House-Brackman Scale (facial nerve palsy)

The House-Brackmann scale ranges between I (normal) and VI (no movement).

Grade I
Normal symmetrical function

Grade II
Slight weakness noticeable only on close inspection
Complete eye closure with minimal effort
Slight asymmetry of smile with maximal effort
Synkinesis barely noticeable, contracture, or spasm absent

Grade III
Obvious weakness, but not disfiguring
May not be able to lift eyebrow
Complete eye closure and strong but asymmetrical mouth movement
Obvious, but not disfiguring synkinesis, mass movement or spasm

Grade IV
Obvious disfiguring weakness
Inability to lift brow
Incomplete eye closure and asymmetry of mouth with maximal effort
Severe synkinesis, mass movement, spasm

Grade V
Motion barely perceptible
Incomplete eye closure, slight movement corner mouth
Synkinesis, contracture, and spasm usually absent

Grade VI
No movement, loss of tone, no synkinesis, contracture, or spasm

Reference

House JW, Brackmann DE. Facial nerve grading system. Otolaryngol. Head Neck Surg 1985; 93: 146–147.