Closed-Loop Force Control by Biorealistic Hand Prosthesis With Visual and Tactile Sensory Feedback.

The ability of a novel biorealistic hand prosthesis for grasp force control reveals improved neural compatibility between the human-prosthetic interaction. The primary purpose here was to validate a virtual training platform for amputee subjects and evaluate the respective roles of visual and tactile information in fundamental force control tasks. We developed a digital twin of tendon-driven prosthetic hand in the MuJoCo environment.

Somatotopically Evoked Tactile Sensation via Transcutaneous Electrical Nerve Stimulation Improves Prosthetic Sensorimotor Performance.

Sensory feedback provides critical interactive information for the effective use of hand prostheses. Non-invasive neural interfaces allow convenient access to the sensory system, but they communicate a limited amount of sensory information. This study examined a novel approach that leverages a direct and natural sensory afferent pathway, and enables an evoked tactile sensation (ETS) of multiple digits in the projected finger map (PFM) of participants with forearm amputation non-invasively.

MovePort: Multimodal Dataset of EMG, IMU, MoCap, and Insole Pressure for Analyzing Abnormal Movements and Postures in Rehabilitation Training.

In most real world rehabilitation training, patients are trained to regain motion capabilities with the aid of functional/epidural electrical stimulation (FES/EES), under the support of gravity-assist systems to prevent falls. However, the lack of motion analysis dataset designed specifically for rehabilitation-related applications largely limits the conduct of pilot research. We provide an open access dataset, consisting of multimodal data collected via 16 electromyography (EMG) sensors, 6 inertial measurement unit (IMU) sensors, and 230 insole pressure sensors (IPS) per foot, together with a 26-sensor motion capture system, under different MOVEments and POstures for Rehabilitation Training (MovePort).

A hybrid sensory feedback system for thermal nociceptive warning and protection in prosthetic hand.

Background: Advanced prosthetic hands may embed nanosensors and microelectronics in their cosmetic skin. Heat influx may cause damage to these delicate structures. Protecting the integrity of the prosthetic hand becomes critical and necessary to ensure sustainable function.

Fusion of dual modalities of non-invasive sensory feedback for object profiling with prosthetic hands.

Introduction: Either non-invasive somatotopic or substitute sensory feedback is capable of conveying a single modality of sensory information from prosthetic hands to amputees. However, the neurocognitive ability of amputees to integrate multi-modality sensory information for functional discrimination is unclear. The purpose of this study was to assess the fusion of non-invasive somatotopic tactile and substitute aperture feedbacks for profile perception of multiple physical features during grasping objects.

Predictive Warning of Nociceptive Temperature during Prosthetic Hand Prehension.

Grasping hot objects may be harmful, and a warning of nociceptive temperature should be provided to prevent prosthetic hands from damage. This study developed a fast algorithm to predict the steady state temperature of grasped objects based on a thermoresistant sensor, and verified a bi-state sensory encoding strategy to inform either contact force or nociceptive temperature at prosthetic finger. Below the threshold, a buzz percept was used to encode fingertip force, and above the threshold, a tingling pain sensation was induced to warn harmful temperature.

Precision Control of Fingertip Force by a Biorealistic Hand with a Pair of Neuromorphic Muscles.

In this paper, the ability of precision control of fingertip forces was investigated in an antagonistic cable-driven prosthetic hand with neuromorphic twin of muscles. Surface electromyography (sEMG) signals collected from able-bodied subjects' forearm were processed and used as alpha motor commands to drive the neuromorphic muscle models. A pair of antagonistic muscles were cascaded by two servo motors to control the index finger.

Substitutive proprioception feedback of a prosthetic wrist by electrotactile stimulation.

Objective: Sensory feedback of upper-limb prostheses is widely desired and studied. As important components of proprioception, position, and movement feedback help users to control prostheses better. Among various feedback methods, electrotactile stimulation is a potential method for coding proprioceptive information of a prosthesis.

A Biorealistic Computational Model Unfolds Human-Like Compliant Properties for Control of Hand Prosthesis.

Human neuromuscular reflex control provides a biological model for a compliant hand prosthesis. Here we present a computational approach to understanding the emerging human-like compliance, force and position control, and stiffness adaptation in a prosthetic hand with a replica of human neuromuscular reflex. A virtual twin of prosthetic hand was constructed in the MuJoCo environment with a tendon-driven anthropomorphic hand structure.

Antagonistic Control of a Cable-Driven Prosthetic Hand with Neuromorphic Model of Muscle Reflex.

In this paper, a novel prototype of a cable-driven prosthetic hand with biorealisitic muscle property was developed. A pair of antagonistic muscles controlled the flexion and extension of the prosthetic index finger. Biorealistic properties of muscle were emulated using a neuromorphic model of muscle reflex in real time.

Non-Invasive Stable Sensory Feedback for Closed-Loop Control of Hand Prosthesis.

The absence of somatotopic sensory feedback limits the function of conventional prosthetic hands. In this study, we integrated a non-invasive sensory feedback system into a commercial Bebionic hand with new customized surface stimulation electrodes. Multiple modalities of tactile and hand aperture sensory information were conveyed to the amputee via the technique of evoked tactile sensation (ETS) elicited at projected finger map (PFM) of residual limb and an additional electrotactile stimulation in the ipsilateral upper arm.

The Effects of Deep Brain Stimulation on Motor Unit Activities in Parkinson's Disease based on High-Density Surface EMG Analysis.

Tremor in Parkinson's disease (PD) is caused by synchronized activation bursts in limb muscles. Deep Brain Stimulation (DBS) is an effective clinical therapy for inhibiting tremor and improving movement disorders in PD patients. However, the neural mechanism of how tremor symptom is suppressed by DBS at motor unit (MU) level remains unclear.

EEG Features of Evoked Tactile Sensation: Two Cases Study.

Sensory feedback for prosthetics is an important issue. The area of forearm stump skin that has evoked tactile sensation (ETS) of fingers is defined as the projected finger map (PFM), and the area close to the PFM region that does not have ETS is defined as the non-projected finger map (NPFM). Previous studies have confirmed that ETS can restore the tactile pathway of the lost finger, which was induced by stimulation of transcutaneous electrical nerve stimulation (TENS) on the end of stump skin.

A pilot study of synergy-based FES for upper-extremity poststroke rehabilitation.

A previous study indicated that synergy-based functional electrical stimulation (FES) may improve instantaneous upper-limb motor performance for stroke survivors. However, it remains unclear whether the improvements will sustain over time to achieve functional gains associated with a task-oriented training (TOT). This pilot study was designed to investigate whether there is any promising sign of functional benefits.

Biorealistic Control of Hand Prosthesis Augments Functional Performance of Individuals With Amputation.

The human hand has compliant properties arising from muscle biomechanics and neural reflexes, which are absent in conventional prosthetic hands. We recently proved the feasibility to restore neuromuscular reflex control (NRC) to prosthetic hands using real-time computing neuromorphic chips. Here we show that restored NRC augments the ability of individuals with forearm amputation to complete grasping tasks, including standard Box and Blocks Test (BBT), Golf Balls Test (GBT), and Potato Chips Test (PCT).

Evaluation of Model-Based Biomimetic Control of Prosthetic Finger Force for Grasp.

Restoring neuromuscular reflex properties in the control of a prosthetic hand may potentially approach human-level grasp functions in the prosthetic hand. Previous studies have confirmed the feasibility of real-time emulation of a monosynaptic spinal reflex loop for prosthetic control. This study continues to explore how well the biomimetic controller could enable the amputee to perform force-control tasks that required both strength and error-tolerance.

Next-Generation Prosthetic Hand: from Biomimetic to Biorealistic.

Integrating a prosthetic hand to amputees with seamless neural compatibility presents a grand challenge to neuroscientists and neural engineers for more than half century. Mimicking anatomical structure or appearance of human hand does not lead to improved neural connectivity to the sensorimotor system of amputees. The functions of modern prosthetic hands do not match the dexterity of human hand due primarily to lack of sensory awareness and compliant actuation.

An Experimental Protocol for Evaluating Pulse Width Modulation Ranges of Evoked Tactile Sensory Feedback in Amputees.

The objective of this study is to develop an experimental protocol to define the range of modulation for different sensory modalities elicited by transcutaneous electrical nerve stimulation (TENS) in amputees with evoked tactile sensation (ETS). Modulation ranges of sensory modalities, such as vibration, buzz, tingling etc., are essential for designing a coding strategy for incoming sensory information from prosthetic hands for each amputee.

Automated functional electrical stimulation training system for upper-limb function recovery in poststroke patients.

Background: This paper describes the design and test of an automated functional electrical stimulation (FES) system for poststroke rehabilitation training. The aim of automated FES is to synchronize electrically induced movements to assist residual movements of patients.

Methods: In the design of the FES system, an accelerometry module detected movement initiation and movement performed by post-stroke patients.

Neuromorphic Model of Reflex for Realtime Human-Like Compliant Control of Prosthetic Hand.

Current control of prosthetic hands is ineffective when grasping deformable, irregular, or heavy objects. In humans, grasping is achieved under spinal reflexive control of the musculotendon skeletal structure, which produces a hand stiffness commensurate with the task. We hypothesize that mimicking reflex on a prosthetic hand may improve grasping performance and safety when interacting with human.

Restoring Finger-Specific Sensory Feedback for Transradial Amputees via Non-Invasive Evoked Tactile Sensation.

This study assessed the feasibility to restore finger-specific sensory feedback in transradial amputees with electrical stimulation of evoked tactile sensation (ETS). Here we investigated primary somatosensory cortical (SI) responses of ETS using Magnetoencephalography. SI activations revealed a causal correlation with peripheral stimulation of projected finger regions on the stump skin.

Simultaneous determination of adenosine and its metabolites by capillary electrophoresis as a rapid monitoring tool for 5'-nucleotidase activity.

A simple and rapid capillary electrophoretic method was developed for the simultaneous determination of micro-molar adenosine, hypoxanthine and inosine in enzyme assays without using radioactive labeled substrates. Prior to electrophoretic separation, addition of acetonitrile and sodium chloride to the assay solution and brief centrifugation are recommended for the purpose of sample cleanup and sample stacking. Under the optimal condition, the good separation with high efficiency was achieved in 6 min.