title: Effect of visual and tactile feedback on kinematic synergies in the grasping hand.
abstract: The human hand uses a combination of feedforward and feedback mechanisms to accomplish high degree of freedom in grasp control efficiently. In this study, we used a synergy-based control model to determine the effect of sensory feedback on kinematic synergies in the grasping hand. Ten subjects performed two types of grasps: one that included feedback (real) and one without feedback (memory-guided), at two different speeds (rapid and natural). Kinematic synergies were extracted from rapid real and rapid memory-guided grasps using principal component analysis. Synergies extracted from memory-guided grasps revealed greater preservation of natural inter-finger relationships than those found in corresponding synergies extracted from real grasps. Reconstruction of natural real and natural memory-guided grasps was used to test performance and generalizability of synergies. A temporal analysis of reconstruction patterns revealed the differing contribution of individual synergies in real grasps versus memory-guided grasps. Finally, the results showed that memory-guided synergies could not reconstruct real grasps as accurately as real synergies could reconstruct memory-guided grasps. These results demonstrate how visual and tactile feedback affects a closed-loop synergy-based motor control system.
authors.affiliation: Department of Biomedical Engineering, Stevens Institute of Technology, Hoboken, NJ, 07030, USA.
authors.forename: Vrajeshri
authors.initials: V
authors.lastname: Patel
authors.affiliation: Department of Biomedical Engineering, Stevens Institute of Technology, Hoboken, NJ, 07030, USA.
authors.forename: Martin
authors.initials: M
authors.lastname: Burns
authors.affiliation: Department of Biomedical Engineering, Stevens Institute of Technology, Hoboken, NJ, 07030, USA. ramana.vinjamuri@stevens.edu.
authors.forename: Ramana
authors.initials: R
authors.lastname: Vinjamuri
mesh_terms: D001696:Biomechanical Phenomena; D003198:Computer Simulation; D056228:Feedback, Sensory; D005385:Fingers; D006225:Hand / Q000502:physiology*; D018737:Hand Strength / Q000502:physiology*; D006801:Humans; D033281:Nontherapeutic Human Experimentation; D025341:Principal Component Analysis; D014110:Touch
keywords: Grasping; Joint kinematics; Memory-guided; Synergies; Tactile feedback; Visual feedback