 [3] Statistics indicate that approximately 75% (772 of 1031) BD patients advanced to parenchymal NBD while 17.7% (183 of 1031) of BD patients advanced to non-parenchymal NBD.The remaining 7.3% were not able to be categorized.If one experiences parenchymal neuro-Behçet's disease, meningoencephalitis, inflammation of brain, primarily occurs.