Hi Terri-
I think you would benefit from Lee Silverman Voice Therapy. What causes your voice to get gravelly is not enough air. You need to learn to take breaths from your belly and keep the air passages in your throat open to let the air through. Parkinson's causes your neck and throat to get stiff. I hope I am explaining all this correctly. My voice still gets gravelly when I talk and/or sing a lot. Sometimes people think I have a sore throat and stay away so they won't catch germs, but it is only PD making my voice hoarse. If I do my voice exercises I learned in LSVT regularly, my voice is better.