Thalamic volume as a biomarker for Disorders Of Consciousness (original) (raw)
Neurobehavioural evaluation of disorders of consciousness
Although diagnostic guidelines for disorders of consciousness (DOC) have been consensually defined and are broadly used worldwide, a very high rate of diagnostic error remains among patients with DOC. Such failure to discern accurately between the different states of altered consciousness may influence tremendously the accuracy of prognosis, the decisionmaking process and medical care management or withdrawal. As there is no direct way to detect consciousness, one needs to infer its presence from behavioural observations and clinical examination at the bedside. Guidelines informing how one should approach clinical assessment of DOC have not yet reached the gold standard of diagnostic methodology. In the context of increasing demand for acute neurorehabilitation in Switzerland, there is a crucial need to improve the accuracy of initial diagnosis and prognosis, which profoundly impact treatment decisions in the short and long term. Validated neurobehavioural scales commonly used in ou...
Background: Previously, I showed theoretically that consciousness might manifest itself in the behaviour of either fundamental fields or quantum particles to be consistent with clinical and behavioural neurosciences of consciousness. This direct correlation between brain metabolism and behaviour indicates that global reduction of cortical neuronal work is a defining characteristic of DOCs (disorders of consciousness) and consit may provide us a unifying neuroenergetical basis for these syndromes. In this theory, consit “binds” the activity of neurons in different brain regions into a unified state: Name - Consit Composition - Elementary particle Statistics - Unidentified energy released statistics Interactions - Consciousness Status - Hypothetical Symbol - Cf Antiparticle - Self Theorized - Year 2010 Mass - 0 Mean lifetime - Stable Electric charge - 0 e Spin - 2 Table 1. Information about consit The above table states that ‘consit’ is a hypothetical elementary particle that mediates the force of consciousness in the brain. If it exists, the consit is expected to be massless (because the consciousness force appears to have unlimited range) and must be a spin-2 boson. Consciousness can be minimally sustained with energy use at only 42% of the level that occurs in healthy conscious individuals, suggesting that much cerebral metabolic activity in normal waking states does not directly contribute to consciousness. Positron emission tomography (PET) studies with [18F]-fluoro-deoxyglucose (FDG) suggest that impaired consciousness following brain injury is associated with overall brain metabolic levels of 40%–60% of normal in conditions of coma, unresponsive wakefulness syndrome (UWS), and minimally conscious state (MCS). Regardless of, relative regional variations in metabolism correlate with the preservation of specific behavioral or perceptual functions in MCS patients , supporting the claim that network activations cause local increases in energy metabolism even in disorders of consciousness (DOCs). Thus the level of tension across the neural networks determines the state of consciousness. The type and volume of traffic over those networks determines the experiences of consciousness. When we become conscious then it increases signals in our brain. The higher the frequency of the brain waves, the higher the consciousness. This unconstrained and hyper-associative quality of consciousness might show us that consciousness is interdependent on the brain waves in distinct distributed proportions, but the brain waves are not consciousness. Objectives: The study aims to review how conscious awareness relates to brain metabolism and how brain metabolism may change over time in brain-injured patients. Material and methods: For this clinical study, I reviewed on validation study of two neuroimaging-based diagnostic methods: PET imaging and functional MRI (fMRI). I conducted review of the research which included patients referred to the University Hospital of Liège, Belgium, between January, 2008, and June, 2012, who were diagnosed by with unresponsive wakefulness syndrome, locked-in syndrome, or minimally conscious state with traumatic or non-traumatic causes. The team at the hospital did repeated standardised clinical assessments with the Coma Recovery Scale–Revised (CRS–R), cerebral 18F-fluorodeoxyglucose (FDG) PET, and fMRI during mental activation tasks. They calculated the diagnostic accuracy of both imaging methods with CRS–R diagnosis as reference. They assessed outcome after 12 months with the Glasgow Outcome Scale–Extended. Results: In this study, Ron Kupers, together with Johan Stender and colleagues from the University of Copenhagen in Denmark and the University of Liège in Belgium, used FDG-PET to measure resting state brain glucose metabolism in 131 DOC patients to identify objective quantitative metabolic indicators and predictors of awareness. Quantitation of images was performed by normalizing to extracerebral tissue. Patients whose glucose metabolism measured under a threshold of 42 percent of normal appeared unconscious and failed to recover consciousness within the following year. Meanwhile, patients whose glucose metabolism measured above 42 percent the threshold had signs of initial responsiveness or recovered responsiveness within a year. Overall, the test was able to accurately predict 94 percent of patients who would wake up from a vegetative state. These findings provide a simple and objective metabolic marker of consciousness, which can readily be implemented clinically. Conclusions and perspectives: Consciousness phenomena can be viewed as signaling models, in the sense that they involve the transmission of information or energy via some sort of particle or field (these concepts being linked in modern physics should also be linked to neuroscience of consciousness). I proposed that jointly measuring the metabolic activity and the electrophysiological complexity of cortical circuits may help us to understand how a single massless unitary spin-2 consit (Table 1) arises with dynamic balance between integrated and differentiated networks of information exchange between different regions of the brain. References: Stender, Johan; Mortensen, Kristian Nygaard; Thibaut, Aurore; Darkner, Sune; Laureys, Steven; Gjedde, Albert; Kupers, Ron. The minimal energetic requirement of sustained awareness after brain injury. In: Current Biology, Vol. 26, No. 11, 06.06.2016, p. 1497. Rizvi, S. I. M. “Is consciousness a new form of energy?” Journal of Consciousness (JofC), The International Academy of Consciousness (IAC), 63 (2017). pp. 27-64. http://jofc.org/telas/home/arquivo.php?id=jofc\_63\_03\_en Stender, Johan; et al. (2016). The minimal energetic requirement of sustained awareness after brain injury. p. 1494. Laureys, S., Owen, A.M., and Schiff, N.D. (2004). Brain function in coma, vegetative state, and related disorders. Lancet Neurol. 3, 537–546. / Stender, J., Kupers, R., Rodell, A., Thibaut, A., Chatelle, C., Bruno, M.-A., Gejl, M., Bernard, C., Hustinx, R., Laureys, S., and Gjedde, A. (2015). Quantitative rates of brain glucose metabolism distinguish minimally conscious from vegetative state patients. J. Cereb. Blood Flow Metab. 35, 58–65. Bruno, M.-A., Majerus, S., Boly, M., Vanhaudenhuyse, A., Schnakers, C., Gosseries, O., Boveroux, P., Kirsch, M., Demertzi, A., Bernard, C., et al. (2012). Functional neuroanatomy underlying the clinical subcategorization of minimally conscious state patients. J. Neurol. 259, 1087–1098. / Bruno, M.-A., Vanhaudenhuyse, A., Schnakers, C., Boly, M., Gosseries, O., Demertzi, A., Majerus, S., Moonen, G., Hustinx, R., and Laureys, S. (2010). Visual fixation in the vegetative state: an observational case series PET study. BMC Neurol. 10, 35. Shulman, R.G., Rothman, D.L., and Hyder, F. (1999). Stimulated changes in localized cerebral energy consumption under anesthesia. Proceedings of the National Academy of Sciences, USA 96, 3245–3250. Ross, C. T & Shirley, F. (2009). Physical foundations of consciousness brain organisation: The role of synapses. 15 Mar 2017. p.3. https://arxiv.org/pdf/0907.2192. Stender J, Gosseries O, Bruno MA, et al. Diagnostic precision of PET imaging and functional MRI in disorders of consciousness: a clinical validation study. Lancet (2014) 384:514–22. Stender, Johan; et al. (2016). The minimal energetic requirement of sustained awareness after brain injury. p. 1496. Ibid., 1496.