Research Library

Electrodes used for measuring electric signals from the body are commonly made of metal making them expensive, stiff, non-efficient potentially toxic. We made electrodes made of graphene induced with a laser allows for an economical, soft, and organic electrode. We tested the graphene electrode on the bench and in humans and found that they were more stable in bench testing and rivals metal electrodes in human testing. Graphene electrodes show potential to replace metal electrodes leading to better and cheaper electrodes.

The term embodiment, often used as a metric of the progress made in prosthetic technologies and a hallmark for user acceptance, has often been left undefined or described incongruently within literature. We reviewed prosthetic embodiment literature and found that prosthetic embodiment is best described as a combination of ownership and agency. We further provide recommendations on how to best measure ownership and agency to create a common reference for further discussions about embodiment within prosthetics research.

We compared the efforts to enhance the bone healing process at the bone-implant interface with electrical stimulation. The main focus was on comparing used electrical stimulation parameters. The result discloses nonuniform protocols, as well as inconsistencies and incomplete reporting in the use of stimulation parameters. The majority of studies report beneficial outcomes of bone healing when using electrical stimulation, however optimal stimulation parameters are not yet thoroughly investigated which is an important step towards clinical translation of this concept.

Investigation of the potential of using pulsed electrical stimulation as a means to promote osseointegration in an in vitro model. Three different stimulation treatments were applied in a novel in vitro setup. The findings suggested that pulsed electrical stimulation with characteristics similar to peripheral nerve stimulation has the potential to improve cell survival and may provide a promising approach to improve implant-bone healing, particularly to neuromusculoskeletal interfaces in which implanted electrodes are readily available.

Integrating tactile and kinesthetic feedback in a bionic arm results in performance closer to able-bodied individuals.

Pattern recognition algorithms have been widely used to map surface electromyographic signals to target movements as a source for prosthetic control. However, most investigations have been conducted offline by performing the analysis on pre-recorded datasets. While real-time data analysis (i.e., classification when new data becomes available, with limits on latency under 200–300 milliseconds) plays an important role in the control of prosthetics, less knowledge has been gained with respect to real-time performance. Recent literature has underscored the differences between offline classification accuracy, the most common performance metric, and the usability of upper limb prostheses. Therefore, a comparative offline and real-time performance analysis between common algorithms had yet to be performed. In this study, we investigated the offline and real-time performance of nine different classification algorithms, decoding ten individual hand and wrist movements. Surface myoelectric signals were recorded from fifteen able-bodied subjects while performing the ten movements. The offline decoding demonstrated that linear discriminant analysis (LDA) and maximum likelihood estimation (MLE) significantly (p < 0.05) outperformed other classifiers, with an average classification accuracy of above 97%. On the other hand, the real-time investigation revealed that, in addition to the LDA and MLE, multilayer perceptron also outperformed the other algorithms and achieved a classification accuracy and completion rate of above 68% and 69%, respectively.

We show that state-of-the-art advanced artificial intelligence algorithms based on “deep neural networks” achieve superior performance compared to two common algorithms for decoding movement intent for prosthetic control. We performed a rigorous analysis to explain why the state-of-the-art algorithms perform better based on an analysis of 11 able-bodied subjects and 4 prosthesis users. This work shows and explains why state-of-the-art algorithms are better which is important since it has been a challenge to demonstrate that new algorithms are better due to external disturbances.

Contrary to previous claims, skin temperature is not a biomarker for ownership. We induced the Rubber Hand Illusion (RHI), the gold standard experiment to study the sense of ownership, while monitoring the participants skin temperature with a precise thermal camera. We found that temperature change does not correlate with the ownership score in the RHI paradigm and thus suggest caution in drawing strong inferences of ownership based on the skin temperature.

Not everyone is susceptible to illusions. We showed that the Rubber Hand Illusion (RHI) can be induced with different types of tactile stimulation but about 30% of people are immune to it. This includes four people implanted with neuromusculoskeletal prostheses who otherwise perceive their prostheses as part of their own body when using it in daily life, thus highlighting limitations to the RHI as an experimental paradigm.

After long-term use of a neuromusculoskeletal prosthesis where the location of a force sensor on a prosthetic hand and the location that electrical nerve stimulation corresponding to grasping force was felt did not originally match, we show that the perceived location of the touch does not change to match the sensor location. Our results with three neuromusculoskeletal prosthesis users conform to previous studies that suggest sensory maps in the brain are stable in adulthood and cannot be modified. Although the sensation and prosthesis sensor locations did not match, participants still indicated greater confidence in their prosthesis control and greater embodiment of the bionic limb. Although congruent sensory location is not required for the benefits of sensory feedback to arise, it may still be preferable for prosthesis users and thus other methods of changing sensory locations remains a future area of development.