My daughter was diagnosed with this illness 2 months ago. She was 13. It's a long story starting when she was 5. She had a back pain; which thinking now, it is possible that it was her neck and not back. She lost mobilization in both hands, arms and legs were weak. After 3 days, she began to gain movement back starting in her fingers. Long story short...she realized 3 years ago that her left hand was smaller than her right. Her left thumb began to 'jump' uncontrollably. We started with dr's again to find out that all of her left side has muscle atrophy. About a year ago now, her right fingers began to jump and then both her hands and arms. I don't think it's as bad now. The dr is trying to figure out why her left leg and foot also has atrophy since it doesn't go with hirayama illness.