PRINCIPAL COMPONENT ANALYSIS OF CHEST-WALL MOVEMENT IN SELECTED PATHOLOGIES

A method is presented for assessing a compact set of parameters charac teristic of respiratory system functional status. 3D movements of poin ts in the chest wall and the volumes of chest wall compartments (pulmo nary rib cage, abdominal rib cage and abdomen) are considered. The cc- ordinates of these points are measured using an optoelectronic system for 3D motion analysis. Principal component analysis is applied to the se data. The behaviour of the eigenvectors of the covariance matrix of the 3D co-ordinates of the points on the chest wall shows close agree ment with the pathology characteristics. The same is found for the per centage of total variance explained by the principal components of the volume variations. In this case, the higher values of variance percen tage explained indicate independent motions (active or passive) in the degrees of freedom of the system identified by partitioning the total volume into compartments.