Biomaterial Database

Neurophysiology of Juvenile and Progressive Myoclonic Epilepsy. 2023

Jayant N Acharya, and Vinita J Acharya

Department of Neurology, Penn State University Hershey Medical Center, Hershey, Pennsylvania, U.S.A.

Myoclonus can be epileptic or nonepileptic. Epileptic myoclonus has been defined in clinical, neurophysiological, and neuroanatomical terms. Juvenile myoclonic epilepsy (JME) is typically considered to be an adolescent-onset idiopathic generalized epilepsy with a combination of myoclonic, generalized tonic-clonic, and absence seizures and normal cognitive status that responds well to anti-seizure medications but requires lifelong treatment. EEG shows generalized epileptiform discharges and photosensitivity. Recent observations indicate that the clinical picture of JME is heterogeneous and a number of neuropsychological and imaging studies have shown structural and functional abnormalities in the frontal lobes and thalamus. Advances in neurophysiology and imaging suggest that JME may not be a truly generalized epilepsy, in that restricted cortical and subcortical networks appear to be involved rather than the entire brain. Some patients with JME may be refractory to anti-seizure medications and attempts have been made to identify neurophysiological biomarkers predicting resistance. Progressive myoclonic epilepsy is a syndrome with multiple specific causes. It is distinct from JME because of the occurrence of progressive neurologic dysfunction in addition to myoclonus and generalized tonic-clonic seizures but may sometimes be difficult to distinguish from JME or misdiagnosed as drug-resistant JME. This article provides an overview of progressive myoclonic epilepsy and focuses on the clinical and neurophysiological findings in the two most commonly recognized forms of progressive myoclonic epilepsy-Unverricht-Lundborg disease (EPM1) and Lafora disease (EPM2). A variety of neurophysiological tests can be used to distinguish between JME and progressive myoclonic epilepsy and between EPM1 and EPM2.

UI	MeSH Term	Description	Entries
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
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
D004829	Epilepsy, Generalized	Recurrent conditions characterized by epileptic seizures which arise diffusely and simultaneously from both hemispheres of the brain. Classification is generally based upon motor manifestations of the seizure (e.g., convulsive, nonconvulsive, akinetic, atonic, etc.) or etiology (e.g., idiopathic, cryptogenic, and symptomatic). (From Mayo Clin Proc, 1996 Apr;71(4):405-14)	Convulsive Generalized Seizure Disorder,Epilepsy, Tonic,Generalized Nonconvulsive Seizure Disorder,Seizure Disorder, Generalized,Convulsive Seizure Disorder, Generalized,Epilepsy, Akinetic,Epilepsy, Atonic,Generalized Convulsive Epilepsy,Generalized Nonconvulsive Epilepsy,Generalized Onset Seizure Disorder,Generalized Seizure Disorder, Convulsive,Generalized Seizure Disorder, Nonconvulsive,Nonconvulsive Generalized Seizure Disorder,Nonconvulsive Seizure Disorder, Generalized,Seizure Disorder, Convulsive, Generalized,Seizure Disorder, Generalized Nonconvulsive,Seizure Disorder, Generalized Onset,Seizure Disorder, Generalized, Convulsive,Seizure Disorder, Nonconvulsive Generalized,Symptomatic Generalized Epilepsy,Akinetic Epilepsies,Akinetic Epilepsy,Atonic Epilepsies,Atonic Epilepsy,Convulsive Epilepsies, Generalized,Convulsive Epilepsy, Generalized,Epilepsies, Akinetic,Epilepsies, Atonic,Epilepsies, Generalized,Epilepsies, Generalized Convulsive,Epilepsies, Tonic,Epilepsy, Generalized Convulsive,Epilepsy, Generalized Nonconvulsive,Epilepsy, Symptomatic Generalized,Generalized Convulsive Epilepsies,Generalized Epilepsies,Generalized Epilepsy,Generalized Epilepsy, Symptomatic,Generalized Seizure Disorder,Generalized Seizure Disorders,Nonconvulsive Epilepsy, Generalized,Seizure Disorders, Generalized,Tonic Epilepsies,Tonic Epilepsy
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000293	Adolescent	A person 13 to 18 years of age.	Adolescence,Youth,Adolescents,Adolescents, Female,Adolescents, Male,Teenagers,Teens,Adolescent, Female,Adolescent, Male,Female Adolescent,Female Adolescents,Male Adolescent,Male Adolescents,Teen,Teenager,Youths
D020190	Myoclonic Epilepsy, Juvenile	A disorder characterized by the onset of myoclonus in adolescence, a marked increase in the incidence of absence seizures (see EPILEPSY, ABSENCE), and generalized major motor seizures (see EPILEPSY, TONIC-CLONIC). The myoclonic episodes tend to occur shortly after awakening. Seizures tend to be aggravated by sleep deprivation and alcohol consumption. Hereditary and sporadic forms have been identified. (From Adams et al., Principles of Neurology, 6th ed, p323)	Epilepsy, Myoclonic, Juvenile,Impulsive Petit Mal, Janz,Janz Syndrome,Juvenile Myoclonic Epilepsy,Adolescent Myoclonic Epilepsy,Epilepsy, Myoclonic Juvenile,Impulsive Petit Mal Epilepsy,JME (Juvenile Myoclonic Epilepsy),Janz Impulsive Petit Mal,Janz Juvenile Myoclonic Epilepsy,Juvenile Myoclonic Epilepsy of Janz,Myoclonic Epilepsy, Adolescent,Myoclonic Epilepsy, Juvenile, 1,Petit Mal, Impulsive,Petit Mal, Impulsive, Janz,Epilepsy, Adolescent Myoclonic,Epilepsy, Juvenile Myoclonic,JMEs (Juvenile Myoclonic Epilepsy),Juvenile Epilepsy, Myoclonic,Myoclonic Juvenile Epilepsy
D020191	Myoclonic Epilepsies, Progressive	A heterogeneous group of primarily familial EPILEPSY disorders characterized by myoclonic seizures, tonic-clonic seizures, ataxia, progressive intellectual deterioration, and neuronal degeneration. These include LAFORA DISEASE; MERRF SYNDROME; NEURONAL CEROID-LIPOFUSCINOSIS; sialidosis (see MUCOLIPIDOSES), and UNVERRICHT-LUNDBORG SYNDROME.	Action Myoclonus-Renal Failure Syndrome,Biotin-Responsive Encephalopathy,Dentatorubral-Pallidoluysian Atrophy,May-White Syndrome,Ataxia, Chorea, Seizures, And Dementia,Atypical Inclusion-Body Disease,Familial Progressive Myoclonic Epilepsy,Haw River Syndrome,Myoclonic Epilepsy, Progressive,Myoclonus-Nephropathy Syndrome,Naito Oyanagi Disease,Naito-Oyanagi Disease,Progressive Myoclonic Epilepsy,Progressive Myoclonus Epilepsies,Action Myoclonus Renal Failure Syndrome,Atrophies, Dentatorubral-Pallidoluysian,Atrophy, Dentatorubral-Pallidoluysian,Atypical Inclusion Body Disease,Atypical Inclusion-Body Diseases,Biotin Responsive Encephalopathy,Biotin-Responsive Encephalopathies,Dentatorubral Pallidoluysian Atrophy,Dentatorubral-Pallidoluysian Atrophies,Encephalopathies, Biotin-Responsive,Encephalopathy, Biotin-Responsive,Epilepsies, Progressive Myoclonic,Epilepsies, Progressive Myoclonus,Epilepsy, Progressive Myoclonic,Epilepsy, Progressive Myoclonus,Haw River Syndromes,Inclusion-Body Disease, Atypical,Inclusion-Body Diseases, Atypical,May White Syndrome,Myoclonus Epilepsies, Progressive,Myoclonus Nephropathy Syndrome,Myoclonus-Nephropathy Syndromes,Naito-Oyanagi Diseases,Progressive Myoclonic Epilepsies,Progressive Myoclonus Epilepsy,River Syndromes, Haw,Syndromes, Myoclonus-Nephropathy
D020194	Unverricht-Lundborg Syndrome	An autosomal recessive condition characterized by recurrent myoclonic and generalized seizures, ATAXIA, slowly progressive intellectual deterioration, DYSARTHRIA, and intention tremor. Myoclonic seizures are severe and continuous, and tend to be triggered by movement, stress, and sensory stimuli. The age of onset is between 8 and 13 years, and the condition is relatively frequent in the Baltic region, especially Finland. (From Menkes, Textbook of Child Neurology, 5th ed, pp109-110)	Baltic Myoclonus,Lundborg-Unverricht Syndrome,Mediterranean Myoclonic Epilepsy,Baltic Myoclonic Epilepsy,Baltic Myoclonus Epilepsy,Epilepsy, Progressive Myoclonic 1,Epilepsy, Progressive Myoclonic 1a,Epilepsy, Progressive Myoclonic Type 1,Epilepsy, Progressive Myoclonus 1,Myoclonic Epilepsy of Unverricht and Lundborg,Myoclonus Progressive Epilepsy of Unverricht and Lundborg,Progressive Myoclonus Epilepsy 1,Progressive Myoclonus Epilepsybaltic Myoclonic Epilepsy,Unverricht Disease,Unverricht-Lundborg Disease,Baltic Myoclonic Epilepsies,Baltic Myoclonus Epilepsies,Disease, Unverricht,Disease, Unverricht-Lundborg,Diseases, Unverricht,Diseases, Unverricht-Lundborg,Epilepsies, Baltic Myoclonic,Epilepsies, Baltic Myoclonus,Epilepsy, Baltic Myoclonic,Epilepsy, Baltic Myoclonus,Epilepsy, Mediterranean Myoclonic,Lundborg Unverricht Syndrome,Myoclonic Epilepsies, Baltic,Myoclonic Epilepsy, Baltic,Myoclonic Epilepsy, Mediterranean,Myoclonus Epilepsies, Baltic,Myoclonus Epilepsy, Baltic,Myoclonus, Baltic,Syndrome, Lundborg-Unverricht,Syndrome, Unverricht-Lundborg,Unverricht Diseases,Unverricht Lundborg Disease,Unverricht Lundborg Syndrome,Unverricht-Lundborg Diseases