Health professionals sometimes discuss dementia in "stages," which refers to how far a person's dementia has progressed. Defining a person's disease stage helps physicians determine the best treatment approach and aids communication between health providers and caregivers. Sometimes the stage is simply referred to as "early stage", "middle stage" or "late-stage" dementia, but often a more exact stage is assigned, based on a person's symptoms.

One of the most commonly used staging scales is the Global Deterioration Scale for Assessment of Primary Degenerative Dementia (GDS), which divides the disease process into seven stages based on the amount of cognitive decline. The GDS is most relevant for people who have Alzheimer's disease, since some other types of dementia (i.e. frontotemporal dementia) do not always include memory loss.

Global Deterioration Scale for Assessment of Primary Degenerative Dementia (GDS) (also known as the Reisberg Scale)

Diagnosis Stage Signs and Symptoms
No Dementia Stage 1:
No Cognitive Decline
In this stage the person functions normally, has no memory loss, and is mentally healthy. People with NO dementia would be considered to be in Stage 1.
No Dementia Stage 2:
Very Mild Cognitive Decline
This stage is used to describe normal forgetfulness associated with aging; for example, forgetfulness of names and where familiar objects were left. Symptoms are not evident to loved ones or the physician.
No Dementia Stage 3:
Mild Cognitive Decline

This stage includes increased forgetfulness, slight difficulty concentrating, decreased work performance. People may get lost more often or have difficulty finding the right words. At this stage, a person's loved ones will begin to notice a cognitive decline. Average duration: 7 years before onset of dementia
Early-stage Stage 4:
Moderate Cognitive Decline

This stage includes difficulty concentrating, decreased memory of recent events, and difficulties managing finances or traveling alone to new locations. People have trouble completing complex tasks efficiently or accurately and may be in denial about their symptoms. They may also start withdrawing from family or friends, because socialization becomes difficult. At this stage a physician can detect clear cognitive problems during a patient interview and exam. Average duration: 2 years
Mid-Stage Stage 5:
Moderately Severe Cognitive Decline

People in this stage have major memory deficiencies and need some assistance to complete their daily activities (dressing, bathing, preparing meals). Memory loss is more prominent and may include major relevant aspects of current lives; for example, people may not remember their address or phone number and may not know the time or day or where they are. Average duration: 1.5 years
Mid-Stage Stage 6:
Severe Cognitive Decline (Middle Dementia)

People in Stage 6 require extensive assistance to carry out daily activities. They start to forget names of close family members and have little memory of recent events. Many people can remember only some details of earlier life. They also have difficulty counting down from 10 and finishing tasks. Incontinence (loss of bladder or bowel control) is a problem in this stage. Ability to speak declines. Personality changes, such as delusions (believing something to be true that is not), compulsions (repeating a simple behavior, such as cleaning), or anxiety and agitation may occur. Average duration: 2.5 years
Late-Stage Stage 7:
Very Severe Cognitive Decline (Late Dementia)

People in this stage have essentially no ability to speak or communicate. They require assistance with most activities (e.g., using the toilet, eating). They often lose psychomotor skills, for example, the ability to walk. Average duration: 2.5 years
(Reisberg, et al., 1982; DeLeon and Reisberg, 1999)

Two other scales that are sometimes used to describe the progression of dementia are:

  • Functional Assessment Staging (FAST): a seven stage system based on level of functioning and daily activities. View the FAST

    Functional Assessment Staging (FAST)

    Another staging method for dementia, the Functional Assessment Staging (FAST), focuses more on an individual's level of functioning and activities of daily living versus cognitive decline. Note: A person may be at a different stage cognitively (GDS stage) and functionally (FAST stage).

    Functional Assessment Staging (FAST)
    Stage 1 -- Normal adult
    No functional decline
    Stage 2 -- Normal older adult
    Personal awareness of some functional decline.
    Stage 3 -- Early Alzheimer's disease
    Noticeable deficits in demanding job situations.
    Stage 4 -- Mild Alzheimer's
    Requires assistance in complicated tasks such as handling finances, planning parties, etc.
    Stage 5 -- Moderate Alzheimer's
    Requires assistance in choosing proper attire.
    Stage 6 -- Moderately severe Alzheimer's
    Requires assistance dressing, bathing, and toileting. Experiences urinary and fecal incontinence.
    Stage 7 -- Severe Alzheimer's
    Speech ability declines to about a half-dozen intelligible words. Progressive loss of abilities to walk, sit up, smile, and hold head up. (Reisberg, et al., 1988)
  • The Clinical Dementia Rating (CDR) scale: a five-stage system based on cognitive (thinking) abilities and the individual's ability to function. Commonly used in dementia research. View the CDR Scale

    Clinical Dementia Rating (CDR)

    This is the most widely used staging system in dementia research. Here, the person with suspected dementia is evaluated by a health professional in six areas: memory, orientation, judgment and problem solving, community affairs, home and hobbies, and personal care and one of five possible stages is assigned.

    Clinical Dementia Rating (CDR) Scale
    CDR-0 -- No dementia
    CDR-0.5 -- Mild
    Memory problems are slight but consistent; some difficulties with time and problem solving; daily life slightly impaired
    CDR-1 Mild
    Memory loss moderate, especially for recent events, and interferes with daily activities. Moderate difficulty with solving problems; cannot function independently at community affairs; difficulty with daily activities and hobbies, especially complex ones.
    CDR-2 -- Moderate
    More profound memory loss, only retaining highly learned material; disoriented with respect to time and place; lacking good judgment and difficulty handling problems; little or no independent function at home; can only do simple chores and has few interests.
    CDR-3 -- Severe
    Severe memory loss; not oriented with respect to time or place; no judgment or problem solving abilities; cannot participate in community affairs outside the home; requires help with all tasks of daily living and requires help with most personal care. Often incontinent.

View References

de Leon MJ and Reisberg B. An Atlas of Alzheimer's Disease. The Encyclopedia of Visual Medicine Series. Parthenon Publishing, Carnforth, 1999. Available at: http://www.alzinfo.org/clinical-stages-of-alzheimers

Reisberg B et al. The Global Deterioration Scale for Assessment of Primary Degenerative Dementia. American Journal of Psychiatry. 1982;139(9):1136-1139.

Resources
Source: 
Alzheimer's Association
Description: 
This site describes the seven stages commonly used to describe the progression of Alzheimer's disease, based on the pattern of symptoms that most people with Alzheimer's exhibit.
Source: 
ElderCare Online
Description: 
This web page describes the Functional Assessment Staging (FAST) scale, a seven stage system for describing the progression of Alzheimer's disease. A section of the web page compares the level of cognitive ability to the age each skill is typically acquired and the stage of Alzheimer's disease at which it is typically lost.
Source: 
The Regional Geriatric Program of Toronto
Description: 
This table describes the Clinical Dementia Rating Scale, a 5 stage rating system with the highest three being mild, moderate and severe dementia. The table describes each stage in terms of loss of memory, orientation to time and place, judgment, community affairs, home and hobbies, and personal care.
Source: 
Mayo Clinic
Description: 
This web page describes the mild, moderate, and severe stages of Alzheimer's disease. It discusses common behaviors to each stage, and the rate of progression of the disease.