The construct validity of the Short Form-36 Health Survey for patients with nonspecific chronic neck pain.

Self-reported disability related to neck pain can be measured using general health questionnaires. The validity of the Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36) in patients with nonspecific chronic neck pain (CNP) in a tertiary outpatient rehabilitation setting is unknown. This study investigates construct validity of the SF-36 in these patients using 16 a-priori formulated hypotheses. Ninety-one patients admitted for rehabilitation completed the SF-36 before the rehabilitation program. SF-36 domain scores of patients with CNP were compared with general population reference values and standardized differences were calculated. For both the SF-36 physical and the mental component summary (PCS and MCS), differences between primary and tertiary care setting, men and women, age groups, litigants and nonlitigants, patients with and without compensation, and with ≥3 versus≤2 concomitant complaints were analyzed using independent t-tests. Differences between PCS and MCS scores were analyzed using a paired t-test. Twelve hypotheses were not rejected and four were rejected. All SF-36 domain scores were significantly lower than the general population references values. The domain scores 'role physical', 'bodily pain', 'vitality', 'social functioning,' and 'role emotional' were relevantly (≥1 SD) lower. SF-36-PCS and SF-36-MCS scores were significantly lower in tertiary care. The SF-36-PCS score was significantly lower for patients with workers compensation and patients with at least three concomitant complaints. The SF-36-MCS score was significantly lower for the age group of at least 39 years. The SF-36 has good construct validity and can be used to measure self-reported general health in patients with nonspecific CNP in outpatient tertiary rehabilitation.

Physical dysfunction and nonorganic signs in patients with chronic neck pain: exploratory study into interobserver reliability and construct validity.

STUDY DESIGN: Repeated-measurement design. OBJECTIVES: To explore interobserver reliability of the modified physical dysfunction severity (mPDS) as a measure for impairment of the cervical spine and the modified cervical nonorganic signs (mcNOS) as a measure for behavioral signs, and to explore construct validity of the mPDS and mcNOS. BACKGROUND: The PDS has been used for evaluation of treatment efficacy in controlled trials in primary care. The cervical nonorganic signs were developed to assess illness behavior in patients with neck pain. METHODS: Two observers independently assessed the mPDS and mcNOS in 51 patients with chronic neck pain in an outpatient tertiary rehabilitation setting, with a 3-week interval between assessments. Interobserver reliability for total scores of the mPDS and mcNOS was expressed as an intraclass correlation coefficient. Interobserver agreement for individual mcNOS tests was calculated as absolute agreement and Cohen kappa. Construct validity was expressed as Spearman correlation between the mPDS and mcNOS with the Neck Pain and Disability Scale and numeric pain rating scale for pain. RESULTS: The interobserver reliability of the mPDS and mcNOS had intraclass correlation coefficients of 0.72 and 0.78, respectively. Agreement for individual mcNOS tests ranged from 63% to 88%, and kappa values ranged from 0.14 to 0.54. Correlation with the Neck Pain and Disability Scale was 0.26 for the mPDS and 0.49 for the mcNOS, and the correlation with the numeric pain rating scale was 0.32 for the mPDS and 0.37 for the mcNOS. CONCLUSION: Interobserver reliability of both the mPDS and mcNOS was acceptable. The interobserver agreement for the individual mcNOS tests ranged from poor to acceptable. Construct validity of the mPDS and mcNOS appeared satisfactory.

Detecting relevant changes and responsiveness of Neck Pain and Disability Scale and Neck Disability Index.

PURPOSE: To investigate relevant change on the Neck Pain and Disability Scale (NPAD) and Neck Disability Index (NDI) and which questionnaire is the most responsive in patients with non-specific chronic neck pain (CNP). METHODS: Seventy-six patients with non-specific CNP in an outpatient tertiary rehabilitation setting were dichotomized into "improved" and "stable" based on global perceived effect (GPE) scores. To investigate relevant change minimal detectable change (MDC) and minimal important change (MIC) with the receiver operator characteristic (ROC) cut-off point were assessed. Comparison of responsiveness was performed using areas under the ROC curve (AUC) and correlations between change scores of NPAD and NDI, and GPE. RESULTS: MDC and MIC on NPAD (scale 0-100) were 31.7 and 11.5 points, respectively. MDC and MIC on NDI (scale 0-50) were 8.4 and 3.5 points, respectively. Changes should exceed this MDC or MIC cut-off to be interpreted as relevant. AUC was 0.75 for both NPAD and NDI. Correlations between change scores of NPAD and NDI, and GPE were, respectively, 0.48 (95 % CI 0.29-0.64) and 0.49 (95 % CI 0.30-0.64). CONCLUSIONS: Relevant change on both NPAD and NDI assessed with MDC and MIC resulted in different cut-offs and consequently with different amounts of certainty that the patient is improved. Responsiveness of NPAD and NDI was similar.

Neck Pain and Disability Scale and Neck Disability Index: validity of Dutch language versions.

PURPOSE: To investigate the validity of the Neck Pain and Disability Scale Dutch Language Version (NPAD-DLV) and the Neck Disability Index (NDI)-DLV. METHODS: NPAD-DLV, NDI-DLV, Short-Form-36 Health Survey (SF-36)-DLV, visual analog scale (VAS)(pain) and VAS(disability) were administered to 112 patients with non-specific chronic neck pain in an outpatient tertiary rehabilitation setting. Twenty seven hypotheses were formulated regarding validity. NPAD-DLV and NDI-DLV were evaluated for content validity (normal distribution total scores, missing items, floor and ceiling effects), internal consistency (Cronbach's alpha and Spearman Item-total correlations), construct validity (Pearson correlations with SF-36 domains, VAS(pain) and VAS(disability) and Pearson correlation between total scores of NPAD-DLV and NDI-DLV). RESULTS: NPAD-DLV and NDI-DLV scores were distributed normally. Missing items were negligible. Floor and ceiling effects were absent in NPAD-DLV and in NDI-DLV two items had floor effects and one item had a ceiling effect. Cronbach's alpha of NPAD-DLV was 0.93 and of NDI-DLV 0.83. Item-total correlations ranged for NPAD-DLV from 0.45 to 0.73 and for NDI-DLV from 0.40 to 0.64. The correlation between, respectively, NPAD-DLV and NDI-DLV and: SF-36 domains ranged from -0.36 to -0.70 and from -0.34 to -0.63; VAS(pain) was 0.54 and 0.43; VAS(disability) was 0.57 and 0.52. The correlation between the total scores of NPAD-DLV and NDI-DLV was 0.77. Twenty six hypotheses were not rejected and one hypothesis was rejected. CONCLUSION: The NPAD-DLV and NDI-DLV are valid measures of self-reported neck-pain related disability.

Neck Pain and Disability Scale and the Neck Disability Index: reproducibility of the Dutch Language Versions.

The first aim of this study was to translate the Neck Pain and Disability Scale (NPAD) from English into Dutch producing the NPAD-Dutch Language Version (DLV). The second aim was to analyze test-retest reliability and agreement of the NPAD-DLV and the Neck Disability Index (NDI)-DLV. The NPAD was translated according to established guidelines. Thirty-four patients (mean age 37.5 years, 68% female) with chronic neck pain (CNP), within an outpatient rehabilitation setting, participated in this study. The NPAD-DLV and the NDI-DLV were filled out twice with a mean test-retest interval of 18 days. The intraclass correlation coefficient of the NPAD-DLV was 0.76 (95% confidence interval (CI) 0.57-0.87) and of the NDI-DLV 0.84 (95% CI 0.69-0.92). The limits of agreement of the NPAD-DLV and the NDI-DLV were, respectively, ±20.9 (scale 0-100) and ±6.5 (scale 0-50). The reliability of the NPAD-DLV and the NDI-DLV was acceptable for patients with CNP. The variation ('instability') in the NPAD-DLV total scores was relatively large and larger than the variation of the NDI-DLV.

Basis for a functional capacity evaluation methodology for patients with work-related neck disorders.

BACKGROUND: Neck pain is a common musculoskeletal complaint and a relationship with reduced work-related functional capacity is assumed. A validated instrument to test functional capacity of patients with neck pain is unavailable. The objective of this study was to develop a Functional Capacity Evaluation (FCE), which is content valid for determining functional capacity in patients with work related neck disorders (WRND). METHODS: A review of epidemiological review literature was conducted to identify physical risk factors for WRND. RESULTS: Evidence was found that physical risk factors contribute in development of WRND. Physical risk factors were related to repetitive movements, forceful movements, awkward positions and static contractions of the neck or the neck/shoulder region. An FCE was designed based on the risk factors identified. Eight tests were selected to cover all risk factors: repetitive side reaching, repetitive reaching overhead, static overhead work, front carry, forward static bend neck, overhead lift and the neck strength test. Content validity of this FCE was established by providing the rationale, specific objectives and operational definitions of the FCE. CONCLUSIONS: Further research is needed to establish reliability and other aspects of validity of the neck-FCE.

Relationship between kinesiophobia and performance in a functional capacity evaluation.

Fear of movement and (re)injury (kinesiophobia) has been postulated to play an important role in the performance in a Functional Capacity Evaluation (FCE). This study was performed to analyze the relationship between kinesiophobia and performance in an FCE. Kinesiophobia and FCE performance of 54 male and 10 female patients (mean age 38.0) suffering chronic low back pain (mean length of episode 9.9 months, 93% off work) were assessed. Kinesiophobia was assessed using the Dutch Version of the Tampa Scale for Kinesiophobia (scale 17-68). A lifting task and an FCE were operationalizations of avoidance. FCE results were transformed into a single measure using the classification of the Dictionary of Occupational Titles (FCE-DOT, scale 1-5). Correlations between the variables were calculated. The results are: kinesiophobia mean 41.6 (SD 7.3), lifting mean 29.5 kg (SD 11.6), FCE-DOT mean 3.6 (SD 0.6). Correlations between kinesiophobia and lifting was r = 0.01 (p = 0.93) and between kinesiophobia and FCE-DOT was rho = -0.04 (p = 0.75). The results indicate that the patients were substantially kinesiophobic, yet they were able to lift a mean of 29.5 kg and were physically able to perform moderate to heavy work. The strength of the correlations was very low. The relationship between kinesiophobia and avoidance, operationalized as lifting and an FCE, could not be confirmed in this study.

Concurrent validity of questionnaire and performance-based disability measurements in patients with chronic nonspecific low back pain.

This study aimed to investigate the concurrent validity of two approaches to disability measurement in patients with chronic nonspecific low back pain (CLBP). It was hypothesized that if both are measuring the same construct, the instruments would lead to similar disability results and would correlate strongly (r > 0.75). The study compared the results of self-reported and performance-based measures of disability in 64 consecutive patients with CLBP. Participants mean age was 38.0 years, the mean duration of the current episode of back pain 9.9 months, and 90% were off work due to CLBP. The self-report measures used were: the Roland Disability Questionnaire (Roland); the Oswestry Disability Questionnaire (Oswestry); and the Quebec Back Pain Disability Questionnaire (Quebec). Performance was measured using the Isernhagen Work Systems Functional Capacity Evaluation (FCE). The mean scores from the self-report measure are as follows: Roland 13.5 (scale 0-24), Oswestry 28.2 (scale 0-100), Quebec 37.8 (scale 0-100) consistent with moderate to severe disability. In contrast the results from the performance-based measures suggested that the subjects should be able to work at a physical intensity level of moderate to heavy. Little to moderate correlation was observed between the self-report and performance-based measures (Spearman rank correlations: Roland-FCE (-0.20), p > 0.05; Oswestry-FCE (-0.52), p < 0.01; Quebec-FCE (-0.50), p < 0.01). Results are interpreted to suggest that both performance-based and self-report measures of disability should be used in order to obtain a comprehensive picture of the disability in patients with CLBP.