Voxel-based morphometry in patients with cryptogenic occipital epilepsies. Preliminary data.

We evaluated the differences in grey matter concentration (GMC) by voxel-based morphometry (VBM) in patients with cryptogenic occipital epilepsies. VBM analysis was performed in 11 patients with cryptogenic occipital epilepsies compared to 11 healthy controls. VBM analysis in patients revealed focal areas of reduced GMC in the occipital cortex and, more interestingly, in- creased GMC in the midbrain tegmentum and basal ganglia (globus pallidus and thalamus). VBM may disclose slight structural abnormalities in the brain of cryptogenic epilepsy patients, not evi- dent with standard MRI. To the best of our knowledge, this is the first literature report describing areas of altered GMC in patients with occipital epilepsy. We hypothesize that these findings might be related to epileptic discharges and/or their diffusion and suggest that midbrain, globus pallidus and thalamus may be part of a functional network originating from the occipital areas.