Don't expect to see any significant change after only a week or two of use.
I do not expect, nor have I experienced a cure of my PD from dextromethorphan. I do know that, having taken it faithfully for the past 6-7 years, I am not aware of anyone else who has been diagnosed with PD for 11+ years who has progressed as slowly as I have. Therefore, I'm convinced that the low-dose approach with the drug is providing me some neuroprotection.