Inclusion Criteria:  Age equal to or greater than 18 years. Inability to communicate verbally or motor. Have a artificial airway. Informed consent of the family member or representative of the patient.  Exclusion Criteria:  Previous pathology of cognitive impairment. Previous brain injury. Previous psychiatric disorder. Previous dementia. Previous chronic substance abuse. Previous chronic diabetics. Previous spinal cord injury. Previous severe polyneuropathy (diagnosed or suspected). Confirmed diagnosis of brain death. Continuous infusion of muscle relaxants and / or barbiturate coma. Level of deep sedation (RASS -5).