Influence of stimulus pulse width on M‐waves, H‐reflexes, and torque during tetanic low‐intensity neuromuscular stimulation

Lagerquist, Olle; Collins, David F.

doi:10.1002/mus.21762

Cited by 65 publications

(56 citation statements)

References 54 publications

(137 reference statements)

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“…Plausible reasons why previous studies of PAD in humans have not reported a similar depression of M-waves are that in some cases the amplitude of the second M-wave was not reported (Trimble et al 2000), stimulation frequencies above 5 Hz were not tested McNulty et al 2008), or trials were excluded if the M-wave amplitude changed more than 2% between pulses (Jeon et al 2007). A depression of M-wave amplitude during 20-Hz stimulation was recently reported when electrical stimulation was delivered using wide (500 and 1,000 s), but not narrow (50 and 200 s), pulse widths (Lagerquist and Collins 2010). This finding suggests that the M-wave depression stems from mechanisms related to the ability to repetitively activate motor axons beneath the stimulating electrodes, rather than reduced transmission across the neuromuscular junction or movement of the electrodes between pulses as a result of the muscle contraction.…”

Section: Discussionmentioning

confidence: 95%

Postactivation depression and recovery of reflex transmission during repetitive electrical stimulation of the human tibial nerve

Clair

Anderson-Reid

Graham

et al. 2011

Journal of Neurophysiology

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H-reflexes are progressively depressed, relative to the first response, at stimulation frequencies above 0.1 Hz (postactivation depression; PAD). Presently, we investigated whether H-reflexes "recover" from this depression throughout 10-s trains of stimulation delivered at physiologically relevant frequencies (5-20 Hz) during functionally relevant tasks (sitting and standing) and contraction amplitudes [relaxed to 20% maximum voluntary contraction (MVC)]. When participants held a 10% MVC, reflex amplitudes did not change during 5-Hz stimulation. During stimulation at 10 Hz, reflexes were initially depressed by 43% but recovered completely by the end of the stimulation period. During 20-Hz stimulation, reflexes were depressed to 10% and recovered to 36% of the first response, respectively. This "postactivation depression and recovery" (PAD&R) of reflex amplitude was not different between sitting and standing. In contrast, PAD&R were strongly influenced by contraction amplitude. Reflexes were depressed to 10% of the first response during the relaxed condition (10-Hz stimulation) and showed no depression during a 20% MVC contraction. A partial recovery of reflex amplitude occurred when participants were relaxed and during contractions of 1-5% MVC. Surprisingly, reflexes could recover completely by the third pulse within a stimulation train when participants held a contraction between 5 and 10% MVC during stimulation at 10 Hz, a finding that challenges classical ideas regarding PAD mechanisms. Our results support the idea that there is an ongoing interplay between depression and facilitation when motoneurons receive trains of afferent input. This interplay depends strongly on the frequency of the afferent input and the magnitude of the background contraction but is relatively insensitive to changes in task.

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Section: Discussionmentioning

confidence: 95%

Postactivation depression and recovery of reflex transmission during repetitive electrical stimulation of the human tibial nerve

Clair

Anderson-Reid

Graham

et al. 2011

Journal of Neurophysiology

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“…Following NMES at 100 Hz, torque and H-reflexes were enhanced when using a 1-ms pulse duration, but not when using a 0.05-ms pulse duration (adapted from Collins 2010) et al 2011;Lagerquist and Collins 2010). Figure 4 shows that both H-reflexes and torque can be augmented after brief bursts of 100 Hz stimulation.…”

Section: Pulse Frequencymentioning

confidence: 85%

“…The sensory volley generated during NMES recruits motor units centrally in two distinct ways. Perhaps the most obvious form of central recruitment is through the Hoffmann-or H-reflex pathway Bergquist et al 2011;Lagerquist and Collins 2010). Like the M-wave, motor units recruited through H-reflex pathways discharge relatively synchronously although at a longer latency, as seen in the EMG traces in Fig.…”

Section: Nmes and The Central Recruitment Of Motor Unitsmentioning

confidence: 94%

“…Thus far, electrically evoked contractions with a robust contribution from H-reflexes have been shown for the TS (Fig. 2a) Bergquist et al 2011;Lagerquist and Collins 2010) and quadriceps (Bergquist et al, in revision). In some individuals, contractions that generate 30-40% of the torque generated during a maximum voluntary contraction (MVC) could be produced almost exclusively by H-reflexes in both muscle groups.…”

Section: Nmes and The Central Recruitment Of Motor Unitsmentioning

confidence: 95%

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Neuromuscular electrical stimulation: implications of the electrically evoked sensory volley

et al. 2011

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Neuromuscular electrical stimulation (NMES) generates contractions by depolarising axons beneath the stimulating electrodes. The depolarisation of motor axons produces contractions by signals travelling from the stimulation location to the muscle (peripheral pathway), with no involvement of the central nervous system (CNS). The concomitant depolarisation of sensory axons sends a large volley into the CNS and this can contribute to contractions by signals travelling through the spinal cord (central pathway) which may have advantages when NMES is used to restore movement or reduce muscle atrophy. In addition, the electrically evoked sensory volley increases activity in CNS circuits that control movement and this can also enhance neuromuscular function after CNS damage. The first part of this review provides an overview of how peripheral and central pathways contribute to contractions evoked by NMES and describes how differences in NMES parameters affect the balance between transmission along these two pathways. The second part of this review describes how NMES location (i.e. over the nerve trunk or muscle belly) affects transmission along peripheral and central pathways and describes some implications for motor unit recruitment during NMES. The third part of this review summarises some of the effects that the electrically evoked sensory volley has on CNS circuits, and highlights the need to identify optimal stimulation parameters for eliciting plasticity in the CNS. A goal of this work is to identify the best way to utilize the electrically evoked sensory volley generated during NMES to exploit mechanisms inherent to the neuromuscular system and enhance neuromuscular function for rehabilitation.

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“…First, the onset of tsDCS is accompanied by an initial itching sensation due to the activation of cutaneous afferents beneath the electrodes. Indeed, it has been shown that cranial (Delwaide and Crenna 1983;Ghanim et al 2009) and peripheral (Baldwin et al 2006;Klakowicz et al 2006;Lagerquist and Collins 2010) cutaneous stimulation may influence Sol H reflex (i.e., cutaneous effects might, by themselves, result in changes in spinal excitability). However, this possibility seems unlikely since 1) none of the subjects was able to differentiate active conditions from verum stimulation, and cutaneous perception has been shown to be similar between anodal and cathodal conditions (Ambrus et al 2011); 2) tsDCS-induced effects were specific to anodal polarity; and 3) spinal excitability was unchanged after both cathodal and sham stimulations.…”

Section: Discussionmentioning

confidence: 99%

Modulation of soleus H reflex by spinal DC stimulation in humans

Lamy

Badel

et al. 2012

Journal of Neurophysiology

105

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Transcranial direct current stimulation (tDCS) of the human motor cortex induces changes in excitability within cortical and spinal circuits that occur during and after the stimulation. Recently, transcutaneous spinal direct current stimulation (tsDCS) has been shown to modulate spinal conduction properties, as assessed by somatosensory-evoked potentials, and transynaptic properties of the spinal neurons, as tested by postactivation depression of the H reflex or by the RIII nociceptive component of the flexion reflex in the lower limb. To further explore tsDCS-induced plastic changes in spinal excitability, we examined, in a double-blind crossover randomized study, the stimulus-response curves of the soleus H reflex before, during, at current offset and 15 min after anodal, cathodal, and sham tsDCS delivered at the Th11 level (2.5 mA, 15 min, 0.071 mA/cm(2), 0.064 C/cm(2)) in 17 healthy subjects. Anodal tsDCS induced a progressive leftward shift of the recruitment curve of the soleus H reflex during the stimulation; the effects persisted for at least 15 min after current offset. In contrast, both cathodal and sham tsDCS had no significant effects. This exploratory study provides further evidence for the use of tsDCS as an expedient, noninvasive tool to induce long-lasting plastic changes in spinal circuitry. Increased spinal excitability after anodal tsDCS may have potential for spinal neuromodulation in patients with central nervous system lesions.

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Influence of stimulus pulse width on M‐waves, H‐reflexes, and torque during tetanic low‐intensity neuromuscular stimulation

Cited by 65 publications

References 54 publications

Postactivation depression and recovery of reflex transmission during repetitive electrical stimulation of the human tibial nerve

Postactivation depression and recovery of reflex transmission during repetitive electrical stimulation of the human tibial nerve

Neuromuscular electrical stimulation: implications of the electrically evoked sensory volley

Modulation of soleus H reflex by spinal DC stimulation in humans

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