P22-14 Cortical and non-cortical myoclonus of Creutzfeldt-Jakob disease (CJD): Precious lesson learned from a patient

Myoclonus

10.2310/im.6350 ◽

2016 ◽

Author(s):

Hiroshi Shibasaki ◽

Marina A J Koning-Tijssen

Keyword(s):

Spinal Cord ◽

Key Words ◽

Loss Of Consciousness ◽

Voluntary Movements ◽

Involuntary Movements ◽

Cortical Myoclonus ◽

Progressive Myoclonus Epilepsy ◽

Myoclonus Epilepsy ◽

Jakob Disease

Myoclonus is defined as sudden, brief, jerky, shocklike, involuntary movements involving the extremities, face, and trunk, without loss of consciousness. Myoclonus is one of the most commonly encountered involuntary movements, and it can be seen in association with a variety of conditions. This review covers the epidemiology, classification, and diagnosis of myoclonus, as well as a thorough discussion of cortical myoclonus, myoclonus of brainstem origin, myoclonus of spinal cord origin, and myoclonus of undetermined origin. Figures show the principle of jerk-locked back-averaging, example data of jerk-lock averaging, schematic diagrams of cortical reflex myoclonus and spontaneous cortical myoclonus, a polygraphic electromyogram (EMG) recorded from a patient with postanoxic, reticular reflex myoclonus, surface negative slow electroencephalographic (EEG) potentials recorded before psychogenic jerks and voluntary movements mimicking the jerks in a patient with a diagnosis of psychogenic truncal movements, and an EEG-EMG polygraph in a patient with Creutzfeldt-Jakob disease. Tables list the classification of myoclonus based on the estimated site of origin, causes of cortical myoclonus, and causes of progressive myoclonus epilepsy and gene abnormalities. Key words: cortical myoclonus, EEG-EMG polygraph, epilepsy syndromes, involuntary movements, myoclonus This review contains 6 highly rendered figures, 3 tables, and 63 references.

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Myoclonus

10.2310/neuro.6350 ◽

2016 ◽

Author(s):

Hiroshi Shibasaki ◽

Marina A J Koning-Tijssen

Keyword(s):

Spinal Cord ◽

Key Words ◽

Loss Of Consciousness ◽

Voluntary Movements ◽

Involuntary Movements ◽

Cortical Myoclonus ◽

Progressive Myoclonus Epilepsy ◽

Myoclonus Epilepsy ◽

Jakob Disease

Myoclonus is defined as sudden, brief, jerky, shocklike, involuntary movements involving the extremities, face, and trunk, without loss of consciousness. Myoclonus is one of the most commonly encountered involuntary movements, and it can be seen in association with a variety of conditions. This review covers the epidemiology, classification, and diagnosis of myoclonus, as well as a thorough discussion of cortical myoclonus, myoclonus of brainstem origin, myoclonus of spinal cord origin, and myoclonus of undetermined origin. Figures show the principle of jerk-locked back-averaging, example data of jerk-lock averaging, schematic diagrams of cortical reflex myoclonus and spontaneous cortical myoclonus, a polygraphic electromyogram (EMG) recorded from a patient with postanoxic, reticular reflex myoclonus, surface negative slow electroencephalographic (EEG) potentials recorded before psychogenic jerks and voluntary movements mimicking the jerks in a patient with a diagnosis of psychogenic truncal movements, and an EEG-EMG polygraph in a patient with Creutzfeldt-Jakob disease. Tables list the classification of myoclonus based on the estimated site of origin, causes of cortical myoclonus, and causes of progressive myoclonus epilepsy and gene abnormalities. Key words: cortical myoclonus, EEG-EMG polygraph, epilepsy syndromes, involuntary movements, myoclonus This review contains 6 highly rendered figures, 3 tables, and 63 references.

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The Neurophysiological Basis of Myoclonus

10.1093/med/9780190228484.003.0037 ◽

2017 ◽

Author(s):

Phillip D. Thompson ◽

Hiroshi Shibasaki ◽

Mark Hallett

Keyword(s):

Subacute Sclerosing Panencephalitis ◽

Sensory Stimuli ◽

Classification Schemes ◽

Clinical Appearance ◽

Cortical Myoclonus ◽

Somatosensory Evoked Response ◽

Spinal Myoclonus ◽

Jakob Disease ◽

Neurophysiological Assessment ◽

Neurophysiological Basis

There are several types of myoclonus, with a variety of classification schemes, and the clinician must determine what type of myoclonus a patient has and what type of neurophysiological assessment can facilitate diagnosis. The electromyographic (EMG) correlate of the myoclonus should be examined, including the response to sensory stimuli (C-reflex). The electroencephalographic (EEG) correlate of the myoclonus should then be examined, possibly including back-averaging from the myoclonus or looking at corticomuscular (EEG–EMG) coherence. The somatosensory evoked response (SEP) should be obtained. Such studies will help determine the myoclonus origin, most commonly cortical or brainstem. One form of cortical myoclonus has the clinical appearance of a tremor (cortical tremor). Brainstem myoclonus includes exaggerated startle (hyperekplexia). Other forms of myoclonus include spinal myoclonus and functional myoclonus, which have their own distinct physiological signature. Several causes of myoclonus are reviewed, including rare types such as Creutzfeldt-Jakob disease and subacute sclerosing panencephalitis.

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