The aim of this study was to translate the Sunnybrook Facial Grading System and its specific criteria into French and validate its use by French-speaking physicians for facial palsy evaluation.

The original English version of the Sunnybrook Facial Grading System and its specific criteria was translated into French according to international standards. Twenty videos of patients with a wide range of facial palsy in terms of duration and severity were independently rated, twice each, by 6 physicians with varied experience in facial palsy care. Internal consistency and intra- and inter-rater reliability were analyzed.

The French version of Sunnybrook Facial Grading System and its specific criteria both showed good internal consistency, with Cronbach alpha of 0.84 and 0.86 respectively. Inter-rater reliability was excellent in both sessions for the composite score, the score of symmetry at rest and during voluntary movement and synkinesis: intraclass correlation coefficient (ICC) between 0.77 and 0.98. Intra-rater reproducibility on the composite score and subscores was also excellent and comparable for expert, experienced and novice physicians, with an average ICC of 0.95.

The French version of the Sunnybrook Facial Grading System and its specific criteria is reliable, reproducible and easy to use by French-speaking teams for facial palsy evaluation.