A method for prediciting localised areas of cerebral ischemia from visual evoked responses

Responses to light flashes recorded from several scalp electrodes of a normal subject at rest and during alternate compression of the carotid arteries in the neck are analysed. The diffences found in response characteristics between the subject at rest and during carotid compression may serve as indicators of localised areas of cerebral ischemia. The results indicate a strong evidence that information about localised areas of cerebral ischemia is contained in the cepstra of the averaged visual evoked responses. The probability with which such areas can be localised using cepstral values as samples and linear multiple regression techniques for classification purposes has been estimated for our procedure and our sample size as being: Pa equals 79 plus or minus 17 per cent for left-right localisation, and Pb equals 61 plus or minus 16 per cent for left-none-right localisation.