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Summary: Piracetam, a derivative of γ‐aminobutyric acid (GABA), has been used extensively for treatment of myoclonus in a variety of conditions, but not in patients with idiopathic generalized epilepsy (IGE). We have treated a patient with juvenile myoclonic epilepsy who had frequent and inconvenient morning myoclonus with 3,200 mg of piracetam daily. She had had only two generalized tonic–clonic seizures, with the last seizure 10 years earlier. Her obesity precluded the use of sodium valproate. She had a dramatic response to piracetam with sustained cessation of myoclonus and no side effects during 1.5 years' follow‐up. Further trials of piracetam for control of myoclonus in patients with IGE are justified.

Summary Juvenile myoclonic epilepsy is the most common idiopathic epilepsy syndrome and is considered a benign seizure disorder that responds well to antiepileptic drug treatment, in particular sodium valproate. By definition, routine brain imaging shows no abnormalities, but advanced imaging studies have identified functional and structural abnormalities in the frontal cortex and thalamus. Neuropsychological studies revealed subtle cognitive deficits in patients with JME, mainly implicating the frontal lobes. These findings are in keeping with anecdotal reports of behavioral problems in JME. Cognitive dysfunction in otherwise healthy siblings of patients with JME and a high heritability support the concept of a genetically determined thalamo‐frontocortical network dysfunction, accounting for the cognitive impairment and cognitively triggered “motor seizures.”

Recent advances in neuroepidemiologic and molecular biological techniques have facilitated a growing understanding of the role that inherited factors play in epileptogenesis. During the last few years linkage analysis has mapped gene loci associated with the following epilepsy syndromes: benign familial neonatal convulsions, juvenile myoclonic epilepsy, Unverricht-Lundborg/Baltic/Mediterranean progressive myoclonic epilepsies, the juvenile form of ceroid lipofuscinosis, sialidosis I, and the myoclonus epilepsy with ragged red fibers (MERRF) syndrome. In addition, characterization of the inheritance patterns of other syndromes such as childhood epilepsy with occipital paroxysms and febrile convulsions has improved. It is apparent that a significant amount of clinical and genetic heterogeneity exists, which emphasizes the importance of accurate clinical classification. As genetic markers are found for well-defmed groups of patients, traditional means of classification (seizure type, pathologic markers, progressive course, etc.) become less meaningful. It is proposed that the components of the phenotype of an epilepsy syndrome (eg, age of onset, seizure type, electroencephalographic pattern) may be controlled by multiple genes. (J Child Neurol 1994;9(Suppl)S12-S19).

Summary Purpose To investigate whether using transcranial magnetic stimulation (TMS) to derive if measures of cortical excitability changes can distinguish between various adolescent/adult‐onset generalized epilepsy syndromes at different phases of the disorder. Methods One hundred thirty‐seven patients with adolescent/adult‐onset generalized epilepsy divided into juvenile myoclonic epilepsy, juvenile absence epilepsy, and generalized epilepsy with tonic–clonic seizures only were studied. The cohorts were further divided into drug naive‐new onset, refractory, and seizure‐free groups. Motor threshold (MT) and paired pulse TMS at short (2, 5, 10, 15 msec) and long (100–300 msec) interstimulus intervals (ISIs) were measured. Results were compared to those of 20 controls. Key Findings In the drug‐naive cohorts MT was reduced (p < 0.05) and cortical excitability increased at 2 and 5 msec and 150, 250, and 300 msec ISIs (p < 0.01) in juvenile myoclonic epilepsy compared to other generalized epilepsy groups and controls. Cortical excitability increased to a lesser degree in other generalized epilepsy syndromes compared to controls, but those two syndromes were not distinguishable from one another. The changes in paired pulse TMS were more prominent in the groups with refractory seizures and very small in the groups who were seizure free. Significance There are syndrome specific changes in cortical excitability associated with generalized epilepsy. These changes are also dependent on seizure control with medication. Juvenile myoclonic epilepsy has a higher cortical excitability profile compared to other adolescent/adult‐onset generalized epilepsy syndromes and can be clearly distinguished from them during all phases.