The influence of anesthetic methods on mental function.

The effect of anesthetic methods on mental function has been the subject of much discussion and debate over many years. Although it is commonly recognized that sedative, narcotic, and anesthetic agents have observable effects on cerebral function at the time of administration, more subtle and less easily detectable effects may persist into the postoperative period. Identifying and describing the effects of these drugs requires reliable and reproducible methods of measurement. The tests used for evaluating the effect of anesthetic methods on mental function are reviewed. The roles played by intraoperative and postoperative factors and their possible involvement in detectable decrement in mental function are described. Early postoperative effects of anesthetic methods on cognitive function are discussed, and the evidence for prolonged changes in mental function following anesthesia (particularly in the elderly) is reviewed.