Since I am close in age to your mother, I will share the symptoms I first noticed only a few years ago. I would unconsciously walk with a stiff right arm and my children would ask why I was walking that way. Then I realized I had no arm swing on that side. Next I became aware that my handwriting was getting smaller. I taught school and the kids commented on my small writing as did a couple of store clerks when I wrote checks. Third, I acquired a tremor and yes it was a tremor at rest. It was worse under stress. My voice also became softer and harder to hear ie kids in back of classroom had a harder time hearing me. The cough could be a side effect of other medication if she is taking something else. I hope tests show she doesn't have Parkinson's but something very treatable. However I have found this site to be encouraging and full of helpful information and you couldn't be in a better place to learn about Parkinson's.