TPress
1.
Taboga, P.; Beck, O. N.; Grabowski, A. M.
In: PLoS ONE, Bd. 15, Nr. 2, 2020, ISSN: 1932-6203.
Abstract | Links | Schlagwörter: adult, aerial time, article, athlete, below knee amputation, below knee prosthesis, biomechanics, clinical article, contact length, contact time, controlled study, Freedom Innovations Catapult FX6, ground reaction force, human, male, Ossur Flex-Foot Cheetah Xtend, Ottobock 1E90 Sprinter, physical parameters, prosthesis design, prosthetic height, prosthetic shape, prosthetic stiffness, running, running specific prosthesis, running speed, standing, vertical stiffness, young adult
@article{Taboga2020,
title = {Prosthetic shape, but not stiffness or height, affects the maximum speed of sprinters with bilateral transtibial amputations},
author = {P. Taboga and O. N. Beck and A. M. Grabowski},
url = {https://www.embase.com/search/results?subaction=viewrecord&id=L2005026109&from=export},
doi = {10.1371/journal.pone.0229035},
issn = {1932-6203},
year = {2020},
date = {2020-01-01},
journal = {PLoS ONE},
volume = {15},
number = {2},
address = {P. Taboga, Department of Kinesiology, California State University, Sacramento, CA, United States},
abstract = {Running-specific prostheses (RSPs) have facilitated an athlete with bilateral transtibial amputations to compete in the Olympic Games. However, the performance effects of using RSPs compared to biological legs remains controversial. Further, the use of different prosthetic configurations such as shape, stiffness, and height likely influence performance. We determined the effects of using 15 different RSP configurations on the maximum speed of five male athletes with bilateral transtibial amputations. These athletes performed sets of running trials up to maximum speed using three different RSP models (Freedom Innovations Catapult FX6, Össur Flex-Foot Cheetah Xtend and Ottobock 1E90 Sprinter) each with five combinations of stiffness category and height. We measured ground reaction forces during each maximum speed trial to determine the biomechanical parameters associated with different RSP configurations and maximum sprinting speeds. Use of the J-shaped Cheetah Xtend and 1E90 Sprinter RSPs resulted in 8.3% and 8.0% (p<0.001) faster maximum speeds compared to the use of the C-shaped Catapult FX6 RSPs, respectively. Neither RSP stiffness expressed as a category (p = 0.836) nor as kNm-1 (p = 0.916) affected maximum speed. Further, prosthetic height had no effect on maximum speed (p = 0.762). Faster maximum speeds were associated with reduced ground contact time, aerial time, and overall leg stiffness, as well as with greater stance-average vertical ground reaction force, contact length, and vertical stiffness (p = 0.015 for aerial time, p<0.001 for all other variables). RSP shape, but not stiffness or height, influences the maximum speed of athletes with bilateral transtibial amputations.},
keywords = {adult, aerial time, article, athlete, below knee amputation, below knee prosthesis, biomechanics, clinical article, contact length, contact time, controlled study, Freedom Innovations Catapult FX6, ground reaction force, human, male, Ossur Flex-Foot Cheetah Xtend, Ottobock 1E90 Sprinter, physical parameters, prosthesis design, prosthetic height, prosthetic shape, prosthetic stiffness, running, running specific prosthesis, running speed, standing, vertical stiffness, young adult},
pubstate = {published},
tppubtype = {article}
}
Running-specific prostheses (RSPs) have facilitated an athlete with bilateral transtibial amputations to compete in the Olympic Games. However, the performance effects of using RSPs compared to biological legs remains controversial. Further, the use of different prosthetic configurations such as shape, stiffness, and height likely influence performance. We determined the effects of using 15 different RSP configurations on the maximum speed of five male athletes with bilateral transtibial amputations. These athletes performed sets of running trials up to maximum speed using three different RSP models (Freedom Innovations Catapult FX6, Össur Flex-Foot Cheetah Xtend and Ottobock 1E90 Sprinter) each with five combinations of stiffness category and height. We measured ground reaction forces during each maximum speed trial to determine the biomechanical parameters associated with different RSP configurations and maximum sprinting speeds. Use of the J-shaped Cheetah Xtend and 1E90 Sprinter RSPs resulted in 8.3% and 8.0% (p<0.001) faster maximum speeds compared to the use of the C-shaped Catapult FX6 RSPs, respectively. Neither RSP stiffness expressed as a category (p = 0.836) nor as kNm-1 (p = 0.916) affected maximum speed. Further, prosthetic height had no effect on maximum speed (p = 0.762). Faster maximum speeds were associated with reduced ground contact time, aerial time, and overall leg stiffness, as well as with greater stance-average vertical ground reaction force, contact length, and vertical stiffness (p = 0.015 for aerial time, p<0.001 for all other variables). RSP shape, but not stiffness or height, influences the maximum speed of athletes with bilateral transtibial amputations.
2.
Schweisfurth, M. A.; Markovic, M.; Dosen, S.; Teich, F.; Graimann, B.; Farina, D.
Electrotactile EMG feedback improves the control of prosthesis grasping force Artikel
In: J. Neural Eng., Bd. 13, Nr. 5, 2016, ISSN: 1741-2560.
Abstract | Links | Schlagwörter: accuracy, adult, amputee, article, case report, controlled study, electromyography, electrotactile electromyography, feedback system, female, force, grip strength, hand prosthesis, human, Michaelangelo Hand, myoelectrically controlled prosthesis, priority journal, sensory feedback, task performance, young adult
@article{Schweisfurth2016,
title = {Electrotactile EMG feedback improves the control of prosthesis grasping force},
author = {M. A. Schweisfurth and M. Markovic and S. Dosen and F. Teich and B. Graimann and D. Farina},
url = {https://www.embase.com/search/results?subaction=viewrecord&id=L612465506&from=export},
doi = {10.1088/1741-2560/13/5/056010},
issn = {1741-2560},
year = {2016},
date = {2016-01-01},
journal = {J. Neural Eng.},
volume = {13},
number = {5},
address = {D. Farina, Institute for NeuroRehabilitation Systems, University Medical Center Göttingen, Georg-August University, Göttingen, Germany},
abstract = {Objective. A drawback of active prostheses is that they detach the subject from the produced forces, thereby preventing direct mechanical feedback. This can be compensated by providing somatosensory feedback to the user through mechanical or electrical stimulation, which in turn may improve the utility, sense of embodiment, and thereby increase the acceptance rate. Approach. In this study, we compared a novel approach to closing the loop, namely EMG feedback (emgFB), to classic force feedback (forceFB), using electrotactile interface in a realistic task setup. Eleven intact-bodied subjects and one transradial amputee performed a routine grasping task while receiving emgFB or forceFB. The two feedback types were delivered through the same electrotactile interface, using a mixed spatial/frequency coding to transmit 8 discrete levels of the feedback variable. In emgFB, the stimulation transmitted the amplitude of the processed myoelectric signal generated by the subject (prosthesis input), and in forceFB the generated grasping force (prosthesis output). The task comprised 150 trials of routine grasping at six forces, randomly presented in blocks of five trials (same force). Interquartile range and changes in the absolute error (AE) distribution (magnitude and dispersion) with respect to the target level were used to assess precision and overall performance, respectively. Main results. Relative to forceFB, emgFB significantly improved the precision of myoelectric commands (min/max of the significant levels) for 23%/36% as well as the precision of force control for 12%/32%, in intact-bodied subjects. Also, the magnitude and dispersion of the AE distribution were reduced. The results were similar in the amputee, showing considerable improvements. Significance. Using emgFB, the subjects therefore decreased the uncertainty of the forward pathway. Since there is a correspondence between the EMG and force, where the former anticipates the latter, the emgFB allowed for predictive control, as the subjects used the feedback to adjust the desired force even before the prosthesis contacted the object. In conclusion, the online emgFB was superior to the classic forceFB in realistic conditions that included electrotactile stimulation, limited feedback resolution (8 levels), cognitive processing delay, and time constraints (fast grasping).},
keywords = {accuracy, adult, amputee, article, case report, controlled study, electromyography, electrotactile electromyography, feedback system, female, force, grip strength, hand prosthesis, human, Michaelangelo Hand, myoelectrically controlled prosthesis, priority journal, sensory feedback, task performance, young adult},
pubstate = {published},
tppubtype = {article}
}
Objective. A drawback of active prostheses is that they detach the subject from the produced forces, thereby preventing direct mechanical feedback. This can be compensated by providing somatosensory feedback to the user through mechanical or electrical stimulation, which in turn may improve the utility, sense of embodiment, and thereby increase the acceptance rate. Approach. In this study, we compared a novel approach to closing the loop, namely EMG feedback (emgFB), to classic force feedback (forceFB), using electrotactile interface in a realistic task setup. Eleven intact-bodied subjects and one transradial amputee performed a routine grasping task while receiving emgFB or forceFB. The two feedback types were delivered through the same electrotactile interface, using a mixed spatial/frequency coding to transmit 8 discrete levels of the feedback variable. In emgFB, the stimulation transmitted the amplitude of the processed myoelectric signal generated by the subject (prosthesis input), and in forceFB the generated grasping force (prosthesis output). The task comprised 150 trials of routine grasping at six forces, randomly presented in blocks of five trials (same force). Interquartile range and changes in the absolute error (AE) distribution (magnitude and dispersion) with respect to the target level were used to assess precision and overall performance, respectively. Main results. Relative to forceFB, emgFB significantly improved the precision of myoelectric commands (min/max of the significant levels) for 23%/36% as well as the precision of force control for 12%/32%, in intact-bodied subjects. Also, the magnitude and dispersion of the AE distribution were reduced. The results were similar in the amputee, showing considerable improvements. Significance. Using emgFB, the subjects therefore decreased the uncertainty of the forward pathway. Since there is a correspondence between the EMG and force, where the former anticipates the latter, the emgFB allowed for predictive control, as the subjects used the feedback to adjust the desired force even before the prosthesis contacted the object. In conclusion, the online emgFB was superior to the classic forceFB in realistic conditions that included electrotactile stimulation, limited feedback resolution (8 levels), cognitive processing delay, and time constraints (fast grasping).
2020
Taboga, P.; Beck, O. N.; Grabowski, A. M.
In: PLoS ONE, Bd. 15, Nr. 2, 2020, ISSN: 1932-6203.
Abstract | Links | Schlagwörter: adult, aerial time, article, athlete, below knee amputation, below knee prosthesis, biomechanics, clinical article, contact length, contact time, controlled study, Freedom Innovations Catapult FX6, ground reaction force, human, male, Ossur Flex-Foot Cheetah Xtend, Ottobock 1E90 Sprinter, physical parameters, prosthesis design, prosthetic height, prosthetic shape, prosthetic stiffness, running, running specific prosthesis, running speed, standing, vertical stiffness, young adult
@article{Taboga2020,
title = {Prosthetic shape, but not stiffness or height, affects the maximum speed of sprinters with bilateral transtibial amputations},
author = {P. Taboga and O. N. Beck and A. M. Grabowski},
url = {https://www.embase.com/search/results?subaction=viewrecord&id=L2005026109&from=export},
doi = {10.1371/journal.pone.0229035},
issn = {1932-6203},
year = {2020},
date = {2020-01-01},
journal = {PLoS ONE},
volume = {15},
number = {2},
address = {P. Taboga, Department of Kinesiology, California State University, Sacramento, CA, United States},
abstract = {Running-specific prostheses (RSPs) have facilitated an athlete with bilateral transtibial amputations to compete in the Olympic Games. However, the performance effects of using RSPs compared to biological legs remains controversial. Further, the use of different prosthetic configurations such as shape, stiffness, and height likely influence performance. We determined the effects of using 15 different RSP configurations on the maximum speed of five male athletes with bilateral transtibial amputations. These athletes performed sets of running trials up to maximum speed using three different RSP models (Freedom Innovations Catapult FX6, Össur Flex-Foot Cheetah Xtend and Ottobock 1E90 Sprinter) each with five combinations of stiffness category and height. We measured ground reaction forces during each maximum speed trial to determine the biomechanical parameters associated with different RSP configurations and maximum sprinting speeds. Use of the J-shaped Cheetah Xtend and 1E90 Sprinter RSPs resulted in 8.3% and 8.0% (p<0.001) faster maximum speeds compared to the use of the C-shaped Catapult FX6 RSPs, respectively. Neither RSP stiffness expressed as a category (p = 0.836) nor as kNm-1 (p = 0.916) affected maximum speed. Further, prosthetic height had no effect on maximum speed (p = 0.762). Faster maximum speeds were associated with reduced ground contact time, aerial time, and overall leg stiffness, as well as with greater stance-average vertical ground reaction force, contact length, and vertical stiffness (p = 0.015 for aerial time, p<0.001 for all other variables). RSP shape, but not stiffness or height, influences the maximum speed of athletes with bilateral transtibial amputations.},
keywords = {adult, aerial time, article, athlete, below knee amputation, below knee prosthesis, biomechanics, clinical article, contact length, contact time, controlled study, Freedom Innovations Catapult FX6, ground reaction force, human, male, Ossur Flex-Foot Cheetah Xtend, Ottobock 1E90 Sprinter, physical parameters, prosthesis design, prosthetic height, prosthetic shape, prosthetic stiffness, running, running specific prosthesis, running speed, standing, vertical stiffness, young adult},
pubstate = {published},
tppubtype = {article}
}
Running-specific prostheses (RSPs) have facilitated an athlete with bilateral transtibial amputations to compete in the Olympic Games. However, the performance effects of using RSPs compared to biological legs remains controversial. Further, the use of different prosthetic configurations such as shape, stiffness, and height likely influence performance. We determined the effects of using 15 different RSP configurations on the maximum speed of five male athletes with bilateral transtibial amputations. These athletes performed sets of running trials up to maximum speed using three different RSP models (Freedom Innovations Catapult FX6, Össur Flex-Foot Cheetah Xtend and Ottobock 1E90 Sprinter) each with five combinations of stiffness category and height. We measured ground reaction forces during each maximum speed trial to determine the biomechanical parameters associated with different RSP configurations and maximum sprinting speeds. Use of the J-shaped Cheetah Xtend and 1E90 Sprinter RSPs resulted in 8.3% and 8.0% (p<0.001) faster maximum speeds compared to the use of the C-shaped Catapult FX6 RSPs, respectively. Neither RSP stiffness expressed as a category (p = 0.836) nor as kNm-1 (p = 0.916) affected maximum speed. Further, prosthetic height had no effect on maximum speed (p = 0.762). Faster maximum speeds were associated with reduced ground contact time, aerial time, and overall leg stiffness, as well as with greater stance-average vertical ground reaction force, contact length, and vertical stiffness (p = 0.015 for aerial time, p<0.001 for all other variables). RSP shape, but not stiffness or height, influences the maximum speed of athletes with bilateral transtibial amputations.
2016
Schweisfurth, M. A.; Markovic, M.; Dosen, S.; Teich, F.; Graimann, B.; Farina, D.
Electrotactile EMG feedback improves the control of prosthesis grasping force Artikel
In: J. Neural Eng., Bd. 13, Nr. 5, 2016, ISSN: 1741-2560.
Abstract | Links | Schlagwörter: accuracy, adult, amputee, article, case report, controlled study, electromyography, electrotactile electromyography, feedback system, female, force, grip strength, hand prosthesis, human, Michaelangelo Hand, myoelectrically controlled prosthesis, priority journal, sensory feedback, task performance, young adult
@article{Schweisfurth2016,
title = {Electrotactile EMG feedback improves the control of prosthesis grasping force},
author = {M. A. Schweisfurth and M. Markovic and S. Dosen and F. Teich and B. Graimann and D. Farina},
url = {https://www.embase.com/search/results?subaction=viewrecord&id=L612465506&from=export},
doi = {10.1088/1741-2560/13/5/056010},
issn = {1741-2560},
year = {2016},
date = {2016-01-01},
journal = {J. Neural Eng.},
volume = {13},
number = {5},
address = {D. Farina, Institute for NeuroRehabilitation Systems, University Medical Center Göttingen, Georg-August University, Göttingen, Germany},
abstract = {Objective. A drawback of active prostheses is that they detach the subject from the produced forces, thereby preventing direct mechanical feedback. This can be compensated by providing somatosensory feedback to the user through mechanical or electrical stimulation, which in turn may improve the utility, sense of embodiment, and thereby increase the acceptance rate. Approach. In this study, we compared a novel approach to closing the loop, namely EMG feedback (emgFB), to classic force feedback (forceFB), using electrotactile interface in a realistic task setup. Eleven intact-bodied subjects and one transradial amputee performed a routine grasping task while receiving emgFB or forceFB. The two feedback types were delivered through the same electrotactile interface, using a mixed spatial/frequency coding to transmit 8 discrete levels of the feedback variable. In emgFB, the stimulation transmitted the amplitude of the processed myoelectric signal generated by the subject (prosthesis input), and in forceFB the generated grasping force (prosthesis output). The task comprised 150 trials of routine grasping at six forces, randomly presented in blocks of five trials (same force). Interquartile range and changes in the absolute error (AE) distribution (magnitude and dispersion) with respect to the target level were used to assess precision and overall performance, respectively. Main results. Relative to forceFB, emgFB significantly improved the precision of myoelectric commands (min/max of the significant levels) for 23%/36% as well as the precision of force control for 12%/32%, in intact-bodied subjects. Also, the magnitude and dispersion of the AE distribution were reduced. The results were similar in the amputee, showing considerable improvements. Significance. Using emgFB, the subjects therefore decreased the uncertainty of the forward pathway. Since there is a correspondence between the EMG and force, where the former anticipates the latter, the emgFB allowed for predictive control, as the subjects used the feedback to adjust the desired force even before the prosthesis contacted the object. In conclusion, the online emgFB was superior to the classic forceFB in realistic conditions that included electrotactile stimulation, limited feedback resolution (8 levels), cognitive processing delay, and time constraints (fast grasping).},
keywords = {accuracy, adult, amputee, article, case report, controlled study, electromyography, electrotactile electromyography, feedback system, female, force, grip strength, hand prosthesis, human, Michaelangelo Hand, myoelectrically controlled prosthesis, priority journal, sensory feedback, task performance, young adult},
pubstate = {published},
tppubtype = {article}
}
Objective. A drawback of active prostheses is that they detach the subject from the produced forces, thereby preventing direct mechanical feedback. This can be compensated by providing somatosensory feedback to the user through mechanical or electrical stimulation, which in turn may improve the utility, sense of embodiment, and thereby increase the acceptance rate. Approach. In this study, we compared a novel approach to closing the loop, namely EMG feedback (emgFB), to classic force feedback (forceFB), using electrotactile interface in a realistic task setup. Eleven intact-bodied subjects and one transradial amputee performed a routine grasping task while receiving emgFB or forceFB. The two feedback types were delivered through the same electrotactile interface, using a mixed spatial/frequency coding to transmit 8 discrete levels of the feedback variable. In emgFB, the stimulation transmitted the amplitude of the processed myoelectric signal generated by the subject (prosthesis input), and in forceFB the generated grasping force (prosthesis output). The task comprised 150 trials of routine grasping at six forces, randomly presented in blocks of five trials (same force). Interquartile range and changes in the absolute error (AE) distribution (magnitude and dispersion) with respect to the target level were used to assess precision and overall performance, respectively. Main results. Relative to forceFB, emgFB significantly improved the precision of myoelectric commands (min/max of the significant levels) for 23%/36% as well as the precision of force control for 12%/32%, in intact-bodied subjects. Also, the magnitude and dispersion of the AE distribution were reduced. The results were similar in the amputee, showing considerable improvements. Significance. Using emgFB, the subjects therefore decreased the uncertainty of the forward pathway. Since there is a correspondence between the EMG and force, where the former anticipates the latter, the emgFB allowed for predictive control, as the subjects used the feedback to adjust the desired force even before the prosthesis contacted the object. In conclusion, the online emgFB was superior to the classic forceFB in realistic conditions that included electrotactile stimulation, limited feedback resolution (8 levels), cognitive processing delay, and time constraints (fast grasping).
2020
Taboga, P.; Beck, O. N.; Grabowski, A. M.
In: PLoS ONE, Bd. 15, Nr. 2, 2020, ISSN: 1932-6203.
@article{Taboga2020,
title = {Prosthetic shape, but not stiffness or height, affects the maximum speed of sprinters with bilateral transtibial amputations},
author = {P. Taboga and O. N. Beck and A. M. Grabowski},
url = {https://www.embase.com/search/results?subaction=viewrecord&id=L2005026109&from=export},
doi = {10.1371/journal.pone.0229035},
issn = {1932-6203},
year = {2020},
date = {2020-01-01},
journal = {PLoS ONE},
volume = {15},
number = {2},
address = {P. Taboga, Department of Kinesiology, California State University, Sacramento, CA, United States},
abstract = {Running-specific prostheses (RSPs) have facilitated an athlete with bilateral transtibial amputations to compete in the Olympic Games. However, the performance effects of using RSPs compared to biological legs remains controversial. Further, the use of different prosthetic configurations such as shape, stiffness, and height likely influence performance. We determined the effects of using 15 different RSP configurations on the maximum speed of five male athletes with bilateral transtibial amputations. These athletes performed sets of running trials up to maximum speed using three different RSP models (Freedom Innovations Catapult FX6, Össur Flex-Foot Cheetah Xtend and Ottobock 1E90 Sprinter) each with five combinations of stiffness category and height. We measured ground reaction forces during each maximum speed trial to determine the biomechanical parameters associated with different RSP configurations and maximum sprinting speeds. Use of the J-shaped Cheetah Xtend and 1E90 Sprinter RSPs resulted in 8.3% and 8.0% (p<0.001) faster maximum speeds compared to the use of the C-shaped Catapult FX6 RSPs, respectively. Neither RSP stiffness expressed as a category (p = 0.836) nor as kNm-1 (p = 0.916) affected maximum speed. Further, prosthetic height had no effect on maximum speed (p = 0.762). Faster maximum speeds were associated with reduced ground contact time, aerial time, and overall leg stiffness, as well as with greater stance-average vertical ground reaction force, contact length, and vertical stiffness (p = 0.015 for aerial time, p<0.001 for all other variables). RSP shape, but not stiffness or height, influences the maximum speed of athletes with bilateral transtibial amputations.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Running-specific prostheses (RSPs) have facilitated an athlete with bilateral transtibial amputations to compete in the Olympic Games. However, the performance effects of using RSPs compared to biological legs remains controversial. Further, the use of different prosthetic configurations such as shape, stiffness, and height likely influence performance. We determined the effects of using 15 different RSP configurations on the maximum speed of five male athletes with bilateral transtibial amputations. These athletes performed sets of running trials up to maximum speed using three different RSP models (Freedom Innovations Catapult FX6, Össur Flex-Foot Cheetah Xtend and Ottobock 1E90 Sprinter) each with five combinations of stiffness category and height. We measured ground reaction forces during each maximum speed trial to determine the biomechanical parameters associated with different RSP configurations and maximum sprinting speeds. Use of the J-shaped Cheetah Xtend and 1E90 Sprinter RSPs resulted in 8.3% and 8.0% (p<0.001) faster maximum speeds compared to the use of the C-shaped Catapult FX6 RSPs, respectively. Neither RSP stiffness expressed as a category (p = 0.836) nor as kNm-1 (p = 0.916) affected maximum speed. Further, prosthetic height had no effect on maximum speed (p = 0.762). Faster maximum speeds were associated with reduced ground contact time, aerial time, and overall leg stiffness, as well as with greater stance-average vertical ground reaction force, contact length, and vertical stiffness (p = 0.015 for aerial time, p<0.001 for all other variables). RSP shape, but not stiffness or height, influences the maximum speed of athletes with bilateral transtibial amputations.
2016
Schweisfurth, M. A.; Markovic, M.; Dosen, S.; Teich, F.; Graimann, B.; Farina, D.
Electrotactile EMG feedback improves the control of prosthesis grasping force Artikel
In: J. Neural Eng., Bd. 13, Nr. 5, 2016, ISSN: 1741-2560.
@article{Schweisfurth2016,
title = {Electrotactile EMG feedback improves the control of prosthesis grasping force},
author = {M. A. Schweisfurth and M. Markovic and S. Dosen and F. Teich and B. Graimann and D. Farina},
url = {https://www.embase.com/search/results?subaction=viewrecord&id=L612465506&from=export},
doi = {10.1088/1741-2560/13/5/056010},
issn = {1741-2560},
year = {2016},
date = {2016-01-01},
journal = {J. Neural Eng.},
volume = {13},
number = {5},
address = {D. Farina, Institute for NeuroRehabilitation Systems, University Medical Center Göttingen, Georg-August University, Göttingen, Germany},
abstract = {Objective. A drawback of active prostheses is that they detach the subject from the produced forces, thereby preventing direct mechanical feedback. This can be compensated by providing somatosensory feedback to the user through mechanical or electrical stimulation, which in turn may improve the utility, sense of embodiment, and thereby increase the acceptance rate. Approach. In this study, we compared a novel approach to closing the loop, namely EMG feedback (emgFB), to classic force feedback (forceFB), using electrotactile interface in a realistic task setup. Eleven intact-bodied subjects and one transradial amputee performed a routine grasping task while receiving emgFB or forceFB. The two feedback types were delivered through the same electrotactile interface, using a mixed spatial/frequency coding to transmit 8 discrete levels of the feedback variable. In emgFB, the stimulation transmitted the amplitude of the processed myoelectric signal generated by the subject (prosthesis input), and in forceFB the generated grasping force (prosthesis output). The task comprised 150 trials of routine grasping at six forces, randomly presented in blocks of five trials (same force). Interquartile range and changes in the absolute error (AE) distribution (magnitude and dispersion) with respect to the target level were used to assess precision and overall performance, respectively. Main results. Relative to forceFB, emgFB significantly improved the precision of myoelectric commands (min/max of the significant levels) for 23%/36% as well as the precision of force control for 12%/32%, in intact-bodied subjects. Also, the magnitude and dispersion of the AE distribution were reduced. The results were similar in the amputee, showing considerable improvements. Significance. Using emgFB, the subjects therefore decreased the uncertainty of the forward pathway. Since there is a correspondence between the EMG and force, where the former anticipates the latter, the emgFB allowed for predictive control, as the subjects used the feedback to adjust the desired force even before the prosthesis contacted the object. In conclusion, the online emgFB was superior to the classic forceFB in realistic conditions that included electrotactile stimulation, limited feedback resolution (8 levels), cognitive processing delay, and time constraints (fast grasping).},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Objective. A drawback of active prostheses is that they detach the subject from the produced forces, thereby preventing direct mechanical feedback. This can be compensated by providing somatosensory feedback to the user through mechanical or electrical stimulation, which in turn may improve the utility, sense of embodiment, and thereby increase the acceptance rate. Approach. In this study, we compared a novel approach to closing the loop, namely EMG feedback (emgFB), to classic force feedback (forceFB), using electrotactile interface in a realistic task setup. Eleven intact-bodied subjects and one transradial amputee performed a routine grasping task while receiving emgFB or forceFB. The two feedback types were delivered through the same electrotactile interface, using a mixed spatial/frequency coding to transmit 8 discrete levels of the feedback variable. In emgFB, the stimulation transmitted the amplitude of the processed myoelectric signal generated by the subject (prosthesis input), and in forceFB the generated grasping force (prosthesis output). The task comprised 150 trials of routine grasping at six forces, randomly presented in blocks of five trials (same force). Interquartile range and changes in the absolute error (AE) distribution (magnitude and dispersion) with respect to the target level were used to assess precision and overall performance, respectively. Main results. Relative to forceFB, emgFB significantly improved the precision of myoelectric commands (min/max of the significant levels) for 23%/36% as well as the precision of force control for 12%/32%, in intact-bodied subjects. Also, the magnitude and dispersion of the AE distribution were reduced. The results were similar in the amputee, showing considerable improvements. Significance. Using emgFB, the subjects therefore decreased the uncertainty of the forward pathway. Since there is a correspondence between the EMG and force, where the former anticipates the latter, the emgFB allowed for predictive control, as the subjects used the feedback to adjust the desired force even before the prosthesis contacted the object. In conclusion, the online emgFB was superior to the classic forceFB in realistic conditions that included electrotactile stimulation, limited feedback resolution (8 levels), cognitive processing delay, and time constraints (fast grasping).