Epileptic seizures and electroencephalographic evolution in genetic leukodystrophies

The purpose of this study is to explore and compare epileptic seizures and EEG evolution in the various types of genetic leukodystrophy (GL). The authors reviewed the medical records and analyzed 69 serial EEGs in 27 patients with GLs: 13 with late infantile metachromatic leukodystrophy, one with juvenile metachromatic leukodystrophy, one with globoid cell leukodystrophy, six with X-linked childhood adrenoleukodystrophy, one with neonatal adrenoleukodystrophy, four with classic Pelizaeus-Merzbacher disease (PMD), and 1 with connatal Pelizaeus-Merzbacher disease. The diagnoses were made by biochemical and molecular studies. Two or more EEG studies with both awake and sleep traces were recorded during the varying clinical stages for each patient. At the beginning of the GLs, the EEGs were normal or showed mild slowing of background activity. Clinical seizures, mainly of focal origin, with progressive slowing and paroxysmal discharges on EEGs, usually appeared during the later stages of metachromatic leukodystrophy, X-linked childhood adrenoleukodystrophy, and classic Pelizaeus-Merzbacher disease. However, intractable seizures, mainly generalized in nature, and more severe slowing and abundant paroxysmal discharges on EEGs, with commensurate neurologic deterioration, were observed during the earlier course of globoid cell leukodystrophy, neonatal adrenoleukodystrophy, and connatal Pelizaeus-Merzbacher disease. These results indicate that GLs involve not only white matter, but gray matter as well. In all types of GL, there is good correlation between the severity of EEG changes, the severity of the diseases, and the clinical state of the patient.