Improved Training Paradigms and Motor-decode Algorithms: Results from Intact Individuals and a Recent Transradial Amputee with Prior Complex Regional Pain Syndrome

George, Jacob A.; Brinton, Mark R.; Duncan, Christopher C.; Hutchinson, Douglas T.; Clark, Gregory A.

doi:10.1109/embc.2018.8513342

Cited by 36 publications

(70 citation statements)

References 9 publications

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“…The first amputee (subject 6; S6) was a 57-year-old, left-hand-dominant male whose left foot and left forearm were amputated 13 years prior, after an electrocution injury [13]. The second amputee (subject 7; S7) was a 48-year-old, left-hand-dominant male, whose right forearm was amputated after Complex Regional Pain Syndrome (CRPS) and multi-year disuse [14]. Our work with five prior subjects (S1 -S5) have been previously published [11], [12], [15].…”

Section: Human Subjectsmentioning

confidence: 99%

Intuitive neuromyoelectric control of a dexterous bionic arm using a modified Kalman filter

George

Davis

Brinton

et al. 2020

Journal of Neuroscience Methods

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Background: Multi-articulate prostheses are capable of performing dexterous hand movements. However, clinically available control strategies fail to provide users with intuitive, independent and proportional control over multiple degrees of freedom (DOFs) in real-time. New Method: We detail the use of a modified Kalman filter (MKF) to provide intuitive, independent and proportional control over six-DOF prostheses such as the DEKA "LUKE" Arm. Input features include neural firing rates recorded from Utah Slanted Electrode Arrays and mean absolute value of intramuscular electromyographic (EMG) recordings. Ad-hoc modifications include thresholds and nonunity gains on the output of a Kalman filter. Results: We demonstrate that both neural and EMG data can be combined effectively. We also highlight that modifications can be optimized to significantly improve performance relative to an unmodified Kalman filter. Thresholds significantly reduced unintended movement and promoted more independent control of the different DOFs. Gain were significantly greater than one and served to amplify participant effort. Optimal modifications can be determined quickly offline and translate to functional improvements online. Using a portable take-home system, participants performed various activities of daily living. Comparison with Existing Methods: In contrast to pattern recognition, the MKF allows users to continuously modulate their force output, which is critical for fine dexterity. The MKF is also computationally efficient and can be trained in less than five minutes. Conclusions: The MKF can be used to explore the functional and psychological benefits associated with long-term, at-home control of dexterous prosthetic hands. HIGHLIGHTS:• Neural and electromyographic signals can be used together to estimate motor intent • Ad-hoc thresholds and gains improve prosthetic control by reducing unintended movement • Thresholds and gains can be optimized offline and translate to functional improvements online

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Section: Human Subjectsmentioning

confidence: 99%

Intuitive neuromyoelectric control of a dexterous bionic arm using a modified Kalman filter

George

Davis

Brinton

et al. 2020

Journal of Neuroscience Methods

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“…The second amputee (subject 6; S6) was a 57-year-old male whose left foot and left forearm were amputated 13 years prior due to trauma [5,6,10,12]. The third amputee (subject 7; S7) was a 48-year-old male whose right forearm was electively amputated due to chronic Complex Regional Pain Syndrome with simultaneous intraoperative implantation of the USEA and iEMG devices [4,5].…”

Section: Human Subjectsmentioning

confidence: 99%

“…A total of 13, 65, and 46 datasets were collected for participants S5, S6, and S7, respectively. Additional experimental sessions were performed with the participants and have been reported previously [4][5][6]9,10,12].…”

Section: Recording Datasetsmentioning

confidence: 99%

“…For S6-U, mappings were completed at 17, 55, 83, 138, 173, 208, 242, 298, and 354 days post-implant. Extensive mappings were not collective with S7 due to a narrow window of current between percept detection and discomfort (potentially due to prior Complex Regional Pain Syndrome) [4].…”

Section: Usea-evoked Perceptsmentioning

confidence: 99%

“…The Utah Slanted Electrode Array (USEA) consists of a 10 × 10 grid of electrodes with depths from 0.5 to 1.5 mm that penetrate peripheral nerves to enable single-unit neural recordings and intraneural microstimulation [1]. USEAs implanted in the peripheral nerves serve as a bi-directional sensorimotor neural interface, and have now been used to reanimate motionless limbs [2,3], to provide intuitive control of and sensory feedback from bionic arms [4][5][6][7][8][9], and to alleviate neuropathic pain [10,11]. The high electrode count and intrafasicular nature of the USEA yields improved specificity [6,12].…”

Section: Introductionmentioning

confidence: 99%

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Long-Term Performance of Utah Slanted Electrode Arrays and Intramuscular Electromyographic Leads Implanted Chronically in Human Arm Nerves and Muscles

George

Page

Davis

et al. 2020

Preprint

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Objective. We explore the long-term performance and stability of seven percutanous Utah Slanted Electrode Arrays (USEAs) and intramuscular recording leads (iEMGs) implanted chronically in the residual arm nerves and muscles of three human amputees as a means to permanently restore sensorimotor function after upper-limb. Approach. We quantify the number of functional recording and functional stimulating electrodes over time. We also calculate the signal-to-noise ratio of USEA and iEMG recordings and quantify the stimulation amplitude necessary to evoke detectable sensory percepts. Furthermore, we quantify the consistency of the sensory modality, receptive field location, and receptive field size of USEAevoked percepts. Main Results. In the most recent subject, involving USEAs with technical improvements, neural recordings persisted for 502 days (entire implant duration) and the number of functional recording electrodes for one USEA increased over time. However, for six out of seven USEAs the number of functional recording electrodes decreased within the first two months after implantation. The signal-to-noise ratio of neural recordings and electromyographic recordings stayed relatively consistent over time. Sensory percepts were consistently evoked over the span of 14 months, were not significantly different in size, and highlighted the nerves' fascicular organization. The percentage of percepts with consistent modality or consistent receptive field location between sessions (~1 month apart) varied between 0-86.2% and 9.1-100%, respectively. Stimulation thresholds and electrode impedances increased initially but then remained relatively stable over time. Significance. This work demonstrates improved performance of USEAs, and provides a basis for comparing the longevity and stability of USEAs to that of other neural interfaces. Although USEAs provide a rich repertoire of neural recordings and sensory percepts, performance still generally declines over time. Future work should leverage the results presented here to further improve USEA design or to develop adaptive algorithms that can maintain a high level of performance. 2

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Advanced technologies for intuitive control and sensation of prosthetics

et al. 2019

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Improved Training Paradigms and Motor-decode Algorithms: Results from Intact Individuals and a Recent Transradial Amputee with Prior Complex Regional Pain Syndrome

Cited by 36 publications

References 9 publications

Intuitive neuromyoelectric control of a dexterous bionic arm using a modified Kalman filter

Intuitive neuromyoelectric control of a dexterous bionic arm using a modified Kalman filter

Long-Term Performance of Utah Slanted Electrode Arrays and Intramuscular Electromyographic Leads Implanted Chronically in Human Arm Nerves and Muscles

Advanced technologies for intuitive control and sensation of prosthetics

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