Biomedical subjects

Julian J Faraway

Publications and source records attributed to Julian J Faraway.

5 recordsLinked to original sources

PubMed2005

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.

Adolescent↗

PubMed2004

A computer algorithm for representing spatial-temporal structure of human motion and a motion generalization method.

Inspired by the generalized motor program (GMP) theory, this study presents a symbolic motion structure representation (SMSR) algorithm that identifies a basic spatial-temporal structure of a human motion. The algorithm resolves each joint angle-time trajectory of a multi-joint motion into a sequence of elemental motion segments and labels each motion segment with a symbol representing its shape ("U": monotonically increasing; "D": monotonically decreasing; "S": stationary). By concatenating symbols according to their order in time, the spatial-temporal structure of a joint angle-time trajectory is represented as a symbolic string. The structure of a multi-joint motion is then represented as a set of symbolic strings. A sample motion, whose structure is identified by the SMSR algorithm, can be generalized to produce an infinite number of similar motion variants. To generate a variant of a sample motion, segment boundary points of the sample motion are first relocated to new locations in the angle-time space, and then individual motion segments of the original joint angle trajectories are shifted and proportionally rescaled to fit the new segment boundary points. This motion generalization method provides a basis for developing GMP-based motion simulation models, and exploring ideas and hypotheses related to the GMP theory through simulation. As an application of the motion generalization method, a motion modification (MoM) algorithm is presented, which adapts existing reach motions for new target locations. Some examples generated by the MoM algorithm are illustrated.

Algorithms↗

PubMed2004

Modeling facial movement: I. A dynamic analysis of differences based on skeletal characteristics.

PURPOSE: To introduce a novel approach to analyze and model facial movements; and to quantify variations in facial movement caused by the extent of skeletal differences between the maxilla and mandible and the middle to lower facial heights. The hypothesis was that there are differences in facial movement related to the underlying facial skeleton which may be explained by the shape of the face rather than the pattern of movement. PATIENTS AND METHODS: The study sample consisted of 43 subjects (23 men, 20 women) with a mean age of 18.5 years (SD = 11.90). Measures of the facial skeletal differences were made from lateral cephalometric radiographs, and subjects were classified as Class I and Class II, and normal to decreased lower anterior face height, respectively. Facial movements were recorded by a video-based tracking system. Descriptive and inferential statistics were performed on principal component scores generated from the movement data. A linear mixed-effects model was used to test for significant differences in movement among the different skeletal types. RESULTS: A dynamic modeling of facial movements was described that has numerous potential clinical applications. Also, differences in movement were found during the lip purse movement. Specifically, skeletal Class I individuals showed greater forward and upward movement during lip purse compared with individuals with severe skeletal Class II who moved their lips straight forward with less magnitude of movement. CONCLUSION: For most of the movements, apart from the lip purse, differences in motion were explained by static facial shape.

Adolescent↗

PubMed2004

Modeling facial movement: II. A dynamic analysis of differences caused by orthognathic surgery.

PURPOSE: The purpose of this study was to determine the facial movement characteristics of patients who underwent orthognathic surgery. The specific aims were to determine the presurgery versus postsurgery differences in facial movements; to determine whether the presurgery facial movements were similar among patients with different dentofacial deformities; and to determine whether patients have a more similar post- than presurgery dentofacial morphology and soft tissue movement. The hypothesis was that there are differences between the pre- and postsurgery facial movements. PATIENTS AND METHODS: The sample consisted of 19 patients (11 women, 8 men) with a mean age of 20.6 years (SD +/- 8.34). Facial movement and lateral cephalometric data were collected at presurgery, and at 6 and 12 months postsurgery. Measures of the facial skeletal differences were made from lateral cephalometric radiographs and facial movements were recorded by a video-based tracking system. Descriptive and inferential statistics were performed on principal component scores generated from the movement data. A linear mixed-effects model was used to test for significant differences in movement. RESULTS: Differences were found between the presurgery and 12-month postsurgery visits for the instructed smile, lip purse, eye closure, grimace, and mouth opening movements as well as the natural smile. Also, there were significant differences at presurgery among the dentofacial groups for the lip purse movement but no differences were found at postsurgery for any of the movements. CONCLUSION: These findings suggest that facial movements are effected by skeletal malocclusion and orthognathic surgical procedures.

Adult↗

PubMed2003

Association between subjective and objective measures of lip form and function: an exploratory analysis.

OBJECTIVE: In patients with cleft lip and palate, the aims of this study were to generate objective measures of different attributes of lip movement and to explore the utility of these objective measures by examining the association between examiners' subjective assessments with the objective measures. PATIENTS AND PARTICIPANTS: Thirteen patients with unilateral cleft lip and palate with varying degrees of cleft scar severity were selected. All patients had a previously repaired complete unilateral cleft lip and palate. INTERVENTIONS: Photographs and videotape recordings were made of the patients with cleft at rest and during smiling. Measurements of lip movement were obtained by means of a motion analysis system. MAIN OUTCOME MEASURES: The study sought to obtain rankings of cleft scar severity and impairment on a 6-point Likert scale by a lay and professional panel and measurements of displacement, asymmetry, speed, and velocity of upper lip during smiling. RESULTS: Displacement was the most consistent and valid objective measurement. An objective analysis of the entire upper lip provided the most information. In general, there was a decrease in the objective measures of upper lip movement as examiners' perceptions of facial appearance or disfigurement at rest and impairment during movement became worse. This relationship was stronger for the at-rest perceptions, implying that subjective assessments should be made with the face at rest. CONCLUSIONS: Objective measures provided the promise for differentiation of the components of movement and should be used to supplement subjective evaluations of lip appearance at rest and during movement.

Adolescent↗