Characterizing the Motor Points of Forearm Muscles for Dexterous Neuroprostheses

RaviChandran, Narrendar; Aw, Kean C.; McDaid, Andrew

doi:10.1109/tbme.2019.2907926

Cited by 11 publications

(23 citation statements)

References 31 publications

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“…The conformability of electrodes is very important for user comfort and when compensating for the displacement of motor points following forearm rotation. Moreover, a previous study on the displacement of motor points under forearm rotation showed that the stimulation of motor points could only displace up to 100% [ 5 ]. The reason for considering 500% strain in this study was to improve the durability of the electrode-array-based sleeve, as it may be exposed to several cycles of putting on and taking off.…”

Section: Discussionmentioning

confidence: 99%

“…As it is important to know the direction of the deformation that a sleeve undergoes, the change in resistance during stretching can be used to sense the direction of shear, thus avoiding the need for external sensors. Then, further calibration can adjust the stimulation parameters or site of stimulation using automated algorithms [ 5 ] or kinematic feedback [ 40 ].…”

Section: Discussionmentioning

confidence: 99%

“…The electrode array had 24 individual electrodes arranged as 8 × 3 elements in a trapezoidal fashion. Such an arrangement was considered to target all motor point clusters of the forearm muscles [ 5 ]. Each electrode had a surface area of 150 mm 2 with a circular geometry and a thickness of 0.5 mm.…”

Section: Methodsmentioning

confidence: 99%

“…Thus, wearable neuroprostheses deploy electrode arrays to stimulate forearm muscles by integrating them into a sleeve [ 2 , 3 ]. However, such systems have limited user acceptance due to challenges in achieving selective activation (due to the complex musculature of the forearm) and poor control with transcutaneous delivery of charges [ 4 , 5 ]. Subject-specific factors also influence the overall stimulation outcome [ 6 ].…”

Section: Introductionmentioning

confidence: 99%

“…In addition, conformable electrodes simplify wearability and maintain good skin contact. The material should also retain its electrical properties under stretching cycles during forearm movements [ 5 , 15 , 16 ]. Notably, elastomers, such as Ecoflex, have enhanced softness and a sticky surface.…”

Section: Introductionmentioning

confidence: 99%

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Conformable Electrode Arrays for Wearable Neuroprostheses

RaviChandran

Teo

McDaid

et al. 2023

Sensors

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Wearable electrode arrays can selectively stimulate muscle groups by modulating their shape, size, and position over a targeted region. They can potentially revolutionize personalized rehabilitation by being noninvasive and allowing easy donning and doffing. Nevertheless, users should feel comfortable using such arrays, as they are typically worn for an extended time period. Additionally, to deliver safe and selective stimulation, these arrays must be tailored to a user’s physiology. Fabricating customizable electrode arrays needs a rapid and economical technique that accommodates scalability. By leveraging a multilayer screen-printing technique, this study aims to develop personalizable electrode arrays by embedding conductive materials into silicone-based elastomers. Accordingly, the conductivity of a silicone-based elastomer was altered by adding carbonaceous material. The 1:8 and 1:9 weight ratio percentages of carbon black (CB) to elastomer achieved conductivities between 0.0021–0.0030 S cm−1 and were suitable for transcutaneous stimulation. Moreover, these ratios maintained their stimulation performance after several stretching cycles of up to 200%. Thus, a soft, conformable electrode array with a customizable design was demonstrated. Lastly, the efficacy of the proposed electrode arrays to stimulate hand function tasks was evaluated by in vivo experiments. The demonstration of such arrays encourages the realization of cost-effective, wearable stimulation systems for hand function restoration.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Conformable Electrode Arrays for Wearable Neuroprostheses

RaviChandran

Teo

McDaid

et al. 2023

Sensors

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Modeling the excitation of nerve axons under transcutaneous stimulation

RaviChandran,

Hope,

et al. 2023

Computers in Biology and Medicine

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Automatic calibration of electrode arrays for dexterous neuroprostheses: a review

RaviChandran

McDaid

2023

Biomed. Phys. Eng. Express

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Background: Electrode arrays can simplify the modulation of shape, size, and position for customized stimulation delivery. However, the intricacy in achieving the desired outcome stems from optimizing for the myriad of possible electrode combinations and stimulation parameters to account for varying physiology across users.Objective: This study reviews automated calibration algorithms that perform such an optimization to realize hand function tasks. Comparing such algorithms for their calibration effort, functional outcome, and clinical acceptance can aid with the development of better algorithms and address technological challenges in their implementation.Methods: A systematic search was conducted across major electronic databases to identify relevant articles. The search yielded 36 suitable articles; among them, 14 articles that met the inclusion criteria were considered for the review.Results: Studies have demonstrated the realization of several hand function tasks and individual digit control using automatic calibration algorithms. These algorithms significantly improved calibration time and functional outcomes across healthy and people with neurological deficits. Also, electrode profiling performed via automated algorithms was very similar to a trained rehabilitation expert. Additionally, emphasis must be given to collecting subject-specific a priori data to improve the optimization routine and simplify calibration effort.Conclusion: With significantly shorter calibration time, delivering personalized stimulation, and obviating the need for an expert, automated algorithms demonstrate the potential for home-based rehabilitation for improved user independence and acceptance.

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Characterizing the Motor Points of Forearm Muscles for Dexterous Neuroprostheses

Cited by 11 publications

References 31 publications

Conformable Electrode Arrays for Wearable Neuroprostheses

Conformable Electrode Arrays for Wearable Neuroprostheses

Modeling the excitation of nerve axons under transcutaneous stimulation

Automatic calibration of electrode arrays for dexterous neuroprostheses: a review

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