Neck Disability Index calculator

An Oswestry, rebuilt for the neck

Howard Vernon built the NDI in the late 1980s by adapting the Oswestry low back index, with its author’s permission. Six Oswestry items survived the cut — pain intensity, personal care, lifting, sleep, driving and sex life — and four neck-specific ones were added: headaches, concentration, reading and work. Whiplash patients in the pilot rejected the sex-life item outright, so recreation replaced it. If you already score the Oswestry Disability Index, the layout will feel familiar; the interpretation bands do not carry over.

It is the neck’s counterpart to the DASH for the arm, and simpler to score: no conversion formula, just ten sections at 0–5 added together. The 1991 validation reported a test-retest correlation of r = 0.89 and an internal consistency of 0.80.

Scoring it by hand

1. Each section has six statements. The first scores 0, the last 5; the patient marks one per section.
2. Add the ten section scores. The total runs 0–50 and higher means more self-rated disability.
3. Double it for a percentage. Then write down which one you recorded — most of the literature reports out of 50, and the bands below are read on the raw score.

Worked example

Blank sections: driving, work and the rest

The author’s manual is specific about the two sections that go unanswered most. A patient who does not drive leaves driving out, and the form is scored out of 45, turned into a percentage and halved back to the 50-point scale. A patient who is not employed often skips work because they read it as a paid job; the manual asks you to re-read that section as housework for anyone not working outside the home, so it gets answered rather than dropped.

Beyond that, up to 2 missed sections can be prorated — score out of 45 or 40 and convert, or drop the patient’s average section score into each blank; the two give the same answer, and it is what the calculator does. Three or more missed and the administration is unacceptable.

Reading the bands

The original report attached five interpretation bands to the raw score. They are a guide for talking about a number, not diagnostic cut-offs: Vernon’s 2008 review notes that later authors revised them, mostly to find a single disabled-versus-recovered line, and the recovery cut-offs used across prognosis studies range from 10–20/50, averaging 15/50.

Recovered patients often keep scoring in the 5–15 range out of 50, back at work and all. Discharge on the goal you set, not on a zero.

That is the author’s own caution against “treating till zero”. Set the discharge target in the plan of care at the evaluation, as a raw score, so nobody argues about it at visit twelve.

What counts as a real change

The author’s manual puts the minimally important change at 5 points (10%) for patients in the mild-to-moderate range, where most of them sit: 15 down to 12 is noise, 15 down to 10 is a change. The 2008 review collects the alternatives — 3.5 points from one study, 10 in a small cervical radiculopathy sample — and settles on 3–5 points for everyday practice. MacDermid’s systematic review put the minimum detectable change near 5/50 for uncomplicated neck pain and up to 10/50 with radiculopathy, and found published clinically important differences anywhere from 5–19/50.

Read the sections, not just the total

Two patients at 20/50 can need different care. In the 1991 sample the heaviest sections were headaches, lifting, recreation, reading and driving:

• Headaches2.6 / 5
• Lifting2.2 / 5
• Recreation2.2 / 5
• Reading2.1 / 5
• Driving2.0 / 5

A profile led by reading and concentration points at sustained postures and desk loading — the ground the neck pain exercise progression covers. One led by driving and lifting sends you to the cervical range of motion norms, because shoulder checks and overhead reach are rotation and extension problems. Record both alongside the NDI with the range of motion chart and a pain rating: disability falling while motion and pain hold steady is a patient doing more with the same neck, which is usually the point.

The Neck Disability Index is copyright Howard Vernon; all use is subject to the author’s permission. Section names here are topic labels and the item wording is not reproduced — use the official form and observe its licence.