Facial Nerve Dysfunction Assessment

Facial Assessment for Facial Nerve Dysfunction

• Facial shape and structure examination assesses contour deformities, soft tissue deficits (atrophy, volume loss, ptosis) and skin thickness, related to prior surgery or trauma. Surgical scars, keloids, hypertrophic scarring, or prior facial paralysis are also noted.

Eyelid Function Assessment

• Eyelid function examination assesses upper and lower eyelid function, including voluntary and involuntary blinking. Lagophthalmos (incomplete eyelid closure) jeopardizes the cornea, so corneal sensation is crucial. Examining medial and lateral canthi laxity helps evaluate ectropion (lower eyelid retraction). The snap or distraction test assesses lower eyelid laxity. The lower lid's normal apposition to the globe ensures proper tear-pumping mechanism (lacrimal punctum contact with lacrimal lake). Lid retraction leads to epiphora (excess tearing) and dry eye symptoms. Lagophthalmos risks exposure keratitis and corneal ulceration. The globe-orbital rim vector (negative vector = globe anterior to orbital rim) affects treatment strategy and risk of ectropion. Proptosis (prominent eyes) also impacts treatment.

Facial Nerve Grading Systems

• Several systems assess facial nerve function. The House-Brackmann Facial Grading System (HBFGS) rates facial motor function on a 6-point scale (I = normal, VI = total paralysis). The Sunnybrook Facial Grading System (SFGS) considers resting symmetry, voluntary muscle excursion, and synkinesis for a composite score. The SFGS is highly reliable, sensitive to recovery over time and is now considered the standard. The revised HBFGS (version 2.0) satisfies most criteria but lacks intraobserver reliability. A review (Fattah et al. 2015) identified 19 facial nerve grading instruments and concluded SFGS as the current standard.