Biomechanics and Ergonomics

The ability of the hands to grasp and manipulate is of vital importance for the development of daily human activities. A key part of this ability lies in the complexity of the hand kinematics, with 25 predominant degrees of freedom. Any biomechanical model that claims to be used in the study of human hand behaviour must rely on a suitable kinematic model. Some researchers have performed partial studies of the kinematics of healthy hand joints, but to date there is no work that has attempted to quantitatively describe the position and orientation of the different joint rotation axes that define the hand kinematics. Moreover, the identification of changes in the kinematic behaviour of the pathological hand are of great interest for the diagnosis of hand diseases as well as for monitoring and control of clinical rehabilitation of the hand; this is a field of research that has been very little explored to date. In particular, it would be especially interesting to replace radiographic analyses by experimental kinematic analyses. Today, doctors and therapists use mobility analyses for diagnosing hand diseases and to establish the level of affection. But these analyses are manual and qualitative.
The project starts from the group’s previous experience in grasp biomechanics and in the development of a biomechanical model of the whole hand. The objective is to go a step further, generating the required information to get a more accurate and correct kinematic model to simulate hand pathologies and associated restoring surgery. Also, the objective is generating valuable information contributing to the generation of tools for the diagnosis, monitoring and rehabilitation of hand disorders.
The ultimate goals of the project can be summarized as: 1) Kinematic characterisation of the healthy hand by obtaining. The position and orientation of the rotation axes of the different joints will be obtained in a parametric way; this will be used to improve the existing biomechanical and ergonomic models. 2) Kinematic characterisation of the pathological hand. Prospectively, the rotation axes of the healthy and pathological hand will be compared to identify changes that may be used in the diagnosis and monitoring of hand diseases. 3) Dimensional reduction of the pathological hand kinematics. Again in a prospective manner, the hand movements while grasping and manipulating on a number of typical daily life activities will be registered in both the healthy and pathological hands. The kinematics of these movements will be reduced using principal component analysis. The postural patterns (principal components) obtained will be studied and compared to detect changes in these patterns that may be used in the diagnosis and monitoring of hand diseases.