Not responsive to medication

I was diagnosed 16 years ago.  I have never had a response to the medication. The Neurologist has never been able to give me an explanation as to why the medication is not effective for me.  I now have serious mobility problems and I cant help but wonder if there is something that could help me.The Neurologist is reluctant to try anything new.  Has anyone else experienced this? can anybody give any advice?

i would really like to hear from people who may have had the same experience with Parkinson's medication.

After 19 years the medication is not now as effective as it once was BUT, if your neurologist won't try anything else, then change your neurologist. There are alternatives out there.