The effects of paired associative stimulation with transcutaneous spinal cord stimulation on corticospinal excitability in multiple lower-limb muscles

Background. Epidural spinal electrical stimulation at the lumbar spinal level evokes rhythmic muscle activation of lower-limb antagonists, attributed to the central pattern generator. However, the efficacy of noninvasive spinal stimulation for the activation of lower-limb muscles is not yet clear. This review aimed to analyze the feasibility and efficacy of noninvasive transcutaneous spinal cord stimulation (tSCS) on motor function in individuals with spinal cord injury. Methods. A search for tSCS studies was made of the following databases: PubMed; Cochrane Registry; and Physiotherapy Evidence Database (PEDro). In addition, an inverse manual search of the references cited by the identified articles was carried out. The keywords transcutaneous, non-invasive, electrical stimulation, spinal cord stimulation [Mesh term], and spinal cord injury were used. Results. A total of 352 articles were initially screened, of which 13 studies met the inclusion criteria for systematic review. The total participant sample comprised 55 persons with spinal cord injury. All studies with tSCS provided evidence of induced muscle activation in the lower and upper limbs, and applied stimulation at the level of the T11-T12 and C4-C7 interspinous space, respectively. All studies reported an increase in motor response measured by recording surface electromyography, voluntary movement, muscle strength, or function. Conclusions. Although this review highlights tSCS as a feasible therapeutic neuromodulatory strategy to enhance voluntary movement, muscle strength, and function in patients with chronic spinal cord injury, the clinical impact and efficacy of electrode location and current intensity need to be characterized in statistically powered and controlled clinical trials.

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Spasms after spinal cord injury show low-frequency intermuscular coherence

Journal of Neurophysiology ◽

10.1152/jn.00112.2018 ◽

2018 ◽

Vol 120 (4) ◽

pp. 1765-1771

Author(s):

Stefane A. Aguiar ◽

Stuart N. Baker ◽

Katie Gant ◽

Jorge Bohorquez ◽

Christine K. Thomas

Keyword(s):

Spinal Cord ◽

Spinal Cord Injury ◽

Lower Limb ◽

Low Frequency ◽

Low Frequencies ◽

First Report ◽

Lower Limb Muscles ◽

Cord Injury ◽

Limb Muscles ◽

Intermuscular Coherence

Intermuscular coherence allows the investigation of common input to muscle groups. Although beta-band (15–30 Hz) intermuscular coherence is well understood as originating from the cortex, the source of intermuscular coherence at lower frequencies is still unclear. We used a wearable device that recorded electromyographic (EMG) signals during a 24-h period in four lower limb muscles of seven spinal cord injury patients (American Spinal Cord Injury Association impairment scale: A, 6 subjects; B, 1 subject) while they went about their normal daily life activities. We detected natural spasms occurring during these long-lasting recordings and calculated intermuscular coherence between all six possible combinations of muscle pairs. There was significant intermuscular coherence at low frequencies, between 2 and 13 Hz. The most likely source for this was the spinal cord and its peripheral feedback loops, because the spinal lesions in these patients had interrupted connections to supraspinal structures. This is the first report to demonstrate that the spinal cord is capable of producing low-frequency intermuscular coherence with severely reduced or abolished descending drive. NEW & NOTEWORTHY This is the first report to demonstrate that intermuscular coherence between lower limb muscles at low frequencies can be produced by the spinal cord with severely reduced or abolished descending drive.

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Evaluation of Descending Spinal Cord Tracts in Patients With Thoracic Cord Lesions Using Motor Evoked Potentials Recorded From the Paravertebral and Lower Limb Muscles

Journal of Spinal Disorders & Techniques ◽

10.1097/00024720-200304000-00008 ◽

2003 ◽

Vol 16 (2) ◽

pp. 163-170 ◽

Cited By ~ 2

Author(s):

Taku Ogura ◽

Hiroshi Takeshita ◽

Hitoshi Hase ◽

Taturo Hayashida ◽

Masaki Mori ◽

...

Keyword(s):

Spinal Cord ◽

Evoked Potentials ◽

Lower Limb ◽

Motor Evoked Potentials ◽

Lower Limb Muscles ◽

Limb Muscles ◽

Thoracic Cord

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Corticospinal Excitability of the Lower Limb Muscles During the Anticipatory Postural Adjustments: A TMS Study During Dart Throwing

Frontiers in Human Neuroscience ◽

10.3389/fnhum.2021.703377 ◽

2021 ◽

Vol 15 ◽

Author(s):

Amiri Matsumoto ◽

Nan Liang ◽

Hajime Ueda ◽

Keisuke Irie

Keyword(s):

Upper Limb ◽

Lower Limb ◽

Primary Motor Cortex ◽

Anticipatory Postural Adjustments ◽

Limb Movement ◽

Corticospinal Excitability ◽

Postural Adjustments ◽

Lower Limb Muscles ◽

Limb Muscles ◽

Dart Throwing

Objective: To investigate whether the changes in the corticospinal excitability contribute to the anticipatory postural adjustments (APAs) in the lower limb muscles when performing the ballistic upper limb movement of the dart throwing.Methods: We examined the primary motor cortex (M1) excitability of the lower limb muscles [tibialis anterior (TA) and soleus (SOL) muscles] during the APA phase by using transcranial magnetic stimulation (TMS) in the healthy volunteers. The surface electromyography (EMG) of anterior deltoid, triceps brachii, biceps brachii, TA, and SOL muscles was recorded and the motor evoked potential (MEP) to TMS was recorded in the TA muscle along with the SOL muscle. TMS at the hotspot of the TA muscle was applied at the timings immediately prior to the TA onset. The kinematic parameters including the three-dimensional motion analysis and center of pressure (COP) during the dart throwing were also assessed.Results: The changes in COP and EMG of the TA muscle occurred preceding the dart throwing, which involved a slight elbow flexion followed by an extension. The correlation analysis revealed that the onset of the TA muscle was related to the COP change and the elbow joint flexion. The MEP amplitude in the TA muscle, but not that in the SOL muscle, significantly increased immediately prior to the EMG burst (100, 50, and 0 ms prior to the TA onset).Conclusion: Our findings demonstrate that the corticospinal excitability of the TA muscle increases prior to the ballistic upper limb movement of the dart throwing, suggesting that the corticospinal pathway contributes to the APA in the lower limb in a muscle-specific manner.

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Differential activation of lumbar and sacral motor pools during walking at different speeds and slopes

Journal of Neurophysiology ◽

10.1152/jn.00167.2019 ◽

2019 ◽

Vol 122 (2) ◽

pp. 872-887 ◽

Cited By ~ 4

Author(s):

A. H. Dewolf ◽

Y. P. Ivanenko ◽

K. E. Zelik ◽

F. Lacquaniti ◽

P. A. Willems

Keyword(s):

Spinal Cord ◽

Body Mass ◽

Lower Limb ◽

Power Production ◽

Negative Slope ◽

Differential Activation ◽

Lower Limb Muscles ◽

Negative Center ◽

Limb Muscles ◽

Differential Involvement

Organization of spinal motor output has become of interest for investigating differential activation of lumbar and sacral motor pools during locomotor tasks. Motor pools are associated with functional grouping of motoneurons of the lower limb muscles. Here we examined how the spatiotemporal organization of lumbar and sacral motor pool activity during walking is orchestrated with slope of terrain and speed of progression. Ten subjects walked on an instrumented treadmill at different slopes and imposed speeds. Kinetics, kinematics, and electromyography of 16 lower limb muscles were recorded. The spinal locomotor output was assessed by decomposing the coordinated muscle activation profiles into a small set of common factors and by mapping them onto the rostrocaudal location of the motoneuron pools. Our results show that lumbar and sacral motor pool activity depend on slope and speed. Compared with level walking, sacral motor pools decrease their activity at negative slopes and increase at positive slopes, whereas lumbar motor pools increase their engagement when both positive and negative slope increase. These findings are consistent with a differential involvement of the lumbar and the sacral motor pools in relation to changes in positive and negative center of body mass mechanical power production due to slope and speed. NEW & NOTEWORTHY In this study, the spatiotemporal maps of motoneuron activity in the spinal cord were assessed during walking at different slopes and speeds. We found differential involvement of lumbar and sacral motor pools in relation to changes in positive and negative center of body mass power production due to slope and speed. The results are consistent with recent findings about the specialization of neuronal networks located at different segments of the spinal cord for performing specific locomotor tasks.

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