Global vs Regional HB Score: Reporting Facial Nerve Function

Abstract

Objective To determine the reliability of the House-Brackmann facial nerve grading scale in the setting of differential function across its branches. Methods 14 physicians of different levels were provided with digital video clips of 11 patients with differential facial nerve functioning, and asked to report facial nerve function as a traditional global score and as a regional score based on the House-Brackmann scale for the forehead, eye, nose, and mouth. Agreements between the traditional global score and the regional scores, as well as inter-rater agreement, were analyzed. Results In patients with variable facial weakness, a single House-Brackmann score did not fully communicate their facial function. The single House-Brackmann score most strongly correlated with the regional scoring of the nose/midface (59%), followed by the mouth (51%), eye (48%), and forehead (35%). Overall inter-reader reliability was relatively strong for the midface (kappa=0.503) and global scores (kappa=0.541), followed by the mouth (k=0.419), the forehead (k=0.330), and the eye (k=0.302). There was a marked tendency for reader agreement to increase among those with more clinical experience. Reader agreement of the forehead (k=0.597) and eye (k=0.469) were strong only among experienced readers. Conclusions In patients with differential facial function, a single global score is inadequate to describe facial function, and in this study, most directly correlated with the function of the midface. Regional assessment using the House-Brackmann grading scale more fully communicates facial function and increases in reliability with experience.