The accuracy of the dichotic, the visual half-field, and the intracarotid sodium amytal memory tests in preoperative neuropsychological investigation of epileptic patients.

Three methods for determining the lateralization of memory functions in patients with pharmacologically resistant intractable partial epilepsy were compared and evaluated. The three methods studied were a dichotic memory test, a visual half-field memory test, and an intracarotid Sodium Amytal memory test. A total of 35 epileptic patients considered for surgical therapy and a group of 20 non-epileptic control subjects took part in the study. The results show that the three tests tap different memory functions and that each of the test pick up a memory dysfunction in the hemisphere indicated by EEG recordings. In combination with an extensive neuropsychological test battery, the three methods produce data that concur with the evaluation made of EEG recordings.