Design, Development and Functionality of a Haptic Force-Matching Device for Measuring Sensory Attenuation

In this paper we describe the design, development and functionality of a haptic force-matching device. This device measures precise sensorimotor perception by determining a subject's ability to successfully attenuate incoming sensory signals. Sensory attenuation provides a novel method of investigating psychophysical aspects of perception and may help to formulate neurocognitive models that may account for maladaptive interoceptive processing. Several similar custom-made devices have been reported in the literature; however, a clear description of the mechanical engineering necessary to build such a device is lacking. We present, in detail, the hardware and software necessary to build such a device. Subjects (N = 25) were asked to match a target force on their right index finger, first by pressing directly on their finger with their other hand, then by controlling the device through an external potentiometer to control the force (indirectly) though a torque motor. In the direct condition, we observed a consistent overestimation of the force reproduced; mean force error 0.50 newtons (standard error = 0.04). In the slider condition we observed a more accurate, yet small, underestimation of reproduced force: -0.30 newtons (standard error = 0.03).