Functional neuroanatomy underlying the clinical subcategorization of minimally conscious state patients

Bruno, Marie-Aurélie; Majerus, Steve; Boly, Mélanie; Vanhaudenhuyse, Audrey; Schnakers, Caroline; Gosseries, Olivia; Boveroux, Philippe; Kirsch, Muriëlle; Demertzi, Athena; Bernard, Claire; Hustinx, Roland; Moonen, Gustave; Laureys, Steven

doi:10.1007/s00415-011-6303-7

“…Minimally conscious state patients show fluctuating awareness and may respond appropriately to some stimuli [14]. Minimally conscious state was recently subcategorized as MCS plus and MCS minus based on the presence or absence, respectively, of language comprehension [15]. Emergence from MCS is defined as the return of reliable communication or functional use of objects [14].…”

Section: Disorders Of Consciousness and Neural Correlates Of Awarenessmentioning

confidence: 99%

Functional neuroanatomy of disorders of consciousness

Perri

¹

,

Stender

²

,

Laureys

³

et al. 2014

Epilepsy & Behavior

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This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues.Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. Our understanding of the mechanisms of loss and recovery of consciousness, following severe brain injury or during anesthesia, is changing rapidly. Recent neuroimaging studies have shown that patients with chronic disorders of consciousness and subjects undergoing general anesthesia present a complex dysfunctionality in the architecture of brain connectivity. At present, the global hallmark of impaired consciousness appears to be a multifaceted dysfunctional connectivity pattern with both within-network loss of connectivity in a widespread frontoparietal network and between-network hyperconnectivity involving other regions such as the insula and ventral tegmental area. Despite ongoing efforts, the mechanisms underlying the emergence of consciousness after severe brain injury are not thoroughly understood. Important questions remain unanswered: What triggers the connectivity impairment leading to disorders of consciousness? Why do some patients recover from coma, while others with apparently similar brain injuries do not? Understanding these mechanisms could lead to a better comprehension of brain function and, hopefully, lead to new therapeutic strategies in this challenging patient population.This article is part of a Special Issue entitled Epilepsy and Consciousness.

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“…MCS (compared with VS), possibly reflecting recovery of voluntary interaction with the environment. 70 Patients who are considered to be in MCS because they display nonreflexive behaviour but fail to follow commands (a condition newly termed MCS-MINUS) 72,73 have been shown to have metabolic dysfunction in the dominant left-hemispheric language network, 74 possibly related to the presence of aphasia.…”

Section: Pet Imagingmentioning

confidence: 99%

Disorders of consciousness after acquired brain injury: the state of the science

Giacino

¹

,

Fins

²

,

Laureys

³

et al. 2014

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| The concept of consciousness continues to defy definition and elude the grasp of philosophical and scientific efforts to formulate a testable construct that maps to human experience. Severe acquired brain injury results in the dissolution of consciousness, providing a natural model from which key insights about consciousness may be drawn. In the clinical setting, neurologists and neurorehabilitation specialists are called on to discern the level of consciousness in patients who are unable to communicate through word or gesture, and to project outcomes and recommend approaches to treatment. Standards of care are not available to guide clinical decision-making for this population, often leading to inconsistent, inaccurate and inappropriate care. In this Review, we describe the state of the science with regard to clinical management of patients with prolonged disorders of consciousness. We review consciousness-altering pathophysiological mechanisms, specific clinical syndromes, and novel diagnostic and prognostic applications of advanced neuroimaging and electrophysiological procedures. We conclude with a provocative discussion of bioethical and medicolegal issues that are unique to this population and have a profound impact on care, as well as raising questions of broad societal interest.

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“…Voxel-based analyses between brain metabolic scans obtained in awake yet unaware VS/UWS patients compared to healthy controls (between-subject) or comparisons with recovery of awareness (within-subject) have highlighted the critical role of the widespread fronto-temporo-parietal associative cortical network [19 ]. Recently, FDG-PET data indicate that recovery of MCSpatients seems to be accompanied by a right-lateralized recovery of the external awareness network whereas the presence of command following, defining MCS+, classically parallels the recovery of the dominant left-lateralized language network [20]. Similar results have been observed in slow wave sleep and general anesthesia [(for review see 21)].…”

Section: Tracking the Recovery Of Consciousness Networkmentioning

confidence: 99%

Consciousness supporting networks

Demertzi¹,

Soddu²,

Laureys³

2013

Current Opinion in Neurobiology

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This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues.Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. Author's personal copy In most cases authors Consciousness supporting networksAthena Demertzi, Andrea Soddu and Steven LaureysFunctional neuroimaging shows that patients with disorders of consciousness exhibit disrupted system-level functional connectivity. Unresponsive/''vegetative state'' patients preserve wakefulness networks of brainstem and basal forebrain but the cerebral networks accounting for external perceptual awareness and internal self-related mentation are disrupted. Specifically, the 'external awareness' network encompassing lateral fronto-temporo-parietal cortices bilaterally, and the 'internal awareness' network including midline anterior cingulate/mesiofrontal and posterior cingulate/ precuneal cortices, are functionally disconnected. By contrast, patients in minimally conscious state 'minus', who show nonreflex behaviors, are characterized by right-lateralized recovery of the external awareness network. Similarly, patients who evolve to minimally conscious state 'plus' and respond to commands recover the dominant left-lateralized language network. Now, the use of active experimental paradigms targeting at detecting motor-independent signs of awareness or even establishing communication with these patients, challenge these two clinical boundaries. Such advances are naturally accompanied by legitimate neuroscientific and ethical queries demanding our attention on the medical implementations of this new knowledge. What is 'minimally conscious'?At present there is no generally accepted definition of consciousness [1]. As clinicians, we will reduce the complexity of this term and define consciousness operationally, separating two main components: wakefulness and awareness [2]. Wakefulness has been shown to critically depend upon the functional integrity of subcortical arousal systems over 50 years ago [(e.g., see 3)]. The level of wakefulness can be estimated by simple behavioral criteria based on eye opening ranging from absent, over stimulus-induced to spontaneous sustained eye opening.For instance, every night when falling asleep, we experience a decrease of the level of wakefulness up to the point we lose awareness of our environment. Awareness is more difficult to define and more challenging to assess behaviorally [4]. We have recently proposed to reduce the phenomenological complexity of awareness into two further components: external awareness, namely everything we perceive through our senses (what we see, hear, feel, smell and taste), and internal awareness or stimulusindependent thoughts. Interestingly, the switch between the external and internal milieu was found not only to characterize overt...

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Functional neuroanatomy underlying the clinical subcategorization of minimally conscious state patients

Cited by 204 publications

References 41 publications

Functional neuroanatomy of disorders of consciousness

Functional neuroanatomy of disorders of consciousness

Disorders of consciousness after acquired brain injury: the state of the science

Consciousness supporting networks

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