The new guidelines released by the National Institute on Aging/Alzheimer’s Association cover three distinct stages of Alzheimer’s disease. The first two stages are mainly useful for research purposes, while the last stage is most relevant for doctors and patients. The stages as they are outlined in guidelines are:

Preclinical – The preclinical stage, describes a phase in which brain changes may already be in process but significant clinical symptoms are not yet evident. It is unknown what the risk for progression to Alzheimer’s dementia is for these individuals.

Mild Cognitive Impairment (MCI) – The MCI stage is marked by symptoms of memory problems, enough to be noticed and measured, but not compromising a person’s independence. People with MCI may or may not progress to Alzheimer’s dementia.

Alzheimer’s Dementia – These criteria apply to the final stage of the disease, and are most relevant for doctors and patients. The guidelines expand the concept of Alzheimer’s dementia beyond memory loss as its most central characteristic. A decline in other aspects of cognition, such as word-finding, vision/spatial issues, and impaired reasoning or judgment may be the first symptom to be noticed.