Table 1.

Global deterioration scale (modified after Reisberg et al.)[4]

Stage	Signs and symptoms
Stage 1: No cognitive decline	In this stage the person functions normally, has no memory loss, and is mentally healthy.
Stage 2: Very mild cognitive decline	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.
Stage 3: Mild cognitive decline	Increased forgetfulness, slight difficulty concentrating, and 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.
Stage 4: Moderate cognitive decline	Difficulty concentrating, decreased memory of recent events, and difficulty 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.
Stage 5: Moderately severe cognitive decline	Major memory deficiencies and the need for 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.
Stage 6: Severe cognitive decline (middle dementia)	Requires 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.
Stage 7: Very severe cognitive decline (late dementia)	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.