A motion control function evaluation system employing a pen tablet

We have developed a new pen tablet based system for evaluation of hand motion control function as influenced by brain disease. The system consists of a laptop computer and a pen tablet data entry device. The pen tablet is placed in front of the subject who is instructed to tap the pen at a constant location. When the subject taps the pen, the tablet transfers the pen position to the laptop computer. The computer then saves the tap position, along with the time elapsed between each tap. The subject is instructed to tap 50 times with each hand with the eyes closed. The absolute distance moved between each two successive tap positions is detected. Tapping period, total tapping time and total distance moved are also calculated. Measurements were performed on ten normal subjects and three subjects with cerebral infarction. The results indicate that cerebral infarction subjects' average total tap point distance moved and absolute distance moved are greater than in the normal subjects. Conversely, all subjects in both groups produced only normal variations in tapping period and total tapping time. Our system can therefore quantitatively evaluate hand motion control function by the total and absolute distance moved.