Neurophysiological diagnosis of the patient in coma

INTRODUCTION: In coma one loses both the ability to waken and consciousness. Patients in coma lie with their eyes shut and absence of psychologically understandable response to external stimuli or internal needs. Currently the most widely used scale for evaluation of coma is the Glasgow Coma Score. From the neurophysiological point of view different graduations of coma have been made based on the electroencephalographic changes found in patients in coma. DEVELOPMENT: Neurophysiological examination should be based on a study protocol which includes the following techniques: EEG lasting 30 minutes, cochlear-brainstem auditory evoked potentials and somatosensory evoked potentials. To obtain a satisfactory result it is advisable to use the three techniques jointly. Four degrees of severity are established for the neurophysiological diagnosis of coma. CONCLUSION: EEG reactivity to noxious stimuli is shown to be a sign of good prognosis, with marked statistical significance.