Cognitive Models of Limb Embodiment in Structurally Varying Bodies: A Theoretical Perspective

Using the seminal rubber hand illusion and related paradigms, the last two decades unveiled the multisensory mechanisms underlying the sense of limb embodiment, that is, the cognitive integration of an artificial limb into one's body representation. Since also individuals with amputations can be induced to embody an artificial limb by multimodal sensory stimulation, it can be assumed that the involved computational mechanisms are universal and independent of the perceiver's physical integrity. This is anything but trivial, since experimentally induced embodiment has been related to the embodiment of prostheses in limb amputees, representing a crucial rehabilitative goal with clinical implications. However, until now there is no unified theoretical framework to explain limb embodiment in structurally varying bodies. In the present work, we suggest extensions of the existing Bayesian models on limb embodiment in normally-limbed persons in order to apply them to the specific situation in limb amputees lacking the limb as physical effector. We propose that adjusted weighting of included parameters of a unified modeling framework, rather than qualitatively different model structures for normally-limbed and amputated individuals, is capable of explaining embodiment in structurally varying bodies. Differences in the spatial representation of the close environment (peripersonal space) and the limb (phantom limb awareness) as well as sensorimotor learning processes associated with limb loss and the use of prostheses might be crucial modulators for embodiment of artificial limbs in individuals with limb amputation. We will discuss implications of our extended Bayesian model for basic research and clinical contexts.

Finger Gesture Recognition Using Sensing and Classification of Surface Electromyography Signals With High-Precision Wireless Surface Electromyography Sensors

Finger gesture recognition (FGR) plays a crucial role in achieving, for example, artificial limb control and human-computer interaction. Currently, the most common methods of FGR are visual-based, voice-based, and surface electromyography (EMG)-based ones. Among them, surface EMG-based FGR is very popular and successful because surface EMG is a cumulative bioelectric signal from the surface of the skin that can accurately and intuitively represent the force of the fingers. However, existing surface EMG-based methods still cannot fully satisfy the required recognition accuracy for artificial limb control as the lack of high-precision sensor and high-accurate recognition model. To address this issue, this study proposes a novel FGR model that consists of sensing and classification of surface EMG signals (SC-FGR). In the proposed SC-FGR model, wireless sensors with high-precision surface EMG are first developed for acquiring multichannel surface EMG signals from the forearm. Its resolution is 16 Bits, the sampling rate is 2 kHz, the common-mode rejection ratio (CMRR) is less than 70 dB, and the short-circuit noise (SCN) is less than 1.5 μV. In addition, a convolution neural network (CNN)-based classification algorithm is proposed to achieve FGR based on acquired surface EMG signals. The CNN is trained on a spectrum map transformed from the time-domain surface EMG by continuous wavelet transform (CWT). To evaluate the proposed SC-FGR model, we compared it with seven state-of-the-art models. The experimental results demonstrate that SC-FGR achieves 97.5% recognition accuracy on eight kinds of finger gestures with five subjects, which is much higher than that of comparable models.

HEALTH SERVICE DELIVERY AND ECONOMIC EVALUATION OF LIMB LOWER BONE-ANCHORED PROSTHESES: A SUMMARY OF THE QUEENSLAND ARTIFICIAL LIMB SERVICE’S EXPERIENCE

The emergence of skeletal prosthetic attachments leaves governmental organizations facing the challenge of implementing equitable policies that support the provision of bone-anchored prostheses (BAPs). In 2013, the Queensland Artificial Limb Service (QALS) started a five-year research project focusing on health service delivery and economic evaluation of BAPs. This paper reflects on the QALS experience, particularly the lessons learned. QALS’ jurisdiction and drivers are presented first, followed by the impact of outcomes, barriers, and facilitators, as well as future developments of this work. The 21 publications produced during this project (e.g., reimbursement policy, role of prosthetists, continuous improvement procedure, quality of life, preliminary cost-utilities) were summarized. Literature on past, current, and upcoming developments of BAP was reviewed to discuss the practical implications of this work. A primary outcome of this project was a policy developed by QALS supporting up to 22 h of labor for the provision of BAP care. The indicative incremental cost-utility ratio for transfemoral and transtibial BAPs was approximately AUD$17,000 and AUD$12,000, respectively, per quality-adjusted life-year compared to socket prostheses. This project was challenged by 17 barriers (e.g., limited resources, inconsistency of care pathways, design of preliminary cost-utility analyses) but eased by 18 facilitators (e.g., action research plan, customized database, use of free repositories). In conclusion, we concluded that lower limb BAP might be an acceptable alternative to socket prostheses from an Australian government prosthetic care perspective. Hopefully, this work will inform promoters of prosthetic innovations committed to making bionic solutions widely accessible to a growing population of individuals suffering from limb loss worldwide. Article PDF Link: https://jps.library.utoronto.ca/index.php/cpoj/article/view/36210/28330 How To Cite: Berg D, Frossard L. Health service delivery and economic evaluation of limb lower bone-anchored prostheses: A summary of the Queensland artificial limb service’s experience. Canadian Prosthetics & Orthotics Journal. 2021; Volume 4, Issue 2, No.12. https://doi.org/10.33137/cpoj.v4i2.36210 Corresponding Author: Laurent Frossard, PhD, Professor of BionicsYourResearchProject Pty Ltd, Brisbane, Australia.E-Mail: [email protected] number: https://orcid.org/0000-0002-0248-9589

Bodily ownership of an independent supernumerary limb: An exploratory study

Can our brain perceive a sense of ownership towards an independent supernumerary limb; one that can be moved independently of any other limb and provides its own independent movement feedback? Following the rubberhand illusion experiment, a plethora of studies has shown that the human representation of ‘self’ is very plastic. But previous studies have almost exclusively investigated ownership towards ‘substitute’ artificial limbs, which are controlled by the movements of a real limb and/or limbs from which non-visual sensory feedback is provided on an existing limb. Here, to investigate whether the human brain can own an independent artificial limb, we first developed a novel independent robotic ‘sixth finger.’ We allowed participants to train using the finger and examined whether it induced changes in the body representation using behavioral as well as cognitive measures. Our results suggest that unlike a substituted artificial limb (like in the rubber hand experiment), it is more difficult for humans to perceive a sense of ownership towards an independent limb. However, ownership does seem possible, as we observed clear tendencies of changes in the body representation that correlated with the cognitive reports of the sense of ownership. Our results provide the first evidence to show that an independent supernumerary limb can be embodied by the human brain.

Voice Enabled Robotic cum Prosthetic Arm for Disabled People

Thriving the use of prevailing technologies in a planned & statistical order so as to achieve something we could make use of, benefiting especially abled common people as well as upcoming vocal based era of robotics, we came up with Voice Enabled prosthetic / robotic Arm. This project was earlier based on providing well-functioning cheap artificial limb, until we explored wide aspects of uses of this technical piece while working on it. Project may be categorized as IoT, based on tech tools used in building it. Working on Natural Language Processing (NLP) this project is able to understand up to 100 daily use commands at its lowest level.

Seeing the whole man: a visualist analysis of artificial limbs at the end of the nineteenth century

The thesis uses the central concerns of visual culture studies to investigate the shift towards artificial limbs that imitate the body as identified by Steven Mihm (2002). Drawing on a modified, less utopian, form of critical discourse analysis, which recognizes the sociocultural power of the visual, this thesis interrogates the promotional literature that the A.A. Marks Company, an artificial limb manufacturer, produced between 1888 and 1920. This thesis critically analyzes the techniques used by the company to assert their authority to frame their relationship to their clients. In addition, this analysis interrogates the company's use of the technologies of vision to champion visually imitative prosthesis. The goal of this analysis is to determine how the company deployed the turn towards the imitative, and what was at stake for the producers, and consumers, as well as the wider culture in the use of imitative limbs.

Seeing the whole man: a visualist analysis of artificial limbs at the end of the nineteenth century

The thesis uses the central concerns of visual culture studies to investigate the shift towards artificial limbs that imitate the body as identified by Steven Mihm (2002). Drawing on a modified, less utopian, form of critical discourse analysis, which recognizes the sociocultural power of the visual, this thesis interrogates the promotional literature that the A.A. Marks Company, an artificial limb manufacturer, produced between 1888 and 1920. This thesis critically analyzes the techniques used by the company to assert their authority to frame their relationship to their clients. In addition, this analysis interrogates the company's use of the technologies of vision to champion visually imitative prosthesis. The goal of this analysis is to determine how the company deployed the turn towards the imitative, and what was at stake for the producers, and consumers, as well as the wider culture in the use of imitative limbs.

Empirical Analysis of Artificial limb for Trans Radial Amputation People with the support of advanced machine learning strategies

For the improvement of performance of trans radial amputees, there will be identification of hand gestures using electromyogram. Whatever the data retrieved from the electrode will be used for controlling the prosthetic hands. In this paper, we are proposing the systematic hand gestures to improve the performance of the trans radial amputation people using the 2-channels amplifier. Different hand gestures like hands up, hands open, hands down, hands close are represented by the different variants and all these gestures will be preprocessed by the discrete approach. Extraction of the features will be done using the combination of ML Strategies. For identifying the pattern, LVQ mechanism is used. By this 2-Channel amplifier the identification of outcome can be evaluated effectively.

Robust neurophysiological correlates of the rubber hand illusion emerge at early latencies but are unrelated to changes in skin conductance accompanying the illusion

The neurophysiological processes reflecting the illusory ownership over an artificial limb remain debated. We used multivariate (cross-)classification of evoked EEG responses to probe for signatures of the illusion that robustly generalize across a number of confounding factors identified based on previous studies: the spatial arrangement of limbs, controls involving either a misaligned artificial object or participant’s own hand, and which provide evidence of illusory ownership directly within an experimental trial. Our results show that sensory-evoked responses differ between illusion and non-illusion epochs from early latencies on. While these responses exhibit distinct sensitivity to the experimental factors at distinct times, around 140 ms the evoked activity reflects the illusory state robustly across experimental manipulations. This neurophysiological signature of illusory ownership was not correlated with increases in skin conductance accompanying the illusion, suggesting that neurophysiological and bodily signals reflect distinct processes related to the embodiment of an artificial limb.