House-Brackmann

Facial nerve function

Grade 1

Normal.

Grade 2

Slight weakness on close inspection.

Grade 3

Obvious weakness but not disfiguring.

Grade 4

Obvious weakness and/or disfiguring asymmetry.

Grade 5

Barely perceptible motion.

Grade 6

No movement.

Reference

Greenberg's Handbook of Neurosurgery, 7th edition