scholarly journals Is the Frequency in Somatosensory Electrical Stimulation theKeyParameter in Modulating the Corticospinal Excitability of Healthy Volunteers and Stroke Patients with Spasticity?

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Marco Antonio Cavalcanti Garcia ◽  
João Marcos Yamasaki Catunda ◽  
Marcio Nogueira de Souza ◽  
Ana Paula Fontana ◽  
Sandro Sperandei ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Healthy Volunteers ◽  
Motor Evoked Potentials ◽  
Wrist Joint ◽  
Motor Impairment ◽  
Low Frequency ◽  
H Reflex ◽  
Stroke Patients ◽  
Before And After ◽  
The Central Nervous System

Somatosensory electrical stimulation (SES) has been proposed as an approach to treat patients with sensory-motor impairment such as spasticity. However, there is still no consensus regarding which would be the adequate SES parameters to treat those deficits. Therefore, the aim of this study was to evaluate the effects of applying SES over the forearm muscles at four different frequencies of stimulation (3, 30, 150, and 300 Hz) and in two intervals of time (5′ and 30′) by means of transcranial magnetic stimulation and Hoffmann’s reflex (H-reflex) in healthy volunteers (Experiments  I and II). A group of stroke patients (Experiment  III) was also preliminary evaluated to ascertain SES effects at a low frequency (3 Hz) applied for 30′ over the forearm spastic flexors muscles by measuring the wrist joint passive torque. Motor evoked potentials and the H-reflex were collected from different forearm and hand muscles immediately before and after SES and up to 5′ (Experiment  I) and 10′ (Experiments  I and II) later. None of the investigated frequencies of SES was able to operate as akeyin switching modulatory effects in the central nervous system of healthy volunteers and stroke patients with spasticity.

scholarly journals Can somatosensory electrical stimulation relieve spasticity in post-stroke patients? A TMS pilot study

2018 ◽  
Vol 63 (4) ◽  
pp. 501-506 ◽  
Author(s):  
André Salles Cunha Peres ◽  
Victor Hugo Souza ◽  
João Marcos Yamasaki Catunda ◽  
Kelley Cristine Mazzeto-Betti ◽  
Taiza Elaine Grespan Santos-Pontelli ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Healthy Subjects ◽  
Motor Evoked Potentials ◽  
Wrist Joint ◽  
Single Pulse ◽  
Stroke Patients ◽  
Passive Resistance ◽  
Before And After ◽  
Carry Over ◽  
Carry Over Effect

Abstract Evidence suggests that somatosensory electrical stimulation (SES) may decrease the degree of spasticity from neural drives, although there is no agreement between corticospinal modulation and the level of spasticity. Thus, stroke patients and healthy subjects were submitted to SES (3 Hz) for 30′ on the impaired and dominant forearms, respectively. Motor evoked potentials induced by single-pulse transcranial magnetic stimulation were collected from two forearm muscles before and after SES. The passive resistance of the wrist joint was measured with an isokinetic system. We found no evidence of an acute carry-over effect of SES on the degree of spasticity.

Comparative study on effect of neutral spinal bath and neutral spinal spray on blood pressure, heart rate and heart rate variability in healthy volunteers

2018 ◽  
Vol 16 (2) ◽  
Author(s):  
Arundhati Goley ◽  
A. Mooventhan ◽  
NK. Manjunath
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Heart Rate Variability ◽  
Healthy Volunteers ◽  
Group Analysis ◽  
Low Frequency ◽  
Single Session ◽  
Arterial Blood ◽  
Before And After ◽  
Instantaneous Heart Rate

Abstract Background Hydrotherapeutic applications to the head and spine have shown to improve cardiovascular and autonomic functions. There is lack of study reporting the effect of either neutral spinal bath (NSB) or neutral spinal spray (NSS). Hence, the present study was conducted to evaluate and compare the effects of both NSB and NSS in healthy volunteers. Methods Thirty healthy subjects were recruited and randomized into either neutral spinal bath group (NSBG) or neutral spinal spray group (NSSG). A single session of NSB, NSS was given for 15 min to the NSBG and NSSG, respectively. Assessments were taken before and after the interventions. Results Results of this study showed a significant reduction in low-frequency (LF) to high-frequency (HF) (LF/HF) ratio of heart rate variability (HRV) spectrum in NSBG compared with NSSG (p=0.026). Within-group analysis of both NSBG and NSSG showed a significant increase in the mean of the intervals between adjacent QRS complexes or the instantaneous heart rate (HR) (RRI) (p=0.002; p=0.009, respectively), along with a significant reduction in HR (p=0.002; p=0.004, respectively). But, a significant reduction in systolic blood pressure (SBP) (p=0.037) and pulse pressure (PP) (p=0.017) was observed in NSSG, while a significant reduction in diastolic blood pressure (DBP) (p=0.008), mean arterial blood pressure (MAP) (p=0.008) and LF/HF ratio (p=0.041) was observed in NSBG. Conclusion Results of the study suggest that 15 min of both NSB and NSS might be effective in reducing HR and improving HRV. However, NSS is particularly effective in reducing SBP and PP, while NSB is particularly effective in reducing DBP and MAP along with improving sympathovagal balance in healthy volunteers.

Electrical Stimulation of the Guinea Pig Cochlea

1987 ◽  
Vol 96 (4) ◽  
pp. 349-361 ◽  
Author(s):  
Mark J. Maslan ◽  
Josef M. Miller
Keyword(s):  
Electrical Stimulation ◽  
Low Frequency ◽  
Damage Threshold ◽  
Auditory Brainstem ◽  
Cochlear Prosthesis ◽  
Before And After ◽  
Auditory Brainstem Evoked Responses ◽  
Straight Lines ◽  
Histopathologic Findings ◽  
Stimulation Of

As a result of practical considerations, histopathologic findings of the temporal bone in humans with cochlear prosthesis implants have been limited. This project attempts to better define safe parameters of electrical stimulation of the inner ear and compare the safe limits of intracochlear vs. extracochlear stimulation sites. Guinea pigs were implanted with single electrodes either on the promontory or in the scala tympani and were stimulated relative to a remote indifferent for 12 hours distributed over a 4-week period. Electrical auditory brainstem evoked responses (EABRs) were tested before and after each of four 3-hour stimulation sessions. Six weeks after implantation, the animals were killed, and their cochleas were examined under the scanning electron microscope. Intracochlear electrodes exhibited thresholds for damage well below one half of that found for most extracochlear stimulation sites. The function-relating damage threshold (in amperes) to frequency of intracochlear stimulation is represented by two straight lines, with an intercept of 1 kHz. The low-frequency limb exhibited a slope of 3 to 4 dB/octave, whereas the high-frequency limb exhibited a slope of 9 to 10 dB/octave. Extracochlear results were too variable to permit speculation. Changes in EABRs were only variably related to histopathologic findings.

The pulse duration of electrical stimulation influences H-reflexes but not corticospinal excitability for tibialis anterior

2014 ◽  
Vol 92 (10) ◽  
pp. 821-825
Author(s):  
Alyssa R. Hindle ◽  
Jenny W.H. Lou ◽  
David F. Collins
Keyword(s):  
Electrical Stimulation ◽  
Pulse Duration ◽  
Peroneal Nerve ◽  
Motor Evoked Potentials ◽  
Common Peroneal Nerve ◽  
H Reflex ◽  
M Wave ◽  
Recruitment Curve ◽  
Afferent Volley ◽  
The Common

The afferent volley generated by neuromuscular electrical stimulation (NMES) influences corticospinal (CS) excitability and frequent NMES sessions can strengthen CS pathways, resulting in long-term improvements in function. This afferent volley can be altered by manipulating NMES parameters. Presently, we manipulated one such parameter, pulse duration, during NMES over the common peroneal nerve and assessed the influence on H-reflexes and CS excitability. We hypothesized that compared with shorter pulse durations, longer pulses would (i) shift the H-reflex recruitment curve to the left, relative to the M-wave curve; and (ii) increase CS excitability more. Using 3 pulse durations (50, 200, 1000 μs), M-wave and H-reflex recruitment curves were collected and, in separate experiments, CS excitability was assessed by comparing motor evoked potentials elicited before and after 30 min of NMES. Despite finding a leftward shift in the H-reflex recruitment curve when using the 1000 μs pulse duration, consistent with a larger afferent volley for a given efferent volley, the increases in CS excitability were not influenced by pulse duration. Hence, although manipulating pulse duration can alter the relative recruitment of afferents and efferents in the common peroneal nerve, under the present experimental conditions it is ineffective for maximizing CS excitability for rehabilitation.

scholarly journals Functional Electrical Stimulation for Upper Limbs Flexion-Extension and Prehension Movements in Rehabilitation

2020 ◽  
Author(s):  
Lullo Francesco ◽  
Coccia Armando ◽  
Saltalamacchia Anna Maria ◽  
Cesarelli Mario ◽  
Lanzillo Bernardo ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Functional Electrical Stimulation ◽  
Upper Limbs ◽  
Clinical Environment ◽  
Flexion Extension ◽  
Before And After ◽  
Electrical Pulses ◽  
Prehension Movements ◽  
The Central Nervous System ◽  
Complex Movement

Functional Electrical Stimulation (FES), is a tecnique that uses low-energy electrical pulses to artificially generate muscle contractions, in individuals with damages regarding the central nervous system. The application of FES in clinical environment involves both patients care and rehabilitation. Aim of this work is to introduce a clinical FES protocol for upper limbs rehabilitation, in order to assist and train the execution of complex movement, such as flexion- extension of wrist and fingers and palmar prehension. The new FES protocol has been tested on a cohort of five subjects with different upper limb neuromotor deficits, during their rehabilitation. The benefits deriving from the application of the new FES protocol have been evaluated by comparing specific quantitative electromyographic parameters assessed before and after the treatment. Results show effective improvements in performances of 4 patients out of 5.

scholarly journals Brain-Computer Interface Coupled to a Robotic Hand Orthosis for Stroke Patients’ Neurorehabilitation: A Crossover Feasibility Study

2021 ◽  
Vol 15 ◽  
Author(s):  
Jessica Cantillo-Negrete ◽  
Ruben I. Carino-Escobar ◽  
Paul Carrillo-Mora ◽  
Marlene A. Rodriguez-Barragan ◽  
Claudia Hernandez-Arenas ◽  
...  
Keyword(s):  
Feasibility Study ◽  
Upper Limb ◽  
Conventional Therapy ◽  
Stroke Rehabilitation ◽  
Motor Evoked Potentials ◽  
Random Order ◽  
Robotic Hand ◽  
Stroke Patients ◽  
Significant Difference ◽  
Before And After

Brain-Computer Interfaces (BCI) coupled to robotic assistive devices have shown promise for the rehabilitation of stroke patients. However, little has been reported that compares the clinical and physiological effects of a BCI intervention for upper limb stroke rehabilitation with those of conventional therapy. This study assesses the feasibility of an intervention with a BCI based on electroencephalography (EEG) coupled to a robotic hand orthosis for upper limb stroke rehabilitation and compares its outcomes to conventional therapy. Seven subacute and three chronic stroke patients (M = 59.9 ± 12.8) with severe upper limb impairment were recruited in a crossover feasibility study to receive 1 month of BCI therapy and 1 month of conventional therapy in random order. The outcome measures were comprised of: Fugl-Meyer Assessment of the Upper Extremity (FMA-UE), Action Research Arm Test (ARAT), motor evoked potentials elicited by transcranial magnetic stimulation (TMS), hand dynamometry, and EEG. Additionally, BCI performance and user experience were measured. All measurements were acquired before and after each intervention. FMA-UE and ARAT after BCI (23.1 ± 16; 8.4 ± 10) and after conventional therapy (21.9 ± 15; 8.7 ± 11) were significantly higher (p < 0.017) compared to baseline (17.5 ± 15; 4.3 ± 6) but were similar between therapies (p > 0.017). Via TMS, corticospinal tract integrity could be assessed in the affected hemisphere of three patients at baseline, in five after BCI, and four after conventional therapy. While no significant difference (p > 0.05) was found in patients’ affected hand strength, it was higher after the BCI therapy. EEG cortical activations were significantly higher over motor and non-motor regions after both therapies (p < 0.017). System performance increased across BCI sessions, from 54 (50, 70%) to 72% (56, 83%). Patients reported moderate mental workloads and excellent usability with the BCI. Outcome measurements implied that a BCI intervention using a robotic hand orthosis as feedback has the potential to elicit neuroplasticity-related mechanisms, similar to those observed during conventional therapy, even in a group of severely impaired stroke patients. Therefore, the proposed BCI system could be a suitable therapy option and will be further assessed in clinical trials.

Changes in TMS measures induced by repetitive TMS

2021 ◽  
Author(s):  
Joseph Classen ◽  
Ying-Zu Huang ◽  
Christoph Zrenner
Keyword(s):  
Primary Motor Cortex ◽  
Motor Evoked Potentials ◽  
Repetitive Transcranial Magnetic Stimulation ◽  
Low Frequency ◽  
Corticospinal Excitability ◽  
After Effects ◽  
Before And After ◽  
Neurophysiological Mechanisms ◽  
Synaptic Changes ◽  
Theta Burst

Commonly used repetitive transcranial magnetic stimulation (rTMS) protocols, including regular rTMS, intermittent and continuous theta-burst stimulation (TBS) and quadripulse stimulation (QPS) are presented with respect to their induced neuromodulatory after-effects and the underlying cellular and synaptic neurophysiological mechanisms. The anatomical target is typically primary motor cortex since motor evoked potentials (MEPs) before and after the intervention can be used to assess effects of the respective rTMS protocol. High-frequency regular rTMS and intermittent TBS protocols tend to increase corticospinal excitability as indexed by MEP amplitude, whereas low-frequency regular rTMS and continuous TBS protocols tend to reduce corticospinal excitability. These effects are primarily due to LTP-like and LTD-like synaptic changes mediated by GABA and NMDA receptors. Changes in the balance between excitatory and inhibitory cortical microcircuits play a secondary role, with inconsistent effects as determined by paired-pulse TMS protocols. Finally, the challenge of large inter-subject response variability, and current directions of research to optimize rTMS effects through EEG-dependent personalized TMS are discussed.

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