What are the key differences in care and management for a patient with severe dementia at FAST (Functional Assessment Staging) scale 7a versus 7b?

FAST Scale 7a vs 7b: Key Differences in Advanced Dementia

FAST stage 7a represents the ability to speak only a single intelligible word during an average day, while FAST stage 7b represents loss of all intelligible vocabulary—the patient can no longer speak even a single word clearly. 1

Understanding the FAST Staging System

The Functional Assessment Staging (FAST) scale is based on the Global Deterioration Scale and tracks the ordinal progression of Alzheimer's disease through 16 substages, with stage 7 representing severe dementia divided into six substages (7a through 7f). 2, 3 The FAST scale is widely used in geriatric medicine and the US Veterans Administration Health Care System, and is often used to determine preliminary eligibility for palliative or hospice care in patients with severe dementia. 1

Specific Characteristics of FAST 7a

Communication Abilities

• Speech limited to approximately one intelligible word during an average day or in the course of an intensive interview. 2, 3
• The patient may still attempt to communicate but vocabulary is severely restricted to a single recognizable word (e.g., "yes," "no," or a person's name). 3

Functional Status

• Complete dependence for all basic activities of daily living (BADLs) including dressing, bathing, toileting, and transferring. 1, 4
• Requires total assistance with feeding, though may still have some ability to participate in the feeding process (e.g., opening mouth when food is presented). 4

Clinical Implications

• Median survival from FAST 7a is measured in months, with progression through subsequent substages typically occurring over 6-12 months. 5
• Patients at this stage commonly experience pain, agitation, anxiety, and resistiveness to care at least weekly. 6

Specific Characteristics of FAST 7b

Communication Abilities

• Complete loss of intelligible vocabulary—no words can be understood. 2, 3
• The patient may still vocalize (moaning, groaning, grunting, calling out) but produces no recognizable words. 1, 3
• Communication assessment must rely entirely on observational pain behaviors including facial expressions (grimacing, frowning), vocalizations (sighing, moaning), and body movements (guarding, rigidity). 1

Functional Status

• Complete functional dependence identical to FAST 7a, with total assistance required for all BADLs. 1, 4
• Feeding assistance remains necessary, though swallowing difficulties may begin to emerge as the disease progresses toward later substages. 4

Clinical Implications

• Loss of all intelligible speech represents a critical threshold for hospice eligibility determination, as it indicates progression into the terminal phase of dementia. 5
• Mean survival time from FAST stage 7b is typically 3-6 months, though individual variation exists. 5

Critical Care Management Differences

Pain Assessment Approaches

For FAST 7a patients:

• Attempt verbal pain assessment first, as the patient may still be able to communicate "yes/no" or indicate pain with their single word. 1
• Supplement with behavioral observation using validated tools like PAINAD (Pain Assessment in Advanced Dementia) or the Functional Pain Scale. 1

For FAST 7b patients:

• Rely exclusively on behavioral pain assessment tools, as verbal communication is impossible. 1, 4
• Monitor six main categories of pain behaviors: facial expressions, vocalizations, body movements, changes in interpersonal interactions, changes in activity patterns, and mental status changes. 1
• The Critical Care Pain Observation Tool (CPOT) and Behavioral Pain Scale (BPS) are valid tools for non-verbal patients. 1

Hospice Eligibility Considerations

Both FAST 7a and 7b meet criteria for hospice enrollment when combined with medical complications. 5 However, the National Hospice Organization guidelines specifically identify FAST stage 7c (loss of ability to ambulate) and beyond as the threshold for very high mortality with mean survival of 3.2 months. 5

Key hospice eligibility factors beyond FAST staging include: 4, 5

• Medical complications such as aspiration pneumonia, pyelonephritis, septicemia, or stage 3-4 pressure ulcers
• Inability to dress, bathe, toilet, transfer, or feed without complete assistance
• Urinary and fecal incontinence
• Weight loss >10% over 6 months or serum albumin <2.5 g/dL

Medication Management Priorities

At both FAST 7a and 7b, reassess continuation of dementia-specific medications (donepezil, rivastigmine, galantamine, memantine), as these drugs provide minimal benefit in severe dementia and may cause burdensome side effects. 1, 4 The focus should shift entirely to comfort-directed pharmacotherapy. 4

Proactive symptom management becomes paramount: 4, 6

• Pain management using scheduled analgesics (acetaminophen every 6 hours unless contraindicated)
• Constipation prevention with bowel regimen
• Agitation management with non-pharmacologic interventions first, reserving antipsychotics as carefully monitored last resort due to increased risk of falls, stroke, and death 1

Common Pitfalls to Avoid

Staging Accuracy Issues

• Approximately 41% of dementia patients do not follow the ordinal FAST progression, particularly those with atypical dementias (vascular dementia, Lewy body dementia, frontotemporal dementia). 5, 2 Do not force-fit patients into FAST stages if their disease progression is non-ordinal.
• FAST staging should be determined through structured interview with the care partner, not brief clinical observation, as patients may perform differently in clinical settings versus home environments. 1

Communication Assessment Errors

• Do not assume complete inability to understand at FAST 7a or 7b—receptive language abilities often outlast expressive abilities. 3 Continue speaking to patients respectfully and providing explanations even when they cannot respond verbally.
• Distinguish between inability to speak (FAST 7b) and refusal to speak due to depression or behavioral symptoms, which requires different management. 1

Premature Withdrawal of Care

• FAST 7a and 7b alone do not define imminent death—patients may remain at these stages for months to over a year, particularly with good supportive care. 5 Avoid nihilistic approaches that withdraw all active management.
• Comfort feeding by hand should continue as long as the patient shows interest and can safely swallow; tube feeding is not recommended but hand feeding maintains quality of life. 4