This calculator is for general information and education. It is not medical advice and does not replace the judgment of a doctor, nurse or pharmacist who knows the full clinical picture.
What the Neck Disability Index measures
The Neck Disability Index (NDI), published by Howard Vernon and Silvano Mior in 1991, adapts the Oswestry low back questionnaire to neck pain. It measures how much neck pain interferes with daily life and is the most widely used self-report scale for neck pain, whiplash and cervical radiculopathy.
The ten sections
Each section is scored from 0 (no difficulty) to 5 (worst possible):
- Pain intensity
- Personal care (washing, dressing)
- Lifting
- Reading
- Headaches
- Concentration
- Work
- Driving
- Sleeping
- Recreation
The calculator uses short labels; each section of the original questionnaire has six statements describing the levels.
The formula
NDI (%) = total score ÷ (5 × sections answered) × 100
With all ten sections answered, the maximum is 50 points. If a section does not apply, such as driving for someone who does not drive, it is left out of the denominator.
Example
A total of 16 points over ten sections gives 16 ÷ 50 = 32%: moderate disability.
| NDI | Points (of 50) | Disability |
|---|---|---|
| 0 to 8% | 0 to 4 | None |
| 10 to 28% | 5 to 14 | Mild |
| 30 to 48% | 15 to 24 | Moderate |
| 50 to 68% | 25 to 34 | Severe |
| 70% or more | 35 or more | Complete |
Using the score
The minimal clinically important change is usually estimated at 5 to 10 points (10 to 20%), depending on the condition. Repeat the questionnaire at the start of treatment and every few weeks to follow progress.
When neck pain needs prompt care
Weakness or numbness in the arms, problems with balance or bladder control, fever, a recent major injury, or severe pain at night are warning signs that need medical assessment whatever the score.