PROSPECTIVE EVALUATION OF VERBAL MEMORY PERFORMANCE AFTER CARDIOPULMONARY BYPASS-SURGERY

One hundred and four patients undergoing cardiac surgery with cardiopu lmonary bypass (CPB) and a surgical control group undergoing major vas cular or thoracic surgery (n = 18) were tested with the Auditory Verba l Learning Test (AVLT) at the following intervals: 1 day before, 1 wee k after, and 6 months after surgery. Early after surgery a significant decline in AVLT-performance was found, characterized by a smaller car ry-over of learned words on subsequent acquisition trials. Six-month f ollow-up data revealed significant improvement in the delayed retentio n of words as compared to the preoperative assessment. No surgical gro up differences or time by group interaction effects were found. In the CPB group, deeper levels of hypothermia, reflecting longer and more e xtensive cardiac surgery, were associated with reduced improvement on retest.