Voxel-based morphometry in narcolepsy

The volume reduction of gray matter in narcoleptic patients could indicate a disease-related atrophy pattern. However, the results of VBM studies in narcolepsy are contradictory. A possible systematic bias due to inhomogeneous patient groups, stimulant medication history or pre-statistical image processing must be considered. We suggest that studies with drug-naive patients and/or region-of-interest-based volumetric studies should be performed in areas defined by VBM.