<i>In vivo</i>demonstration of injectable microstimulators based on charge-balanced rectification of epidermically applied currents

Ivorra, Antoni; Becerra-Fajardo, Laura; Castellví, Quim

doi:10.1088/1741-2560/12/6/066010

Cited by 18 publications

(21 citation statements)

References 23 publications

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“…This last parameter allowed gradual variation of the induced force, which is a common observation when conventional LF pulses are delivered for neuromuscular stimulation [24]. As stated in [17], this suggests that the half-rectified HF currents delivered by the implants are equivalent in terms of excitatory behavior to conventional LF current pulses.…”

Section: Discussionmentioning

confidence: 83%

“…We have already in vivo demonstrated non-addressable, flexible injectable devices (Ø = 1 mm) which consist of a few passive components and which are capable of performing charge-balanced local electrical stimulation [17]. However, these simple stimulators lacked a mechanism to independently control them.…”

Section: Demonstration Of 2 MM Thick Microcontrolled Injectable Stimumentioning

confidence: 99%

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Demonstration of 2 mm Thick Microcontrolled Injectable Stimulators Based on Rectification of High Frequency Current Bursts

Becerra-Fajardo

Schmidbauer

Ivorra

2017

IEEE Trans. Neural Syst. Rehabil. Eng.

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Existing implantable stimulators use powering approaches that result in stiff and bulky systems or result in systems incapable of producing the current magnitudes required for neuromuscular stimulation. This hampers their use in neuroprostheses for paralysis. We previously demonstrated an electrical stimulation method based on electronic rectification of high frequency (HF) current bursts. The implants act as rectifiers of HF current that flows through the tissues by galvanic coupling, transforming this current into low frequency current capable of performing neuromuscular stimulation. Here we developed 2 mm thick, semi-rigid, injectable and addressable stimulators made of off-the-shelf components and based on this method. The devices were tested in vitro to illustrate how they are powered by galvanic coupling. In addition they were tried in an animal model to demonstrate their ability to perform controlled electrical stimulation. The implants were deployed by injection into two antagonist muscles of an anesthetized rabbit and were addressed resulting in independent isometric contractions. Low frequency currents of 2 mA were delivered by the implants. The HF currents are safe in terms of unwanted electrostimulation and tissue heating according to standards. This indicates that the proposed electrical stimulation method will allow unprecedented levels of miniaturization for neuroprostheses.

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Section: Discussionmentioning

confidence: 83%

Section: Demonstration Of 2 MM Thick Microcontrolled Injectable Stimumentioning

confidence: 99%

Demonstration of 2 mm Thick Microcontrolled Injectable Stimulators Based on Rectification of High Frequency Current Bursts

Becerra-Fajardo

Schmidbauer

Ivorra

2017

IEEE Trans. Neural Syst. Rehabil. Eng.

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“…The thin-film intramuscular electrodes used here allow simultaneous stimulation and recording within the same implant. Once improvements in SW/WH that allow concurrent real time EMG recording, artifact removal [33], processing and stimulation emerge, intramuscular electrodes can be developed into fully long-term implantable solutions [34], [35] that will allow tailored tremor reduction through recording and stimulation from/at multiple body parts.…”

Section: Discussionmentioning

confidence: 99%

Intramuscular Stimulation of Muscle Afferents Attains Prolonged Tremor Reduction in Essential Tremor Patients

Pascual-Valdunciel¹,

González-Sánchez²,

Muceli³

et al. 2021

IEEE Trans. Biomed. Eng.

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This study proposes and clinically tests intramuscular electrical stimulation below motor threshold to achieve prolonged reduction of wrist flexion/extension tremor in Essential Tremor (ET) patients. The developed system consisted of an intramuscular thin-film electrode structure that included both stimulation and electromyography (EMG) recording electrodes, and a control algorithm for the timing of intramuscular stimulation based on EMG (closed-loop stimulation). Data were recorded from nine ET patients with wrist flexion/extension tremor recruited from the Gregorio Marañón Hospital (Madrid, Spain). Patients participated in two experimental sessions comprising: 1) sensory stimulation of wrist flexors/extensors via thin-film multichannel intramuscular electrodes; and 2) surface stimulation of the nerves innervating the same target muscles. For each session, four of these patients underwent random 60-s trials of two stimulation strategies for each target muscle: 1) selective and adaptive timely stimulation (SATS)-based on EMG of the antagonist muscle; and 2) continuous stimulation (CON) of target muscles. Two patients underwent SATS stimulation trials alone while the other three underwent CON stimulation trials alone in each session. Kinematics of wrist, elbow, and shoulder, together with clinical scales, were used to assess tremor before, right after, and 24 h after each session. Intramuscular SATS achieved, on average, 32% acute (during stimulation) tremor reduction on each trial, while continuous stimulation augmented tremorgenic activity. Furthermore, tremor reduction was significantly higher using intramuscular than surface stimulation. Prolonged reduction of tremor amplitude (24 h after the experiment) was

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“…More sophisticated wearable devices and algorithms should be pursued, especially combining both EMG and kinematic based-control to disregard voluntary movement components while reducing tremorgenic activity as well as the potential to focus stimulation at multiple muscles or joints of the tremorous limb. The development and testing of implantable technologies using intramuscular electrodes controlled with external wireless devices could also serve as a long-term solution [66,67]. The preliminary evidence of prolonged tremor reduction after stimulation also opens the scope to develop longitudinal interventions towards a standardized therapy widely accessible to patients unresponsive to medication or ineligible for surgical treatments.…”

Section: Discussionmentioning

confidence: 99%

Peripheral electrical stimulation to reduce pathological tremor: a review

Pascual-Valdunciel

Hoo

Avrillon

et al. 2021

J NeuroEngineering Rehabil

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Interventions to reduce tremor in essential tremor (ET) and Parkinson’s disease (PD) clinical populations often utilize pharmacological or surgical therapies. However, there can be significant side effects, decline in effectiveness over time, or clinical contraindications for these interventions. Therefore, alternative approaches must be considered and developed. Some non-pharmacological strategies include assistive devices, orthoses and mechanical loading of the tremorgenic limb, while others propose peripheral electrical stimulation. Specifically, peripheral electrical stimulation encompasses strategies that activate motor and sensory pathways to evoke muscle contractions and impact sensorimotor function. Numerous studies report the efficacy of peripheral electrical stimulation to alter tremor generation, thereby opening new perspectives for both short- and long-term tremor reduction. Therefore, it is timely to explore this promising modality in a comprehensive review. In this review, we analyzed 27 studies that reported the use of peripheral electrical stimulation to reduce tremor and discuss various considerations regarding peripheral electrical stimulation: the stimulation strategies and parameters, electrodes, experimental designs, results, and mechanisms hypothesized to reduce tremor. From our review, we identified a high degree of disparity across studies with regard to stimulation patterns, experimental designs and methods of assessing tremor. Having standardized experimental methodology is a critical step in the field and is needed in order to accurately compare results across studies. With this review, we explore peripheral electrical stimulation as an intervention for tremor reduction, identify the limitations and benefits of the current state-of-the-art studies, and provide ideas to guide the development of novel approaches based on the neural circuitries and mechanical properties implied in tremor generation.

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In vivodemonstration of injectable microstimulators based on charge-balanced rectification of epidermically applied currents

Cited by 18 publications

References 23 publications

Demonstration of 2 mm Thick Microcontrolled Injectable Stimulators Based on Rectification of High Frequency Current Bursts

Demonstration of 2 mm Thick Microcontrolled Injectable Stimulators Based on Rectification of High Frequency Current Bursts

Intramuscular Stimulation of Muscle Afferents Attains Prolonged Tremor Reduction in Essential Tremor Patients

Peripheral electrical stimulation to reduce pathological tremor: a review

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