For the first time in 27 years, clinical diagnostic criteria for Alzheimer’s disease dementia have been revised, and research guidelines for earlier stages of the disease have been characterized to reflect a deeper understanding of the disorder.

The National Institute on Aging/Alzheimer’s Association Diagnostic Guidelines for Alzheimer’s Disease outline some new approaches for clinicians and provide scientists with more advanced guidelines for moving forward with research on diagnosis and treatments. they mark a major change in how experts think about and study Alzheimer’s disease. Development of the new guidelines was led by the National Institutes of Health and the Alzheimer’s Association.

The original criteria were the first to address the disease and described only later stages, when symptoms of dementia are already evident. The updated guidelines announced today cover the full spectrum of the disease as it gradually changes over many years. they describe the earliest preclinical stages of the disease, mild cognitive impairment, and dementia due to Alzheimer’s pathology. Importantly, the guidelines now address the use of imaging and biomarkers in blood and spinal fluid that may help determine whether changes in the brain and those in body fluids are due to Alzheimer’s disease. Biomarkers are increasingly employed in the research setting to detect onset of the disease and to track progression, but cannot yet be used routinely in clinical diagnosis without further testing and validation.

The new guidelines appear online April 19, 2011 in Alzheimer’s & Dementia: The Journal of the Alzheimer’s Association. They were developed by expert panels convened last year by the National Institute on Aging (NIA), part of the NIH, and the Alzheimer’s Association. Preliminary recommendations were announced at the Association’s International Conference on Alzheimer’s Disease in July 2010, followed by a comment period.