Given the fact that SPECT scanners are available in many larger hospitals, the differential diagnosis of FTD and DLB against AD with SPECT is feasible and clinicaly relevant, since antidementive drugs like cholinesterase-inhibitors are unlikely to be of therapeutic benefit in FTD, but are approved for AD, Parkinson's disease dementia (PDD) and are beneficial in DLB (positive therapeutic studies, but off-label use). This evidence concerns the gene BCHE and frontotemporal dementia.