Research

A1

Morphometry

Dimensions, areas, volumes and asymmetry are measured on three-dimensional surface models of regions such as the face, the whole trunk, the back and the extremities. Topics studied in this area include the effect of body position on facial soft tissue, the comparison of asymmetry calculation methods and the anthropometric accuracy of low-cost depth sensors. The methods are also applied to patient groups such as facial palsy, adolescent idiopathic scoliosis, Parkinson's disease, thalassaemia and stroke.

Intersection of morphometry and kinematics

Dynamic morphometry

Changes of the face during facial expressions are assessed by comparing three-dimensional scans taken at rest and during movement. The main topics in this area are the assessment of asymmetry and the monitoring of recovery in facial palsy, the quantification of facial movements in facioscapulohumeral dystrophy, the study of hypomimia in Parkinson's disease and the reliability of scanning methods.

A2a · Biomechanics

Kinematics

Facial and joint movements are measured by tracking passive reflective markers with an optoelectronic system. Topics studied include displacement and angular change during facial expressions, anatomical landmarks that remain relatively stable during movement, and shoulder range of motion. Depth sensors and markerless methods are compared against this system. Kinematic analysis of whisker movement in experimental facial nerve repair models in laboratory animals has also been carried out in this area using markerless systems.

This area also includes a wearable measurement system developed in the laboratory, which aims to track facial movement with flexible (flex) sensors placed on the forehead and cheeks. The study validating the sensors against synchronous optoelectronic recordings has been completed as an undergraduate student project; a manuscript is in preparation.

At the whole-body level, markerless gait analysis is performed with two Azure Kinect depth sensors and iPi Soft software. Joint angles are obtained from the recordings with the iPi Biomech add-on; a study of gait and lower-extremity tasks involving hip and knee movements in Parkinson's disease and in healthy individuals is ongoing.

A2b · Biomechanics

Kinetics

This area covers two levels of measurement: measurement of force and passive mechanical properties in living facial tissue with a dynamometer and, in the laboratory, study of the behaviour of biological tissues and materials under tension, compression and bending with a universal testing machine. Studies on the force and stiffness properties of facial tissue are ongoing.

A3

Neuromuscular activity

The electrical activity of facial muscles is studied with surface EMG recorded synchronously with motion analysis. Studies in this area include the relationship between surface morphometry, kinematics and muscle activity during smiling, and facial kinematics and muscle activity in different age groups.