Yes Low Dose naltrexone has helped me with my rigidity on My Right side. it is completely gone. I do have rigidity in my left arm still.
I take 4.5 MG at bedtime. There aren't any side effects from taking LDN.
Please note that this is a compound medication. It isn't the whole 50 mg that is used by people who are addicted to Heroin

I did write a long answer that was more than the 3000 letters that are allowed. So I have to figure out how to divide it up and send the whole thing.I did bookmark it so it wasn't lost
I will try to do this some time today. Sorry.

I mentioned LDN to my PD doctor , he was not interested . So my question is did your doctor prescribe , I would dearly like to try this myself

I asked the question because I started taking it a month ago. My sense is that there has been a mild decease in overall rigidity, but nothing dramatic. No adverse side effects. 4.4 mg at bedtime.

Good questions