Keywords: بیش از حد مفرط روزانه; 5-HT; hydroxytryptophan (serotonin); BPND; non-displaceable binding potential; DASB; [N,N-dimethyl-2-(2-amino-4-cyanophenylthio) benzylamine]; EDS; excessive daytime somnolence; ROI; region of interest; RBD; rapid eye movement behaviours disorders; SERT;