Validation of the Arabic version of the Neck Pain and Disability Scale in patients with chronic neck pain

Abstract

Background
Neck pain significantly contributes to physical disability and interferes with daily functioning and cognitive performance. The Neck Pain and Disability Scale (NPAD) is widely used to assess the severity of neck pain and its broader impact. This study aimed to validate the Arabic version of the NPAD in individuals with chronic neck pain.


Methods
This cross-sectional validation study included 120 participants with chronic neck pain. The Arabic NPAD was developed using international protocols for forward–backward translation and cultural adaptation. Internal consistency was evaluated using Cronbach’s alpha, and test–retest reliability was assessed using intraclass correlation coefficients (ICCs). Factor analysis was conducted to explore the scale's underlying structure. Construct validity was examined via correlations of Arabic NPAD with the Visual Analog Scale (VAS) and the Arabic validated Neck Disability Index (NDI) and the Copenhagen Neck Functional Disability Scale (CNFDS).


Results
Cronbach’s alpha values ranged from 0.941 to 0.950 at baseline and from 0.942 to 0.951 at follow-up, indicating excellent internal consistency. Item-level ICCs ranged from 0.899 to 0.977, with the total NPAD score yielding an ICC of 0.950, confirming excellent test–retest reliability. Significant correlations with VAS, NDI, and CNFDS (P = 0.001) supported construct validity. No floor or ceiling effects were observed. Exploratory factor analysis revealed a dominant factor primarily associated with pain severity.


Conclusion
The Arabic version of the NPAD is a reliable and valid instrument for evaluating chronic neck pain among Arabic-speaking populations, with strong psychometric properties suitable for clinical and research settings.