Dysphagia Knowledge Hub — 吞嚥困難知識庫
FOIS: Functional Oral Intake Scale
Overview
The FOIS (Functional Oral Intake Scale) is a validated 7-level ordinal scale that measures the actual oral food and liquid intake of patients with dysphagia, from complete tube feeding dependence to unrestricted oral diet. Developed by Crary et al. (2005), it is designed to capture functional outcomes — what the patient is actually eating — rather than the underlying swallowing physiology.
This makes FOIS complementary to instrumental assessments (VFSS, FEES) and physiological measures (Penetration-Aspiration Scale). A patient may have residue or mild penetration on VFSS but still maintain FOIS Level 6 in daily practice.
The 7 Levels
Tube Dependent:
- Level 1: Nothing by mouth
- Level 2: Tube dependent with minimal attempts of food or liquid
- Level 3: Tube supplemented with consistent oral intake of food or liquid
Full Oral Diet:
- Level 4: Total oral diet of a single consistency
- Level 5: Total oral diet with multiple consistencies, but requiring special preparation or compensations
- Level 6: Total oral diet with multiple consistencies, without special preparation, but with specific food limitations
- Level 7: Total oral diet with no restrictions
Validation and Psychometric Properties
Crary et al. (2005) validated FOIS in 61 patients with neurogenic dysphagia following stroke:
- Inter-rater reliability: κ = 0.86 (excellent)
- Intra-rater reliability: κ = 0.91
- Concurrent validity: Significant correlation with Penetration-Aspiration Scale (r = −0.60) and VFSS-based diet recommendations
- Responsiveness: Significant FOIS improvement from admission to discharge in rehabilitation cohorts (mean change ~1.5 levels)
PMID: 16224716
The scale has since been validated or applied in head and neck cancer, Parkinson’s disease, traumatic brain injury, and paediatric populations.
Clinical Use
Admission baseline: Document FOIS level at admission to establish baseline oral intake status.
Goal-setting: FOIS levels provide concrete, measurable rehabilitation goals (“target FOIS Level 5 by discharge”).
Progress tracking: Change of ≥1 FOIS level represents a clinically meaningful improvement in functional oral intake.
Discharge planning: FOIS Level 5 or 6 typically corresponds to safe home discharge on texture-modified diet; Level 7 indicates dietary normalisation.
Research and audit: FOIS is widely used as a primary or secondary outcome in dysphagia intervention trials.
FOIS vs. Other Measures
| Measure | What it captures |
|---|---|
| FOIS | Actual oral intake (functional outcome) |
| PAS (Penetration-Aspiration Scale) | Depth and response to penetration/aspiration on VFSS/FEES |
| IDDSI level | Recommended texture of food/liquid |
| EAT-10 | Patient-reported symptom burden |
FOIS is the only measure in this group that directly quantifies whether and what the patient is eating. It should be recorded alongside IDDSI-recommended levels to give a complete picture.
Common Errors
- Confusing FOIS with IDDSI: FOIS measures actual intake; IDDSI describes the texture that is safe or recommended. A patient on IDDSI Level 4 diet may be FOIS Level 4 (tube supplemented) or FOIS Level 5 (full oral intake on that texture).
- Not updating FOIS with clinical changes: FOIS should be updated whenever feeding status changes — not only on weekly formal reviews.
- Using FOIS as the sole outcome: FOIS does not capture aspiration risk, nutritional adequacy, or symptom burden. Use alongside other measures.
References
- Crary MA, et al. (2005). Initial psychometric assessment of a functional oral intake scale for dysphagia in stroke patients. Arch Phys Med Rehabil, 86(8):1516–20. PMID: 16224716
- Wirth R, et al. (2016). Oropharyngeal dysphagia in older persons — from pathophysiology to adequate intervention. Clin Interv Aging, 11:189–208. DOI: 10.2147/CIA.S97481
- Dziewas R, et al. (2021). Neurology and dysphagia. J Neurol, 268(10):3521–3543. DOI: 10.1007/s00415-021-10627-7