Hi Doctor, I have been told by a sleep expert that I probably have REM behavioral disorder, from having dreams where I am attacked and acting out dreams. This of course is a strong precursor of Parkinson's. Also, this week I began noticing phantom smells--rubbing alcohol, a pleasant citrus-y smell, smoke, and a musty odor. This evening I ill-advisedly sniffed a jug of ammonia to see if I had that smell, and it's still with me. My question is, I know that phantom smells, like REM behavioral disorder, can be an early sign of Parkinson's. But how likely are phantom smells to be an indicator of a brain tumor, if I have no other symptoms of a brain tumor?