Validation of Objective Measures for Facial Paralysis

Abstract

A shift from subjective scales to objective measures of facial paralysis requires physical models against which to validate and calibrate the new objective techniques. The purpose of this report was to demonstrate such a model and to test the capacity of an objective computer system to accurately measure physical change. The physical model consisted of an advancing edge of a spreading gelatin film. The model was measured in submillimeter increments. Concurrent measurements were made using the computed system. Ten trials were conducted. The objective system proved to be exquisitely sensitive (0.03 mm) and highly correlated with the physical criterion model (Pearson's product moment correlation coefficient [r]=0.9849). Sensitive and calibrated objective methods of analysis of facial motion are crucial to the design of clinical trials, clinical studies of nerve regeneration, and comparisons of reanimation techniques.

Objective Facial Motion Analysis in Patients With Facial Nerve Dysfunction

“…The light reflectance was taken as a two‐dimensional marker of the three‐dimensional surface deformation occurring during facial expression. Helling and Neely 25 studied the proprietary Neely‐Cheung Facial Analysis Computerized Evaluation (FACE) System against a physical model consisting of the advancing edge of a spreading gelatin film. They demonstrated that their objective system (FACE) for the measurement of degrees of paresis and synkinesis was highly correlated with minute increments of movement of the physical model.…”

Automated Facial Image Analysis

“…The Neely-Cheung Facial Analysis Computerized Evaluation (FACE) system 21,[37][38][39] and objective scaling of facial nerve function based on area analysis (OSCAR) 40 provide direct measures of facial contour changes based on changes in light reflectance but require head fixation and yield no information about direction or magnitude of motion. The Vicon Motion system, 41 Peak Motus Motions System, 42 Motion Analysis system, [43][44][45][46] and Expert Vision Motion Analysis System 47 all use automated tracking of reflective markers affixed to the face to quantify displacement, speed, acceleration, and direction of motion in 3 dimensions.…”

Response: Objective Computerized versus Subjective Analysis of Facial Synkinesis

“…We measured synkinesis with a landmark‐based video and computer system, an accepted, reliable, and valid way of measuring facial motion. Several other investigators have used similar techniques for measurement of facial motion in paralyzed and synkinetic faces 3–6 …”