The introduction of amyloid positron emission tomography and cerebrospinal fluid biomarkers, along with the advent of anti-amyloid β antibodies, has brought about significant changes in the diagnosis and treatment of dementia. Furthermore, new technologies, such as plasma biomarkers, are being developed. Therefore, it is increasingly important to accurately convey the latest and most appropriate information in daily clinical practice. This paper outlines the latest diagnostic criteria, advancements in diagnostic technology, and anti-amyloid β antibody therapy for Alzheimer's disease, and discusses important points in communicating diagnoses.