P2‐109: CSF CHOLINERGIC INDEX, A NEW BIOMEASURE OF TREATMENT EFFECT IN PATIENTS WITH ALZHEIMER'S DISEASE. (1st July 2019) - Karami, Azadeh; Eriksdotter, Maria; Kadir, Ahmadul; Almkvist, Ove; Nordberg, Agneta K.; Darreh-Shori, Taher