The FAST is an acronym for Functional Assessment Staging Tool, authored by Dr. Barry Reisberg and designed to assess the stage of dementia of a person with Alzheimer's disease. Barry Reisberg, M.D. is a psychiatrist, geriatric psychiatrist, and psychopharmacologist who is a leading expert in Alzheimer's disease and related areas. For the past two decades, Dr. Reisberg has served as the Clinical Director of NYU's Aging and Dementia Research Center and has directed, as Principal Investigator, U.S. National Institutes of Health sponsored studies of Aging and Alzheimer's disease. He is Professor of Psychiatry at the New York University School of Medicine and Adjunct Professor at the Center for the Study of Aging at the McGill University in Montreal, Canada.

His research has also recently uncovered a new fundamental biologic process, which he has termed "retrogenesis," which occurs in Alzheimer's disease (AD) and other dementing disorders. The retrogenesis process explains the nature of the clinical symptoms of AD and associated management needs and provides a new direction for fundamental treatment investigation.

Dr. Reisberg's studies have resulted in descriptions of the characteristic clinical course of Alzheimer's disease. One scale that contains these descriptors is the FAST. The Functional Assessment Staging Test (FAST) is the most well validated measure of the course of AD in the published, scientific literature.

Dr. Reisberg has found that in many important and fundamental ways, the progression of AD reverses pattern of acquisition in normal human development, a phenomenon which he has termed retrogenesis. Because this retrogenic phenomenon applies to cognitive and functional changes in AD, as well as to neurophysiologic and other aspects, the stages of AD can be translated into developmental ages.

The National Alzheimer's Association has recently described the dementia stages using the Retrogenesis/FAST framework.

The information in quotations below can be found at

"Experts have documented common patterns of symptom progression that occur in many individuals with Alzheimer's disease and developed several methods of 'staging' based on these patterns.

Staging systems provide useful frames of reference for understanding how the disease may unfold and for making future plans. But it is important to note that not everyone will experience the same symptoms or progress at the same rate. People with Alzheimer's live an average of 8 years after diagnosis, but may survive anywhere from 3 to 20 years.

The framework for this section is a system that outlines key symptoms characterizing seven stages ranging from unimpaired function to very severe cognitive decline. This framework is based on a system developed by Barry Reisberg, M.D., Clinical Director of the New York University School of Medicine's Silberstein Aging and Dementia Research Center.

Within this framework, we have noted which stages correspond to the widely used concepts of mild, moderate, moderately severe and severe Alzheimer's disease. We have also noted which stages fall within the more general divisions of early-stage, mid-stage, and late-stage categories.

Stage 1:
No impairment (normal function)
Unimpaired individuals experience no memory problems and none are evident to a health care professional during a medical interview.

Stage 2:
Very mild cognitive decline (may be normal age-related changes or earliest signs of Alzheimer's disease)
Individuals may feel as if they have memory lapses, especially in forgetting familiar words or names or the location of keys, eyeglasses or other everyday objects. But these problems are not evident during a medical examination or apparent to friends, family or co-workers.

Stage 3:
Mild cognitive decline
Early-stage Alzheimer's can be diagnosed in some, but not all, individuals with these symptoms.
Friends, family or co-workers begin to notice deficiencies. Problems with memory or concentration may be measurable in clinical testing or discernible during a detailed medical interview. Common difficulties include:

  • Word- or name-finding problems noticeable to family or close associates
  • Decreased ability to remember names when introduced to new people
  • Performance issues in social or work settings noticeable to family, friends or co-workers
  • Reading a passage and retaining little material
  • Losing or misplacing a valuable object
  • Decline in ability to plan or organize

Stage 4:
Moderate cognitive decline
(Mild or early-stage Alzheimer's disease)
At this stage, a careful medical interview detects clear-cut deficiencies in the following areas:

  • Decreased knowledge of recent occasions or current events
  • Impaired ability to perform challenging mental arithmetic-for example, to count backward from 75 by 7s
  • Decreased capacity to perform complex tasks, such as planning dinner for guests, paying bills and managing finances
  • Reduced memory of personal history
  • The affected individual may seem subdued and withdrawn, especially in socially or mentally challenging situations

Stage 5:
Moderately severe cognitive decline
(Moderate or mid-stage Alzheimer's disease) 
Major gaps in memory and deficits in cognitive function emerge. Some assistance with day-to-day activities becomes essential. At this stage, individuals may:

  • Be unable during a medical interview to recall such important details as their current address, their telephone number or the name of the college or high school from which they graduated
  • Become confused about where they are or about the date, day of the week or season
  • Have trouble with less challenging mental arithmetic; for example, counting backward from 40 by 4s or from 20 by 2s
  • Need help choosing proper clothing for the season or the occasion
  • Usually retain substantial knowledge about themselves and know their own name and the names of their spouse or children
  • Usually require no assistance with eating or using the toilet

Stage 6:
Severe cognitive decline
(Moderately severe or mid-stage Alzheimer's disease)
Memory difficulties continue to worsen, significant personality changes may emerge and affected individuals need extensive help with customary daily activities. At this stage, individuals may:

  • Lose most awareness of recent experiences and events as well as of their surroundings
  • Recollect their personal history imperfectly, although they generally recall their own name
  • Occasionally forget the name of their spouse or primary caregiver but generally can distinguish familiar from unfamiliar faces
  • Need help getting dressed properly; without supervision, may make such errors as putting pajamas over daytime clothes or shoes on wrong feet
  • Experience disruption of their normal sleep/waking cycle
  • Need help with handling details of toileting (flushing toilet, wiping and disposing of tissue properly)
  • Have increasing episodes of urinary or fecal incontinence
  • Experience significant personality changes and behavioral symptoms, including suspiciousness and delusions (for example, believing that their caregiver is an impostor); hallucinations (seeing or hearing things that are not really there); or compulsive, repetitive behaviors such as hand-wringing or tissue shredding
  • Tend to wander and become lost

Stage 7:
Very severe cognitive decline
(Severe or late-stage Alzheimer's disease)
This is the final stage of the disease when individuals lose the ability to respond to their environment, the ability to speak and, ultimately, the ability to control movement.

  • Frequently individuals lose their capacity for recognizable speech, although words or phrases may occasionally be uttered
  • Individuals need help with eating and toileting and there is general incontinence of urine
  • Individuals lose the ability to walk without assistance, then the ability to sit without support, the ability to smile, and the ability to hold their head up. Reflexes become abnormal and muscles grow rigid. Swallowing is impaired."

The FAST or adapted FAST can be administered by interviewing a caregiver who is an accurate reporter, the patient (if at a high cognitive stage) and/or by watching the person engage in activity. The description that best fits the person's performance may be the stage in which the person is functioning.

Our Dementia Care Specialists team has used this tool for years. Approximately four years ago we modified this tool to create the adapted FAST. The adapted FAST has eight stages versus Reisberg's seven. And, the descriptions were changed to add Allen terminology. Our team has used both the Allen Cognitive Levels and the adapted FAST for many years and have found that the two tools correlate extremely well.

Our recommendation is for this quick adapted or the original FAST to be administered on a routine basis to identify a person's dementia stage. This information can then guide treatment recommendations made by the interdisciplinary care team. There is little training required to use this brief assessment tool. We have been able to train nurses, activity directors, administrators, social service directors, and others to competently utilize this tool. We recommend the therapist administer the more in-depth Allen assessments during billable interventions.

The use of the adapted FAST as the primary method of cognitive assessment by a health care team is an exceptional way to immediately gather meaningful cognitive status information that can be translated into practical care interventions.

The adapted FAST and the correlation to Allen Cognitive Levels can be found in Dementia Care Specialists, Inc. publications including:

  • The Activity Planning Book
  • Dementia Therapy: Achieving Positive Outcomes for the Person With Dementia – Self Study and Live Course Manuals

In addition, we have created an interdisciplinary model of dementia care called Forget-Me-Not Care Model™ in which the dementia stages, as defined by both "The Theory of Retrogenesis" and "The Allen Cognitive Disabilities Theory" have been assimilated into practical care guidelines and a complete dementia program for an interdisciplinary health care team.