Pain and non-pain processing during hypnosis: a thulium-YAG event-related fMRI study.
Vanhaudenhuyse, Audrey ; Boly, Mélanie ; Balteau, Evelyne et al
in NeuroImage (2009), 47(3), 1047-54
The neural mechanisms underlying the antinociceptive effects of hypnosis still remain unclear. Using a parametric single-trial thulium-YAG laser fMRI paradigm, we assessed changes in brain activation and ... [more ▼]
The neural mechanisms underlying the antinociceptive effects of hypnosis still remain unclear. Using a parametric single-trial thulium-YAG laser fMRI paradigm, we assessed changes in brain activation and connectivity related to the hypnotic state as compared to normal wakefulness in 13 healthy volunteers. Behaviorally, a difference in subjective ratings was found between normal wakefulness and hypnotic state for both non-painful and painful intensity-matched stimuli applied to the left hand. In normal wakefulness, non-painful range stimuli activated brainstem, contralateral primary somatosensory (S1) and bilateral insular cortices. Painful stimuli activated additional areas encompassing thalamus, bilateral striatum, anterior cingulate (ACC), premotor and dorsolateral prefrontal cortices. In hypnosis, intensity-matched stimuli in both the non-painful and painful range failed to elicit any cerebral activation. The interaction analysis identified that contralateral thalamus, bilateral striatum and ACC activated more in normal wakefulness compared to hypnosis during painful versus non-painful stimulation. Finally, we demonstrated hypnosis-related increases in functional connectivity between S1 and distant anterior insular and prefrontal cortices, possibly reflecting top-down modulation. [less ▲]Detailed reference viewed: 123 (28 ULg)
Detecting consciousness in a total Locked-in syndrome: an active event related paradigm
Schnakers, Caroline ; ; et al
in Neurocase : Case Studies in Neuropsychology, Neuropsychiatry & Behavioural Neurology (2009), 25
Total locked-in syndrome is characterized by tetraplegia, anarthria and paralysis of eye motility. In this study, consciousness was detected in a 21-year-old woman who presented a total locked-in syndrome ... [more ▼]
Total locked-in syndrome is characterized by tetraplegia, anarthria and paralysis of eye motility. In this study, consciousness was detected in a 21-year-old woman who presented a total locked-in syndrome after a basilar artery thrombosis (49 days post-injury) using an active event-related paradigm. The patient was presented sequences of names containing the patient's own name and other names. The patient was instructed to count her own name or to count another target name. Similar to 4 age- and gender-matched healthy controls, the P3 response recorded for the voluntarily counted own name was larger than while passively listening. This P3 response was observed 14 days before the first behavioral signs of consciousness. 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. [less ▲]Detailed reference viewed: 68 (9 ULg)
Functional connectivity in the default network during resting state is preserved in a vegetative but not in a brain dead patient.
Boly, Mélanie ; Tshibanda, Luaba ; Vanhaudenhuyse, Audrey et al
in Human Brain Mapping (2009), 30(8), 2393-400
Recent studies on spontaneous fluctuations in the functional MRI blood oxygen level-dependent (BOLD) signal in awake healthy subjects showed the presence of coherent fluctuations among functionally ... [more ▼]
Recent studies on spontaneous fluctuations in the functional MRI blood oxygen level-dependent (BOLD) signal in awake healthy subjects showed the presence of coherent fluctuations among functionally defined neuroanatomical networks. However, the functional significance of these spontaneous BOLD fluctuations remains poorly understood. By means of 3 T functional MRI, we demonstrate absent cortico-thalamic BOLD functional connectivity (i.e. between posterior cingulate/precuneal cortex and medial thalamus), but preserved cortico-cortical connectivity within the default network in a case of vegetative state (VS) studied 2.5 years following cardio-respiratory arrest, as documented by extensive behavioral and paraclinical assessments. In the VS patient, as in age-matched controls, anticorrelations could also be observed between posterior cingulate/precuneus and a previously identified task-positive cortical network. Both correlations and anticorrelations were significantly reduced in VS as compared to controls. A similar approach in a brain dead patient did not show any such long-distance functional connectivity. We conclude that some slow coherent BOLD fluctuations previously identified in healthy awake human brain can be found in alive but unaware patients, and are thus unlikely to be uniquely due to ongoing modifications of conscious thoughts. Future studies are needed to give a full characterization of default network connectivity in the VS patients population. [less ▲]Detailed reference viewed: 82 (20 ULg)
Different beliefs about pain perception in the vegetative and minimally conscious states: a European survey of medical and paramedical professionals.
Demertzi, Athina ; Schnakers, Caroline ; Ledoux, Didier et al
in Progress in Brain Research (2009), 177
Pain management in severely brain-damaged patients constitutes a clinical and ethical stake. At the bedside, assessing the presence of pain and suffering is challenging due to both patients' physical ... [more ▼]
Pain management in severely brain-damaged patients constitutes a clinical and ethical stake. At the bedside, assessing the presence of pain and suffering is challenging due to both patients' physical condition and inherent limitations of clinical assessment. Neuroimaging studies support the existence of distinct cerebral responses to noxious stimulation in brain death, vegetative state, and minimally conscious state. We here provide results from a European survey on 2059 medical and paramedical professionals' beliefs on possible pain perception in patients with disorders of consciousness. To the question "Do you think that patients in a vegetative state can feel pain?," 68% of the interviewed paramedical caregivers (n=538) and 56% of medical doctors (n=1166) answered "yes" (no data on exact profession in 17% of total sample). Logistic regression analysis showed that paramedical professionals, religious caregivers, and older caregivers reported more often that vegetative patients may experience pain. Following professional background, religion was the highest predictor of caregivers' opinion: 64% of religious (n=1009; 850 Christians) versus 52% of nonreligious respondents (n=830) answered positively (missing data on religion in 11% of total sample). To the question "Do you think that patients in a minimally conscious state can feel pain?" nearly all interviewed caregivers answered "yes" (96% of the medical doctors and 97% of the paramedical caregivers). Women and religious caregivers reported more often that minimally conscious patients may experience pain. These results are discussed in terms of existing definitions of pain and suffering, the remaining uncertainty on the clinical assessment of pain as a subjective first-person experience and recent functional neuroimaging findings on nociceptive processing in disorders of consciousness. In our view, more research is needed to increase our understanding of residual sensation in vegetative and minimally conscious patients and to propose evidence-based medical guidelines for the management of possible pain perception and suffering in these vulnerable patient populations. [less ▲]Detailed reference viewed: 42 (11 ULg)
Diagnostic accuracy of the vegetative and minimally conscious state: clinical consensus versus standardized neurobehavioral assessment.
Schnakers, Caroline ; Vanhaudenhuyse, Audrey ; et al
in BMC Neurology (2009), 9
BACKGROUND: Previously published studies have reported that up to 43% of patients with disorders of consciousness are erroneously assigned a diagnosis of vegetative state (VS). However, no recent studies ... [more ▼]
BACKGROUND: Previously published studies have reported that up to 43% of patients with disorders of consciousness are erroneously assigned a diagnosis of vegetative state (VS). However, no recent studies have investigated the accuracy of this grave clinical diagnosis. 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). METHODS: We prospectively followed 103 patients (55 +/- 19 years) with mixed etiologies and compared the clinical consensus diagnosis provided by the physician on the basis of the medical staff's daily observations to diagnoses derived from CRS-R assessments performed by research staff. All patients were assigned a diagnosis of 'VS', 'MCS' or 'uncertain diagnosis.' RESULTS: Of the 44 patients diagnosed with VS based on the clinical consensus of the medical team, 18 (41%) were found to be in MCS following standardized assessment with the CRS-R. In the 41 patients with a consensus diagnosis of MCS, 4 (10%) had emerged from MCS, according to the CRS-R. We also found that the majority of patients assigned an uncertain diagnosis by clinical consensus (89%) were in MCS based on CRS-R findings. CONCLUSION: Despite the importance of diagnostic accuracy, the rate of misdiagnosis of VS has not substantially changed in the past 15 years. Standardized neurobehavioral assessment is a more sensitive means of establishing differential diagnosis in patients with disorders of consciousness when compared to diagnoses determined by clinical consensus. [less ▲]Detailed reference viewed: 42 (4 ULg)
The problem of aphasia in the assessment of consciousness in brain damaged patients.
Majerus, Steve ; Bruno, Marie-Aurélie ; Schnakers, Caroline et al
in Progress in Brain Research (2009), 177Detailed reference viewed: 60 (13 ULg)
Behavioral Assessment in Patients with Disorders of Consciousness: Gold Standard or Fool’s Gold?
Schnakers, Caroline ; ; et al
in Progress in Brain Research (2009), 177Detailed reference viewed: 37 (6 ULg)
Assessment of visual pursuit in post-comatose states: use a mirror
Vanhaudenhuyse, Audrey ; Schnakers, Caroline ; Brédart, Serge et al
in Journal of Neurology, Neurosurgery & Psychiatry (2008), 79(2),Detailed reference viewed: 10 (2 ULg)
Sleep modulates the neural substrates of both spatial and contextual memory consolidation
; ; Schmidt, Christina et al
in PLoS ONE (2008), 3(8), 2949Detailed reference viewed: 4 (0 ULg)
Le Locked-In Syndrome : la conscience emmurée
Bruno, Marie-Aurélie ; ; Schnakers, Caroline et al
in Revue Neurologique (2008), 164
The Locked-In syndrome(LIS) is deﬁned by: (i) the presence of sustained eye opening (bilateral ptosis should be ruled out as a complicating factor);(ii) preserved awareness; (iii) aphonia or hypophonia ... [more ▼]
The Locked-In syndrome(LIS) is deﬁned by: (i) the presence of sustained eye opening (bilateral ptosis should be ruled out as a complicating factor);(ii) preserved awareness; (iii) aphonia or hypophonia; (iv) quadriplegia or quadriparesis; and (v) a primary mode of communication that uses vertical or lateral eye movement or blinking. Acute ventral pontine lesions are its most common cause. Following such brainstem lesions patients may remain comatose for sometime and then gradually awaken, remaining paralyzed and voiceless, superﬁcially resembling the vegetative state. Background. – It has been shown that more than half of the time physicians fail to recognize early signs of awareness in LIS. Given appropriate medical care,life expectancy may be several decades but the chances of good motor recovery remain small. Eye-controlled computer technology now allows LIS patients to communicate and control their environment. Recent studies show that most LIS patients self-report meaningful quality of life and the demand for euthanasia is infrequent. Conclusion. – Patients suffering from LIS should not be denied the right to die – and to die with dignity –but also they should not be denied the right to live–and to live with dignity and the best possible pain and symptom management and revalidation. [less ▲]Detailed reference viewed: 61 (19 ULg)
Measuring the effect of amantadine in chronic anoxic minimally conscious state
Schnakers, Caroline ; Hustinx, Roland ; Vandewalle, Gilles et al
in Brain Injury (2008)Detailed reference viewed: 18 (1 ULg)
Consciousness and cerebral baseline activity fluctuations
Boly, Mélanie ; Phillips, Christophe ; Balteau, Evelyne et al
in Human Brain Mapping (2008), 29
The origin of within-subject variability in perceptual experiments is poorly understood. We here review evidence that baseline brain activity in the areas involved in sensory perception predict subsequent ... [more ▼]
The origin of within-subject variability in perceptual experiments is poorly understood. We here review evidence that baseline brain activity in the areas involved in sensory perception predict subsequent variations in sensory awareness. 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. [less ▲]Detailed reference viewed: 12 (4 ULg)
Experiences de mort imminente: phenomenes paranormaux ou neurologiques?
Thonnard, Marie ; Schnakers, Caroline ; Boly, Mélanie et al
in Revue Médicale de Liège (2008), 63(5-6), 438-44
Seeing a bright light at the end of a tunnel or having a sense of being out of the physical body are phenomena that some patients report after having been close to death. Some spiritual and psychological ... [more ▼]
Seeing a bright light at the end of a tunnel or having a sense of being out of the physical body are phenomena that some patients report after having been close to death. Some spiritual and psychological theories have been developed in order to explain these near-death-experiences. Clinical studies have aimed to determine their frequency and to assess their precipitating factors. Recent neuroimaging studies, however, have shown the involvement of the temporo-parietal cortex in the generation of out-of-body experiences and are offering a physiological, neurological account for the phenomenon, rebuffing dualistic, non-physical explanations. [less ▲]Detailed reference viewed: 48 (5 ULg)
Is there anybody in there? Detecting awareness in disorders of consciousness.
; Vanhaudenhuyse, Audrey ; et al
in Expert Review of Neurotherapeutics (2008), 8(11), 1719-30
The bedside detection of awareness in disorders of consciousness (DOC) caused by acquired brain injury is not an easy task. For this reason, differential diagnosis using neuroimaging and ... [more ▼]
The bedside detection of awareness in disorders of consciousness (DOC) caused by acquired brain injury is not an easy task. For this reason, differential diagnosis using neuroimaging and electrophysiological tools in search for objective markers of consciousness is being employed. However, such tools cannot be considered as diagnostic per se, but as assistants to the clinical evaluation, which, at present, remains the gold standard. Regarding therapeutic management in DOC, no evidence-based recommendations can be made in favor of a specific treatment. The present review summarizes clinical and paraclinical studies that have been conducted with neuroimaging and electrophysiological techniques in search of residual awareness in DOC. We discuss the medical, scientific and ethical implications that derive from these studies and we argue that, in the future, the role of neuroimaging and electrophysiology will be important not only for the diagnosis and prognosis of DOC but also in establishing communication with these challenging patients. [less ▲]Detailed reference viewed: 6 (0 ULg)
A twitch of consciousness: defining the boundaries of vegetative and minimally conscious states.
Noirhomme, Quentin ; Schnakers, Caroline ; Laureys, Steven
in Journal of Neurology, Neurosurgery & Psychiatry (2008), 79(7), 741-2Detailed reference viewed: 10 (0 ULg)
Voluntary brain processing in disorders of consciousness
Schnakers, Caroline ; ; et al
in Neurology (2008), 71(20), 1614-1620
Background: Disentangling the vegetative state from the minimally conscious state is often difficult when relying only on behavioral observation. In this study, we explored a new active evoked related ... [more ▼]
Background: Disentangling the vegetative state from the minimally conscious state is often difficult when relying only on behavioral observation. In this study, we explored a new active evoked related potentials paradigm as an alternative method for the detection of voluntary brain activity. Methods: The participants were 22 right-handed patients (10 traumatic) diagnosed as being in a vegetative state (VS) (n 8) or in a minimally conscious state (MCS) (n 14). They were presented sequences of names containing the patient’s own name or other names, in both passive and active conditions. In the active condition, the patients were instructed to count her or his own name or to count another target name. Results: Like controls, MCS patients presented a larger P3 to the patient’s own name, in the passive and in the active conditions. Moreover, the P3 to target stimuli was higher in the active than in the passive condition, suggesting voluntary compliance to task instructions like controls. These responses were even observed in patients with low behavioral responses (e.g., visual fixationand pursuit). In contrast, no P3 differences between passive and active conditions were observed for VS patients. Conclusions: The present results suggest that active evoked-related potentials paradigms may permit detection of voluntary brain function in patients with severe brain damage who present with a disorder of consciousness, even when the patient may present with very limited to questionablyany signs of awareness. [less ▲]Detailed reference viewed: 13 (1 ULg)
Revelations from the unconscious: studying residual brain function in coma and related states.
Laureys, Steven ; Boly, Mélanie ; Schnakers, Caroline et al
in Bulletin et Mémoires de l'Académie Royale de Médecine de Belgique (2008), 163(7-9), 381-8388-90
The purpose of our research is to contribute to a better understanding of the residual brain function of patients who survive an acute brain damage but remain in a coma, vegetative state, minimally ... [more ▼]
The purpose of our research is to contribute to a better understanding of the residual brain function of patients who survive an acute brain damage but remain in a coma, vegetative state, minimally conscious state or locked-in syndrome. The diagnosis, prognosis, therapy and medical management of these patients remain difficult. These studies are also of interest scientifically, as they help to elucidate the neural correlates of human consciousness. We here review our studies on bedside behavioral evaluation scales, electrophysiology and functional neuroimaging in these disorders of consciousness and conclude by discussing methodological and ethical issues and current concepts of the standards for care and quality of life in these challenging conditions. [less ▲]Detailed reference viewed: 19 (4 ULg)