In vivo Estimation of Human Forearm and Wrist Dynamic Properties
It is important to estimate the 3 degree-of-freedom (DOF) impedance of human forearm and wrist (i.e., forearm prono-supination, and wrist flexion-extension and radial-ulnar deviation) in motor control and in the diagnosis of altered mechanical resistance following stroke. There is, however, a lack of methods to characterize 3 DOF impedance. Thus, we developed a reliable and accurate impedance estimation method, the distal internal model based impedance control (dIMBIC)-based method, to characterize the 3 DOF impedance, including cross-coupled terms between DOFs, for the first time.
Quantifying Nonlinear Contributions to Cortical Responses Evoked by Continuous Wrist Manipulation
Cortical responses to continuous stimuli as recorded using either magneto- or electroencephalography (EEG) have shown power at harmonics of the stimulated frequency, indicating nonlinear behavior. Even though the selection of analysis techniques depends on the linearity of the system under study, the importance of nonlinear contributions to cortical responses has not been formally addressed. The goal of this paper is to quantify the nonlinear contributions to the cortical response obtained from continuous sensory stimulation.
Epileptic Focus Localization Using Discrete Wavelet Transform Based on Interictal Intracranial EEG
Over the past decade, with the development of machine learning, Discrete Wavelet Transform (DWT) has been widely used in computer-aided epileptic EEG signal analysis as a powerful time-frequency tool. But some important problems have not yet been benefitted from DWT, including epileptic focus localization, a key task in epilepsy diagnosis and treatment. Additionally, the parameters and settings for DWT are chosen empirically or arbitrarily in previous work. In this work, we propose a framework to use DWT and Support Vector Machine (SVM) for epileptic focus localization problem based on EEG.
Multichannel Electrotactile Feedback With Spatial and Mixed Coding for Closed-Loop Control of Grasping Force in Hand Prostheses
Providing somatosensory feedback to the user of a myoelectric prosthesis is an important goal since it can improve the utility as well as facilitate the embodiment of the assistive system. Most often, the grasping force was selected as the feedback variable and communicated through one or more individual single channel stimulation units (e.g., electrodes, vibration motors). In the present study, an integrated, compact, multichannel solution comprising an array electrode and a programmable stimulator was presented.
An Empirical Evaluation of Force Feedback in Body-Powered Prostheses
Myoelectric prostheses have many advantages over body-powered prostheses, yet the absence of sensory feedback in myoelectric devices is one reason body-powered devices are often preferred by amputees. While considerable progress has been made in the mechanical design and control of myoelectric prostheses, research on haptic feedback has not had a similar impact. In this study, we seek to develop a fundamental understanding of the utility of force feedback and vision in the functional operation of a body-powered upper-limb prosthesis.
The Fabrication, Implantation, and Stability of Intraspinal Microwire Arrays in the Spinal Cord of Cat and Rat
Intraspinal microstimulation (ISMS) is currently under investigation for its ability to restore function following spinal cord injury and aid in addressing basic investigations of the spinal cord in feline and murine (rat) models. In this report we describe the procedures for fabricating and implanting intraspinal microwires, with special emphasis on the rat model. We also report our results on targeting success and long-term stability and functionality of the implants.