Significance of House-Brackmann facial nerve grading global score in the setting of differential facial nerve function

Objective: To determine the clinical significance of the House-Brackmann facial nerve grading scale (HBFNGS) in the setting of differential function along the branches of the facial nerve. Study Design: Prospective study of 38 patients with facial palsy who demonstrated differential facial function. Setting: Tertiary referral center. Patients: Patients with facial nerve dysfunction from any cause. Patients with complete facial nerve paralysis (House-Brackmann Grade 6) were excluded. Intervention: Physicians were provided with printed description of the HBFNGS 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. This was reported as FwExNYMz, where w, x, y, and z ranged from 1 to 6 based on the HBFNGS. Synkinesis was graded as none, mild, or severe. Main Outcome Measures: The traditional HBFNGS score was compared with a regional grading facial nerve grading system based on the HBFNGS for the forehead, eye, nose, and mouth. Agreement between the traditional global score and the regional scores was analyzed. Results: In patients with variable facial weakness, the single House-Brackmann score did not fully communicate their facial function. Further, the single grade did not always correlate with the best or worst function along the four facial regions. The single House-Brackmann score most strongly correlated with the regional scoring of the eye (61 %), followed by the nose/midface (40%), mouth (32%), and forehead (18%). The global score did not correlate with the worst regional score in 30 patients (79%). In 3 of 5 patients with synkinesis and an obligatory Grade 3 or higher in the global House-Brackmann grading system, the regional facial function was Grade 2 or better at one or more areas of the face. Conclusions: In patients with differential facial function; a single global number is inadequate to describe facial function and primarily reflects the function of the eye. Regional assessment using the HBFNGS and reported as FwExNyMz, more fully communicates facial function.