Brain function in coma, vegetative state, and related disorders

Laureys, Steven; Owen, Adrian M.; Schiff, Nicholas D.

doi:10.1016/s1474-4422(04)00852-x

Cited by 894 publications

(667 citation statements)

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“…In the past 15 years, functional neuroimaging [e.g., positron emission tomography and functional MRI (fMRI)] and cognitive evoked potential studies have offered the possibility to measure directly and non-invasively severely brain damaged patients' brain activity at rest and during external activation (for review, see [58]). More recently, however, these techniques have been developed aiming to detect neural (motor-independent) command following.…”

Section: Para-clinical Neuroimaging Assessment Independent Of Motor Rmentioning

confidence: 99%

From unresponsive wakefulness to minimally conscious PLUS and functional locked-in syndromes: recent advances in our understanding of disorders of consciousness

et al. 2011

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Functional neuroimaging and electrophysiology studies are changing our understanding of patients with coma and related states. Some severely brain damaged patients may show residual cortical processing in the absence of behavioural signs of consciousness. Given these new findings, the diagnostic errors and their potential effects on treatment as well as concerns regarding the negative associations intrinsic to the term vegetative state, the European Task Force on Disorders of Consciousness has recently proposed the more neutral and descriptive term unresponsive wakefulness syndrome. When vegetative/unresponsive patients show minimal signs of consciousness but are unable to reliably communicate the term minimally responsive or minimally conscious state (MCS) is used. MCS was recently subcategorized based on the complexity of patients' behaviours: MCS? describes highlevel behavioural responses (i.e., command following, intelligible verbalizations or non-functional communication) and MCS-describes low-level behavioural responses (i.e., visual pursuit, localization of noxious stimulation or contingent behaviour such as appropriate smiling or crying to emotional stimuli). Finally, patients who show nonbehavioural evidence of consciousness or communication only measurable via para-clinical testing (i.e., functional MRI, positron emission tomography, EEG or evoked potentials) can be considered to be in a functional locked-in syndrome. An improved assessment of brain function in coma and related states is not only changing nosology and medical care but also offers a better-documented diagnosis and prognosis and helps to further identify the neural correlates of human consciousness.

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Section: Para-clinical Neuroimaging Assessment Independent Of Motor Rmentioning

confidence: 99%

From unresponsive wakefulness to minimally conscious PLUS and functional locked-in syndromes: recent advances in our understanding of disorders of consciousness

et al. 2011

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“…FDG-PET studies have demonstrated that when patients recover from coma to VS/UWS, they recover the wakefulness network (encompassing brainstem and basal forebrain) which explains the restoration of sustained spontaneous or stimulus-induced eye opening and of autonomic functions including spontaneous breathing [18]. However, recovery from VS/UWS does not coincide with near-normal metabolic activity in overall brain function.…”

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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“…Posterior cingulate and adjacent precuneal cortices were reported to show most impaired metabolism in UWS/VS (Laureys et al, 1999) and seem to differentiate MCS from UWS/VS patients (Laureys et al, 2004). More recently, a study on patients in the chronic stage of traumatic diffuse brain injury confirmed this bilateral frontoparietal hypometabolism and showed that these regions were more dysfunctional in UWS/VS than MCS patients (Nakayama et al, 2006).…”

Section: Discussionmentioning

confidence: 93%

Multimodal neuroimaging in patients with disorders of consciousness showing “functional hemispherectomy”

Bruno

Fernández‐Espejo

Léhembre

et al. 2011

Progress in Brain Research

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Beside behavioral assessment of patients with disorders of consciousness, neuroimaging modalities may offer objective paraclinical markers important for diagnosis and prognosis. They provide information on the structural location and extent of brain lesions (e.g., morphometric MRI and diffusion tensor imaging (DTI-MRI) assessing structural connectivity) but also their functional impact (e.g., metabolic FDG-PET, hemodynamic fMRI, and EEG measurements obtained in "resting state" conditions). We here illustrate the role of multimodal imaging in severe brain injury, presenting a patient in unresponsive wakefulness syndrome (UWS; i.e., vegetative state, VS) and in a "fluctuating" minimally conscious state (MCS). In both cases, resting state FDG-PET, fMRI, and EEG showed a functionally preserved right hemisphere, while DTI showed underlying differences in structural connectivity highlighting the complementarities of these neuroimaging methods in the study of disorders of consciousness.

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Brain function in coma, vegetative state, and related disorders

Cited by 894 publications

References 98 publications

From unresponsive wakefulness to minimally conscious PLUS and functional locked-in syndromes: recent advances in our understanding of disorders of consciousness

From unresponsive wakefulness to minimally conscious PLUS and functional locked-in syndromes: recent advances in our understanding of disorders of consciousness

Consciousness supporting networks

Multimodal neuroimaging in patients with disorders of consciousness showing “functional hemispherectomy”

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