Agreement between the Sunnybrook, House-Brackmann, and Yanagihara facial nerve grading systems in Bell's palsy

Objective: To assess the agreement between the Sunnybrook facial nerve grading system and the House-Brackmann and Yanagihara systems. Study Design: Prospective clinical facial nerve grading. Setting: Tertiary referral center. Patients: One-hundred assessments, 94 in patients with Bell's palsy and 6 with herpes zoster. Intervention: Diagnostic. Main Outcome Measures: Evaluation according to the weighted regional Sunnybrook system, the gross House-Brackmann system, and the unweighted regional Yanagihara system. Weighted K statistics was used to measure agreement between the grading systems. Results: The average weighted K value between the Sunnybrook, House-Brackmann, and Yanagihara grading systems was 0.65; kappa values increased temporally (but not statistically significantly) up to day 180. The highest agreement value, 0.72, was found between the Sunnybrook and Yanagihara grading systems. The weighted K value between the Sunnybrook and House-Brackmann systems was 0.59. In Sunnybrook gradings less than 63, there was an overlap between House-Brackmann scores of III to VI. Reliable conversion tables between the gross House-Brackmann system and the regional Sunnybrook and Yanagihara systems could not be established. Conclusion: The Sunnybrook system scores at the same agreement level as the House-Brackmann and Yanagihara grading systems. There is an evaluative difference between the weighted regional Sunnybrook and the gross House-Brackmann systems. Substantial agreement was found between the regional Sunnybrook and Yanagihara scales. Sunnybrook grading is easy and quick. By adding objective measurements and additional secondary defects, the Sunnybrook system can be an alternative to the other predominating grading systems.