Shabbir Hussain I Merchant1, Felipe Vial-Undurraga2, Giorgio Leodori3, Jay A van Gerpen4, Mark Hallett5. 1. Department of Neurology Medical University of South Carolina Charleston South Carolina USA. 2. Facultad de Medicina Clínica Alemana Universidad del Desarrollo Santiago Chile. 3. IRCCS Neuromed Pozzilli Isernia Italy. 4. Department of Neurology University of Alabama Huntsville Alabama USA. 5. National Institute of Neurological Disorders and Stroke National Institutes of Health Bethesda Maryland USA.
Abstract
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 that can be difficult to distinguish solely based on clinical exam. However, they have distinctive physiologic characteristics that 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 the electrophysiologic assessment of jerk-like movements are reviewed. A simplistic pragmatic approach for the 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 argue that the categorization of movement disorders as myoclonus can be refined based on objective physiology that can have important prognostic and therapeutic implications.
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 that can be difficult to distinguish solely based on clinical exam. However, they have distinctive physiologic characteristics that 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 the electrophysiologic assessment of jerk-like movements are reviewed. A simplistic pragmatic approach for the 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 argue that the categorization of movement disorders as myoclonus can be refined based on objective physiology that can have important prognostic and therapeutic implications.