Development, Validity, and Test Reliability and Reproducibility of Facial Palsy-Associated Facial Movement: A...

Facial palsy impairs facial muscle function, impacting both physical and psychosocial well-being. Existing assessment tools often lack sensitivity or functional comprehensiveness. This study aimed to develop and validate a novel facial palsy functional assessment scale (FPFAS) to address these limitations.

A cross-sectional study was conducted in two phases. Phase 1 involved item generation through literature review, expert interviews, and patient input to identify key functional domains. In Phase 2, content validation was performed using the Delphi technique with a panel of eight clinical experts, evaluating item relevance and clarity. The finalized scale was then subjected to test-retest reliability analysis in 48 patients with facial palsy over a three-day interval.

The FPFAS demonstrated excellent content validity, with a scale-level content validity index (S-CVI/Ave) of 0.97. Test-retest reliability was high, with an intraclass correlation coefficient (ICC) of 0.893, indicating strong consistency. Cronbach's alpha of 0.999 further supported the scale's internal reliability.

The FPFAS is a valid and reliable tool for assessing functional impairments in facial palsy. Its comprehensive, patient-centered approach offers a significant improvement over existing grading systems. Further research is recommended to evaluate construct validity and clinical responsiveness.