Pre- and postoperative memory of dichotically presented words in patients with complex partial seizures

Dichotic listening tests were used to determine cerebral hemisphere memory functions in patients with complex partial seizures before, 10 days after, and 1-3 yr after right (RTE) or left (LTE) temporal-lobe excisions. Control subjects were also tested on two occasions. The tests consisted of presenting a series of 12-word lists and 7-word lists alternately to the two ears while backward speech was presented to the other ear. Measures of immediate free recall, final free recall, final cued recall, and serial recall were employed. The results revealed: (a) that both groups of patients were inferior the control group in tests tapping long-term memory functions rather than short-term memory functions, (b) a right-ear advantage for RTE patients at postoperative testing, (c) that the LTE group was more affected by surgery than the RTE group, and (d) a general improvement in recall performance from early to late postoperative testing. Taken together, these results indicate that the present dichotic test can be used as a non-invasive hemisphere memory test to complement invasive techniques for diagnosis of patients considered for epilepsy surgery.