Perception of pain in the minimally conscious state with PET activation: an observational study.

in Lancet Neurology (2008), 7(11), 1013-20

BACKGROUND: Patients in a minimally conscious state (MCS) show restricted self or environment awareness but are unable to communicate consistently and reliably. Therefore, better understanding of cerebral ... [more ▼]

BACKGROUND: Patients in a minimally conscious state (MCS) show restricted self or environment awareness but are unable to communicate consistently and reliably. Therefore, better understanding of cerebral noxious processing in these patients is of clinical, therapeutic, and ethical relevance. METHODS: We studied brain activation induced by bilateral electrical stimulation of the median nerve in five patients in MCS (aged 18-74 years) compared with 15 controls (19-64 years) and 15 patients (19-75 years) in a persistent vegetative state (PVS) with (15)O-radiolabelled water PET. By way of psychophysiological interaction analysis, we also investigated the functional connectivity of the primary somatosensory cortex (S1) in patients and controls. Patients in MCS were scanned 57 (SD 33) days after admission, and patients in PVS 36 (9) days after admission. Stimulation intensities were 8.6 (SD 6.7) mA in patients in MCS, 7.4 (5.9) mA in controls, and 14.2 (8.7) mA in patients in PVS. Significant results were thresholded at p values of less than 0.05 and corrected for multiple comparisons. FINDINGS: In patients in MCS and in controls, noxious stimulation activated the thalamus, S1, and the secondary somatosensory or insular, frontoparietal, and anterior cingulate cortices (known as the pain matrix). No area was less activated in the patients in MCS than in the controls. All areas of the cortical pain matrix showed greater activation in patients in MCS than in those in PVS. Finally, in contrast with patients in PVS, those in MCS had preserved functional connectivity between S1 and a widespread cortical network that includes the frontoparietal associative cortices. INTERPRETATION: Cerebral correlates of pain processing are found in a similar network in controls and patients in MCS but are much more widespread than in patients in PVS. These findings might be objective evidence of a potential pain perception capacity in patients in MCS, which supports the idea that these patients need analgesic treatment. [less ▲]

The changing spectrum of coma

in Nature Clinical Practice Neurology (2008), 4(10), 544-546

The boundaries of consciousness: lessons from coma and related states

in Advances in Clinical Neuroscience and Rehabilitation [=ACNR] (2008), 8(2),

Assessment of visual pursuit in post-comatose states: use a mirror

in Journal of Neurology, Neurosurgery & Psychiatry (2008), 79(2),

Le Locked-In Syndrome : la conscience emmurée

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 ▲]

Consciousness and cerebral baseline activity fluctuations

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 ▲]

Is there anybody in there? Detecting awareness in disorders of consciousness.

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 ▲]

Locked-in: don't judge a book by its cover.

in Journal of Neurology, Neurosurgery & Psychiatry (2008), 79(1), 2

Bewusstseinsstörungen - Diagnose und Prognose

in Junginger, T. (Ed.) Grenzsituationen der Intensivmedizin-Entscheidungsgrundlagen (2008)

Imagerie cérébrale de la réflexion sur soi

in Revue Médicale de Liège (2008), 63

Precise brain regions are activated when a subject gives a judgment on himself. Those are the medial parietal cortex, essentially related to episodic memory processing, and the ventromedial prefrontal ... [more ▼]

Precise brain regions are activated when a subject gives a judgment on himself. Those are the medial parietal cortex, essentially related to episodic memory processing, and the ventromedial prefrontal cortex, recruited for evaluating the personal valence of an information. These regions are not activated in Alzheimer's disease. The decrease of awareness for own deficits in a patient with Alzheimer's disease would depend on a reduction of episodic memory capacities and a worsening of judgment for self significance. [less ▲]