Validation of the Spanish version of the Sunnybrook facial grading system.

Purpose: The Sunnybrook facial grading system (SFGS) is one of the most widely employed tools to assess facial function. The present study aimed to determine the validity and reliability of the Spanish language version of the SFGS.

Methods: Forward-backward translation from the original English version was performed by fluent speakers of English and Spanish. Videos from 65 patients with facial paralysis (FP) were evaluated twice by five otolaryngologists with experience in FP evaluation. Internal consistency and intra- and inter-rater reliability were assessed. The House-Brackmann scale was used to display concurrent validity which was established by Spearman's rho correlation.

Results: The Cronbach's α score exceeded 0.70. The intra-rater intraclass correlation coefficient (ICC) was nearly perfect for the composite score (0.96-0.99), voluntary movements (0.97-0.99), and synkinesis (0.91-0.98), and important to almost perfect for symmetry at rest (0.79-0.97). In both evaluations, the inter-rater ICC was higher than 0.90 for the composite score (0.92-0.96) and voluntary movements (0.91-0.96) and slightly lower for symmetry at rest (0.66-0.85) and synkinesis (0.72-0.87). A strong negative correlation was found between the H-B scale and SFGS (Spearman's rho coefficient = - 0.92, p < 0.001) in both evaluations.

Conclusion: The Spanish version of the SFGS is a reliable and valuable instrument for the assessment of facial function in the diagnosis and treatment of patients with FP.