The NeckPix(©): development of an evaluation tool for assessing kinesiophobia in subjects with chronic neck pain.

PURPOSE: To develop and validate NeckPix(©), a multi-image instrument for assessing daily activities in the context of pain-related fear, in order to allow its use in patients with chronic neck pain (NP).
METHODS: The measure was developed by means of item generation followed by reduction/selection. The psychometric testing included exploratory factor analysis; content validity by investigating clarity, specificity, appropriateness for the target population, relevance and completeness; reliability by internal consistency (Cronbach's alpha) and test-retest stability (intra-class coefficient correlation, ICC); and construct validity by comparing NeckPix with the Tampa Scale of Kinesiophobia (TSK), the Pain Catastrophising Scale (PCS), the Neck Disability Index (NDI) and a Numerical Rating Scale of pain intensity (NRS) (Pearson's correlation).
RESULTS: The measure, which includes ten images used to assess everyday activities in the context of pain-related fear, was administered to 118 subjects with chronic non-specific NP, and proved to be acceptable and feasible. Factor analysis revealed a one-factor solution (which explained 71.12 % of variance). The content of the images was considered adequate, appropriate for the target population, comprehensive, and relevant for evaluating activity-related kinesiophobia. The instrument's internal consistency was good (α = 0.954), as was its test-retest stability (ICC 0.979). Construct validity demonstrated a close correlation with the TSK (r = 0.759), and moderate correlations with the PCS (r = 0.583), the NDI (r = 0.520), and a NRS (r = 0.455).
CONCLUSION: NeckPix(©), which was successfully developed following international recommendations, proved to have a good factorial structure and satisfactory psychometric properties. Its use is recommended for research purposes.