To the Editor: “Ms. IS” was diagnosed with moderate Alzheimer’s disease (AD) and displayed a particular delusion: she was convinced that a toy doll was her living baby. Neuropsychological investigations showed that familiarity recognition was increased for unfamiliar faces, while normal for famous faces and both famous and unfamiliar buildings. IS recognized more pictures of humans and dolls as “living” when the face was visible, compared with when the face was not visible. FDG-PET showed severe prefrontal hypometabolism in addition to the associated AD pattern. The findings illustrate that face-selective hyper-animacy and hyper-familiarity processing constitute the neuropsychological deficits as originating factors in IS’s delusion.