title: Multiunit Activity-Based Real-Time Limb-State Estimation from Dorsal Root Ganglion Recordings.
abstract: Proprioceptive afferent activities could be useful for providing sensory feedback signals for closed-loop control during functional electrical stimulation (FES). However, most previous studies have used the single-unit activity of individual neurons to extract sensory information from proprioceptive afferents. This study proposes a new decoding method to estimate ankle and knee joint angles using multiunit activity data. Proprioceptive afferent signals were recorded from a dorsal root ganglion with a single-shank microelectrode during passive movements of the ankle and knee joints, and joint angles were measured as kinematic data. The mean absolute value (MAV) was extracted from the multiunit activity data, and a dynamically driven recurrent neural network (DDRNN) was used to estimate ankle and knee joint angles. The multiunit activity-based MAV feature was sufficiently informative to estimate limb states, and the DDRNN showed a better decoding performance than conventional linear estimators. In addition, processing time delay satisfied real-time constraints. These results demonstrated that the proposed method could be applicable for providing real-time sensory feedback signals in closed-loop FES systems.
authors.affiliation: Biomedical Research Institute, Korea Institute of Science and Technology, 5, Hwarang-ro 14-gil, Seongbuk-gu, Seoul, 02791, Korea.|Department of Biomedical Science, Korea University College of Medicine, 73, Inchan-ro, Seongbuk-gu, Seoul, 02841, Korea.
authors.forename: Sungmin
authors.initials: S
authors.lastname: Han
authors.affiliation: Daegu Research Center for Medical Devices and Rehabilitation Engineering, Korea Institute of Machinery and Materials, 330, Techno Sunhwan-ro, Yuga-myeon, Dalseong-gun, Daegu, 42994, Korea.
authors.forename: Jun-Uk
authors.initials: JU
authors.lastname: Chu
authors.affiliation: Biomedical Research Institute, Korea Institute of Science and Technology, 5, Hwarang-ro 14-gil, Seongbuk-gu, Seoul, 02791, Korea.|Department of Biomedical Engineering, Korea University of Science and Technology, 217, Gajeong-ro, Yuseong-gu, Daejeon, 34113, Korea.
authors.forename: Hyungmin
authors.initials: H
authors.lastname: Kim
authors.affiliation: Department of Biomedical Science, Korea University College of Medicine, 73, Inchan-ro, Seongbuk-gu, Seoul, 02841, Korea.
authors.forename: Jong Woong
authors.initials: JW
authors.lastname: Park
authors.affiliation: Biomedical Research Institute, Korea Institute of Science and Technology, 5, Hwarang-ro 14-gil, Seongbuk-gu, Seoul, 02791, Korea.|Department of Biomedical Engineering, Korea University of Science and Technology, 217, Gajeong-ro, Yuseong-gu, Daejeon, 34113, Korea.
authors.forename: Inchan
authors.initials: I
authors.lastname: Youn
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D004566:Electrodes; D005727:Ganglia, Spinal / Q000502:physiology*; D006614:Hindlimb / Q000502:physiology*; D008297:Male; D011434:Proprioception / Q000502:physiology*; D011817:Rabbits