Use of Dynamic, Automated Facial Analysis in Quantifying Oral-Ocular Synkinesis.

BACKGROUND

Oral-ocular synkinesis is a frequent sequela of idiopathic facial paralysis (IFP), yet objective, dynamic methods to quantify associated palpebral fissure changes remain limited.

OBJECTIVE

To objectively measure palpebral changes in IFP using automated facial tracking.Design Type: Case-control.

METHODS

A novel, video-based facial tracking software assessed facial expressions in 12 controls and 30 IFP cases with synkinesis at least 12 months from onset of IFP. Palpebral fissure dimensions were measured at rest and during smile, laugh, and pucker. Bilateral differences across expressions were analyzed using Wilcoxon signed-rank, Kruskal-Wallis, and linear regression.

RESULTS

Puckering showed the greatest asymmetry (p < 0.001), with a 30.0% reduction in palpebral fissure size on the paralyzed side versus 21.6% on the non-paralyzed side, compared to a 1.7% reduction in controls. No significant differences were observed between paralyzed and non-paralyzed sides during rest-to-smile or rest-to-laugh expressions. Dynamic modeling found that puckering elicited the fastest and largest decline in palpebral fissure symmetry (slope = -0.196; standard error: 0.011; p < 0.001). Paralysis duration following 12 months had no significant effect on palpebral fissure changes.

CONCLUSION

Dynamic facial tracking effectively quantifies expression-specific disruptions in oral-ocular coordination in IFP, particularly during puckering, offering objective data to support treatment planning and patient counseling.