Muscle-eye-brain disease: clinical features, visual evoked potentials and brain imaging in 20 patients

Clinical features, magnetic resonance imaging and visual evoked potentials were analysed and correlated in 20 Finnish patients with muscle-eye-brain disease. Significantly enhanced visual evoked potentials were found in 15 patients (giant in 14 of them). Magnetic resonance images were available in 17 cases. The images of 12 patients with giant visual evoked potentials showed typical brain malformation pachygyria with a nodular cortical surface i.e. cobblestone cortex, midline defect and hypoplastic pons but no significant abnormalities in the grey-white matter. One male had typical structural changes but flat visual evoked potentials. His extreme hydrocephalus with optic nerve compression may explain the findings. No structural changes on magnetic resonance images were found in the remaining four patients; however, in two of them marked alterations in the white matter were found. Three of these patients showed normal and one flat visual evoked potentials. Only one patient with giant visual evoked potentials and typical structural findings on magnetic resonance imaging had changes in a large area in the white matter (several attacks of status epilepticus might have caused the alterations in the white matter). Thus, the combination of giant visual evoked potentials and typical structural changes on magnetic resonance imaging with normal intensities of white matter and deep grey matter seems to be a good marker for patients with muscle-eye-brain disease.