Counted cycles method to measure the block inception time of kiloHertz frequency mammalian motor nerve block

Bhadra, Niloy; Foldes, Emily; Gerges, Meana; Ackermann, D. Michael; Kilgore, Kevin L.

doi:10.1016/j.jneumeth.2019.108561

Cited by 6 publications

(7 citation statements)

References 20 publications

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“…Nevertheless, peak onset response vs. normalized amplitude profiles revealed that onset response was generally smallest at amplitudes well below or well above block threshold irrespective of waveform, with profiles overlapped across waveforms for a given animal and frequency and for the modeled data at 20 kHz (figure 6(f)). The results are consistent with previous studies in which higher KHF amplitudes reduced onset response (Bowman and Mcneal 1986, Bhadra and Kilgore 2005, Tai et al 2005b, Bhadra et al 2019.…”

Section: Discussionsupporting

confidence: 93%

“…Some of our data showed onset responses that increased and then plateaued across amplitudes (e.g., Figure 6, nerve 16 at 20 kHz (square), nerve 17 at 10 and 20 kHz)-rather than exhibiting a clear mound-shaped onset response profile-and those profiles generally had smaller onset responses than the others. Onset response in rat sciatic nerve block was described in terms of an initial summated muscle twitch that was always present (Phase I) followed by asynchronous muscle contraction that was not always present (Phase II) (Bhadra et al 2019). Examples in which onset response plateaued may contain only Phase I onset responses.…”

Section: Discussionmentioning

confidence: 99%

“…In the fourth nerve (18), we randomized amplitudes first (in 0.5 mA increments), then randomized waveform tests for each amplitude. In all trials, we applied KHF for 0.5 s, which was longer than the minimum time for inducing nerve block (Bhadra et al 2019), and paused for 1-2 s between trials, with an additional 5 s between amplitudes in nerve 18. During each experiment but prior to running any trials, we measured block threshold for all waveforms using the method described in section 2.6.…”

Section: Onset Response Peak Was Non-monotonically Related To Normali...mentioning

confidence: 99%

“…Blocking with KHF signals requires amplitudes more than double those needed to evoke activity (Bowman and McNeal 1986;Pelot and Grill 2020), and thus applications require consideration of the potential for tissue damage with high charge densities (Cogan et al 2016) and of reduced battery life with high power consumption (Patel et al 2017). An additional challenge is the transient nerve excitation evoked when the KHF signal is turned on (Crosby et al 2017;Bhadra et al 2019). This onset response may pose an obstacle for clinical translation because undesired, and potentially uncomfortable activation occurs every time the KHF signal is turned on (Bhadra et al 2018b), and there are currently no methods to eliminate onset response using solely charge-balanced KHF signals.…”

Section: Introductionmentioning

confidence: 99%

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Quantitative comparisons of block thresholds and onset responses for charge-balanced kilohertz frequency waveforms

Peña

Pelot²,

Grill³

2020

J. Neural Eng.

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Objective: There is growing interest in delivering kilohertz frequency (KHF) electrical signals to block conduction in peripheral nerves for treatment of various diseases. Previous studies used different KHF waveforms to achieve block, and it remains unclear how waveform affects nerve block parameters. Approach:We quantified the effects of waveform on KHF block of the rat tibial nerve in vivo and in computational models. We compared block thresholds and onset responses across currentcontrolled sinusoids and charge-balanced rectangular waveforms with different asymmetries and duty cycles.Main Results: Sine waves had higher block thresholds than square waves, but used less power at block threshold. Block threshold had an inverse relationship with duty cycle of rectangular waveforms irrespective of waveform asymmetry. Computational model results were consistent with relationships measured in vivo, although the models underestimated the effect of duty cycle on increasing thresholds. The axonal membrane substantially filtered waveforms, the filter transfer function was strikingly similar across waveforms, and filtering resulted in post-filtered rms block thresholds that were approximately constant across waveforms in silico and in vivo. Onset response was not consistently affected by waveform shape, but onset was smaller at amplitudes well above block threshold. Therefore, waveforms with lower block thresholds (e.g., sine waves or square waves) could be more readily increased to higher amplitudes relative to block threshold to reduce onset response. We also observed a reduction in onset responses across consecutive trials after initial application of supra-block threshold amplitudes.

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Section: Discussionsupporting

confidence: 93%

Section: Discussionmentioning

confidence: 99%

Section: Onset Response Peak Was Non-monotonically Related To Normali...mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Quantitative comparisons of block thresholds and onset responses for charge-balanced kilohertz frequency waveforms

Peña

Pelot²,

Grill³

2020

J. Neural Eng.

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“…Upon cessation of the KHFAC, the nerve usually resumes normal action potential conduction, unless the KHFAC duration produces a carry-over block effect as a result of prolonged block (Bhadra et al 2018 ). Experimentally, it has been demonstrated that the block is effective within milliseconds and can be reversed within 1 s (Bhadra and Kilgore 2005 ; Bhadra et al 2020 ). Investigators have used different waveforms (primarily continuous sinusoidals and discontinuous square waveforms) (Table 1 ) to achieve KHFAC block (reviewed in Kilgore and Bhadra 2004 (Kilgore and Bhadra 2004 )).…”

Section: Introductionmentioning

confidence: 99%

Effects of waveform shape and electrode material on KiloHertz frequency alternating current block of mammalian peripheral nerve

et al. 2022

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Objectives KiloHertz frequency alternating current waveforms produce conduction block in peripheral nerves. It is not clearly known how the waveform shape affects block outcomes, and if waveform effects are frequency dependent. We determined the effects of waveform shape using two types of electrodes. Materials and methods Acute in-vivo experiments were performed on 12 rats. Bipolar electrodes were used to electrically block motor nerve impulses in the sciatic nerve, as measured using force output from the gastrocnemius muscle. Three blocking waveforms were delivered (sinusoidal, square and triangular) at 6 frequencies (10–60 kHz). Bare platinum electrodes were compared with carbon black coated electrodes. We determined the minimum amplitude that could completely block motor nerve conduction (block threshold), and measured properties of the onset response, which is a transient period of nerve activation at the start of block. In-vivo results were compared with computational modeling conducted using the NEURON simulation environment using a nerve membrane model modified for stimulation in the kilohertz frequency range. Results For the majority of parameters, in-vivo testing and simulations showed similar results: Block thresholds increased linearly with frequency for all three waveforms. Block thresholds were significantly different between waveforms; lowest for the square waveform and highest for triangular waveform. When converted to charge per cycle, square waveforms required the maximum charge per phase, and triangular waveforms the least. Onset parameters were affected by blocking frequency but not by waveform shape. Electrode comparisons were performed only in-vivo. Electrodes with carbon black coatings gave significantly lower block thresholds and reduced onset responses across all blocking frequencies. For 10 and 20 kHz, carbon black coating significantly reduced the charge required for nerve block. Conclusions We conclude that both sinusoidal and square waveforms at frequencies of 20 kHz or higher would be optimal. Future investigation of carbon black or other high charge capacity electrodes may be useful in achieving block with lower BTs and onsets. These findings will be of importance for designing clinical nerve block systems.

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Electrical Block of Peripheral Nerves

Eggers

Green

Vrabec

et al. 2021

Handbook of Neuroengineering

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Counted cycles method to measure the block inception time of kiloHertz frequency mammalian motor nerve block

Cited by 6 publications

References 20 publications

Quantitative comparisons of block thresholds and onset responses for charge-balanced kilohertz frequency waveforms

Quantitative comparisons of block thresholds and onset responses for charge-balanced kilohertz frequency waveforms

Effects of waveform shape and electrode material on KiloHertz frequency alternating current block of mammalian peripheral nerve

Electrical Block of Peripheral Nerves

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