Myoclonus: An electrophysiological diagnosis

Background Many different movement disorders have similar ‘jerk‐like' phenomenology and can be misconstrued as myoclonus. Different types of myoclonus also share similar phenomenological characteristics which can be difficult to distinguish, solely based on clinical exam. However, they have distinctive physiologic characteristics which can help refine categorization of ‘jerk‐like' movements. Objectives In this review, we briefly summarize the clinical, physiologic and pathophysiologic characteristics of different types of myoclonus. The methodology and technical considerations for electrophysiologic assessment of ‘jerk‐like' movements is reviewed. A simplistic pragmatic approach for classification of myoclonus and other ‘jerk‐like' movements based on objective electrophysiologic characteristics is proposed. Conclusions Clinical neurophysiology is an underutilized tool in the diagnosis and treatment of movement disorders. Various jerk‐like movements have distinguishing physiologic characteristics, differentiated in the milliseconds range which is beyond human capacity. We wish to argue that the categorization of movement disorders as myoclonus can be refined based on objective physiology which can have important prognostic and therapeutic implications.