Cognitive Impairment Classifications

Dementia symptoms generally vary in severity and progress over time from no impairment to very severe dementia. Both the Global Deterioration Scale/Reisberg Scale and the Functional Assessment Staging Test (FAST) assign seven stages to the progression of dementia (Table 1).44

Table 1. Dementia Stages and Associated Symptoms.44
Diagnosis Stage Signs and Symptoms
No Dementia Stage 1:
No Cognitive Decline
In this stage a person functions normally and has no memory loss and is mentally healthy. People without dementia would be in stage 1.
No Dementia Stage 2:
Very Mild Cognitive Decline
This stage is used to describe normal forgetfullness associated with aging. For example, forgetting names and where familiar objects were left. Symptoms of dementia are not evident to the individual or their physician.
No Dementia Stage 3:
Mild Cognitive Decline
This stage includes increased forgetfullness, slight difficulty concentrating, and decreased work performance. People may get lost more frequently or have difficulty finding the right words. At this stage, a person's loved ones will begin to notice a cognitive decline.
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.
Mid-Stage Stage 5:
Moderately Severe Cognitive Decline
People in this stage have major memory deficiencies and need some assistance to complete their daily living activities (dressing, bathing, preparing meals, ect.). 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 of day or where they are.
Mid-Stage Stage 6:
Severe Cognitive Delcine (Middle Dementia)
People in Stage 6 require extensive assistance to carry out their Activities of Daily Living (ADLs). 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. Individuals 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 / emotional 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.
Late-Stage Stage 7:
Very Severe Cognitive Decline
(Severe Dementia)
People in this stage have essentially no ability to speak or communicate. They require assistance with most acitivities (e.g., using the toliet, eating). They often lose psychomotor skills. For example, the ability to walk.