<qa>  What is the name of the brain wave patients who have problems with memory and thinking after surgery?This study will recruit surgical patients more than 65 years old. Patients who participate will wear a sticker on their forehead during surgery which monitors their brain waves electroencephalogram, EEG and participate in memory testing before and after surgery. Brain wave patterns will be compared between patients who have problems with memory and thinking after surgery and those who do not. The hypothesis is that there will be characteristic brain wave patients for who will go on to have problems with memory and thinking after surgery. 