RESUMO
OBJECTIVES: This study aims to describe resting state networks (RSN) in patients with disorders of consciousness (DOC)s after acute severe traumatic brain injury (TBI). METHODS: Adult patients with TBI with a GCS score <8 who remained in a coma, minimally conscious state (MCS), or unresponsive wakefulness syndrome (UWS), between 2017 and 2020 were included. Blood-oxygen-level dependent imaging was performed to compare their RSN with 10 healthy volunteers. RESULTS: Of a total of 293 patients evaluated, only 13 patients were included according to inclusion criteria: 7 in coma (54%), 2 in MCS (15%), and 4 (31%) had an UWS. RSN analysis showed that the default mode network (DMN) was present and symmetric in 6 patients (46%), absent in 1 (8%), and asymmetric in 6 (46%). The executive control network (ECN) was present in all patients but was asymmetric in 3 (23%). The right ECN was absent in 2 patients (15%) and the left ECN in 1 (7%). The medial visual network was present in 11 (85%) patients. Finally, the cerebellar network was symmetric in 8 patients (62%), asymmetric in 1 (8%), and absent in 4 (30%). CONCLUSIONS: A substantial impairment in activation of RSN is demonstrated in patients with DOC after severe TBI in comparison with healthy subjects. Three patterns of activation were found: normal/complete activation, 2) asymmetric activation or partially absent, and 3) absent activation.
Assuntos
Lesões Encefálicas Traumáticas , Transtornos da Consciência , Humanos , Lesões Encefálicas Traumáticas/complicações , Lesões Encefálicas Traumáticas/fisiopatologia , Lesões Encefálicas Traumáticas/diagnóstico por imagem , Masculino , Feminino , Adulto , Pessoa de Meia-Idade , Transtornos da Consciência/fisiopatologia , Transtornos da Consciência/etiologia , Transtornos da Consciência/diagnóstico por imagem , Rede Nervosa/diagnóstico por imagem , Rede Nervosa/fisiopatologia , Imageamento por Ressonância Magnética , Idoso , Adulto Jovem , Descanso/fisiologia , Estado Vegetativo Persistente/fisiopatologia , Estado Vegetativo Persistente/diagnóstico por imagem , Estado Vegetativo Persistente/etiologiaRESUMO
To determine the role of early acquisition of blood oxygen level-dependent (BOLD) signals and diffusion tensor imaging (DTI) for analysis of the connectivity of the ascending arousal network (AAN) in predicting neurological outcomes after acute traumatic brain injury (TBI), cardiopulmonary arrest (CPA), or stroke. A prospective analysis of 50 comatose patients was performed during their ICU stay. Image processing was conducted to assess structural and functional connectivity of the AAN. Outcomes were evaluated after 3 and 6 months. Nineteen patients (38%) had stroke, 18 (36%) CPA, and 13 (26%) TBI. Twenty-three patients were comatose (44%), 11 were in a minimally conscious state (20%), and 16 had unresponsive wakefulness syndrome (32%). Univariate analysis demonstrated that measurements of diffusivity, functional connectivity, and numbers of fibers in the gray matter, white matter, whole brain, midbrain reticular formation, and pontis oralis nucleus may serve as predictive biomarkers of outcome depending on the diagnosis. Multivariate analysis demonstrated a correlation of the predicted value and the real outcome for each separate diagnosis and for all the etiologies together. Findings suggest that the above imaging biomarkers may have a predictive role for the outcome of comatose patients after acute TBI, CPA, or stroke.
Assuntos
Transtornos da Consciência , Vias Neurais , Adulto , Idoso , Nível de Alerta , Biomarcadores , Encéfalo/diagnóstico por imagem , Encéfalo/fisiopatologia , Lesões Encefálicas/fisiopatologia , Lesões Encefálicas Traumáticas/complicações , Lesões Encefálicas Traumáticas/diagnóstico , Coma/diagnóstico por imagem , Coma/etiologia , Coma/fisiopatologia , Estado de Consciência/fisiologia , Transtornos da Consciência/diagnóstico por imagem , Transtornos da Consciência/etiologia , Transtornos da Consciência/fisiopatologia , Imagem de Tensor de Difusão , Feminino , Parada Cardíaca/complicações , Parada Cardíaca/diagnóstico , Humanos , Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Vias Neurais/diagnóstico por imagem , Vias Neurais/fisiopatologia , Saturação de Oxigênio , Prognóstico , Acidente Vascular Cerebral/complicações , Acidente Vascular Cerebral/diagnósticoRESUMO
Recent evidence on resting-state functional magnetic resonance imaging (rs-fMRI) suggests that healthy human brains have a temporal organization represented in a widely complex time-delay structure. This structure seems to underlie brain communication flow, integration/propagation of brain activity, as well as information processing. Therefore, it is probably linked to the emergence of highly coordinated complex brain phenomena, such as consciousness. Nevertheless, possible changes in this structure during an altered state of consciousness remain poorly investigated. In this work, we hypothesized that due to a disruption in high-order functions and alterations of the brain communication flow, patients with disorders of consciousness (DOC) might exhibit changes in their time-delay structure of spontaneous brain activity. We explored this hypothesis by comparing the time-delay projections from fMRI resting-state data acquired in resting state from 48 patients with DOC and 27 healthy controls (HC) subjects. Results suggest that time-delay structure modifies for patients with DOC conditions when compared with HC. Specifically, the average value and the directionality of latency inside the midcingulate cortex (mCC) shift with the level of consciousness. In particular, positive values of latency inside the mCC relate to preserved states of consciousness, whereas negative values change proportionally with the level of consciousness in patients with DOC. These results suggest that the mCC may play a critical role as an integrator of brain activity in HC subjects, but this role vanishes in an altered state of consciousness.
Assuntos
Encéfalo/diagnóstico por imagem , Transtornos da Consciência/diagnóstico por imagem , Estado de Consciência/fisiologia , Imageamento por Ressonância Magnética/métodos , Oxigênio/sangue , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Encéfalo/fisiopatologia , Transtornos da Consciência/fisiopatologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Descanso , Índice de Gravidade de Doença , Fatores de Tempo , Adulto JovemRESUMO
INTRODUCTION: Functional connectivity alterations within individual resting state networks (RSNs) are linked to disorders of consciousness (DOC). If these alterations influence the interaction quality with other RNSs, then, brain alterations in patients with DOC would be characterized by connectivity changes in the large-scale model composed of RSNs. How are functional interactions between RSNs influenced by internal alterations of individual RSNs? Do the functional alterations induced by DOC change some key properties of the large-scale network, which have been suggested to be critical for the consciousness emergence? Here, we use network analysis to measure functional connectivity in patients with DOC and address these questions. We hypothesized that network properties provide descriptions of brain functional reconfiguration associated with consciousness alterations. METHODS: We apply nodal and global network measurements to study the reconfiguration linked with the disease severity. We study changes in integration, segregation, and centrality properties of the functional connectivity between the RSNs in subjects with different levels of consciousness. RESULTS: Our analysis indicates that nodal measurements are more sensitive to disease severity than global measurements, particularly, for functional connectivity of sensory and cognitively related RSNs. CONCLUSION: The network property alterations of functional connectivity in different consciousness levels suggest a whole-brain topological reorganization of the large-scale functional connectivity in patients with DOC.