[From 'Involuntary Movements' to 'Movement Disorders'].

Apart from the term 'involuntary movements', the term 'movement disorders' encompasses not only classical hyperkinesias but also hypokinesias including catalepsy or apraxia. It enables us to understand abnormal movements by their phenomena instead of by their localization. To advance the grasping of movement disorders, we discuss the clinical and pathophysiological features of abnormal movements in catatonia/catalepsy, anti-NMDAR encephalitis, paroxysmal dyskinesias, stiff person/leg syndrome, corticobasal degeneration/syndrome, and hysteria. Particular emphasis is placed on the roles of consciousness/unconsciousness, voluntariness/involuntariness, paroxysmal/sustained aspects, and cortical/subcortical networks.