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RehabMeasures Instrument

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Purpose

The Neck Disability Index (NDI) is a self-report questionnaire used to determine how neck pain affects a patient’s daily life and to assess the self-rated disability of patients with neck pain.

Acronym NDI

Area of Assessment

Activities of Daily Living
Attention & Working Memory
Functional Mobility
Life Participation
Occupational Performance
Pain
Quality of Life
Sleep

Assessment Type

Patient Reported Outcomes

Administration Mode

Paper & Pencil

Cost

Free

Cost Description

Free to access for students, physicians, clinical practice, and non-funded academic users. Fees may apply for funded academic users, healthcare organizations, commercial users, and IT companies. More details can be found on the Mapi Research Trust website: https://eprovide.mapi-trust.org/instruments/neck-disability-index

Diagnosis/Conditions

  • Pain Management

Key Descriptions

  • Originally developed in 1991, the NDI is now the most widely used instrument for assessing self-rated disability in patients with neck pain.
  • The NDI consists of ten questions in the following domains: Pain Intensity, Personal Care, Lifting, Reading, Headaches, Concentration, Work, Driving, Sleeping, and Recreation.
  • Scoring: Each question contains six answer choices, scored from 0 (no disability) to 5 (complete disability). All section scores are then totaled. Scoring is reported on a 0-50 scale, 0 being the best possible score and 50 being the worst. Alternately, the score can be reported from 0-100. The score is often reported as a percentage (0-100%).

Number of Items

10

Equipment Required

  • Pen or pencil
  • Copy of outcome measure

Time to Administer

5 minutes

5 minutes or less

Required Training

No Training

Age Ranges

Adult

18 - 64

years

Elderly Adult

65 +

years

Instrument Reviewers

Lauren Alpert, SPT Allison Bell, SPT Sarah Casten, SPT Cassandra Deitrick, SPT Taylor Harrington, SPT David Lawton, SPT Kenny Palmer, SPT Monica Pamer, SPT Susan Rhea, SPT Katrina Schenck, SPT in July 19, 2013. Updated by James Dunning, DPT, MSPT, MSc in March 2014

Body Part

Neck

ICF Domain

Body Function
Activity
Participation

Measurement Domain

Activities of Daily Living
Motor
Sensory

Professional Association Recommendation

Childs & colleagues (2008) recommend the use of the NDI as a validated self-report questionnaire for patients with neck pain. The NDI is useful in identifying a patient’s baseline pain, function, and disability status and for monitoring change in a patient’s status through the course of treatment.

Considerations

(Young et al, 2009)

Consider NDI changes of 10 points to be clinically meaningful for patients presenting with mechanical neck pain both with and without concurrent UE symptoms. 

(Young et al, 2010)

Consider NDI changes of 13 points to be clinically meaningful for patients presenting with cervical radiculopathy. 

(Richardson et al, 2011)

Translational healthcare economic models demonstrate that NDI scores are predictive of SF-6D utility scores in patients receiving either a total disc arthroplasty or anterior cervical discectomy and fusion for treatment of symptomatic cervical disc disease involving one vertebral level between C3 and C7. Utility scores derived from the NDI may be useful in making cost-effective choices in guiding evidence based care among and between healthcare disciplines. 

(Jorritsma et al, 2012)

Clinicians should be aware that choosing either the minimal detectable change (MDC) or the minimal important change (MIC) gives different cut-off values and amounts of certainty on whether the observed change is relevant in patients with non-specific neck pain of duration greater than 3 months. Of the two options, application of the MDC is the more conservative choice. Thus, the use of MDC over the MIC increases the certainty that the observed change score is relevant and larger than measurement error. 

(Aillet et al, 2013)

Sports and computer work are important aspects to consider in regards to the modern disablement process of neck pain. These components are not addressed by the NDI, which suggests the NDI may be an incomplete primary outcome measure. 

(Alliet et al, 2013)

Medication use can have an impact on the scoring of the different items of the NDI and also on the interpretation of the score. Medication use is not addressed by the NDI, which suggests the NDI may be an incomplete primary outcome measure. 

(Hoving et al, 2003, Neito et al, 2008, Chan Ci En et al, 2009)

Several relevant items, such as social and emotional items, of whiplash-associated disorders are out of the scope of the NDI. This suggests the NDI may be an incomplete primary outcome measure in the whiplash-associated disorder population. 

(Carreon et al, 2010)

The change in NDI score at which a cervical spine fusion patient will perceive a marked improvement, compared to before surgery, is a 10 point decrease. 

(Shaheen et al, 2013)

Missing data for driving (item 8) occurs with a high frequency. This may be due to the fact that driving is restricted to certain genders in certain cultures. Cultural factors should be considered when selecting the NDI as a primary outcome measure. 

(Nieto et al, 2008)

The NDI demonstrates a two factor structure in the whiplash-associated disorder population. The first factor, referred to as “pain and interference with cognitive functioning”, encompasses the following items: neck pain intensity, reading, headaches, concentration, and sleeping. This factor alludes to the extent to which neck pain interferes with a person’s cognitive functioning. The second factor, referred to as “functional disability”, encompasses the following items: personal care, lifting, work, driving, and recreation. This second factor refers to the extent to which neck pain influences the performance of a person’s usual physical activity.

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Movement and Gait Disorders

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Standard Error of Measurement (SEM)

Cervical Radiculopathy: 

(Cleland et al, 2006; n = 38; mean age = 51.2 (10.6) years

  • SEM = 4.4 (on a scale of 0 - 50)

(Young et al, 2010; n = 165; mean age = 49 (9.7) years)

  • SEM = 5.7 (on a scale of 0 - 50) 

 

Mechanical Neck Disorder: 

(Cleland et al, 2008; n = 138; mean age = 42.5 (11.9) years

  • SEM = 8.4 (on a scale of 0 - 50) 

(Young et al, 2009; n = 91; mean age = 47.8 (14.6) years

  • SEM = 4.3 (on a scale of 0 - 50) 

 

Non-Specific Neck Pain: 

(Jorristsma et al, 2012; n = 76; mean age = 38.5 years) 

  • SEM = 3.0 (on a scale of 0 - 50) 

 

Mixed NSNP:

(Vos C.J., Verhagen A.P., Koes B.W., 2006; n = 187)

  • SEM = 0.60 (WAD, arm pain, shoulder pain, headaches)

(Westaway M.D., Stratford P.W., Binkley J.M., 1998; n = 31, average age = 40.4)

  • SEM = 1.80 (torticollis, radiologically confirmed osteoarthritis, radicular findings, history of MVA)

Minimal Detectable Change (MDC)

Mechanical Neck Disorders

(Cleland et al, 2008)

  • MDC = 19.6% (on a scale of 0 - 100%) 

(Young et al, 2009)

  • MDC = 10.2 (on a scale of 0 - 50) 

 

Cervical Radiculopathy: 

(Cleland et al, 2006)

  • MDC = 10.2 (on a scale of 0 - 50) 

(Young et al, 2010)

  • MDC = 13.4 (on a scale of 0 - 50) 

 

Non-specific Neck Pain: 

(Pool et al, 2007; n = 183; mean age = 45.8 (11.6) years)

  • MDC = 10.5 calculated (on a scale of 0 - 50) 

(Jorristsma et al, 2012)

  • MDC = 8.4 (on a scale of 0 - 50)

 

CR:

(Young I.A., Cleland J.A., Michener L.A., Brown C., 2010)

  • MDC = 13.4

(Cleland J.A., Fritz J.M., Whitman J.M., Palmer J.A., 2006; n = 38)

  • MDC = 10.2

 

Mixed NSNP:

(Pool J.J., Ostelo R.W., Hoving J.L., Bouter L.M., de Vet H.C., 2007; n = 183)

  • MDC = 10.5

(Vos C.J., Verhagen A.P., Koes B.W., 2006)

  • MDC = 1.66 (WAD, arm pain, shoulder pain, headaches)

(Westaway M.D., Stratford P.W., Binkley J.M., 1998)

  • MDC = 4.20 (torticollis, radiologically confirmed osteoarthritis, radicular findings, history of MVA)

Minimally Clinically Important Difference (MCID)

Mechanical Neck Disorders: 

(Young et al, 2009)

  • MCID = 7.5 (on a scale of 0 - 50) 

(Cleland et al, 2008)

  • MCID = 19% (on a scale of 0 - 100%) 

(Stratford P.W., Riddle D.L., Binkley J.M., Spadoni G., Westaway M.D., Padfield B., 1999)

  • MCID = 5.0

 

Cervical Radiculopathy: 

(Young et al, 2010)

  • MCID = 8.5 (on a scale of 0 - 50) 

(Cleland et al, 2006)

  • MCID = 7.0 (on a scale of 0 - 50) 

 

Non-specific Neck Pain: 

(Pool et al, 2007)

  • MCID = 3.5 

(Jorristsma et al, 2012)

  • MCID = 3.5 (on a scale of 0 - 50) 

 

Cervical Spine Fusion: 

(Carreon et al, 2010; n = 505; mean age = 52.6 (10.2) years)

  • MCID = 7.5 (on a scale of 0 - 50)

Test/Retest Reliability

Mechanical neck disorders:

(Stratford P.W., Riddle D.L., Binkley J.M., Spadoni G., Westaway M.D., Padfield B., 1999)

  • r = 0.94

(Ackelman B.H., Lindgren U., 2002; n = 97)

  • r = 0.81 – 0.99

(Vernon H., Mior S., 1991)

  • r = 0.89 

(Young et al, 2009)

  • Adequate test retest reliability (ICC = 0.64) 
  • According to Hogg-Johnson (2009), the low test retest reliability in this study, when compared to other studies, could be due to the inclusion criteria or due to methodological problems. Precision of the estimate could also have been affected by small sample size or the study's definition of a 'stable' sample. 

 

Cervical Radiculopathy:

(Young et al, 2010) 

  • Adequate test retest reliability (ICC = 0.55) 

 

Neck Pain: Mechanical:

(Cleland et al, 2008)

  • Adequate test retest reliability (ICC = 0.50) 

 

Neck Pain:

(Westaway M.D., Stratford P.W., Binkley J.M., 1998)

  • ICC = 0.89 (included torticollis, radiologically confirmed osteoarthritis, radicular findings ,and patients with a history of MVA)

(Vos C.J., Verhagen A.P., Koes B.W., 2006)

  • ICC = 0.90 (23% had WAD, 37% had ‘arm pain’, 56% had ‘shoulder pain’, and 62% had headaches) 

(Shaheen et al, 2013; n = 65, mean age = 41.3 (10.2) years)

  • Excellent test retest reliability (ICC = 0.96) 

 

Cervical Radiculopathy:

(Cleland et al, 2006)

  • Adequate test retest reliability (ICC = 0.68) 

 

Neck Pain: Degenerative, post-traumatic and other:

(McCarthy et al, 2007; n = 160 patients attending the Spinal Out-Patients Department at Queen’s Medical Centre in Nottingham, UK; mean age = 51.2 (14-93 years); sex = 64 males and 96 females; 34 patients completed a survery 2 weeks later; average NDI score = 46%)

  • Excellent test retest reliability (ICC = 0.93) 

 

Neck Pain: Chronic, non-specific:

(Jorristsma et al, 2012) 

  • Excellent test retest reliability (ICC = 0.86) 

 

Patients who underwent cervical fusion for degenerative disorders:

(Carreon et al, 2010)

  • Excellent test retest reliability (ICC = 0.90 to 0.93)

Internal Consistency

Neck pain: Chronic, uncomplicated: 

(Gay et al, 2007; n = 23; mean age = 49.6 (14.6) years)

  • Adequate internal consistency (Cronbach alpha= 0.72 pretreatment and 0.77 post-treatment) 

 

Neck Pain: 

(Shaheen et al, 2013)

  • Excellent internal consistency (Cronbach alpha= 0.89) 

 

Neck Pain: Degenerative, post-traumatic and other:

(McCarthy et al, 2007;  n = 160; mean age = 51.2 years)

  • Excellent internal consistency (Cronbach alpha= 0.864) 

 

Patients who underwent cervical fusion for degenerative disorders:

(Carreon et al, 2010)

  • Adequate to Excellent internal consistency (Cronbach alpha ranged from 0.74 – 0.93) 

 

Subacute whiplash patients with neck pain:

(Nieto et al, 2008; n =150; mean age = 35 (11.13) years)

  • Excellent internal consistency (Cronbach alpha= 0.87) 

 

Neck pain: Mechanical, non-specific:

(Van Der Velde et al, 2009; n = 521 subjects with neck pain; mean age = 44.95 (11.50 years); sex = 338 women and 183 men; mean neck pain intensity in week prior to study = 5.17 (1.87); mean NDI score = 13.57 (5.75))

  • Adequate internal consistency (Cronbach alpha ranged from 0.73 - 0.80)

(Hains F., Waalen J., Mior S., 1998; n = 237)

  • Cronbach's alpha = 0.92

 

Whiplash

(Vernon H., Mior S., 1991)

  • Cronbach's alpha = 0.80

Criterion Validity (Predictive/Concurrent)

Cervical Fusion for Degenerative Disorders Population:

(Carreon et al, 2011; n = 2080 patients undergoing cervical fusion for degenerative disorders; NDI scores were collected before surgery and 12 and 24 months after surgery; sex = 33% male; mean age = 50.4 (11.0) years) 

  • Excellent concurrent validity with SF - 6D (r = 0.82) 
  • Excellent predictive validity with SF - 6D (r = 0.81) 

 

General Neck Pain Population: 

(McCarthy et al, 2007) 

  • Adequate to Excellent concurrent validity with SF - 36 (r = 0.45 to 0.74) 

 

Subacute Whiplash Patients with Neck Pain: 

(Nieto et al, 2008) 

  • Adequate concurrent validity with pain intensity (r = 0.51) 
  • Adequate concurrent validity with pain interference index (= 0.50) 
  • Adequate concurrent validity with depression scale (= 0.51)

Construct Validity

Mechanical Neck Disorders: 

(Young et al, 2009) 

  • Adequate construct validity with global rating of change (r = 0.52) 

Young (2010): 

  • Examined by comparing baseline scores and follow-up scores for stable and unstable groups using 2-way ANOVA. Showed significant change (P<0.001) in disability among self-rating patients. 

(Shaheen A.A., Omar M.T., Vernon H., 2013)

  • Strong correlation with GRC: r = 0.81

 

Cervical Radiculopathy (CR)

(Cleland J.A., Fritz J.M., Whitman J.M., Palmer J.A., 2006)

  • Poor construct validity

 

Neck pain: Chronic, uncomplicated:

Gay (2007): 

  • Adequate construct validity with the VAS (r=0.45) 
  • Excellent construct validity with the NBQ on pre and posttest respectively (r=0.8 and 0.77 respectively)

(McCarthy M.J., Grevitt M.P., Silcocks P., Hobbs G., 2007)

  • Correlation with SF-36 (each of the eight domains): r = -0.45 to -0.76 (spinal surgery outpatient setting)

(Riddle D.L., Stratford P.W., 1998; n = 146)

  • Adequate correlation with Mental Component Summary (MCS) of SF-36: r = 0.47
  • Adequate correlation with  Physical Component Summary (PCS) of SF-36: r = 0.53

(Westaway M.D., Stratford P.W., Binkley J.M., 1998)

  • Correlation with Patient-Specific Functional Scale (PSFS): r = 0.73 (at admission)
  • r = 0.81 (at discharge)

 

Neck Pain: Chronic, non-traumatic: 

Chan Ci En (2009, n = 20; mean age = 64.5 (12.8) years): 

  • Excellent construct validity with the NPAD (r= 0.86)

 

Neck Pain: With or without radiation to arm: 

Alliet (2013; n = 338; mean age = 41.3 (11.8) years):

  • Excellent construct validity with the DASH (r= 0.75)

 

Whiplash-associated disorders:

Hoving (2003, n = 71; mean age = 40.1 (14.3) years)

  • Excellent construct validity with the NPQ (r =0.88)

 

Symptomatic cervical disc disease:

Richardson (2011, n = 430; mean age = 43.2 (7.9) years): 

  • Excellent construct validity with the SF-6D for all tested algorithms (r= >0.82).

Content Validity

Whiplash associated disorders:

(Hoving et al, 2003)

  • The NDI and NPQ do not assess the full range of disabilities indicated as important to the patient in the PET. Of the 9 problems most frequently identified by the PET, only 3 are measured by the NDI (work, driving, and sleeping) and 4 by the NPQ (work, driving, sleeping, and social activities.) Other problems such as emotional and social functioning are not addressed by the NDI or NPQ

 

Neck Pain: Chronic, non-traumatic:

(Chan Ci En et al, 2009)

  • Of the 11 problems identified by the majority of subjects in the PET, the NDI contained 6 of these problems and the NPAD contained 7

 

Neck Pain: With or without radiation to arm:

(Ailliet et al, 2013)

  • Review of the literature and personal communication with the developer of the NDI confirmed that the NDI was based on the concept of disability; 11 neck pain experts and 10 patients commented on the construct, comprehensiveness, and relevance of the NDI 

 

Subacute whiplash patients with neck pain:

(Nieto et al, 2008)

  • Based on factor analysis the NDI can be viewed as a two-factor instrument. It can be broken down to pain intensity and interference with the level of cognitive functioning as well as interference with the level of physical functioning

Face Validity

Neck Pain: With or without radiation to arm:

(Ailliet et al, 2013)

  • Reviewed with 10 patients, who commented on construct, comprehensiveness, and relevance of NDI

Floor/Ceiling Effects

Neck Pain: With or without radiation to arm:

(Ailliet et al, 2013)

  • Propose that a 10 - item computerized adaptive test can make it so that ceiling and floor effects are very unlikely to occur in the clinical applications (alternative to NDI) 

 

Neck pain: Chronic, uncomplicated:

(Gay et al, 2007)

  • There were no apparent floor or ceiling effects for either the NDI or the NBQ 

 

Whiplash associated disorders:

(Hoving et al, 2003)

  • The overall scores for the NDI and NPQ showed no floor/ceiling effects. However, ceiling effects existed for some individual items on the NDI

 

Symptomatic cervical disc disease:

(Richardson et al, 2011)

  • Ceiling and floor effects were generated in the utility scores: >0.9 or <0.2 

 

Neck Pain:

(Shaheen et al, 2013)

  • No floor/ceiling effects as less than 15% of patients achieved the minimum possible scores

Responsiveness

Mechanical Neck Pain

(Cleland J.A., Childs J.D., Whitman J.M., 2008)

  • AUC = 0.83, acceptable 

(Stratford P.W., Riddle D.L., Binkley J.M., Spadoni G., Westaway M.D., Padfield B., 1999)

  • AUC = 0.9, acceptable 

(Jorritsma W., Dijkstra P.U., de Vries G.E., Geertzen J.H., Reneman M.F., 2012)

  • AUC = 0.75, acceptable

(Young B.A., Walker M.J., Strunce J.B., Boyles R.E., Whitman J.M., Childs J.D., 2009)

  • AUC = 0.79, acceptable 

 

Neck pain: Chronic, uncomplicated:

(Gay et al, 2007)

  • Large effect size = 1.12 

 

Mechanical Neck Disorders:

(Cleland et al, 2008)

  • Moderate responsiveness; NDI and GRCS (r = 0.58), NDI and NRS (r= 0.57) 

 

Neck Pain:

(Shaheen et al, 2013)

  • Responsiveness was calculated by comparing change in NDI scores between improved and stable patients 1 week post treatment 
  • The results were statistically significant (P < 0.05) 

 

Cervical Radiculopathy:

(Young I.A., Cleland J.A., Michener L.A., Brown C., 2010)

  • AUC = 0.74, acceptable

(Cleland et al, 2006)

  • AUC = 0.57 indicating an “inability to identify changes in patient’s perceived levels of disability when such a change had occurred”
  • Correlation between change scores on NDI and GROC and NPRS was not significant 

 

Cervical Fusion for Degenerative Disorders Population: 

(Carreon et al, 2010)

  • Excellent responsiveness (Effect size = 0.85)

Bibliography

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Carreon, L. Y., Glassman, S. D., et al. (2010). "Neck Disability Index, short form-36 physical component summary, and pain scales for neck and arm pain: the minimum clinically important difference and substantial clinical benefit after cervical spine fusion." Spine J 10(6): 469-474. Find it on PubMed

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