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

## TL;DR

This study validates an Arabic version of a scale to assess jaw function limitations, ensuring it is reliable and suitable for Arabic-speaking populations.

## Contribution

The study provides a validated and reliable Arabic version of the 8-item Jaw Function Limitation Scale (JFLS-8).

## Key findings

- The JFLS-8 Arabic version has a three-factor structure confirmed by CFA.
- The scale shows high internal reliability with ω = 0.93 and α = 0.93.
- Greater jaw function limitation is associated with insomnia, psychological distress, and neck disability.

## Abstract

Background: 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.
Methods: 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. Results: 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. Conclusions: 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.