos da Consciência , Eletroencefalografia , Imageamento por Ressonância Magnética , Humanos , Feminino , Masculino , Adulto , Estudos Prospectivos , Pessoa de Meia-Idade , Transtornos da Consciência/etiologia , Transtornos da Consciência/fisiopatologia , Cognição/fisiologia , Encéfalo/diagnóstico por imagem , Encéfalo/fisiopatologia , Lesões Encefálicas/fisiopatologia , Lesões Encefálicas/complicações , Lesões Encefálicas/diagnóstico por imagem , Idoso , Adulto Jovem , Estado Vegetativo Persistente/fisiopatologia , Estado Vegetativo Persistente/etiologiaRESUMO
Neuroimaging studies have suggested an important role for the default mode network (DMN) in disorders of consciousness (DoC). However, the extent to which DMN connectivity can discriminate DoC states-unresponsive wakefulness syndrome (UWS) and minimally conscious state (MCS)-is less evident. Particularly, it is unclear whether effective DMN connectivity, as measured indirectly with dynamic causal modelling (DCM) of resting EEG can disentangle UWS from healthy controls and from patients considered conscious (MCS+). Crucially, this extends to UWS patients with potentially "covert" awareness (minimally conscious star, MCS*) indexed by voluntary brain activity in conjunction with partially preserved frontoparietal metabolism as measured with positron emission tomography (PET+ diagnosis; in contrast to PET- diagnosis with complete frontoparietal hypometabolism). Here, we address this gap by using DCM of EEG data acquired from patients with traumatic brain injury in 11 UWS (6 PET- and 5 PET+) and in 12 MCS+ (11 PET+ and 1 PET-), alongside with 11 healthy controls. We provide evidence for a key difference in left frontoparietal connectivity when contrasting UWS PET- with MCS+ patients and healthy controls. Next, in a leave-one-subject-out cross-validation, we tested the classification performance of the DCM models demonstrating that connectivity between medial prefrontal and left parietal sources reliably discriminates UWS PET- from MCS+ patients and controls. Finally, we illustrate that these models generalize to an unseen dataset: models trained to discriminate UWS PET- from MCS+ and controls, classify MCS* patients as conscious subjects with high posterior probability (pp > .92). These results identify specific alterations in the DMN after severe brain injury and highlight the clinical utility of EEG-based effective connectivity for identifying patients with potential covert awareness.
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Transtornos da Consciência , Estado de Consciência , Eletroencefalografia , Lobo Parietal , Humanos , Masculino , Feminino , Adulto , Eletroencefalografia/métodos , Pessoa de Meia-Idade , Lobo Parietal/fisiopatologia , Lobo Parietal/diagnóstico por imagem , Transtornos da Consciência/fisiopatologia , Transtornos da Consciência/diagnóstico por imagem , Estado de Consciência/fisiologia , Tomografia por Emissão de Pósitrons , Lobo Frontal/diagnóstico por imagem , Lobo Frontal/fisiopatologia , Lesões Encefálicas Traumáticas/fisiopatologia , Lesões Encefálicas Traumáticas/diagnóstico por imagem , Estado Vegetativo Persistente/fisiopatologia , Estado Vegetativo Persistente/diagnóstico por imagem , Estudos de Coortes , Estudos de Casos e Controles , Adulto Jovem , Rede Nervosa/fisiopatologia , Rede Nervosa/diagnóstico por imagemRESUMO
Cognitive motor dissociation (CMD) is characterized by a dissociation between volitional brain responses and motor control, detectable only through techniques such as electroencephalography (EEG) and functional magnetic resonance imaging. Hence, it has recently emerged as a major challenge in the assessment of patients with disorders of consciousness. Specifically, this review focuses on the prognostic implications of CMD detection during the acute stage of brain injury. CMD patients were identified in each diagnostic category (coma, unresponsive wakefulness syndrome/vegetative state, minimally conscious state minus) with a relatively similar prevalence of around 20%. Current knowledge tends to indicate that the diagnosis of CMD in the acute phase often predicts a more favorable clinical outcome compared with other unresponsive non-CMD patients. Nevertheless, the review underscores the limited research in this domain, probably at least partially explained by its nascent nature and the lack of uniformity in the nomenclature for CMD-related disorders, hindering the impact of the literature in the field.
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Transtornos da Consciência , Humanos , Transtornos da Consciência/diagnóstico , Transtornos da Consciência/fisiopatologia , Transtornos Dissociativos/diagnóstico , Transtornos Dissociativos/fisiopatologia , PrognósticoRESUMO
OBJECTIVES: The aim of this study was to systematically review the literature to identify factors that may influence quality of life in people with lower-limb amputation (all etiologies). Our primary focus was on identifying factors that can be modified, enabling a more concentrated integration of these aspects into the care and treatment of amputated patients. DATA SOURCE: Medline (via Ovid) and Scopus were searched in January 2023 for studies assessing quality of life for people with lower-limb loss. Studies were included if they reported on factors that could influence quality of life. Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed. STUDY SELECTION: Studies were identified and assessed independently by 2 reviewers. DATA EXTRACTION: Data were extracted by 2 independent reviewers. DATA SYNTHESIS: After removing duplicates, the search yielded 2616 studies, of which 24 met our inclusion criteria (cross-sectional n = 13; prospective n = 9; retrospective n = 2). The most commonly used quality-of-life instruments were the Short Form 36, followed by the World Health Organization Quality of Life-BREF and the EuroQoL 5 dimension. Younger age, traumatic etiology, unilateral or below-knee amputation, presence of comorbidities, and social integration were found to influence quality of life in people with lower-limb amputation, whereas sex and socioeconomic context do not seem to have a clear influence. CONCLUSIONS: This systematic review of the literature identified several factors that influence quality of life in patients with lower-limb amputation. However, the results are not always consistent across studies and there is still no consensus on some factors. Conclusive findings regarding sex and socioeconomic status remain elusive, primarily because of substantial disparities observed across the literature. Future prospective longitudinal studies with clear a priori inclusion of a wide range of potential factors are needed to clarify the impact of the identified factors. Factors such as age, type of amputation, comorbidities and social integration should be considered in the management of patients with amputation.
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BACKGROUND: In the context of managing persistent post-concussive symptoms (PPCS), existing treatments like pharmacotherapy, cognitive behavioral therapy, and physical rehabilitation show only moderate effectiveness. The emergence of neuromodulation techniques in PPCS management has led to debates regarding optimal stimulation parameters and their overall efficacy. METHODS: this scoping review involved a comprehensive search of PubMed and ScienceDirect databases, focusing on controlled studies examining the therapeutic potential of non-invasive brain stimulation (NIBS) techniques in adults with PPCS. RESULTS: Among the 940 abstracts screened, only five studies, encompassing 103 patients (12 to 29 per study), met the inclusion criteria. These studies assessed the efficacy of transcranial direct current stimulation (tDCS), or repetitive transcranial magnetic stimulation (rTMS), applied to specific brain regions (i.e., the left dorsolateral pre-frontal cortex (DLPFC) or left motor cortex (M1)) for addressing cognitive and psychological symptoms, headaches, and general PPCSs. The results indicated improvements in cognitive functions with tDCS. In contrast, reductions in headache intensity and depression scores were observed with rTMS, while no significant findings were noted for general symptoms with rTMS. CONCLUSION: although these pilot studies suggest promise for rTMS and tDCS in PPCS management, further research with larger-scale investigations and standardized protocols is imperative to enhance treatment outcomes for PPCS patients.
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Following severe brain injuries, a subset of patients may remain in an altered state of consciousness; most of these patients require artificial feeding. Currently, a functional oral phase and the presence of exclusive oral feeding may constitute signs of consciousness. Additionally, the presence of pharyngo-laryngeal secretions, saliva aspiration, cough reflex and tracheostomy are related to the level of consciousness. However, the link between swallowing and consciousness is yet to be fully understood. The primary aim of this review is to establish a comprehensive overview of the relationship between an individual's conscious behaviour and swallowing (reflexive and voluntary). Previous studies of brain activation during volitional and non-volitional swallowing tasks in healthy subjects are also reviewed. We demonstrate that the areas activated by voluntary swallowing tasks (primary sensorimotor, cingulate, insula, premotor, supplementary motor, cerebellum, and operculum) are not specific to deglutitive function but are shared with other motor tasks and brain networks involved in consciousness. This review also outlines suitable assessment and treatment methods for dysphagic patients with disorders of consciousness. Finally, we propose that markers of swallowing could contribute to the development of novel diagnostic guidelines for patients with disorders of consciousness.
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Transtornos de Deglutição , Deglutição , Humanos , Deglutição/fisiologia , Estado de Consciência , Transtornos da Consciência/diagnóstico por imagem , Transtornos da Consciência/terapia , Encéfalo/diagnóstico por imagem , Encéfalo/fisiologia , Transtornos de Deglutição/diagnóstico por imagem , Transtornos de Deglutição/etiologia , NeuroimagemRESUMO
BACKGROUND: Following a severe acquired brain injury, neuro-orthopaedic disorders are commonplace. While these disorders can impact patients' functional recovery and quality of life, little is known regarding the assessment, management and treatment of neuro-orthopaedic disorders in patients with disorders of consciousness (DoC). OBJECTIVE: To describe neuro-orthopaedic disorders in the context of DoC and provide insights on their management and treatment. METHODS: A review of the literature was conducted focusing on neuro-orthopaedic disorders in patients with prolonged DoC. RESULTS: Few studies have investigated the prevalence of spastic paresis in patients with prolonged DoC, which is extremely high, as well as its correlation with pain. Pilot studies exploring the effects of pharmacological treatments and physical therapy show encouraging results yet have limited efficacy. Other neuro-orthopaedic disorders, such as heterotopic ossification, are still poorly investigated. CONCLUSION: The literature of neuro-orthopaedic disorders in patients with prolonged DoC remains scarce, mainly focusing on spastic paresis. We recommend treating neuro-orthopaedic disorders in their early phases to prevent complications such as pain and improve patients' recovery. Additionally, this approach could enhance patients' ability to behaviourally demonstrate signs of consciousness, especially in the context of covert awareness.
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Transtornos da Consciência , Ortopedia , Humanos , Transtornos da Consciência/diagnóstico , Transtornos da Consciência/etiologia , Transtornos da Consciência/terapia , Espasticidade Muscular/diagnóstico , Espasticidade Muscular/etiologia , Espasticidade Muscular/terapia , Qualidade de Vida , Estado de Consciência , Paresia , Dor , Estado Vegetativo Persistente/reabilitaçãoRESUMO
BACKGROUND: Patients with disorders of consciousness who are behaviorally unresponsive may demonstrate volitional brain responses to motor imagery or motor commands detectable on functional magnetic resonance imaging or electroencephalography. This state of cognitive motor dissociation (CMD) may have prognostic significance. METHODS: The Neurocritical Care Society's Curing Coma Campaign identified an international group of experts who convened in a series of monthly online meetings between September 2021 and April 2023 to examine the science of CMD and identify key knowledge gaps and unmet needs. RESULTS: The group identified major knowledge gaps in CMD research: (1) lack of information about patient experiences and caregiver accounts of CMD, (2) limited epidemiological data on CMD, (3) uncertainty about underlying mechanisms of CMD, (4) methodological variability that limits testing of CMD as a biomarker for prognostication and treatment trials, (5) educational gaps for health care personnel about the incidence and potential prognostic relevance of CMD, and (6) challenges related to identification of patients with CMD who may be able to communicate using brain-computer interfaces. CONCLUSIONS: To improve the management of patients with disorders of consciousness, research efforts should address these mechanistic, epidemiological, bioengineering, and educational gaps to enable large-scale implementation of CMD assessment in clinical practice.
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Lesões Encefálicas , Transtornos da Consciência , Humanos , Encéfalo , Estado de Consciência/fisiologia , Imageamento por Ressonância MagnéticaRESUMO
BACKGROUND: Over the past 30 years, there have been significant advances in the understanding of the mechanisms associated with loss and recovery of consciousness following severe brain injury. This work has provided a strong grounding for the development of novel restorative therapeutic interventions. Although all interventions are aimed at modulating and thereby restoring brain function, the landscape of existing interventions encompasses a very wide scope of techniques and protocols. Despite vigorous research efforts, few approaches have been assessed with rigorous, high-quality randomized controlled trials. As a growing number of exploratory interventions emerge, it is paramount to develop standardized approaches to reporting results. The successful evaluation of novel interventions depends on implementation of shared nomenclature and infrastructure. To address this gap, the Neurocritical Care Society's Curing Coma Campaign convened nine working groups and charged them with developing common data elements (CDEs). Here, we report the work of the Therapeutic Interventions Working Group. METHODS: The working group reviewed existing CDEs relevant to therapeutic interventions within the National Institutes of Health National Institute of Neurological Disorders and Stroke database and reviewed the literature for assessing key areas of research in the intervention space. CDEs were then proposed, iteratively discussed and reviewed, classified, and organized in a case report form (CRF). RESULTS: We developed a unified CRF, including CDEs and key design elements (i.e., methodological or protocol parameters), divided into five sections: (1) patient information, (2) general study information, (3) behavioral interventions, (4) pharmacological interventions, and (5) device interventions. CONCLUSIONS: The newly created CRF enhances systematization of future work by proposing a portfolio of measures that should be collected in the development and implementation of studies assessing novel interventions intended to increase the level of consciousness or rate of recovery of consciousness in patients with disorders of consciousness.
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Pesquisa Biomédica , Elementos de Dados Comuns , Humanos , Estado de Consciência , Transtornos da Consciência/diagnóstico , Transtornos da Consciência/terapiaRESUMO
BACKGROUND: The number of patients with disorders of consciousness (DoC) has increased dramatically with the advancement of intensive care and emergency medicine, which brings tremendous economic burdens and even ethical issues to families and society. OBJECTIVE: To evaluate the effectiveness of neuromodulation therapy for patients with DoC. METHODS: First, we conducted a literature review of individual patient data (IPD) on PubMed, EMBASE, and Cochrane-controlled trials following PRISMA guidelines. Then, we collected neuromodulation cases from our institution. Finally, we conducted a pooled analysis using the participants from the medical literature (nâ=â522) and our local institutions (nâ=â22). RESULTS: In this pooled analysis of 544 patients with DoC with a mean age of 46.33 years, our results revealed that patients have improved CRS-R scores [1.0 points (95% CI, 0.57-1.42)] after neuromodulation. Among them, patients have better effectiveness in traumatic than non-traumatic etiology (Pâ<â0.05). The effectiveness of consciousness improvement could be affected by the age, baseline consciousness state, and duration of stimulation. Compared with non-invasive intervention, an invasive intervention can bring more behavioral improvement (Pâ<â0.0001) to MCS rather than UWS/VS patients. Importantly, neuromodulation is a valuable therapy even years after the onset of DoC. CONCLUSION: This pooled analysis spotlights that the application of neuromodulation can improve the behavioral performance of patients with DoC. A preliminary trend is that age, etiology, baseline consciousness state, and stimulation duration could impact its effectiveness.
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Transtornos da Consciência , Estado de Consciência , Estimulação Elétrica Nervosa Transcutânea , Humanos , Pessoa de Meia-Idade , Estado de Consciência/fisiologia , Transtornos da Consciência/terapia , Estimulação Elétrica Nervosa Transcutânea/métodosRESUMO
Background: The mechanism of stroke recovery is related to the reorganization of cerebral activity that can be enhanced by rehabilitation therapy. Two well established treatments are Robot-Assisted Therapy (RT) and Constraint-Induced Movement Therapy (CIMT), however, it is unknown whether there is a difference in the neuroplastic changes induced by these therapies, and if the modifications are related to motor improvement. Therefore, this study aims to identify neurophysiological biomarkers related to motor improvement of participants with chronic stroke that received RT or CIMT, and to test whether there is a difference in neuronal changes induced by these two therapies. Methods: This study included participants with chronic stroke that took part in a pilot experiment to compare CIMT vs. RT. Neurophysiological evaluations were performed with electroencephalography (EEG) and transcranial magnetic stimulation (TMS), pre and post rehabilitation therapy. Motor function was measured by the Wolf Motor Function Test (WMFT) and Fugl-Meyer Assessment Upper Limb (FMA-UL). Results: Twenty-seven participants with chronic stroke completed the present study [mean age of 58.8 years (SD ± 13.6), mean time since stroke of 18.2 months (SD ± 9.6)]. We found that changes in motor threshold (MT) and motor evoked potential (MEP) in the lesioned hemisphere have a positive and negative correlation with WMFT improvement, respectively. The absolute change in alpha peak in the unlesioned hemisphere and the absolute change of the alpha ratio (unlesioned/lesioned hemisphere) is negatively correlated with WMFT improvement. The decrease of EEG power ratio (increase in the lesioned hemisphere and decrease in the unlesioned hemisphere) for high alpha bandwidths is correlated with better improvement in WMFT. The variable "type of treatment (RT or CIMT)" was not significant in the models. Conclusion: Our results suggest that distinct treatments (RT and CIMT) have similar neuroplastic mechanisms of recovery. Moreover, motor improvements in participants with chronic stroke are related to decreases of cortical excitability in the lesioned hemisphere measured with TMS. Furthermore, the balance of both EEG power and EEG alpha peak frequency in the lesioned hemisphere is related to motor improvement.
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Objectives: We describe an atypical delayed neurologic recovery from coma and unresponsive wakefulness syndrome (i.e., persistent vegetative state) in a patient with severe drug-induced toxic leukoencephalopathy (presumably due to synthetic cannabinoid intake). Methods: The patient underwent standardized behavioral and multimodal neuroimaging assessments to monitor clinical evolution and brain function over a 5-month period after presumed intoxication. Results: A progressive clinical recovery was observed, from an initial state of coma to emergence from a minimally conscious state after 2 months. Despite the stability of extensive white matter lesions documented by CT and structural MRI, fluorodeoxyglucose PET showed partial recovery of cortical metabolism after 5 months. Discussion: This case report illustrates that the temporal dynamics of recovery from toxic acute leukoencephalopathy may be atypical and delayed. Multimodal monitoring with repeated behavioral and functional neuroimaging assessments tends to improve the prognosis reliability, while early prognosis based on structural damage may result in misleading statements.
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Severe traumatic brain injury (sTBI) is an important cause of disability and mortality and affects people of all ages. Current scientific evidence indicates that motor dysfunction and cognitive impairment are the main limiting factors in patients with sTBI. Transcranial direct current stimulation (tDCS) seems to be a good therapeutic option, but when it comes to patients with sTBI, the results are inconclusive, and some protocols have not yet been tested. In addition, there is still a lack of information on tDCS-related physiological mechanisms, especially during the acute phase. In the present study, based on current evidence on tDCS mechanisms of action, we hypothesized that performing tDCS sessions in individuals with sTBI, especially in the acute and subacute phases, together with conventional therapy sessions, could improve cognition and motor function in this population. This hypothesis presents a new possibility for treating sTBI, seeking to elucidate the extent to which early tDCS may affect long-term clinical outcomes.
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Background: Improving the functional recovery of patients with DoC remains one of the greatest challenges of the field. Different theories exist about the role of the anterior (prefrontal areas) versus posterior (parietal areas) parts of the brain as hotspots for the recovery of consciousness. Repetitive transcranial magnetic stimulation (rTMS) is a powerful non-invasive brain stimulation technique for the treatment of DoC. However, a direct comparison of the effect of TMS treatment on the front versus the back of the brain has yet to be performed. In this study, we aim to assess the short- and long-term effects of frontal and parietal rTMS on DoC recovery and characterize responders phenotypically. Methods/design: Ninety patients with subacute and prolonged DoC will be included in a two-part multicenter prospective study. In the first phase (randomized controlled trial, RCT), patients will undergo four rTMS sessions in a crossover design over 10 days, targeting (i) the left dorsolateral prefrontal cortex (DLPFC) and (ii) the left angular gyrus (AG), as well as (iii & iv) their sham alternatives. In the second phase (longitudinal personalized trial), patients will receive personalized stimulations for 20 working days targeting the brain area that showed the best results in the RCT and will be randomly assigned to either active or sham intervention. The effects of rTMS on neurobehavioral and neurophysiological functioning in patients with DoC will be evaluated using clinical biomarkers of responsiveness (i.e., the Coma Recovery Scale-Revised; CRS-R), and electrophysiological biomarkers (e.g., power spectra, functional and effective connectivity, perturbational complexity index before and after intervention). Functional long-term outcomes will be assessed at 3 and 6 months post-intervention. Adverse events will be recorded during the treatment phase. Discussion: This study seeks to identify which brain region (front or back) is best to stimulate for the treatment of patients with DoC using rTMS, and to characterize the neural correlates of its action regarding recovery of consciousness and functional outcome. In addition, we will define the responders' profile based on patients' characteristics and functional impairments; and develop biomarkers of responsiveness using EEG analysis according to the clinical responsiveness to the treatment. Clinical Trial Registration: https://clinicaltrials.gov/ct2/show/NCT04401319, Clinicaltrials.gov, n° NCT04401319.
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BACKGROUND AND PURPOSE: Transcranial direct current stimulation (tDCS) has been shown to improve signs of consciousness in a subset of patients with disorders of consciousness (DoC). However, no multicentre study confirmed its efficacy when applied during rehabilitation. In this randomized controlled double-blind study, the effects of tDCS whilst patients were in rehabilitation were tested at the group level and according to their diagnosis and aetiology to better target DoC patients who might repond to tDCS. METHODS: Patients received 2 mA tDCS or sham applied over the left prefrontal cortex for 4 weeks. Behavioural assessments were performed weekly and up to 3 months' follow-up. Analyses were conducted at the group and subgroup levels based on the diagnosis (minimally conscious state [MCS] and unresponsive wakefulness syndrome) and the aetiology (traumatic or non-traumatic). Interim analyses were planned to continue or stop the trial. RESULTS: The trial was stopped for futility when 62 patients from 10 centres were enrolled (44 ± 14 years, 37 ± 24.5 weeks post-injury, 18 women, 32 MCS, 39 non-traumatic). Whilst, at the group level, no treatment effect was found, the subgroup analyses at 3 months' follow-up revealed a significant improvement for patients in MCS and with traumatic aetiology. CONCLUSIONS: Transcranial direct current stimulation during rehabilitation does not seem to enhance patients' recovery. However, diagnosis and aetiology appear to be important factors leading to a response to the treatment. These findings bring novel insights into possible cortical plasticity changes in DoC patients given these differential results according to the subgroups of patients.
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Estimulação Transcraniana por Corrente Contínua , Humanos , Feminino , Estimulação Transcraniana por Corrente Contínua/métodos , Resultado do Tratamento , Transtornos da Consciência/terapia , Transtornos da Consciência/diagnóstico , Córtex Pré-Frontal , Estado Vegetativo Persistente/terapia , Estado Vegetativo Persistente/diagnósticoRESUMO
We assess cerebral integrity with cortical and subcortical FDG-PET and cortical electroencephalography (EEG) within the mesocircuit model framework in patients with disorders of consciousness (DoCs). The mesocircuit hypothesis proposes that subcortical activation facilitates cortical function. We find that the metabolic balance of subcortical mesocircuit areas is informative for diagnosis and is associated with four EEG-based power spectral density patterns, cortical metabolism, and α power in healthy controls and patients with a DoC. Last, regional electrometabolic coupling at the cortical level can be identified in the θ and α ranges, showing positive and negative relations with glucose uptake, respectively. This relation is inverted in patients with a DoC, potentially related to altered orchestration of neural activity, and may underlie suboptimal excitability states in patients with a DoC. By understanding the neurobiological basis of the pathophysiology underlying DoCs, we foresee translational value for diagnosis and treatment of patients with a DoC.
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Estado de Consciência , Tomografia por Emissão de Pósitrons , Humanos , Eletroencefalografia , Transtornos da Consciência/metabolismo , Encéfalo/metabolismoRESUMO
The study of the brain's dynamical activity is opening a window to help the clinical assessment of patients with disorders of consciousness. For example, glucose uptake and the dysfunctional spread of naturalistic and synthetic stimuli has proven useful to characterize hampered consciousness. However, understanding of the mechanisms behind loss of consciousness following brain injury is still missing. Here, we study the propagation of endogenous and in-silico exogenous perturbations in patients with disorders of consciousness, based upon directed and causal interactions estimated from resting-state fMRI data, fitted to a linear model of activity propagation. We found that patients with disorders of consciousness suffer decreased capacity for neural propagation and responsiveness to events, and that this can be related to severe reduction of glucose metabolism as measured with [18 F]FDG-PET. In particular, we show that loss of consciousness is related to the malfunctioning of two neural circuits: the posterior cortical regions failing to convey information, in conjunction with reduced broadcasting of information from subcortical, temporal, parietal and frontal regions. These results shed light on the mechanisms behind disorders of consciousness, triangulating network function with basic measures of brain integrity and behavior.
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Transtornos da Consciência , Estado de Consciência , Humanos , Transtornos da Consciência/diagnóstico por imagem , Encéfalo/diagnóstico por imagem , Mapeamento Encefálico/métodos , Imageamento por Ressonância Magnética/métodos , Fluordesoxiglucose F18 , InconsciênciaRESUMO
The assessment and management of pain and nociception is very challenging in patients unable to communicate functionally such as patients with disorders of consciousness (DoC) or in locked-in syndrome (LIS). In a clinical setting, the detection of signs of pain and nociception by the medical staff is therefore essential for the wellbeing and management of these patients. However, there is still a lot unknown and a lack of clear guidelines regarding the assessment, management and treatment of pain and nociception in these populations. The purpose of this narrative review is to examine the current knowledge regarding this issue by covering different topics such as: the neurophysiology of pain and nociception (in healthy subjects and patients), the source and impact of nociception and pain in DoC and LIS and, finally, the assessment and treatment of pain and nociception in these populations. In this review we will also give possible research directions that could help to improve the management of this specific population of severely brain damaged patients.