Biomaterial Database

Jerk-locked averaging: technique and application. 1992

G Barrett

Department of Psychology, National Hospital for Neurology and Neurosurgery, London, U.K.

Jerk-locked averaging (JLA) is used to record the timing and distribution of brain activity preceding brisk involuntary movements such as those observed in patients with myoclonus. JLA is capable of revealing a premyoclonus spike in the absence of paroxysmal activity in the routine EEG. The technique of JLA is described together with a consideration of the way in which the presence or absence of premyoclonus activity and the somatosensory evoked potential (SEP) can help to classify patients with involuntary movement disorders. The relationship between the premyoclonus spike and the N25-P33 complex of the SEP is discussed. Although the most common finding in patients with myoclonus of cortical origin is a large, well-defined positive-negative spike with the positive peak occurring about 20 ms before electromyographic onset, a wide variety of time relationships and topographies has been observed in other disorders of involuntary movement and some of these are described. The lack of correlation between the apparent origin of the premyoclonus spike in motor cortex and pathology in patients with myoclonus is discussed.

UI	MeSH Term	Description	Entries
D009068	Movement	The act, process, or result of passing from one place or position to another. It differs from LOCOMOTION in that locomotion is restricted to the passing of the whole body from one place to another, while movement encompasses both locomotion but also a change of the position of the whole body or any of its parts. Movement may be used with reference to humans, vertebrate and invertebrate animals, and microorganisms. Differentiate also from MOTOR ACTIVITY, movement associated with behavior.	Movements
D009069	Movement Disorders	Syndromes which feature DYSKINESIAS as a cardinal manifestation of the disease process. Included in this category are degenerative, hereditary, post-infectious, medication-induced, post-inflammatory, and post-traumatic conditions.	Dyskinesia Syndromes,Etat Marbre,Status Marmoratus,Movement Disorder Syndromes,Dyskinesia Syndrome,Movement Disorder,Movement Disorder Syndrome
D009207	Myoclonus	Involuntary shock-like contractions, irregular in rhythm and amplitude, followed by relaxation, of a muscle or a group of muscles. This condition may be a feature of some CENTRAL NERVOUS SYSTEM DISEASES; (e.g., EPILEPSY, MYOCLONIC). Nocturnal myoclonus is the principal feature of the NOCTURNAL MYOCLONUS SYNDROME. (From Adams et al., Principles of Neurology, 6th ed, pp102-3).	Myoclonus, Action,Myoclonus, Nocturnal,Myoclonus, Palatal,Polymyoclonus,Myoclonic Jerk,Myoclonic Jerking,Myoclonus Simplex,Myoclonus, Eyelid,Myoclonus, Intention,Myoclonus, Lower Extremity,Myoclonus, Oculopalatal,Myoclonus, Segmental,Myoclonus, Sleep,Myoclonus, Upper Extremity,Action Myoclonus,Extremity Myoclonus, Lower,Extremity Myoclonus, Upper,Eyelid Myoclonus,Intention Myoclonus,Jerk, Myoclonic,Jerking, Myoclonic,Jerks, Myoclonic,Lower Extremity Myoclonus,Myoclonic Jerks,Nocturnal Myoclonus,Oculopalatal Myoclonus,Palatal Myoclonus,Segmental Myoclonus,Simplex, Myoclonus,Sleep Myoclonus,Upper Extremity Myoclonus
D012018	Reflex	An involuntary movement or exercise of function in a part, excited in response to a stimulus applied to the periphery and transmitted to the brain or spinal cord.
D001921	Brain	The part of CENTRAL NERVOUS SYSTEM that is contained within the skull (CRANIUM). Arising from the NEURAL TUBE, the embryonic brain is comprised of three major parts including PROSENCEPHALON (the forebrain); MESENCEPHALON (the midbrain); and RHOMBENCEPHALON (the hindbrain). The developed brain consists of CEREBRUM; CEREBELLUM; and other structures in the BRAIN STEM.	Encephalon
D001931	Brain Mapping	Imaging techniques used to colocalize sites of brain functions or physiological activity with brain structures.	Brain Electrical Activity Mapping,Functional Cerebral Localization,Topographic Brain Mapping,Brain Mapping, Topographic,Functional Cerebral Localizations,Mapping, Brain,Mapping, Topographic Brain
D004569	Electroencephalography	Recording of electric currents developed in the brain by means of electrodes applied to the scalp, to the surface of the brain, or placed within the substance of the brain.	EEG,Electroencephalogram,Electroencephalograms
D004576	Electromyography	Recording of the changes in electric potential of muscle by means of surface or needle electrodes.	Electromyogram,Surface Electromyography,Electromyograms,Electromyographies,Electromyographies, Surface,Electromyography, Surface,Surface Electromyographies
D005073	Evoked Potentials, Somatosensory	The electric response evoked in the CEREBRAL CORTEX by stimulation along AFFERENT PATHWAYS from PERIPHERAL NERVES to CEREBRUM.	Somatosensory Evoked Potentials,Evoked Potential, Somatosensory,Somatosensory Evoked Potential
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man