Fourty-four patients, ranging from 14-65 in age, will be recruited. Patients and normal volunteers may be male or female; however, female subjects of child bearing potential will have a pregnancy test and an interview prior to the study to ensure that pregnant subjects will not participate in the study. Patients will be asked to stop any medication that can influence their central nervous system for one week prior to exam. They will be asked to abstain from alcohol for one week before the study.