Abstract
The purpose of this study was to develop a finger-tapping acceleration measurement system for the quantitative diagnosis of Parkinson's disease. The system was composed of 3-axis piezoelectric element accelerometers, touch sensors made of thin stainless steel sheets, an analog-digital (AD) converter and a personal computer (PC). Fingerstalls, with these sensors, were attached to the index finger and thumb. The acceleration and output of the touch sensor were recorded using the PC during the finger-tapping movements. Intervals between the single finger-tapping movements were calculated from the measured output of the touch sensor. Velocities during the single finger-tapping movements were calculated by integrating the measured acceleration. The amplitudes were calculated by integrating the velocities. Forces generated when the fingers contacted were estimated from the acceleration using a filter, G (jω). The standard deviation of the single finger-tapping intervals, average of maximum single finger-tapping velocities, average of maximum single finger-tapping amplitudes and standard deviation of maximum force were calculated from them. They were used as features for the quantitative diagnosis of Parkinson's disease. Preliminary experiments were executed with a normal subject. The results showed that maximum single finger-tapping velocity, maximum single finger-tapping amplitude and maximum force could be measured fairly accurately when single finger-tapping movement interval times were less than 0.4 s. The system developed was used to conduct finger-tapping tests employing 27 normal subjects and 16 Parkinson's diseases subjects. The subjects executed continuous finger-tapping movement for 60 s. It was shown that the acceleration and output of the touch sensor could be measured and the features could be extracted.
