Implantable FES Stimulation Systems: What is Needed?

Troyk, Philip R.; Donaldson, Nick

doi:10.1046/j.1525-1403.2001.00196.x

Cited by 31 publications

(11 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Therefore, recreating biological control through artificial algorithms remains a complex problem. Furthermore, the number of implanted devices necessary for selectively activating sufficient fibers to create fine-graded motion will always be difficult to justify [12].…”

Section: Introductionmentioning

confidence: 99%

Intraspinal microstimulation generates functional movements after spinal-cord injury

Saigal

Renzi

Mushahwar

2004

IEEE Trans. Neural Syst. Rehabil. Eng.

116

113

View full text Add to dashboard Cite

Restoring locomotion after spinal-cord injury has been a difficult problem to solve with traditional functional electrical stimulation (FES) systems. Intraspinal microstimulation (ISMS) is a novel approach to FES that takes advantage of spinal-cord locomotor circuits by stimulating in the spinal cord directly. Previous studies in spinal-cord intact cats showed near normal recruitment order, reduced fatigue, and functional, synergistic movements induced by stimulation through a few microwires implanted over a 3-cm region in the lumbosacral cord. The present study sought to test the feasibility of ISMS for restoring locomotion after complete spinal-cord transection. In four adult male cats, the spinal cord was severed at T10, T11, or T12. Two to four weeks later, 30 wires (30 microm, stainless steel) were implanted, under anesthesia, in both sides of the lumbosacral cord. The cats were then decerebrated. Stimulus pulses (40-50 Hz, 200 micros, biphasic) with amplitudes ranging from 1-4x threshold (threshold = 32 +/- 19 microA) were delivered through each unipolar electrode. Kinetics, kinematics, and electromyographic (EMG) measurements were obtained with the cats suspended over a stationary treadmill with embedded force platforms for the hindlimbs. Phasic, interleaved stimulation through electrodes generating flexor or extensor movements produced bilateral weight-bearing stepping of the hindlimbs with ample foot clearance during swing. Minimal changes in kinematics and little fatigue were seen during episodes of 40 consecutive steps. The results indicate that ISMS is a promising technique for restoring locomotion after injury.

show abstract

Section: Introductionmentioning

confidence: 99%

Intraspinal microstimulation generates functional movements after spinal-cord injury

Saigal

Renzi

Mushahwar

2004

IEEE Trans. Neural Syst. Rehabil. Eng.

116

113

View full text Add to dashboard Cite

show abstract

“…As explained in Section I, in the event of a semiconductor failure in an output stage [25]- [28], continuous direct current could flow through the electrodes. A simple method to improve safety is to insert blocking capacitors in the stimulation paths [29], [30] which will limit the charge imbalance to the product of the rail voltage and the capacitance. The disadvantages of using blocking capacitors are the added voltage required during the stimulation phase and their physical size.…”

Section: B Output Stage Circuitmentioning

confidence: 99%

An Integrated Stimulator With DC-Isolation and Fine Current Control for Implanted Nerve Tripoles

Liu

Demosthenous

Donaldson

2011

IEEE J. Solid-State Circuits

View full text Add to dashboard Cite

This paper presents the design of an integrated nerve stimulator for use with tripole electrodes. The main features of the design are: it is a constant current stimulator with passive electrode discharge; it is fail-safe without requiring discrete capacitors in series with the electrodes; and the anode current ratio can be adjusted to minimize the electric field outside the electrode mount (cuff, book, etc) so as to prevent crosstalk to adjacent nerves. The safety feature uses high-frequency current switching (HFCS) employing small on-chip blocking capacitors. The charge loss due to the parasitic capacitances in the HFCS output stage is reduced by bootstrapping. In addition, a method is described to implement the current generator featuring small silicon area and good linearity. A two-channel stimulator was implemented in a 0.6-m silicon-on-insulator CMOS process. The current generator occupies a silicon area of 0.3 mm . It consists of a 4-bit coarse amplitude section with 100 A steps and a 4-bit differential adjustment section with 6.25 A steps. The output stage achieves a charge efficiency of about 90% for a 1 k load and occupies a silicon area of 0.5 mm . The performance of the stimulator, including crosstalk nulling measurements, was verified using tripoles in saline. The HFCS method should be considered for stimulators which must be small and sited close to the target nervous tissue.

show abstract

“…It provides a means to integrate anticipatory function into man-made processes. Furthermore, unlike the "embedded electrode" HMI strategies being investigated by many others [45], it is totally non-invasive.…”

Section: Machine-to-human Couplingmentioning

confidence: 99%

Some Radical Implications of Bach-Y-Rita's Discoveries

Kercel

Reber²,

Manges³

2005

J. Integr. Neurosci.

View full text Add to dashboard Cite

Bach-y-Rita's clinical results in restoring lost sensory function are based on several phenomena not widely appreciated in cognitive science. First, there is volume transmission. Extensive laboratory observation has shown that the brain is much more than a network of synaptically connected neurons. Bach-y-Rita has found that a key implication of volume transmission is that it is a functional component in adult brain plasticity, also widely observed experimentally. Plasticity has led him to conclude that the structure of brain dynamics is beyond the scope of algorithmic computation. If the brain is not a computer, this insight would have a significant impact on the development of new technologies based on brain function. Bach-y-Rita's work is being extended from restoration of lost senses to the creation of new senses. This in turn could lead to a new technology of "wiring a human-in-the-loop" that would be utterly unlike any computationally based technology. Instead of mere interaction with a machine, the human "becomes one" with it.

show abstract

Implantable FES Stimulation Systems: What is Needed?

Cited by 31 publications

References 26 publications

Intraspinal microstimulation generates functional movements after spinal-cord injury

Intraspinal microstimulation generates functional movements after spinal-cord injury

An Integrated Stimulator With DC-Isolation and Fine Current Control for Implanted Nerve Tripoles

Some Radical Implications of Bach-Y-Rita's Discoveries

Contact Info

Product

Resources

About