Belgrade Grasping-Reaching System

The Belgrade Grasping-Reaching System (BGS) as proposed by Popovic et al. (1998) is a neuroprosthesis device designed for grasping and it also provides a reaching function. The device has four stimulation channels (three for generating grasping function and fourth to stimulate triceps brachii muscle for elbow extension). The grasping function is controlled via a push button that triggers hand opening and closing. The motion of grasp is performed in three phases; prehension that forms the correct aperature of the hand, a relaxation phase that allows the hand to get into good contact with the object and closure of the hand by opposing either the palm and the thumb or side of index finger and thumb. The act of hand release is completed in two stages; opening of the hand and resting. Measuring the subject’s shoulder velocity with a goniometer and then generating a synergistic elbow motion by stimulation of the triceps brachii muscle achieves the reaching function of the upper limb. It is reported that the BGS system requires more time to place electrodes compared to Handmaster system, and it is not commercially available (Popovic et al. 2002).