I ve had the same problem. Playing Wii Tennis, the movement sensor stopped working in the remote.
The on-screen-hand icon works fine and allows me to navigate through menus but I have no movement control.
This only affects one out of two remotes, the other works great.
Batteries are good. Have resynced both remotes to the console. Have tried moving the handset in different ways. The sensor bar is in full view and I'me standing within the advised distance from the sensor bar.
None of this works !
Any other feedback would be much appreciated.