Global Deterioration Scale (GDS): Reisberg's 7 Stages of Dementia

The Global Deterioration Scale (GDS) is Barry Reisberg's 7-stage scale for staging primary degenerative dementia such as Alzheimer's disease, from normal cognition to very severe decline ^[1]. Its functional companion is the FAST (Functional Assessment Staging) ^[4].

What does the Global Deterioration Scale measure?

The Global Deterioration Scale rates the overall severity of cognitive decline in primary degenerative dementia, and places a person in one of seven stages that run from no decline through the earliest complaints to very severe dementia ^[1]. Reisberg, Ferris, de Leon and Crook published it in 1982 and reported validating it against behavioural, neuroanatomic and neurophysiologic measures ^[1].

Each stage combines memory and other cognitive abilities, everyday function and, in later stages, behaviour and emotional change, so the rating is a single global judgement rather than a test score ^{[1] [12]}. The first three stages come before dementia. Reisberg's group later labelled stage 2 subjective cognitive impairment, stage 3 mild cognitive impairment and stage 4 mild dementia ^[6].

The Global Deterioration Scale is not the same as the Geriatric Depression Scale, which is also abbreviated GDS and screens for depression.

The Global Deterioration Scale and the FAST

Reisberg's FAST was derived from the Global Deterioration Scale and rates function only ^{[3] [5]}. The two are used together as the GDS/FAST staging system, which spans normal ageing through the final substages of Alzheimer's disease ^[4]. FAST stage numbers line up with Global Deterioration Scale stage numbers, and the FAST divides stages 6 and 7 into substages (6a to 6e and 7a to 7f) to describe late-stage decline in more detail ^{[3] [5]}.

Terms of use

Published copies of the scale carry the notice "copyright 1983 by Barry Reisberg, M.D." No general licence terms from the copyright holder were found. The stage descriptions on this page are paraphrased; use the scale itself from an authorized source.

How do you give the Global Deterioration Scale?

• Who rates it. A clinician. It is a clinician's interview-based global severity rating, not a questionnaire the person completes ^[12].
• Sources of information. A clinical interview with the person, plus a caregiver or other informant where possible. Denial is common from stage 3, so a person at that stage may not report memory problems ^[6].
• What to ask about. Memory for recent and past events, orientation, concentration, work and social performance, travel, finances, dressing, toileting and behaviour, as described at each stage ^[1].
• Repeat ratings. Re-staging over time tracks the course of decline ^[4].
• Who it is for. Adults with suspected or diagnosed primary degenerative dementia. It stages severity; it does not diagnose dementia.

How do you score and interpret the Global Deterioration Scale?

Choose the one stage whose description best fits the person overall. There is no total to add up ^[1].

Stage names come from Reisberg et al. (1982) ^[1]; the labels for stages 2 to 4 in brackets come from Reisberg et al. (2008) ^[6]; the FAST correspondence comes from the GDS/FAST staging system ^{[4] [5]}. Use the FAST alongside it to rate function and to place a person within stages 6 and 7.

Psychometric properties

• Original validation. The developers reported using the scale for more than five years and validating it against behavioural, neuroanatomic and neurophysiologic measures in people with primary degenerative dementia ^[1].
• Interrater reliability. In 43 adults with probable Alzheimer's disease, interrater reliability for the Global Deterioration Scale, the BPRS and the Hamilton depression scale was high, with intraclass correlations of 0.82 to 0.998 across the three scales ^[8].
• Vascular dementia. In 39 people with vascular dementia, the stage correlated with memory, overall cognitive ability and instrumental activities of daily living, and accurately classified 87% of participants ^[9].
• Stage 2 outcomes. In a 7-year outcome study, people at stage 2 had a hazard ratio of 4.5 for progression compared with stage 1. In 98 people at stage 2 followed for about two years, the observed decline on the scale was 6.7% per year ^[7].
• Severe stages. MMSE scores were at the floor for virtually everyone at stage 7 (46 people), and close to the floor (within one standard deviation of it) at stage 6 ^[13]. The scale keeps separating people where cognitive tests such as the MMSE cannot.
• Sensitivity to treatment. In pivotal trials in mild to moderate Alzheimer's disease, the Global Deterioration Scale showed a significant medication effect where the MMSE did not ^[12].
• Review. A review of global scales used in Alzheimer's drug trials rated reported reliability and validity as fair to very good, but noted small samples and little published evidence on responsiveness to change ^[11].

Limitations

• Not a diagnosis. The scale stages severity; it does not diagnose dementia or tell dementia types apart.
• Domains do not always move together. In 324 people with Alzheimer's disease, psychiatric symptoms and functional impairment appeared earlier than the scale predicts, and the significant increase in psychiatric symptoms came between stages 3 and 4 rather than 5 and 6. The authors suggested separate scales for cognitive, clinical and functional status ^[10].
• One global rating. Because each stage bundles several domains, a person who fits parts of two stages needs clinical judgement to place.
• Built for Alzheimer's-type decline. It was designed for primary degenerative dementia ^[1]; evidence in other dementias, such as vascular dementia, is limited to small samples ^[9].
• Coarse in early stages. Use cognitive tests such as the MoCA or SLUMS to describe early cognitive change in more detail.
• Name confusion. "GDS" also means the Geriatric Depression Scale; write the full name in records and referrals.