Tremor amplitude determination for use in clinical applications

This paper presents new methodologies for measuring the hand tremor of surgeons. A means to measure and evaluate the surgeon hand tremor in real time during operating practice can serve to assess the ergonomics of operating conditions. Tremor information is also important for determining surgical performance, particularly in microsurgical tasks. Micro-surgeons often work continuously for several hours with the most complex part occurring toward the end of the procedure. During these procedures the surgeon often uses a binocular microscope and is working at the threshold of perception and manual tool point control. The resulting performance is sensitive to hand tremor. In this paper, maximum tremor amplitude was determined by integrating the acceleration signals measured from three-axis piezoelectric accelerometers. New methods of removing the drift in the acceleration signals through empirical mode decomposition, and of determining the maximum tremor amplitude through proper orthogonal decomposition are presented. An experimental calibration demonstrates that the average error between the maximum tremor calculated by the proposed new method and the measured amplitude is below 5%. The paper also presents the results of the new techniques applied in the operating room in practice. Some of the tasks investigated focused on tool control in microsurgery.