FAST scale vs GDS: how clinicians stage dementia
Three scales turn up in letters, care plans and hospice forms: FAST, GDS and CDR. They measure different things, they roughly line up, and only one of them describes what a caregiver actually sees at home.
The Functional Assessment Staging Tool (FAST)
Published by Barry Reisberg in 1988, FAST describes everyday function: what the person can still do without help. Its seven stages run from no change to full dependence, with stage 6 split into five steps (dressing, washing, toileting, bladder, bowel) and stage 7 into six (speech down to a few words, then one word, walking, sitting, smiling, holding the head up). The order matters: in Alzheimer's disease these abilities are usually lost in roughly the sequence they were gained in childhood, which is why the scale works as a ladder.
Because it is about function, FAST is the scale a family can track. Our monthly checklist uses its structure in plain words.
The Global Deterioration Scale (GDS)
Also from Reisberg's group (1982), the GDS has the same seven stages but describes thinking and memory: recent recall, orientation to time and place, awareness of events, recognition of people. It is rated by a clinician after an assessment and is often written as "GDS 5". FAST and GDS stages correspond, so a person at GDS 5 will usually read as FAST stage 5.
The Clinical Dementia Rating (CDR)
The CDR scores six areas (memory, orientation, judgement, community affairs, home and hobbies, personal care) from 0 to 3 after a structured interview with the person and someone who knows them. It is written as CDR 0.5 (questionable), 1 (mild), 2 (moderate) or 3 (severe). It is common in memory clinics and research and is not something a family scores at home.
How the three line up
| FAST / GDS stage | Everyday picture | Roughly CDR |
|---|---|---|
| 1–2 | No change, or forgetfulness only the person notices | 0 |
| 3 | Others notice in demanding tasks | 0.5 |
| 4 | Help with money, shopping, planning | 1 |
| 5 | Help choosing clothes | 2 |
| 6 | Help dressing, washing, toileting; incontinence | 3 |
| 7 | Few words, then walking, sitting, smiling, head control | 3 |
The alignment is approximate; the scales were not built to convert into each other.
Why the stage is worth recording
A stage is a shared language. "Stage 6b" tells a new carer, a care home or a hospice assessor what help is needed today without a long explanation. Recorded monthly, it also shows the pace of change, which guides when to arrange equipment, day care or respite. What it is not is a prediction for one person: the durations quoted in the literature are averages across many people with Alzheimer's disease.
Dementias other than Alzheimer's do not always follow the ladder. In Lewy body dementia, mobility and hallucinations can come early; in frontotemporal dementia, behaviour and language change before memory. A person who does not fit a single step is common, and the clinician will know how to read that.
Frequently asked questions
Is the FAST scale only for Alzheimer’s disease?
It was built on Alzheimer’s disease, where abilities are usually lost in a predictable order. In vascular dementia, Lewy body dementia or frontotemporal dementia the order can differ, so a person may not fit a single step. The checklist is still a useful description of what help is needed.
Who uses the FAST scale?
Clinicians, care homes and hospices. In the United States, a FAST stage of 7 is part of the usual hospice eligibility guidance for dementia, which is one reason the scale is so widely known.
Can I score the GDS at home?
The GDS describes thinking and memory in clinical terms and is meant to be rated by a clinician after an assessment. FAST describes everyday function, which is what a caregiver sees, so it is the one a family can record at home and bring to the appointment.
Keep it over time in Anchorly
Anchorly records the FAST stage monthly in plain words, next to the daily log and the life story, and puts it on the one-page care snapshot for the care team.
Free, no account, works offline. Your loved one's information stays on the phone.
Sources and wording
- Reisberg B. Functional Assessment Staging (FAST). Psychopharmacology Bulletin 1988;24(4):653–659. The seven-stage structure, the order of steps 6a–6e and 7a–7f, and the typical durations quoted here come from this paper. The checklist lines on this page are Anchorly's own plain-language descriptions, not the published instrument.
- Reisberg B, Ferris SH, de Leon MJ, Crook T. The Global Deterioration Scale for assessment of primary degenerative dementia. American Journal of Psychiatry 1982;139:1136–1139.
- Alzheimer's Association, Stages of Alzheimer's; National Institute on Aging, What happens to the brain in Alzheimer's disease; NHS, Symptoms of dementia.
Last reviewed 2026-10-17. Found something wrong? dev@adelyons.com.
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