Scientists at the Alzheimer's Association International Conference on Alzheimer's Disease (AAICAD) in Honolulu this week presented the first draft reports from three workgroups convened by the National Institute on Aging (NIA) and the Alzheimer's Association to update the diagnostic criteria for Alzheimer's disease for the first time in 25 years.

The current criteria for the diagnosis of Alzheimer's were established by a National Institute of Neurological Disorders and Stroke (NINDS)/Alzheimer's Disease and Related Disorders Association (ADRDA) workgroup in 1984.

Even though these criteria were almost universally adopted and have been useful, the experts noted at AAICAD that the field has evolved to a great extent since then.

"Important scientific discoveries have been made in Alzheimer's, and there have been significant changes in our knowledge and conception of the disease," said Creighton H. Phelps, PhD, director of the Alzheimer's Disease Centers Program and from the division of neuroscience, NIA at the National Institutes of Health in Bethesda, Md. "The NIA and the Alzheimer's Association, after consultation with the Alzheimer's scientific and medical community, concluded that the diagnostic criteria may need to be revised to incorporate scientific advances. We decided to convene workgroups to examine the literature and make recommendations."

The leaders of the three workgroups – which covered Alzheimer's disease, dementia, mild cognitive impairment due to Alzheimer's disease and preclinical Alzheimer's disease – presented preliminary reports at a special session for initial comment by the Alzheimer's community at AAICAD.

"The proposals would change the 1984 criteria by better reflecting the various stages of the disease and the inclusion of Alzheimer's disease biomarkers," said William Thies, PhD, chief medical and scientific officer at the Alzheimer's Association in Chicago. "While the role of biomarkers differs in each of the three stages, much remains to be understood concerning their reliability and validity in diagnosis. This makes it critical that we thoroughly test any new recommendations."

"The proposed criteria for Alzheimer's disease dementia must be flexible enough to eventually be used – once they are validated – by both general healthcare providers without access to neuropsychological testing, advanced imaging, and cerebrospinal fluid measures, as well as specialized investigators involved in research or clinical trial studies with access to these measures," said Guy McKhann, MD, from John Hopkins University School of Medicine in Baltimore, who chaired the workgroup.

Further input will be solicited through the website  www.alz.org/research/diagnostic_criteria. After that input is incorporated, next steps are publication in a peer-reviewed journal followed by systematic validation through incorporation of the criteria into clinical trials, added the Alzheimer's Association.