A SPECIAL KIND OF ANTERIOR HORN CELL INVOLVEMENT IN JUVENILE MYOCLONIC EPILEPSY DEMONSTRATED BY MACRO ELECTROMYOGRAPHY

Juvenile myoclonic epilepsy (JME) is not an uncommon seizure disorder, occurring in 5-10% of epileptic patients, A subclinical anterior horn cell involvement has been suggested in some JME patients by concentri c needle electromyography (EMG) and turn/amplitude analysis, In this s tudy, 22 JME patients and 17 normal control subjects have been studied with macro EMG, which is a sensitive method to assess the size of mot or units, Most JME patients (19 of 22) had a pathologically increased number of individual large macro motor unit action potentials (MUAPs) compared to control subjects. For both biceps brachii and tibialis ant erior muscles, means of median macro MUAP amplitudes were significantl y greater than those of normal controls, whereas the fiber density val ues were only slightly increased. This suggested another kind of anter ior horn cell involvement in JME than seen in motor neuron diseases. ( C) 1997 John Wiley & Sons, Inc.