Visual and statistical modeling of facial movement in patients with cleft lip and palate.

OBJECTIVE: To analyze and display facial movement data from noncleft subjects and from patients with cleft lip and palate by using a new dynamic approach. The hypothesis was that there are differences in facial movement between the patients with cleft lip and palate and the noncleft subjects. SETTING: Subjects were recruited from the University of North Carolina School of Dentistry Orthodontic and Craniofacial Clinics. PATIENTS, PARTICIPANTS: Sixteen patients with cleft lip and palate and eight noncleft "control" subjects. INTERVENTIONS: Video recordings and measurements in three dimensions of facial movement. MAIN OUTCOME MEASURES: Principal component (PC) scores for each of six animations or movements and dynamic modeling of mean animations. STATISTICS: Multivariate statistics were used to test for significant differences in the PC mean scores between the patient groups and the noncleft groups. RESULTS: No statistically significant differences were found in PC mean scores between the patient groups and the noncleft groups; however, the variability of the effect of clefting on the soft tissues during animation was noted when the noncleft data were used to establish a "normal" scale of movement. Compensatory movements were seen in some of the patients with cleft lip and palate, and the compensation was not unidirectional. CONCLUSION: Measures of mean movement differences as summarized by PC scores between patients with cleft lip and palate and noncleft subjects may be misleading because of extreme variations about the mean in the patient group that may neutralize group differences. It may be more appropriate to compare patients to a noncleft normal scale of movement.