My Elderly Mother Has Shaky Legs. This Occurred In The

My elderly Mother has shaky legs. This occurred in the past month. What would cause this? She eats well, drinks lots of water and sleeps good also. She has a pacemaker and high blood pressure, which she is on medicine for. She had a stroke almost two years ago and other than her bit of instability walking, she does o.k. I'm just wondering if there is something I can do to help her rid this feeling.