This girl is using her bad hand to play piano,
The C Major scale is used in this video lesson. That is what the above therapy video is using, although it is broken to the first few notes. Stick to something simple when retraining your bad hand.
The very first song I played after a stroke was "Mary Had a Little Lamb." I used my left hand. This song is based on the C Major scale.
Don't go out and buy an expensive piano. There's no need for a professional keyboard. Get an inexpensive child's toy at a discount store. I'm no virtuoso. I just needed something to practice on. I got a toy. Children of friends and family can use it and stay out of trouble when visiting.
The technique is called Constraint-Induced Movement Therapy. "Constraint-induced movement therapy (CI or CIMT) is a form of rehabilitation therapy that improves upper extremity function in stroke and other central nervous system damage victims by increasing the use of their affected upper limb." [Now it looks to me, that this therapy can roughly be done at home.
Wear an oven mitt on the good hand. The idea is to restrain it and force
yourself to use the bad hand. You "constrain" your good hand, and by doing so, you are
"induced" to "move" your bad one. The focus is on moving your bad hand
and not playing beautifully. Doing it at home is no replacement for the real thing, but you sometimes have to make do. Besides piano playing, other activities are used in the therapy. I just happened to find a piano video.]
Practicing
playing scales builds finger strength and your agility on the keyboard.
Your music will sound better. I could say something about the
presentation of this next video. It has good theory, but where are this man's
shoes?
The very first song I played after a stroke was "Mary Had a Little Lamb." I used my left hand. This song is based on the C Major scale.
As you listen, pieces will have scales in the song. It's good to know your scales for these:
*A larger keyboard such as a piano will exercise the shoulder. It may take some time to switch.