A brief 5-item version of the Neck Disability Index shows good psychometric properties

BackgroundThe purpose of this secondary analysis of clinical databases of people with neck pain was to use a mixed unique conceptual and statistical approach to develop a brief version of the Neck Disability Index (NDI).MethodsAn a priori framework of neck-related function based on the International Classification of Functioning, Disability and Health was used to identify items from the original 10-item NDI that do not conceptually fit. …