Grasping objects with a sensory substitution glove

People with a visual impairment often find it difficult to detect information about distant objects they may want to grasp. To overcome this difficulty, we developed a sensory substitution glove that facilitates non-visual grasping. The glove includes two vibration motors, one on the index finger and one on the thumb. The motors vibrate whenever the corresponding finger points toward the object. The vibration intensity increases when the hand approaches the target. Three experiments were performed with the glove, with blindfolded participants. Experiment 1 tested the ability of participants to point to cylindrical targets. The absolute angular error (1.38°) was lower than the angular size of the object (3.82°). In Experiment 2, participants aimed to grasp differently sized cylinders at different distances. They were successful in 83% of the trials. The observed movements showed distinguishable reaching and grasping phases. Experiment 3 manipulated the direction, size, and distance of the targets, hence representing a more real-world situation. In this case, the action was completed successfully in 93% of the trials. An orientation phase preceded the reaching and grasping components. Oscillatory explorations were observed in all experiments, permitting the detection of the information that is needed to successfully complete the action.