A new device to measure the three dimensional forces and torques in precision grip.

Fine prehension is ubiquitous in everyday skilled hand manipulations. The anticipatory nature of the control of normal grip forces exerted against tangential loads has been extensively used to provide insights into the working of neural control of movements. We designed a new versatile device to measure the three dimensional forces and torques during a broad panel of precision grip tasks. The instrument measures constraints exerted independently on two grip surfaces by the thumb and the opposing fingers. In addition, the device can be loaded to increase the weight and/or induce torques and can be easily integrated in a variety of experimental contexts. Its compactness improves its stability during movement and allows an ergonomic manipulation for impaired persons or children.