Strict 2-Surface Proximal Classification of Knee-joint Vibroarthrographic Signals

Externally detected vibroarthrographic (VAG) signals contain information that can be used to characterize certain pathological aspects of the knee joint. To classify VAG signals as normal or abnormal, we propose to apply both the linear and nonlinear strict 2-surface proximal (S2SP) classifiers based on statistical parameters derived from VAG signals and selected by using a genetic algorithm (GA). A database of VAG signals of 89 human knee joints (51 normal and 38 abnormal) was studied. The classification performance of the linear S2SP classifier reached 0.82 in terms of the area under the receiver operating characteristics curve (A_z) and 74.2% in average classification accuracy with the leave-one-out (LOO) procedure. The classification performance of the nonlinear S2SP classifier reached 0.95 in A_z value and 91.0% in average classification accuracy using the Gaussian kernel with the LOO procedure, and possessed good robustness around the selected kernel parameter.