Annales françaises d'anesthèsie et de rèanimation
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Ann Fr Anesth Reanim · Feb 2014
ReviewAssessing consciousness in coma and related states using transcranial magnetic stimulation combined with electroencephalography.
Thanks to advances in medical care, an increased number of patients recover from coma. However, some remain in vegetative/unresponsive wakefulness syndrome or in a minimally conscious state. Detection of awareness in severely brain-injured patients is challenging because it relies on behavioral assessments, which can be affected by motor, sensory and cognitive impairments of the patients. ⋯ We will then describe a non-invasive technique, transcranial magnetic stimulation combined with high-density electroencephalography (TMS-EEG), which has allowed us to detect the presence or absence of consciousness in different physiological, pathological and pharmacological states. Some potential underlying mechanisms of the loss of consciousness will then be discussed. In conclusion, TMS-EEG is highly promising in identifying markers of consciousness at the individual level and might be of great value for clinicians in the assessment of consciousness.
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When a severe traumatic brain-injured patient arrives to hospital, fear of failure and definite opinions about the outcome modify early care and provoke self-fulfilling prophecies. It is obvious that working on prognosis is not only useful to inform relatives but also permits to maintain a high level of care, key for a better outcome. Mortality is high (40-50%) if deaths in the first days are not excluded. ⋯ Studies with complex statistical methodology give a good estimated probability of bad outcome but must be confirmed by more validation studies. Progress will come from a better understanding of physiopathology. Focuses on processing chain, rapid multi-monitoring, biomarkers, and investigations in MRI and TDI will help to establish opportunities for treatments and to determine limits.
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Ann Fr Anesth Reanim · Feb 2014
ReviewElectrical modulation of neuronal networks in brain-injured patients with disorders of consciousness: A systematic review.
Six clinical studies of chronic electrical modulation of deep brain circuits published between 1968 and 2010 have reported effects in 55 vegetative or minimally conscious patients. The rationale stimulation was to activate the cortex through the reticular-thalamic complex, comprising the tegmental ascending reticular activating system and its thalamic targets. The most frequent intended target was the central intralaminar zone and adjacent nuclei. ⋯ Other treatments that have offered some clinical benefit include drugs, repetitive magnetic transcranial stimulation, median nerve stimulation, stimulation of dorsal column of the upper cervical spinal cord, and stimulation of the fronto-parietal cortex. No one treatment has emerged as a gold standard for practice, which is why clinical trials are still on-going. Further clinical studies are needed to decipher the altered dynamics of neuronal network circuits in patients suffering from severe disorders of consciousness as a step towards novel therapeutic strategies.
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Transcranial magnetic stimulations (TMS) have been used for many years as a diagnostic tool to explore changes in cortical excitability, and more recently as a tool for therapeutic neuromodulation. We are interested in their applications following brain injury: stroke, traumatic and anoxic brain injury. ⋯ TMS is a useful non-invasive brain stimulation tool to diagnose the effects of brain injury, to study the mechanisms of recovery and a non-invasive neuromodulation promising tool to influence the post-lesional recovery.
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Ann Fr Anesth Reanim · Feb 2014
ReviewNeurological consequences of cardiac arrest: Where do we stand?
With increasing public education in basic life support and with the widespread use of automated defibrillators, post-cardiac arrest comatose patients represent a growing part of ICU admissions. However the prognosis remains very poor and only a very low proportion of these resuscitated patients will recover and will leave the hospital without major neurological impairments. Neurological dysfunction predominantly includes disorders of consciousness, and may also include other manifestations such as seizures, myoclonus status epilepticus and other forms of movement disorders including post-anoxic myoclonus. ⋯ Currently, early use of mild therapeutic hypothermia is the only treatment that demonstrated its ability to decrease neurological consequences and to improve the prognosis. Prognostication outcome is still mainly based on a rigorous clinical evaluation coupled with neuro-physiological investigations, but brain functional imaging could become a valuable tool in the near future. Clinical research focusing on survivors should be strongly encouraged in order to assess the mid- and long-terms outcome of survivors and to evaluate the impact of new treatments or strategies.