R(+)-pramipexole will be provided as Good Manufacturing Practice powder and taken as a liquid and start at one teaspoon (5 ml) twice a day for a total dose of 100 mg/day. After 4 weeks, the dose will double (two teaspoons twice a day, or a total of 200mg/day). Four weeks later the dose will be increased again to 2 1/2 teaspoons twice a day (total of 300mg/day) where it will remain for the remaining 16 weeks of study treatment. Prior to each increase, participants and their study partners will be interviewed regarding any possible side effects or problems. These findings will be discussed with Dr. Burns prior to increasing the study drug dose. The dose will only increase if the participant is not having side effects.