Browsing by Author "Sturma, Agnes"

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    Biomechanical Analysis of Body Movements of Myoelectric Prosthesis Users During Standardized Clinical Tests
    (IEEE, 2023-03-01) Vujaklija, Ivan; Jung, Moon Ki; Hasenoehrl, Timothy; Roche, Aidan D.; Sturma, Agnes; Muceli, Silvia; Crevenna, Richard; Aszmann, Oskar C.; Farina, Dario; Bionic and Rehabilitation Engineering; Imperial College London; Medical University of Vienna; St John's Hospital; Chalmers University of Technology; Department of Electrical Engineering and Automation
    Objective: The objective clinical evaluation of user's capabilities to handle their prosthesis is done using various tests which primarily focus on the task completion speed and do not explicitly account for the potential presence of compensatory motions. Given that the excessive body compensation is a common indicator of inadequate prosthesis control, tests which include subjective observations on the quality of performed motions have been introduced. However, these metrics are then influenced by the examiner's opinions, skills, and training making them harder to standardize across patient pools and compare across different prosthetic technologies. Here we aim to objectively quantify the severity of body compensations present in myoelectric prosthetic hand users and evaluate the extent to which traditional objective clinical scores are still able to capture them. Methods: We have instructed 9 below-elbow prosthesis users and 9 able-bodied participants to complete three established objective clinical tests: Box-and-Blocks-Test, Clothespin-Relocation-Test, and Southampton-Hand-Assessment-Procedure. During all tests, upper-body kinematics has been recorded. Results: While the analysis showed that there are some correlations between the achieved clinical scores and the individual body segment travel distances and average speeds, there were only weak correlations between the clinical scores and the observed ranges of motion. At the same time, the compensations were observed in all prosthesis users and, for the most part, they were substantial across the tests. Conclusion: The sole reliance on the currently available objective clinical assessment methods seems inadequate as the compensatory movements are prominent in prosthesis users and yet not sufficiently accounted for.
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    Long-term Functional and Clinical Outcome of Combined Targeted Muscle Reinnervation and Osseointegration for Functional Bionic Reconstruction in Transhumeral Amputees : A Case Series
    (Medical Journals Sweden AB, 2024-05-21) Sturma, Agnes; Boesendorfer, Anna; Gstoettner, Clemens; Baumgartner, Benedikt; Salminger, Stefan; Farina, Dario; Brånemark, Rickard; Vujaklija, Ivan; Hobusch, Gerhard M.; Aszmann, Oskar C.; Department of Electrical Engineering and Automation; Bionic and Rehabilitation Engineering; University of Applied Sciences FH Campus Wien; Medical University of Vienna; AUVA Trauma Hospital Lorenz Böhler; Imperial College London; University of Gothenburg
    Objective: To describe and evaluate the combination of osseointegration and nerve transfers in 3 transhumeral amputees. Design: Case series. Patients: Three male patients with a unilateral traumatic transhumeral amputation. Methods: Patients received a combination of osseointegration and targeted muscle reinnervation surgery. Rehabilitation included graded weight training, range of motion exercises, biofeedback, table-top prosthesis training, and controlling the actual device. The impairment in daily life, health-related quality of life, and pain before and after the intervention was evaluated in these patients. Their shoulder range of motion, prosthesis embodiment, and function were documented at a 2- to 5-year follow-up. Results: All 3 patients attended rehabilitation and used their myoelectric prosthesis on a daily basis. Two patients had full shoulder range of motion with the prosthesis, while the other patient had 55° of abduction and 45° of anteversion. They became more independent in their daily life activities after the intervention and incorporated their prosthesis into their body scheme to a high extent. Conclusion: These results indicate that patients can benefit from the combined procedure. However, the patients’ perspective, risks of the surgical procedures, and the relatively long rehabilitation procedure need to be incorporated in the decision-making.
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    Prosthetic Embodiment and Body Image Changes in Patients Undergoing Bionic Reconstruction Following Brachial Plexus Injury
    (FRONTIERS MEDIA SA, 2021-04-30) Sturma, Agnes; Hruby, Laura A.; Boesendorfer, Anna; Pittermann, Anna; Salminger, Stefan; Gstoettner, Clemens; Politikou, Olga; Vujaklija, Ivan; Farina, Dario; Aszmann, Oskar C.; Medical University of Vienna; Bionic and Rehabilitation Engineering; Imperial College London; Department of Electrical Engineering and Automation
    Brachial plexus injuries with multiple-root involvement lead to severe and long-lasting impairments in the functionality and appearance of the affected upper extremity. In cases, where biologic reconstruction of hand and arm function is not possible, bionic reconstruction may be considered as a viable clinical option. Bionic reconstruction, through a careful combination of surgical augmentation, amputation, and prosthetic substitution of the functionless hand, has been shown to achieve substantial improvements in function and quality of life. However, it is known that long-term distortions in the body image are present in patients with severe nerve injury as well as in prosthetic users regardless of the level of function. To date, the body image of patients who voluntarily opted for elective amputation and prosthetic reconstruction has not been investigated. Moreover, the degree of embodiment of the prosthesis in these patients is unknown. We have conducted a longitudinal study evaluating changes of body image using the patient-reported Body Image Questionnaire 20 (BIQ-20) and a structured questionnaire about prosthetic embodiment. Six patients have been included. At follow up 2.5–5 years after intervention, a majority of patients reported better BIQ-20 scores including a less negative body evaluation (5 out of 6 patients) and higher vital body dynamics (4 out of 6 patients). Moreover, patients described a strong to moderate prosthesis embodiment. Interestingly, whether patients reported performing bimanual tasks together with the prosthetic hand or not, did not influence their perception of the prosthesis as a body part. In general, this group of patients undergoing prosthetic substitution after brachial plexus injury shows noticeable inter-individual differences. This indicates that the replacement of human anatomy with technology is not a straight-forward process perceived in the same way by everyone opting for it.
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    Simultaneous and Proportional Real-Time Myocontrol of up to Three Degrees of Freedom of the Wrist and Hand
    (IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2023-02-01) Nowak, Markus; Vujaklija, Ivan; Sturma, Agnes; Castellini, Claudio; Farina, Dario; Department of Electrical Engineering and Automation; Bionic and Rehabilitation Engineering; German Aerospace Center; Imperial College London
    Achieving robust, intuitive, simultaneous and proportional control over multiple degrees of freedom (DOFs) is an outstanding challenge in the development of myoelectric prosthetic systems. Since the priority in myoelectric prosthesis solutions is robustness and stability, their number of functions is usually limited. Objective: Here, we introduce a system for intuitive concurrent hand and wrist control, based on a robust feature-extraction protocol and machine-learning. Methods: Using the mean absolute value of high-density EMG, we train a ridge-regressor (RR) on only the sustained portions of the single-DOF contractions and leverage the regressor's inherent ability to provide simultaneous multi-DOF estimates. In this way, we robustly capture the amplitude information of the inputs while harnessing the power of the RR to extrapolate otherwise noisy and often overfitted estimations of dynamic portions of movements. Results: The real-time evaluation of the system on 13 able-bodied participants and an amputee shows that almost all single-DOF tasks could be reached (96% success rate), while at the same time users were able to complete most of the two-DOF (62%) and even some of the very challenging three-DOF tasks (37%). To further investigate the translational potential of the approach, we reduced the original 192-channel setup to a 16-channel configuration and the observed performance did not deteriorate. Notably, the amputee performed similarly well to the other participants, according to all considered metrics. Conclusion: This is the first real-time operated myocontrol system that consistently provides intuitive simultaneous and proportional control over 3-DOFs of wrist and hand, relying on only surface EMG signals from the forearm. Significance: Focusing on reduced complexity, a real-time test and the inclusion of an amputee in the study demonstrate the translational potential of the control system for future applications in prosthetic control.
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    Toward higher-performance bionic limbs for wider clinical use
    (Nature Publishing Group, 2023-04) Farina, Dario; Vujaklija, Ivan; Brånemark, Rickard; Bull, Anthony M.J.; Dietl, Hans; Graimann, Bernhard; Hargrove, Levi J.; Hoffmann, Klaus Peter; Huang, He (Helen); Ingvarsson, Thorvaldur; Janusson, Hilmar Bragi; Kristjánsson, Kristleifur; Kuiken, Todd; Micera, Silvestro; Stieglitz, Thomas; Sturma, Agnes; Tyler, Dustin; Weir, Richard F.ff; Aszmann, Oskar C.; Department of Electrical Engineering and Automation; Bionic and Rehabilitation Engineering; Imperial College London; Massachusetts Institute of Technology; Ottobock SE & Co. KGaA; Northwestern University; Fraunhofer Institute for Biomedical Engineering; North Carolina State University; Össur Iceland; University of Iceland; Scuola Superiore Sant’Anna; Universität Freiburg; Case Western Reserve University; University of Colorado Denver; Medical University of Vienna
    Most prosthetic limbs can autonomously move with dexterity, yet they are not perceived by the user as belonging to their own body. Robotic limbs can convey information about the environment with higher precision than biological limbs, but their actual performance is substantially limited by current technologies for the interfacing of the robotic devices with the body and for transferring motor and sensory information bidirectionally between the prosthesis and the user. In this Perspective, we argue that direct skeletal attachment of bionic devices via osseointegration, the amplification of neural signals by targeted muscle innervation, improved prosthesis control via implanted muscle sensors and advanced algorithms, and the provision of sensory feedback by means of electrodes implanted in peripheral nerves, should all be leveraged towards the creation of a new generation of high-performance bionic limbs. These technologies have been clinically tested in humans, and alongside mechanical redesigns and adequate rehabilitation training should facilitate the wider clinical use of bionic limbs.