Spotlight on Early myoclonic encephalopathy

Early myoclonic encephalopathy is an epileptic encephalopathy syndrome with onset either in the neonatal period or within the first 3 months of life, characterized by erratic, fragmentary, or massive myoclonus, focal seizures, and late tonic spasms. The prognosis is severe. Early myoclonic encephalopathy and Ohtahara syndrome together are recognized as 2 of the epileptic encephalopathies seen in early infancy and characterized by suppression burst on electroencephalogram.

In this updated article, Dr. Jules Beal of Weill Cornell Medicine and New York-Presbyterian Queens Hospital and Dr. Solomon Moshé of Albert Einstein College of Medicine review the clinical and neurophysiological data, management, and etiologic factors. Early myoclonic encephalopathy is believed to have various prenatal etiologies that often remain unknown; inborn errors of metabolism and genetic disorders are sometimes found.

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Spotlight on Myoclonus

In this article, Dr. John Caviness of the Mayo Clinic College of Medicine presents an overview of myoclonus with an emphasis on differential diagnosis, etiology, and treatment.

Myoclonus occurs as a symptom or sign in numerous diseases and conditions, necessitating an organized approach to diagnostic evaluation. Noting the clinical circumstances that surround the myoclonus is key. The first step in focusing on the myoclonus is to determine its category of clinical classification. Subsequent phases of testing can then be added as necessary. The physiological classification of myoclonus compliments the other information for diagnostic purposes. Once the diagnosis is determined, treatment of the underlying cause or symptomatic treatment of the myoclonus can be undertaken. For this update, the author has organized the treatment of myoclonus according to its pathophysiology with new treatment information added. This includes instances where deep brain stimulation or botulinum toxin injection may treat myoclonus.

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Spotlight on Benign adult familial myoclonic epilepsy

In this article, Dr. Pasquale Striano of the University of Genova, Istituto Gaslini discusses benign adult familial myoclonic epilepsy, which is an inherited epileptic syndrome characterized by cortical hand tremors, myoclonic jerks, and rare convulsive seizures. In most affected individuals, the disease takes a benign course; however, at advanced age, worsening of the tremor and myoclonus is common, and slight intellectual disability is present in a subset of patients. Prevalence is unknown but is estimated to be less than 1 out of 35,000. It is transmitted autosomal dominantly, and penetrance is high.

This is a well-delineated disease with remarkable features that clearly distinguish it from other forms of myoclonic epilepsies. Genetic studies of the families show heterogeneity, and different susceptible chromosomal loci have been identified. Diagnosis is based on clinical and electrophysiological findings. It must be differentiated from epilepsy syndromes with prominent myoclonus features. Valproate, levetiracetam, and benzodiazepines are the most beneficial treatments.

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Spotlight on Psychogenic (functional) movement disorders

Psychogenic movement disorders represent a challenge for the clinical practitioner, as the diagnosis and treatment are usually difficult and the prognosis may be poor in some patients. Sometimes also referred to as “functional,” “conversion,” or “psychogenic,” these disorders must be differentiated from “organic” disorders. Psychogenic movement disorders may have several presentations, including tremor, dystonia, myoclonus, tics, parkinsonism, gait disorders, hemifacial spasm, opsoclonus, oculogyric crisis, painful legs, moving toes, etc. and are not uncommonly accompanied by psychogenic speech and voice disorders.

In this article, Dr. Jose Fidel Baizabal-Carvallo of Baylor College of Medicine discusses current advances in the diagnosis, pathophysiology, and treatment of psychogenic movement disorders.

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