Usefulness of standard EEG in predicting the outcome of patients with disorders of consciousness after anoxic coma.

Although standard EEG is performed routinely in patients with disorders of consciousness after coma, its prognostic value is still debated. The aim of the present study was to evaluate the role of standard EEG in predicting the recovery of cognitive functioning in patients affected by severe disturbances of consciousness after coma caused by cerebral anoxia. A standard EEG was recorded at admission to our Rehabilitation Department in 15 patients experiencing impaired consciousness because of cerebral anoxia. We quantified EEG abnormalities using the Synek scale (1988). Cognitive functioning was measured with the levels of cognitive functioning scale at the time of admission and after 3 months of recovery. EEG scores were significantly correlated with both levels of cognitive functioning scores at admission (P = 0.004) and change in levels of cognitive functioning score after 3 months (P < 0.001). The first correlation confirms the relationship between EEG and cognitive functioning, while the second correlation indicates the prognostic value of EEG in cognitive outcome. In conclusion, standard EEG is a simple and readily available tool with significant prognostic value in patients with disorders of consciousness after coma caused by cerebral anoxia.