Steven Laureys

....

....

..We here review these advances in measurement and the scientific and broader implications of this rapidly progressing field of research...

..However its mode of action remains elusive. Since the long delay to meaningful effect suggests that ONS induces slow neuromodulation, we have searched for changes in central pain-control areas using metabolic neuroimaging...

..This study shows that our active event-related paradigm allowed to identify voluntary brain activity in a patient who would behaviorally be diagnosed as comatose...

..This case shows that old dogmas need to be oppugned, as recovery with meaningful reduction in disability continued in this case for nearly 2 decades after extremely severe traumatic brain injury...

..We discuss the problems of evidence-based neurorehabilitation in disorders of consciousness, and recent functional neuroimaging data obtained in the vegetative state and minimally conscious state...

..Based on these results we discuss what we currently do and do not know about the functional significance of the neural network involved in "automatic" and "conscious" self-referential processing...

..Cognitive potentials showed preserved P300 responses to the patient's own name...

..Here we review current possibilities and limitations of clinical and para-clinical assessment of chronic disorders of consciousness...

..Brain activity is much more complex for words, and different networks can be recruited when phonological, lexical and semantic levels of processing are engaged...

..Neuroimaging techniques remain important tools for clinical research that will extend our understanding of the underlying mechanisms of these disorders...

..We suggest that the results are relevant to clinical practice, to the formulation of scientific questions about the nature of consciousness, and to the reception of scientific theories of consciousness by the general public...

....

..However, this activation of primary cortex seems to be isolated and dissociated from higher-order associative cortices...

..In our opinion, there is an urgent need for a renewed ethical and medicolegal framework for our care of locked-in patients...

..In addition to novel behavioural 'consciousness-scales', the role of para-clinical markers of consciousness, such as event related potentials and functional neuroimaging is reviewed...

..However, this activation is limited to primary cortices and dissociated from higher-order associative cortices, thought to be necessary for conscious perception...

..This syndrome has been coined vegetative state. We here present a new name for this challenging neurological condition: unresponsive wakefulness syndrome (abbreviated UWS)...

..Therefore, better understanding of cerebral noxious processing in these patients is of clinical, therapeutic, and ethical relevance...

..Overall, the results suggest that AD patients use altered pathways to process phonological and lexicosemantic information, possibly related to a progressive loss of specialization of phonological and lexicosemantic neural networks...

..These results emphasize the importance of recurrent corticocortical communication in the maintenance of consciousness and suggest a direct effect of propofol on cortical dynamics...

..e., represents "automatic" subcortical processing) or is a sufficient sign of consciousness and higher order cortical processing...

....

..Moreover, the involvement of a parietal area in the dual task is in keeping with the hypothesis that a parieto-frontal network sustains executive functioning...

..Future studies are needed before using this tool in routine clinical practice, and these should seek to improve automated EEG quantification paradigms in order to reduce the remaining false negative and false positive findings...

..However, in the absence of a generally accepted neural correlate of consciousness as measured by functional neuroimaging, clinical assessment remains the gold standard for the evaluation and management of severely brain damaged patients...

..Classically, communication remains possible by means of spared vertical eye movements and/or blinking. To allow assessing cognitive functions in LIS patients, we propose here a neuropsychological testing based on eye-coded communication...

..This result emphasizes the importance of top-down projections in recurrent processing that involve high-order associative cortices for conscious perception...

..The results of this neuroimaging study are in agreement with cognitive studies demonstrating that executive functioning is characterized by both unity and diversity of processes...

..This study measured brain metabolism in both networks in patients with severe brain damage...

..The minimally conscious state (MCS) is a recently defined clinical condition; it differs from the persistent vegetative state (PVS) by the presence of inconsistent, but clearly discernible, behavioral evidence of consciousness...

..The implementation of these methods in clinical routine could permit to reduce the current high rate of misdiagnosis (40%)...

....

..This suggests a functional reorganization of central cardiovascular regulation during REMS...

..Consequently, this rCBF distribution might preferentially reflect a particular modulation of the cellular processes involved in the generation of cortical delta waves during NREM sleep...

..In particular, we discuss the potential provided by assessment of these slow spontaneous BOLD fluctuations as a novel tool in assessing the cognitive state and chances of recovery from brain pathologies underlying DOCs...

....

..s proposal. Based on the above considerations, we suggest and discuss a revised model for upper limb apraxia that might best account for both brain imaging findings and neuropsychological dissociations reported in the apraxia literature...

..Standard EEG recorded in clinical conditions could be used as a tool to help the clinician in the diagnosis of disorders of consciousness...

..We compared the FOUR and GLS/GCS in intensive care unit patients who were admitted in a comatose state...

..Our goal in this observational study was to map brain regions whose activity is modified by clonidine infusion so as to better understand its loci of action, especially in relation to sedation...

..e., VS or MCS). The NCS constitutes a sensitive clinical tool for assessing nociception in severely brain-injured patients. This scale constitutes the first step to a better management of patients recovering from coma...

..Future prospective studies in a larger patient population are needed in order to evaluate the prognostic value of the presented methodology...

....

..Such studies are disentangling the neural correlates of the vegetative state from the minimally conscious state, and have major clinical consequences in addition to empirical importance for the understanding of consciousness...

..Resting-state functional magnetic resonance imaging allows investigating whole-brain connectivity changes during pharmacological modulation of the level of consciousness...

....

....

..To determine if brain-computer interfaces (BCIs) could serve as supportive tools for detecting consciousness in patients with disorders of consciousness by detecting response to command and communication...

..We place these findings in light of recent findings on the architecture of spontaneous BOLD fluctuations in the awake human brain, and discuss the possible origins of the observed baseline brain activity fluctuations...

..In coma-survivors, cognitive potentials are more frequently obtained when using stimuli that are more ecologic or have an emotional content (such as the patient's own name) than when using classical sine tones...

..These findings raise important ethical considerations in terms of quality of life and end-of-life decisions in such challenging cases...

..They stress the important role played by parietal and frontal areas in the generation of consciousness...

..We will also discuss the relevance of the study of the level versus the contents of consciousness in this context...

..We here aimed to identify the DMN in the challenging patient population of disorders of consciousness encountered following coma...

..This review will focus on the interest of comatose patients MRI multimodal assessment with MRS and DTI. It will emphasize the advantages and pitfalls of these techniques in particular in predicting the coma survivors' outcome...

..Therefore, RVM classification of cerebral metabolic images obtained in coma survivors could become a useful tool for the automated PET-based diagnosis of altered states of consciousness...

..We welcome the opportunity to provide more details about our methods and results and to resolve their concerns. We substantiate our interpretation of the results and provide a point-by-point response to the issues raised...

..The combined use of behavioral and neuroimaging assessment techniques appears to be particularly promising for disentangling impaired consciousness and aphasia...

..Results indicate that the human brain has already extensively processed recent memories during the first hours of post-training wakefulness, even when simultaneously coping with unrelated cognitive demands...

..It is suggested that the VMPFC is crucial for representing knowledge pertaining to the self and that this is an important function of the resting state...

..Activity in the hypothalamus decreased in proportion to previous illumination. These findings have important implications for understanding the effects of light on human behavior...

....

..Such modifications in brain connectivity, possibly driven by sleep ultraslow oscillations, could hinder the brain's ability to integrate information and account for decreased consciousness during NREM sleep...

....

..Pain monitoring in these patients is hence of medical and ethical importance. In this article, we will focus on the possible use of behavioral scales for the assessment and detection of pain in noncommunicative patients...

..The clinical application of these functional neuroimaging techniques awaits validation from ongoing multi-centric cohort studies in these challenging patients with chronic disorders of consciousness...

..At the present time the interactions of sleep and consciousness in brain-injured patients are a little studied subject but, the authors suggest, a potentially very interesting field of research...

..Our data provide the first experimental evidence for a link between behavioral performance and cerebral reactivation during REM sleep...

..In this study, we compared consensus-based diagnoses of VS and MCS to those based on a well-established standardized neurobehavioral rating scale, the JFK Coma Recovery Scale-Revised (CRS-R)...

....

..e., medical management and rehabilitation) but also from a scientific-theoretical perspective (i.e., the brain's plastic abilities and the pursuit of the neural correlate of consciousness)...

..The latter is known to occur in drug dependence and could predispose subgroups of migraineurs to recurrent analgesic overuse...

....

..The optimization of this visuo-motor network during sleep could explain the gain in performance observed during the following day...

..Thus, although mainly derived from frontal EEG, BIS could represent a wider index of cerebral activity...

..We argue that the emotional value or the high familiarity of one's own face may explain its attention-grabbing property...

..g., the temporoparietal junction). We hypothesize that these patients are impaired in the ability to see themselves with a third-person perspective (i.e., being able to see themselves as other people see them)...

..To describe recent studies exploring brain function under the influence of hypnotic anesthetic agents, and their implications on the understanding of consciousness physiology and anesthesia-induced alteration of consciousness...

..In this commentary, we illustrate the relationship between oriented eye movements, consciousness, and emotion by using the case of severely brain-injured patients recovering from coma (i.e., vegetative and minimally conscious patients)...

..These data suggest that impaired verbal STM at late outcome of LKS might indeed be related to a persistent decrease of activity in those posterior superior temporal gyri that were involved in the epileptic focus during the active phase...

..All these aspects are reviewed in this paper, at the light of the most recent literature...

..In this study, we explored a new active evoked-related potentials paradigm as an alternative method for the detection of voluntary brain activity...

....

..Future studies are needed to give a full characterization of default network connectivity in the VS patients population...

..In early stages of CBD, FDOPA and FDG PET patterns differed from those observed in PD. In CBD the asymmetry in FDOPA uptake was less pronounced than that of clinical signs or metabolic impairment...

..These results suggest that baseline brain-activity fluctuations may profoundly modify our conscious perception of the external world...

..In this study, we used positron emission tomography in 11 healthy volunteers to identify the brain areas in which hypnosis modulates cerebral responses to a noxious stimulus...

..Science 313, 1402] strongly suggest that this paradigm may provide a method for assessing the presence of volitional brain activity, and thus of consciousness, in non-communicative brain-injured patients...

..These results support the hypothesis that memory traces are processed during REM sleep in humans...

..These changes do not involve isolated brain areas but entire macroscopic cerebral networks. These data suggest a role for sleep in the processing of recent memory traces...

....

..This includes chemistry, radiochemistry, animal data (rats, cats, and monkeys) with autoradiography and PET, human data with PET, toxicity, and metabolism...

....

....

..To investigate the neural and cognitive bases of upper limb apraxia in corticobasal degeneration (CBD)...

..The interest in the presence of PGO waves in humans is outstanding because the cellular processes involved in, or triggered by, PGO waves might favor brain plasticity during PS...