Neck Disability Index (NDI)

Evaluates the degree of perceived pain neck and the disability status.

You can read more about this disability index and its interpretation in the text below the calculator.

The neck disability index consists of a series of activities of daily living that the subject is asked to evaluate in respect to perceived neck and cervical spine pain.

The NDI is based upon the Oswestry Low Back Pain Disability Index and is a self-report condition specific questionnaire. It is aimed at becoming the first assessment of patients with neck pain, especially that caused by trauma.

Each of the 10 items in the score is awarded a number of points which is then summed to provide the final result.

This is a numeric value which can be transformed in percentage (by multiplication by 2) and is associated with a level of disability.

NDI result (points) NDI result (percentage) Interpretation (level of disability)
0 – 4 0 – 8% None
5 – 14 10 – 28% Mild
15 – 24 30 – 48% Moderate
25 – 34 50 – 64% Severe
35 – 50 70 – 100% Complete


Pain Intensity


Personal Care (Washing, Dressing etc.)

















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NDI explained

This is a self report questionnaire that evaluates the degree of disability in patients with injuries to the cervical spine (that cause chronic disability).

It is based and adapted from the Oswestry Low Back Pain Disability Index. There are 10 items that assess functional status (related to activities of daily living):

NDI item Description
Pain Intensity Pain occurrence and perceived severity
Personal Care Ability to care for oneself and degree of perceived accuracy in doing so
Lifting Capacity to lift different weights with or without pain
Reading Degree of experienced pain in the neck during and in different reading positions
Headache Frequency and perceived severity of recurrent headaches
Concentration Degree of difficulty encountered when trying to concentrate
Work Comparison between current and past work capacity
Driving Ability to drive and length of time to drive before pain occurs
Seeping Quantification of sleep disturbance
Recreation Perceived impairment to partaking in leisure activities

The assessment is recommended to be applied at 2-week intervals, because it can help monitor response to treatment.

The cervical conditions for which the NDI can be applied include:

■ Mechanical neck pain;

■ Cervical radiculopathy;

■ Whiplash Associated Disorders (WAD);

■ Chronic, non-specific neck pain;

■ Chronic, non-traumatic and chronic uncomplicated neck pain;

■ Degenerative, post-traumatic and other neck pain.


Result interpretation

Each of the 10 items in the NDI is awarded a number of points from 0 to 5, therefore the overall score range is between 0 and 50.

Scores closer to 0 indicate little neck pain and discomfort while scores closer to 50 indicate a severe degree of pain and disability that limits activities considerably.

Patients in recovery after injury, score in the range 5 to 20 points.

The score in points can be transformed in a percentage of function.

There are no specific cut-off points but the original score provides an interpretation of the scores in terms of level of disability:

NDI score (points) NDI score (percentage) Interpretation (level of disability)
0 – 4 0 – 8% None
5 – 14 10 – 28% Mild
15 – 24 30 – 48% Moderate
25 – 34 50 – 64% Severe
35 – 50 70 – 100% Complete

The Minimum Detectable Change (90% confidence) is 5 points or 10 %, in subsequent evaluations, in most conditions. However, in mechanical neck pain MDC is 10 (20%) and in cervical radiculopathy is 13 (26%).

The NDI is only criticised for not including psychosocial and emotional aspects of neck disabilities, despite their common occurrence in patients with chronic neck pain, cervical radiculopathy and whiplash associated disorders.


About the study

The NDI was published by Vernon and Mior in 1991 as a modification of the Oswestry Low Back Pain Index, that is addressed to patients with neck pain.

Face validity was ensured through peer-review and patient feedback sessions. The index was also checked for test-retest reliability on a sample of 17 whiplash injured patients.

The alpha coefficients were calculated from a pool of questionnaires completed by 52 patients whilst concurrent validity was assessed on a subset of 10 and then 30 patients. In the larger subset, the NDI results were compared to scores on the McGill Pain Questionnaire (and achieved moderately high correlations).

The neck disability index is an assessment with a high degree of reliability and internal consistency.


Original source

Vernon H, Mior S. The Neck Disability Index: a study of reliability and validity. J Manipulative Physiol Ther. 1991; 14(7):409-15.

Other references

1. Hains F, Waalen J, Mior S. Psychometric properties of the neck disability index. Journal of Manipulative and Physiological Therapeutics 1998; 21(2):75-80.

2. Cleland JA, Childs JD, Whitman JM. Psychometric properties of the Neck Disability Index and Numeric Pain Rating Scale in patients with mechanical neck pain. Arch Phys Med Rehabil. 2008; 89(1):69-74.

3. Hogg-Johnson S. Differences in reported psychometric properties of the Neck Disability Index: patient population or choice of methods? Spine J. 2009; 9(10):854-6.

Specialty: Disability

Objective: Evaluation

Type: Index

No. Of Items: 10

Year Of Study: 1991

Abbreviation: NDI

Article By: Denise Nedea

Published On: June 14, 2017

Last Checked: June 14, 2017

Next Review: June 14, 2023