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Taking inspiration from neurophysiological studies on synergies in the human grasping action, this paper tries to demonstrate that it is possible to find a general rule for performing a stable, human-like cylindrical grasp with a robotic hand. To this purpose, the theoretical formulation and the experimental validation of a reach-and-grasp algorithm for determining the optimal hand position and the...
Functional motor impairment due to Parkinson's disease and other movement disorders are currently assessed with visual rating scales such as the Unified Parkinson's Disease Rating Scale (UPDRS). These methods rely on the subjective judgment of a rater to assign scores representing the extent of impairment while subjects perform prescribed activities. We describe a new model-based framework that uses...
People with stroke typically must perform much of their hand exercise at home without professional assistance as soon as two weeks after the stroke. Without feedback and encouragement, individuals often lose motivation to practice using the affected hand, and this disuse contributes to further declines in hand function. We developed the MusicGlove as a way to facilitate and motivate at home practice...
Rehabilitation interventions for the hand have shown benefits for children with Hemiplegia due to cerebral palsy or traumatic brain injury. Longer interventions are facilitated if training is provided in the patient's home, due to easier access to care and reduced impact on school or work activities. Providing remote rehabilitation over lengthy periods of time has however its own challenges. This...
Recent studies in primate neurophysiology have focused on decoding multi-joint kinematics from single unit and local field potential recordings. However, the extent to which these results can be generalized to human subjects is not known. We have recorded simultaneous electrocorticographic (ECoG) and hand kinematics in a human subject performing reach-grasp-hold of objects varying in shape and size...
An important function for a tactile navigation system of a handheld tool, such as a surgical scalpel, is the spatial transparency of the device. This paper proposed a new tactile display that can augment touch sensation at the finger pulps without the need for a stimulator between the tool and the finger pulps. We utilized transcutaneous electrical nerve stimulation at the middle phalanx of a finger...
This paper describes a novel method to estimate pulse arrival time (PAT) from the electrocardiogram (ECG) and the impedance plethysmogram (TPG) obtained by using a compact and easy-to-use handheld device with only four electrodes. A proof-of-concept has been carried out where PAT values obtained with the proposed device have been compared to PAT values measured between the ECG and the photoplethysmogram...
This study describes the design and feasibility testing of a hand rehabilitation system that provides haptic assistance for hand opening in moderate to severe hemiplegia while subjects attempt to perform bilateral hand movements. A cable-actuated exoskeleton robot assists the subjects in performing impaired finger movements but is controlled by movement of the unimpaired hand. In an attempt to combine...
This study investigates patterns of brain reorganization in chronic stroke subjects after two weeks of robot-assisted arm and hand training in virtual reality (VR). Four subjects were studied with event-related fMRI while doing simple paretic hand finger movements before (double baseline) and after training. Bilateral hand movements were recorded and used to provide real-time feedback to subjects...
We tackle the problem of classifying multichannel electrocorticogram (ECoG) related to individual finger movements for a brain machine interface (BMI). For this particular aim we applied a recently developed hierarchical spatial projection framework of neural activity for feature extraction from ECoG. The algorithm extends the binary common spatial patterns algorithm to multiclass problem by constructing...
This paper proposes a framework for tracking both human hand kinematics and object contour during grasping task. The framework is based on modeling the object as point cloud and the use of marker-based tracking. We introduce how to estimate contact sites on both the hand and object, hand enclosing space, and graspable features from recorded data. Two experiments were performed to 1) verify the accuracy...
Robotic rehabilitation techniques have the capacity to provide high dosage therapy without the labor burden of conventional methods. The most effective means of using robots to retrain function is not yet known, though many studies now support providing assistance to movement while the user actively participates in that movement. In this study, we compare, in three chronic stroke subjects, a novel...
Functional motor impairment caused by Parkinson's disease and other movement disorders is currently measured with rating scales such as the Unified Parkinson's Disease Rating Scale (UPDRS). These are typically comprised of a series of simple tasks that are visually scored by a trained rater. We developed a method to objectively quantify three upper extremity motor tasks directly with a wearable inertial...
Neuroprostheses (NPs) are electrical stimulators that help to restore sensory or motor functions lost as a result of neural damage. The Stimulus Router System (SRS) is a new type of NP developed in our laboratory. The system uses fully implanted, passive leads to “capture” and “route” some of the current flowing between pairs of surface electrodes to the vicinity of the target nerves, hence eliminating...
This paper outlines the design and development of a robotic exoskeleton based rehabilitation system. A portable direct-driven optimized hand exoskeleton system has been proposed. The optimization procedure primarily based on matching the exoskeleton and finger workspaces guided the system design. The selection of actuators for the proposed system has emerged as a result of experiments with users of...
Prosthetic hands are becoming more advanced and gaining degrees-of-freedom similar to their human counterparts. However, the command interface enabling control of these prostheses needs to be improved for more intuitive functional use. One barrier to using electromyographic (EMG) signals as the command interface is measuring independent muscle control sites in the residual limb. Surface electrodes...
This case study demonstrates the ability of sensory cortical representations to remap following arm amputation and subsequent targeted reinnervation (TR). Previous human studies have demonstrated functional plasticity in the primary sensory cortex months or years after amputation of the upper arm, forearm, the hand or a single finger, or after subsequent replantation. Targeted reinnervation, a surgical...
We present a method to automatically detect two new stable anatomical landmarks L1 and L2 on the Central Sulcus (CS). Those landmarks are shown to be representative of the Central Sulcus morphology and linked to the functional primary motor area of the hand. Detection is performed after introducing a new morphological characteristic, the sulcal profile. We show that when matching explicitly L1 and...
An efficient way to investigate the neural basis of nociceptive responses is the event-related brain potentials (ERPs). One component belonging to this family of ERPs is the mismatch negativity (MMN). It reflects pre-attentive detection of changes in the incoming stimulus by comparing the new stimulus with sensory memory traces. In this work, single trials of ERP taken from EEG signal recorded under...
Brain-computer interface (BCI) may be used to control a prosthetic or orthotic hand using neural activity from the brain. The core of this sensorimotor BCI lies in the interpretation of the neural information extracted from electroencephalogram (EEG). It is desired to improve on the interpretation of EEG to allow people with neuromuscular disorders to perform daily activities. This paper investigates...
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