(Gresham, OR)  --  Gresham police are looking for a woman with dementia who's been reported missing.  Authorities say 87-year-old Mary Ruth Cain left home Monday morning at eleven o'clock to go to the Bank of America near East Powell and Northeast Hood Avenue.  Police say Cain, who is without her medication, may have been spotted Wednesday night in the area of Northeast 8th Street and Northeast Cleveland Avenue.  She was last seen wearing beige slacks and a floral-print top, and she uses a red-and-black walker.