Quantitative Evaluation of Human Finger Tapping Movements Through Magnetic Measurements

In this study, a magnetic sensor consisting of two coils was used to measure and evaluate finger tapping (FT) movements for diagnosis support and assessment of motor function. The sensor enables estimation of the distance between the two coil-bearing fingertips according to the nonlinear relationships between voltage and distance. The finger movements measured are evaluated by computing 12 indices, such as the FT interval and maximum amplitude, and radar charts of the evaluation indices are then displayed in real time on a monitor. The user can thus intuitively understand the features of FT movements. Verification experiments on magnetic measurement of finger movements were performed, and the results showed that finger movement could be measured with a high degree of accuracy. The results of finger movement evaluation for 30 Parkinson's disease (PD) patients and 32 normal elderly subjects showed that all evaluation indices differed significantly for each group, and the proposed system could be used to assess the Unified PD Rating Scale part III FT score by evaluating the number of indices with values greater or smaller than plus/minus double the standard deviation from the measured data of 32 normal elderly subjects. We therefore concluded that the proposed system can be used to quantitatively evaluate the motor function of finger taps.