In the management of patients with acute cerebral disturbances, it is essential to determine precisely the degree of impaired consciousness. However, a coma scale for assessing impaired levels of consciousness has not yet been standardized internationally. The Edinburgh-2 coma scale (E2 CS) is introduced and compared with the Glasgow coma scale (GCS). The reliability of the E2 CS was tested by comparing levels of the E2 CS with the outcome of patients who underwent neurosurgical operations. A good correlation was observed between the levels of the E2 CS and the outcome. A change of two levels suggests that some change influencing the outcome has occurred or exists within the cranium of the patient. A correlation between the E2 CS and the GCS was proven to exist. The merits and drawbacks of both scales are discussed. One advantage of the E2 CS is that it has removed ambiguous terms, which are still present in the GCS. Also it is easier to grasp changes in a patient's condition shown on a chart because the levels of the E2 CS are arranged first-dimensionally. Use of the GCS should not preclude the use of other scales, such as the E2 CS; the E2 CS could be used together with the GCS. The accumulation of data on both scales would provide information useful in improving the existing coma scales.