Reliability of the “Sydney,” “Sunnybrook,” and “House Brackmann” facial grading systems to assess voluntary movement and synkinesis after facial nerve paralysis

For clinical grading of voluntary movement, there is good correlation between ratings given on the Sydney and Sunnybrook systems, and within each system there is good reliability. The assessment of synkinesis was far less reliable within, and less related between, systems. Although the reliability of the House Brackmann system was found to be high, examination of individual grades revealed some wide variation between trained observers.