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Effects of Patterns of Pressure Application on Resting Electromyography During Massage

DOI:10.3822/ijtmb.v4i1.25
Authors:
Langdon Roberts at Santa Cruz Neurofeedback Center
Langdon Roberts
  • Santa Cruz Neurofeedback Center
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Abstract and Figures

To increase the understanding of the physiological mechanisms by which massage therapy produces health benefits such as pain relief and anxiety reduction, the relationship between specific elements of massage and physiological outcomes must be addressed. The effects on resting muscular activity of applying varying levels of pressure during massage were investigated. In this clinical crossover study, conducted in a simulated clinical setting, human subjects (n = 25; mean age: 34.1 years) received 3 different levels of massage pressure to the legs. A licensed therapist applied pressure to the rectus femoris in a distal-to-proximal direction. Each volunteer received the 3 levels of pressure in 2 different orders-increasing (IP) and decreasing pressures (DP)-separated by at least 4 weeks. Surface electromyography (EMG) was used to measure muscle activity levels at baseline and after each pressure level. During the trials of IP, EMG did not vary significantly [Greenhouse-Geisser corrected analysis of variance F(1.71 df) = 0.30, p = 0.71]. During the trials of DP, EMG varied significantly [Greenhouse-Geisser corrected analysis of variance F(1.58 df) = 4.49, p = 0.03], with the largest variation, an increase of 235%, noted between baseline activity and activity after deep pressure. After application of light pressure, activity returned to baseline levels. Interestingly, the overall levels of force required to achieve subjective pressure levels as reported by the client were higher in the DP protocol than in the IP protocol (p < 0.02). These results suggest that the physiological response of the muscle depends on the pattern of applied pressure during massage. That finding is consistent with a mechanism by which light- or moderate-pressure massage (or a combination) may reduce the gain of spinal nociceptive reflexes. As those reflexes are elevated in chronic pain syndromes, pressure variation provides a possible mechanism for the relief of chronic pain by massage therapy.
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... We can reach the sensorimotor zone of the central nervous system and the cerebral cortex. Through the pyramid and extra-pyramid motor paths, the signals of the cerebral cortex reach each intervertebral segment (Roberts, 2011;Milanov, 2014). Although the mechanisms for these positive results have not been studied enough in the scientific lit-erature, there are a few theories. ...
... Norrbrink and Lundeberg (2011) proved the efficiency of Chinese massage therapy as a means of reducing neuropathic pain in patients with spinal cord injury. In another survey with such patients, Roberts L. (2011) also found that acupressure improved the nervous conductivity of the limbs and significantly reduced pain. The good thing is that both surveys did not find any short-term or longterm negative effects. ...
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Conference Paper
Full-text available
  • Dec 2022
Chronic neck pain is something common which can be hard to treat. There is limited evidence for the efficiency of differ-ent alternative therapies. This research aimed to assess the efficiency of the traditional Chinese massage on the range of motion and intensity of pain in the cervical area of the spinal column. Objects and methods: 38 patients with chronic neck pain were randomly divided into experimental and control groups. The control group performed only controlled therapeutic exercises. The patients from the experimental group were subjected to ten Chinese therapeutic massages and therapeutic exercises twice a week. The range of motion in the neck was assessed with a universal goniometer for flexion, potations, and lateral flexion. The intensity of the pain was assessed with the visual-analogical scale. At the end of the research, we found statistically significant, better results in the EG in the left rotation (58,4° ± 2°), right rotation (54,4° ± 2,1°), right lateral flexion (32,6° ± 4,7°), and left lateral flexion (37,2° ± 5,6°), with a statistical significance level (p < .05). Tracing the dynamics in the pain symptoms showed a reduction in the pain in both groups of patients, with a significant downward trend in the experimental group. Conclusion: Traditional Chinese massagе alleviates pain symptoms and relaxes the increased muscle tone, which leads to an increase in the range of motion in the neck area. Compared to routine physiotherapy, the Chinese massage methods has a proven effect on the traced indicators.
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... Peristaltic transport has been previously applied in robotic systems for liquid pumping [30] or swallowing robots [31]. When applied to the exterior of the body, peristalsis can supply forces similar to those used in compression and massage therapies [7]. ...
A peristaltic soft, wearable robot for compression and massage therapy
Preprint
Full-text available
  • Jun 2022
Soft robotics is attractive for wearable applications that require conformal interactions with the human body. Soft wearable robotic garments hold promise for supplying dynamic compression or massage therapies, such as are applied for disorders affecting lymphatic and blood circulation. In this paper, we present a wearable robot capable of supplying dynamic compression and massage therapy via peristaltic motion of finger-sized soft, fluidic actuators. We show that this peristaltic wearable robot can supply dynamic compression pressures exceeding 22 kPa at frequencies of 14 Hz or more, meeting requirements for compression and massage therapy. A large variety of software-programmable compression wave patterns can be generated by varying frequency, amplitude, phase delay, and duration parameters. We first demonstrate the utility of this peristaltic wearable robot for compression therapy, showing fluid transport in a laboratory model of the upper limb. We theoretically and empirically identify driving regimes that optimize fluid transport. We second demonstrate the utility of this garment for dynamic massage therapy. These findings show the potential of such a wearable robot for the treatment of several health disorders associated with lymphatic and blood circulation, such as lymphedema and blood clots.
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... It can be performed in combination with relaxing massage therapy, connective massage, and electrotherapy. It has benefits in terms of improving pain, anxiety and depression, health, and quality of life [14,26]. ...
Neck Pain in Fibromyalgia: Treatment with Exercise and Mesotherapy
Article
Full-text available
  • Mar 2023
Background and objectives: Fibromyalgia is a very common musculoskeletal disease. The purpose of this study is to assess, on a population of fibromyalgic patients, the clinical efficacy of antalgic mesotherapy with diclofenac and thiocolchicoside in the treatment of cervical pain reduction for improvement of the functional capacity and quality of life of these patients. Materials and methods: We conducted an observational study of 78 fibromyalgia patients recruited using our hospital database. Based on the different types of treatment received, the patients were divided into two groups: the treatment group (TG), who received antalgic mesotherapy with diclofenac, thiococolchicoside, and mepivacaina; and the placebo group (PG), who received mesotherapy with sodium chloride solution. Patients in both groups also received the same rehabilitation protocol of 20 sessions. The primary outcome evaluated was the extent of pain. The secondary outcomes were the functional capacity and quality of life. Results: Pain improved both in the treatment group (7.4 ± 1.2 vs. 5.1 ± 1.1; p < 0.05) and placebo group (7.5 ± 1.4 vs. 6.1 ± 1.6; p < 0.05). The treatment group, compared to the placebo group, also showed significant statistical improvements in functional capacity (NDI: 35.6 ± 5.23 vs. 19.3 ± 3.41; p < 0.05) and quality of life (SF-12: 18.3 ± 4.11 vs. 33.1 ± 2.41; p < 0.05). Conclusions: Mesotherapy treatment with diclofenac and thiocolchicoside is a safe and effective procedure in the management of neck pain in fibromyalgia patients in the short term in terms of pain reduction, functional recovery and quality of life.
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... Ces mouvements de pression punctiforme sont également efficaces en termes de soulagement rapide des douleurs, par activation du mécanisme de contrôle de la douleur. À cette fin, il est indispensable d'exercer une pression importante au niveau d'un point sensible particulier jusqu'à disparition de la sensation douloureuse (figure 3) [7]. [8]. ...
Lamassothérapieenprothèsemaxillo-faciale
Article
  • Aug 2021
La prothèse maxillo-faciale est une discipline permettant de réhabiliter, grâce à une prothèse ou une épithèse amovible, une perte ou une absence de substance du revêtement cutané́ et des structures ostéoarticulaires sous-jacentes maxillo-faciales. Ces pertes de substance peuvent avoir des étiologies diverses : congénitales, tumorales, traumatiques ou infectieuses. Les séquelles de ces pertes de substance sont innombrables et mutilantes, elles touchent l’aspect fonctionnel, psychologique et esthétique de nos patients. De ce fait, la pratique de la prothèse maxillo-faciale se décline selon trois principes fondamentaux : psychosocial, prothétique et fonctionnel. Le principe fonctionnel repose sur la prévention et la limitation des effets secondaires des traitements étiologiques et chirurgicaux, en faisant appel à̀ des thérapeutiques massokinésithérapiques. Ainsi, la massothérapie maxillo-faciale trouve son indication, en tant que traitement fonctionnel de base, facilitant la future réhabilitation prothétique. L’objectif de cet article est de présenter la massothérapie et son intérêt dans la prise en charge prothétique maxillo-faciale. Nous présentons d’abord les différentes techniques massothérapiques utilisées en prothèse maxillo-faciale, puis les champs d’application du massage lors de la réhabilitation prothétique maxillo-faciale et, enfin, l’interrelation entre prosthodontiste MaxilloFacial et massokinésithérapeute, et son intérêt dans l’éducation thérapeutique, l’évolution et la réussite du traitement prothétique.
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... Results showed reduction of 30 m sprint performance in both massage and rest conditions, highlighting that either warm-up or extenuated activities could disguise the influence of massage on performance. Furthermore, the authors argue that the use of two massage therapists demonstrated a serious limitation in controlling the massage intensity 12 . In another study regarding the warm-up effects, Wiktorsson-Möller et al. 4 analyzed 8 individuals who underwent three experimental sessions: i) warm-up conditionfor 15 min at moderate intensity in a cycloergometer; ii) massage conditionby only one massage therapist performing the amassment technique during 6 to 15 min, where the variation in length of time was justified by the authors due to the level of tension verified by the therapist; and iii) warm-up and massage condition. ...
Effect of massage and pseudo massage on acute performance and self-perceived recovery: a study placebo-controlled
Article
Full-text available
  • Aug 2021
The aim of this study was to verify the effect of massage or pseudo massage on vertical jump performance. Fifteen participants were randomly subjected to three experimental conditions: massage, pseudo massage and rest. The massage condition required three unipodal vertical jumps followed by two minutes of manual massage on plantar flexor muscles and, before performing another three jumps, the Total Quality Recover Scale (TQR) was applied. The two following conditions were structured with the same procedures, although participants were submitted either at pseudo massage (single-blinded) or two minutes of rest. Results showed no statistical differences on jump height between pre and post analysis nor between experimental conditions (massage 18.7 ± 4.1 vs 18.2 ± 4.1; pseudo massage 19.1 ± 4.0 vs 8.3 ± 3.8; rest 19.0 ± 4.0 vs 18.7 ± 3.9 cm). There were also no statistical differences in the TQR results between experimental conditions (massage 16.2 ± 4.3; pseudo massage 16.4 ± 3.9; rest 15.9 ± 2.6 ua). Both massage and pseudo massage did not affect performance on vertical jump and TQR.
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... 4 Other studies showed MT could improve MS patients' QOL 4,14,[18][19][20][21] and decrease pain and fatigue in other patients with different diagnoses. [22][23][24][25][26][27][28] However, MT is one of the most frequently used complementary and alternative treatment methods by MS patients. 29 But the evidence on the efficacy of MT in MS patients is insufficient. ...
Effectiveness of massage therapy on fatigue and pain in patients with multiple sclerosis: A systematic review and meta-analysis
Article
Full-text available
  • Apr 2021
Background Fatigue and pain are prevalent symptoms of multiple sclerosis (MS) and frequent complaint in MS patients, which reduce their quality of life. This study aimed to assess the effect of massage therapy on pain and fatigue in MS Patients. Method The original and Persian databases were searched included PubMed, web of science, embase, ovid, scopus, and the Cochrane Library, SID, and Iranedex from inception to November 2020. Studies that reported the effect of massage on fatigue and pain were included. Two investigators extracted all relevant data, independently. For deriving analysis, mean difference (MD) and standardized mean difference (SMD) were used. Result Ten studies were eligible acoording criteria. The effect of massage on fatigue showed significant improvement (−1.62; 95% CL −2.40, −0.83; p < .00001), also results of the systematic review showed a significant reduction in pain severity. Conclusion Massage as a complementary and non-pharmacological therapy might have been associated with alleviating fatigue and pain in M.S. patients. Based on the current study, massage intervention for MS patients could have possible clinical value for palliating pain and fatigue and improving quality of life; however, this matter needs further and more significant trial studies.
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Multimodal non-invasive non-pharmacological therapies for chronic pain: mechanisms and progress
Article
Full-text available
Background Chronic pain conditions impose significant burdens worldwide. Pharmacological treatments like opioids have limitations. Non-invasive non-pharmacological therapies (NINPT) encompass diverse interventions including physical, psychological, complementary and alternative approaches, and other innovative techniques that provide analgesic options for chronic pain without medications. Main body This review elucidates the mechanisms of major NINPT modalities and synthesizes evidence for their clinical potential across chronic pain populations. NINPT leverages peripheral, spinal, and supraspinal mechanisms to restore normal pain processing and limit central sensitization. However, heterogeneity in treatment protocols and individual responses warrants optimization through precision medicine approaches. Conclusion Future adoption of NINPT requires addressing limitations in standardization and accessibility as well as synergistic combination with emerging therapies. Overall, this review highlights the promise of NINPT as a valuable complementary option ready for integration into contemporary pain medicine paradigms to improve patient care and outcomes.
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A Peristaltic Soft, Wearable Robot for Compression Therapy and Massage
Article
  • Aug 2023
Soft robotics is attractive for wearable applications that require conformal interactions with the human body. Soft wearable robotic garments hold promise for supplying dynamic compression or massage therapies to improve lymphatic and blood circulation. In this paper, we present a wearable robot capable of supplying dynamic compression and massage therapy via peristaltic motion of finger-sized, soft, fluidic actuators. We show that this peristaltic wearable robot can supply dynamic compression pressures exceeding 22 kPa at frequencies of 14 Hz or more, meeting requirements for compression and massage therapy. A large variety of software-programmable compression wave patterns can be generated by varying frequency, amplitude, phase delay, and duration parameters. We finally demonstrate the utility of this peristaltic wearable robot for compression therapy, showing fluid transport in a laboratory model of the upper limb. We theoretically and empirically identify driving regimes that optimize fluid transport. These findings show the potential of such a wearable robot for the treatment of several health disorders associated with lymphatic and blood circulation, such as lymphedema and blood clots.
View
POSSIBILITIES OF MANUAL TECHNIQUES IN COMPLEX REHABILITATION IN PATIENTS WITH TEMPOROMANDIBULAR JOINT MYOFASCIAL PAIN SYNDROME
Article
  • Jan 2023
Manual therapy, as a type of rehabilitation for TMJ pain, should be considered as an effective technique due to the low risk of complications at all stages of medical rehabilitation.
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Ischemic stroke-induced polyaxonal innervation at the neuromuscular junction is attenuated by robot-assisted mechanical therapy
Article
Ischemic stroke is a leading cause of disability world-wide. Mounting evidence supports neuromuscular pathology following stroke, yet mechanisms of dysfunction and therapeutic action remain undefined. The objectives of our study were to investigate neuromuscular pathophysiology following ischemic stroke and to evaluate the therapeutic effect of Robot-Assisted Mechanical massage Therapy (RAMT) on neuromuscular junction (NMJ) morphology. Using an ischemic stroke model in male rats, we demonstrated longitudinal losses of muscle contractility and electrophysiological estimates of motor unit number in paretic hindlimb muscles within 21 days of stroke. Histological characterization demonstrated striking pre- and postsynaptic alterations at the NMJ. Stroke prompted enlargement of motor axon terminals, acetylcholine receptor (AChR) area, and motor endplate size. Paretic muscle AChRs were also more homogenously distributed across motor endplates, exhibiting fewer clusters and less fragmentation. Most interestingly, NMJs in paretic muscle exhibited increased frequency of polyaxonal innervation. This finding of increased polyaxonal innervation in stroke-affected skeletal muscle suggests that reduction of motor unit number following stroke may be a spurious artifact due to overlapping of motor units rather than losses. Furthermore, we tested the effects of RAMT – which we recently showed to improve motor function and protect against subacute myokine disturbance – and found significant attenuation of stroke-induced NMJ alterations. RAMT not only normalized the post-stroke presentation of polyaxonal innervation but also mitigated postsynaptic expansion. These findings confirm complex neuromuscular pathophysiology after stroke, provide mechanistic direction for ongoing research, and inform development of future therapeutic strategies. Significance Ischemic stroke is a leading contributor to chronic disability, and there is growing evidence that neuromuscular pathology may contribute to the impact of stroke on physical function. Following ischemic stroke in a rat model, there are progressive declines of motor unit number estimates and muscle contractility. These changes are paralleled by striking pre- and postsynaptic maladaptive changes at the neuromuscular junction, including polyaxonal innervation. When administered to paretic hindlimb muscle, Robot-Assisted Mechanical massage Therapy – previously shown to improve motor function and protect against subacute myokine disturbance – prevents stroke-induced neuromuscular junction alterations. These novel observations provide insight into the neuromuscular response to cerebral ischemia, identify peripheral mechanisms of functional disability, and present a therapeutic rehabilitation strategy with clinical relevance.
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Massage Therapy: Is Its Evidence-Base Getting Stronger
Article
Full-text available
  • Oct 2007
The aim of this article is to evaluate trends in the development of the evidence-base for the effectiveness of massage therapy. For this purpose, a comparison of two systematic reviews was conducted. The first related to the evidence-base in 2000, the second to 2005. Both employed the same methodology and criteria for evaluation. The results indicate that, in several areas, the evidence has become more solid and, for anxiety and back pain, it has become more positive. For a host of other indications, the evidence seems encouraging, but more studies are required to test the effectiveness of massage therapy as well as its use for specific conditions.
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Short-Term Synaptic Plasticity in the Nociceptive Thalamic-Anterior Cingulate Pathway
Article
Full-text available
Although the mechanisms of short- and long-term potentiation of nociceptive-evoked responses are well known in the spinal cord, including central sensitization, there has been a growing body of information on such events in the cerebral cortex. In view of the importance of anterior cingulate cortex (ACC) in chronic pain conditions, this review considers neuronal plasticities in the thalamocingulate pathway that may be the earliest changes associated with such syndromes. A single nociceptive electrical stimulus to the sciatic nerve induced a prominent sink current in the layer II/III of the ACC in vivo, while high frequency stimulation potentiated the response of this current. Paired-pulse facilitation by electrical stimulation of midline, mediodorsal and intralaminar thalamic nuclei (MITN) suggesting that the MITN projection to ACC mediates the nociceptive short-term plasticity. The short-term synaptic plasticities were evaluated for different inputs in vitro where the medial thalamic and contralateral corpus callosum afferents were compared. Stimulation of the mediodorsal afferent evoked a stronger short-term synaptic plasticity and effectively transferred the bursting thalamic activity to cingulate cortex that was not true for contralateral stimulation. This short-term enhancement of synaptic transmission was mediated by polysynaptic pathways and NMDA receptors. Layer II/III neurons of the ACC express a short-term plasticity that involves glutamate and presynaptic calcium influx and is an important mechanism of the short-term plasticity. The potentiation of ACC neuronal activity induced by thalamic bursting suggest that short-term synaptic plasticities enable the processing of nociceptive information from the medial thalamus and this temporal response variability is particularly important in pain because temporal maintenance of the response supports cortical integration and memory formation related to noxious events. Moreover, these modifications of cingulate synapses appear to regulate afferent signals that may be important to the transition from acute to chronic pain conditions associated with persistent peripheral noxious stimulation. Enhanced and maintained nociceptive activities in cingulate cortex, therefore, can become adverse and it will be important to learn how to regulate such changes in thalamic firing patterns that transmit nociceptive information to ACC in early stages of chronic pain.
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Specificity of Reflex Adaptation for Task-Relevant Variability
Article
Full-text available
The motor system responds to perturbations with reflexes, such as the vestibulo-ocular reflex or stretch reflex, whose gains adapt in response to novel and fixed changes in the environment, such as magnifying spectacles or standing on a tilting platform. Here we demonstrate a reflex response to shifts in the hand's visual location during reaching, which occurs before the onset of voluntary reaction time, and investigate how its magnitude depends on statistical properties of the environment. We examine the change in reflex response to two different distributions of visuomotor discrepancies, both of which have zero mean and equal variance across trials. Critically one distribution is task relevant and the other task irrelevant. The task-relevant discrepancies are maintained to the end of the movement, whereas the task-irrelevant discrepancies are transient such that no discrepancy exists at the end of the movement. The reflex magnitude was assessed using identical probe trials under both distributions. We find opposite directions of adaptation of the reflex response under these two distributions, with increased reflex magnitudes for task-relevant variability and decreased reflex magnitudes for task-irrelevant variability. This demonstrates modulation of reflex magnitudes in the absence of a fixed change in the environment, and shows that reflexes are sensitive to the statistics of tasks with modulation depending on whether the variability is task relevant or task irrelevant.
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Acquisition, Processing and Analysis of the Surface Electromyogram
Chapter
  • Jan 1999
During muscle activation but prior to contraction and the production of force, small electrical currents are generated by the exchange of ions across muscle fiber membranes. The electric signal generated during muscle activation, often referred to as the myoelectric signal, can be measured through electrodes (conductive elements) applied to the skin surface or inserted into the muscle (cf. Chapter 27). The signal represents the electrical activation of the mechanical system of the muscle fibers and thus the activity preceding the mechanical events. An example of one indwelling recording technique is outlined in Chapter 27. For a complementary overview of other indwelling techniques the reader is referred to (Sanders and Stålberg 1996; Stålberg 1980; Yu and Murray 1984)
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The effects of slow stroking on spasticity in patients with multiple sclerosis: A pilot study
Article
  • Jul 2009
Slow stroking applied for 3 min over the posterior primary rami region is believed to decrease muscle tone by reducing arousal via activation of the inhibitory reticular system (O'Sullivan, 1988). The efficacy of this intervention and insight into the possible mechanisms whereby changes in muscle tone might occur were examined in 10 patients with multiple sclerosis (MS) having mild to moderate plantarflexor spasticity. Electrophysiological measures of spasticity reflecting the excitability of the alpha-motoneuron pool associated with the triceps surae muscles indicated significant differences between the MS group and a group of 12 healthy controls. In the MS group only, amplitudes of the H-reflex, H-reflex during vibration and the Achilles tendon jerk were obtained pre-, post- and 30 min post-stroking. A significant decrease in H-reflex amplitude (normalised to the maximum M-wave) was found 30 min post-stroke when compared with baseline values. This was not attributable to bedrest alone. Other measures obtained prior to and after stroking did not change significantly. Patients reported that they felt more relaxed following the intervention. These preliminary findings suggest that 3 min of stroking can reduce alpha-motoneuron excitability in MS patients with spasticity.
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Current Research on Myofascial Trigger Points–Pathophysiological Studies
Article
  • Jan 2010
SUMMARY Objectives: To summarize recent studies on myofascial trigger point [MTrP] to further clarify the mechanism of MTrP. Methods: To review recent clinical and basic science studies related to the pathophysiology of MTrPs. Results: There are multiple loci in an MTrP region. A clinical MTrP characteristically exhibits a sensory component [sensitive locus] and a motor component [active locus]. A sensitive locus is the site from which spot tenderness, referred pain [ReP], and local twitch response [LTR] can be elicited by mechanical stimulation. Sensitive loci [probably sensitized nociceptors] can be widely distributed in the whole muscle, but are concentrated in the endplate zone. An active locus is the site from which spontaneous electrical activity [SEA] can be recorded. Active loci are dysfunctional endplates, since SEA is essentially the same as electrical activity recorded from an abnormal endplate as reported by neurophysiologists. An MTrP is always found in a taut band which is histologically related to contraction knots caused by excessive release of acetylcholine in an abnormal endplate. Both ReP and LTR are mediated through spinal cord mechanisms, demonstrated in both human and animal studies. Conclusions: The pathogenesis of MTrPs appears to involve serious disturbance of the nerve ending and contractile mechanism at multiple dysfunctional endplates.
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The effect of darkness on knee-jerk reflexes
Article
  • Sep 2009
In considering the processes that regulate motor functions in darkness, the following factors should be taken into account: the fear of losing spatial orientation, daily processes in the circadian system, stimulating influence of the light, and a mechanism that induces anxiety, probably of rudimentary origin, serving as a sentinel center monitoring the probable aggressiveness of the environment, which increases in the dark. The results of published studies suggest that the anxiety response to darkness induces emotional stress, and, consequently, an increase in the background supraspinal excitatory influence mediated by the corticospinal tract and leading to decreased α-motoneuron thresholds.
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Modulatory influence on somatosensory perception from vibration and heterotopic noxious conditioning stimulation (HNCS) in fibromyalgia patients and healthy subjects
Article
  • Apr 1997
In order to assess the function of endogenous mechanisms modulating somatosensory input in fibromyalgia (FM), the effect of vibratory stimulation (VS) and heterotopic noxious conditioning stimulation (HNCS) on perception of various somatosensory modalities was assessed. Ten female FM patients and 10 healthy, age-matched, females participated. VS (100 Hz) was applied to the left forearm for 45 min and quantitative sensory testing (QST) was performed within the vibrated area and in the right thigh before, during and 45 min following vibration. Pressure pain thresholds (PPTs) were assessed by pressure algometry. Perception thresholds to non-painful cold (CT) and warmth (WT), heat pain thresholds (HPTs), cold pain thresholds (CPTs) and stimulus-response curves of pain intensity as a function of graded nociceptive heat stimulation were assessed using a Peltier element based thermal stimulator. The effects of HNCS were tested using the upper extremity submaximal effort tourniquet test. Subjects rated tourniquet induced pain intensity on a visual analogue scale (VAS). QST was performed in the right thigh before, during and 60 min following the tourniquet. FM patients did not differ from controls in the response to VS. There was a local increase of PPTs during vibration (P<0.001) and of WTs following vibration (P<0.001). HPTs increased in the forearm and in the thigh (P<0.009) during vibration. CTs and sensitivity to suprathreshold heat pain were not influenced by VS. The intensity of pain induced by the tourniquet did not differ between groups. PPTs increased during the tourniquet in controls (P<0.001) but not in FM patients (difference between groups P<0.001). Decreased sensitivity to non-painful cold (P<0.001) and non-painful warmth (P<0.001) was seen during and following (P<0.01; P<0.05, respectively) the tourniquet in both groups alike. HPTs and perception of suprathreshold heat pain remained unaffected in both groups. In conclusion, FM patients did not differ from healthy controls in their response to vibration, but no modulation of pressure pain was induced by HNCS, as opposed to controls, suggesting a dysfunction in systems subserving `diffuse noxious inhibitory controls' (DNIC).
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Cortical Plasticity: From Synapses to Maps
Article
  • Mar 1998
It has been clear for almost two decades that cortical representations in adult animals are not fixed entities, but rather, are dynamic and are continuously modified by experience. The cortex can preferentially allocate area to represent the particular peripheral input sources that are proportionally most used. Alterations in cortical representations appear to underlie learning tasks dependent on the use of the behaviorally important peripheral inputs that they represent. The rules governing this cortical representational plasticity following manipulations of inputs, including learning, are increasingly well understood. In parallel with developments in the field of cortical map plasticity, studies of synaptic plasticity have characterized specific elementary forms of plasticity, including associative long-term potentiation and long-term depression of excitatory postsynaptic potentials. Investigators have made many important strides toward understanding the molecular underpinnings of these fundamental plasticity processes and toward defining the learning rules that govern their induction. The fields of cortical synaptic plasticity and cortical map plasticity have been implicitly linked by the hypothesis that synaptic plasticity underlies cortical map reorganization. Recent experimental and theoretical work has provided increasingly stronger support for this hypothesis. The goal of the current paper is to review the fields of both synaptic and cortical map plasticity with an emphasis on the work that attempts to unite both fields. A second objective is to highlight the gaps in our understanding of synaptic and cellular mechanisms underlying cortical representational plasticity.
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