Grading Severity

As facial muscle weakness can vary from mild to complete, grading it can help in the prognosis and follow-up. The modified House-Brackmann classification is the most commonly used scale as in the table below.

Table 1: The modified House-Brackmann classification

Grade Description Characteristics
I Normal Normal facial function
II Mild dysfunction Slight weakness noticeable on close inspection. May have slight synkinesis
III Moderate dysfunction Obvious, but not disfiguring, difference between two sides. Compete eye closure with effort. Noticeable but not severe synkinesis, contracture or hemifacial spasm
IV Moderately severe dysfunction Obvious weakness or disfiguring asymmetry. Normal symmetry or tone at rest. Incomplete eye closure
V Severe dysfunction Only barely perceptible motion. Asymmetry at rest
VI Total paralysis No movement