The prior probability of 1 in 10^7 is already lower than I can handle in a well calibrated manner, and it would only get smaller after accounting for the evidence that I observe my left arm moving when I try to move, and I am successfully using it to type right now, and from the descriptions I read, anosognosiacs do not claim to make these observations, but attempt to make excuses for the lack of such observations.

In any event, it is not something I am too concerned about.