122 patients with acute stroke were examined in order to demonstrate the sensitivity and the specificity of EEG versus CT findings, in distinguishing cortical from subcortical lesions. To do this the electroencephalographic diagnosis performed by two different electroencephalographers was compared with the neuroimaging diagnosis. The results showed a sensitivity of 77% and a specificity of 75%. Furthermore, the EEG findings can also provide physiopathological data, in that the cortical lesions are likely to be due to embolism, while the subcortical lesions are more likely to be due to the pathological process of the intracerebral blood-vessels and the lesions of the watershed territories to hemodynamic phenomena.