Video 1.

Segment 1: patient diagnosed with corticobasal syndrome is asked to move his right foot when, simultaneously, he performed involuntary movements in his left hand, with a similar pattern and pace. Despite explaining to him to only move his feet, seconds later both hands were involuntarily moving. The patient also presented bradykinesia and rigidity at both arms (worse on the right side) and bilateral ideomotor apraxia (also worse in the right arm). Segment 2: patient diagnosed with probable CBS developed involuntary movements in his right hand when asked to move his right foot and later demonstrated the same movements in his left hand. In this patient, myoclonus in both upper limbs is also notable (worse on the right side).