Validity and reliability of the 8-item version of the jaw functional limitation scale (JFLS-8) in the Arabic language

The Jaw Function Limitation Scale (JFLS) is a recently developed instrument that assesses specific jaw function limitations and objective restrictions in daily activities such as chewing, jaw mobility, and verbal communication in a valid and reliable manner. The scale has been translated and validated in several languages and contexts, but no Arabic version is currently available. To address the absence of a validated tool for assessing jaw dysfunction in Arabic-speaking populations, this study aimed to evaluate the validity, reliability, and factor structure of the 8-item version of the JFLS.

This cross-sectional study was conducted between August and October 2025 and included 427 Arabic-speaking adults from Lebanon. Confirmatory factor analysis (CFA) was used to validate the scale.

The analysis supported a three-factor structure. Internal reliability was satisfactory, with high internal consistency coefficients (ω = 0.93/α = 0.93). Measurement invariance across gender was confirmed, with no significant differences between males and females in jaw function limitation scores. Greater jaw function limitation was significantly associated with increased insomnia, psychological distress, and neck disability, supporting the scale's convergent validity.

This study provides a brief, valid, and reliable Arabic version of the 8-item JFLS for assessing jaw and masticatory functional limitations in Arabic-speaking populations. The scale has potential applications in clinical assessment, intervention planning, and cross-cultural research.