VEGETATIVE STATE AND MINIMALLY CONSCIOUS STATE: HOW TO DIFFERENCIATE THEM CLINICALLY? NEUROBIOLOGY OF CONSCIOUSNESS, RETICULAR ACTIVATING SYSTEM, MECHANISMS OF ATTENTION

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Introduction: The clinical differentiation between the Minimally Conscious State (EMC) and the Vegetative State (VS) constitutes an important challenge faced by intensive care doctors, since this is crucial for decision making end of life, as patients have different prognoses. Literature Review: The action of the ascending reticular activating system (ARAS), arises in the brain stem and continues until the area of the cortex and is related to the level of consciousness1. The cortical activation depends of neurons on the top of the bridge and the midbrain, which receive information from main ascending pathways, that include intrinsic stimuli (proprioceptive and visceral) and extrinsic (taste, smell, sight, touch and hearing).The VS represents a state in which the patient presents return of excitation without consciousness signals. On the other hand, MCS patients are characterized by the presence of behaviors targeted by objectives (response to command, verbalizations, visual search). The medicine makes use of various devices in an attempt to obtain this distinction: neurobehavioral scales, such as the Glasgow Coma Scale (GCS), Full Outline of Unresponsiveness (FOUR), Coma Recovery Scale Revised (CRS- R), Wessex Head Injury Matrix; electrophysiological methods such as the event-related potentials (ERP), the evoked potential (EP) and electroencephalogram (EEG); and positron emission tomography (PET), functional magnetic resonance imaging (fMRI) and magnetoencephalography (MEG). Conclusion: Note that among all the methods presented, none is conclusive for the differentiation of patients with VS and MCS, since individuals at the same level of consciousness present with different clinical manifestations. The integration of various these methods improves more accurate diagnosis.