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At least 505 records · Page 28Linked to original sources
PubMed1988

Afferents contributing to the exaggerated long latency reflex response to electrical stimulation in Parkinson's disease.

Reflex pathways to tibialis anterior motoneurons from low threshold afferents of the common peroneal nerve were examined in 13 Parkinsonian subjects and 12 age-matched normals. Post-synaptic events occurring in single motoneurons were derived from changes in the firing probability of single voluntarily activated motor units during afferent stimulation. A period of increased firing probability of "monosynaptic" latency (about 33 ms) occurred in all subjects in both groups. A second, later, period of increased firing probability (latency about 64 ms) was seen in 2/12 normals and 8/13 Parkinsonian subjects. Neither of these responses could be produced by cutaneous stimulation. The electrical threshold of the afferents mediating the later effect was 0.82 of the threshold of alpha motoneuron axons which is similar to that of the afferents mediating the shorter latency response. Thus, large non cutaneous afferents contribute to this long latency response in man presumably through polysynaptic pathways. Transmission in these pathways is enhanced in Parkinson's disease.

Adult↗
PubMed1980

[Threshold characteristics of cardiac excitability on electrical stimulation].

Threshold characteristics of excitability of the myocardium stimulated by electric current were studied in experiments on frogs. It was established that the magnitude of threshold charge is the main constant characterizing myocardial excitability. A convenient method was suggested for its measurement. It allows an accurate charge measuring at any voltage and current. The results obtained can be used for an optimal make up of the outlet cascade of implanted cardiostimulators.

Animals↗
PubMed2002

Comparison of the experience with acute and chronic electrically stimulated detrusor myoplasty.

AIMS: To evaluate the acute and chronic urodynamic effects of electrically stimulated detrusor myoplasty in dogs. METHODS: Eight female mongrel dogs were studied acutely and six dogs chronically (0 to 12 weeks postoperatively). Bladders were wrapped with the rectus abdominis muscle, keeping an intact blood supply and at least two intercostal nerves of the flap preserved. Bladders were electrically stimulated with bipolar electrodes inserted into the muscle. Urodynamics and post void residual were measured post operatively in the acute studies and every 2 weeks for 3 months in chronic studies. RESULTS: Acutely, the increase in intravesical pressure was 45+/-7 cm H(2)O, which resulted in a postvoid residual of 26+/-3%. In the chronic study, increases of intravesical pressure sufficient to empty the bladder during myoplasty electrical stimulation were not sustained, although detrusor compliance and flap viability were preserved. CONCLUSIONS: The electrically stimulated detrusor myoplasty worked well acutely to increase vesical pressure sufficient to empty the bladder, but the chronically stimulated myoplasty did not maintain efficient bladder emptying primarily due to electrode problems. Further studies with improved electrode material and placement are required before clinical application of the electrically stimulated detrusor myoplasty can be assessed.

Animals↗
PubMed1977

The mechanisms of the action of electrical stimulation of muscles.

The mechanisms of the action of electrical stimulation of muscles are discussed. We believe that the principal cause for the good results obtained in cases of stress incontinence with electrical stimulation must be due to the formation of a better reflex in contraction of the muscles of the pelvic floor. This, however, envolves changes at the level of the spinal cord. By the help of stimulation the patient learns to use the urethral sphincter and secondary forces of retention in a better and a more proper way. The good results obtained in the treatment of some cases of nocturnal enuresis by anal plugs require yet another explanation. It can be considered that in nocturnal enuresis the unconscious inhibition of the reflex mechanism for emptying the bladder is not developed enough. From the experience we know that vigorous voluntary activation of the muscles of the pelvic floor inhibits the contraction of the detrusor muscle. In this way it is possible to depress the urging sensation to urinate. In the paper we have tried to demonstrate this mechanism objectively. On the basis of our findings we believe that the good results in treating nocturnal enuresis may be due to this mechanism of stimulation.

Electric Stimulation↗
PubMed1974

The effects of electrical stimulation of VL and sub-VL on muscle tonus.

VL and sub-VL were electrically stimulated at 1-mm intervals and the influence on three muscles (anterior tibial muscle, gastrocnemius muscle and soleus muscle) of the contralateral limb was studied by the method of RE-EMG. The effect of VL and sub-VL stimulation was examined on ether clonus as an indicator of hyperactive muscle, especially for spasticity. The results are summarized as follows: 1. Clonus was apparently suppressed by electrical stimulation in an area (F, 10.0 mm; L, 4.0 mm; D, from +2 to -2; there was especially marked suppression of clonus by stimulation in sub-VL. 2. On electrical stimulation of the lateral third of VL, hypertonicity of anterior tibial muscle (T), hypotonicity of gastrocnemius muscle (G), and also hypotonicity of soleus muscle (S), was observed on stimulation of the middle third, T, G, S, and of the medial third, no effect was observed. 3. Electrical stimulation of the anterior part of VL showed T, G, S, and electrical stimulation of the posterior part of VL showed T, G, S.

Animals↗
PubMed2003

[Effect of electric stimulation on denervated skeletal muscle atrophy].

OBJECTIVE: To study the influence of the electric stimulation of denervated muscle atrophy. METHODS: Sixteen SD rats were made the model of denervated skeletal muscle in two lower limbs by cutting off the sciatic nerve and femoral nerve. The right gastrocnemius muscle was stimulated with JNR-II nerve & muscle recovery instrument by skin as the experimental side and the left was not treated as the control side. The muscle histology, ultrastructure, fibrillation potential amplitude, Na(+)-K(+)-ATPase and Ca(2+)-ATPase activities were observed 2 weeks and 4 weeks after operation. RESULTS: Electric stimulation could protect mitochondria and sarcoplasmic reticulum from the degeneration. The reduction rates of muscle cell diameter and cross section in the experimental side were slower significantly than those in control side. There was no influence on fibrillation potential amplitude in the both sides after electric stimulation. The reduction rates of Na(+)-K(+)-ATPase activity in the experimental side were slower 15.59% and 27.38% respectively than those in the control side. The reduction rates of Ca(2+)-ATPase activity in the experimental side were slower 4.83% and 21.64% respectively than those in the control side. CONCLUSION: The electric stimulation can protect muscle histology, electrophysiology and enzymic histochemistry of denervated skeletal muscle from the degeneration. The electric stimulation is an effective method to prevent and treat muscle atrophy.

Animals↗
PubMed2004

The effects of different electrical stimulation protocols on nerve regeneration through silicone conduits.

BACKGROUND: The effects of electrical stimulation on the regeneration of transected nerves through silicone rubber conduits may depend on the stimulation protocol. METHODS: Rat sciatic nerve was transected and reconnected using a silicone rubber conduit with a 7-mm gap. The subjects were divided into nine groups. Each group received one protocol of electrical stimulation 30 minutes each day for 3 weeks. The effects of electrical stimulation were evaluated through morphologic methods. RESULTS: Direct current stimulation increased nerve fiber bundle area without significantly affecting the number of myelinated fibers, resulting in decreased nerve fiber density. All the pulse current stimulation protocols as a group decreased the nerve fiber bundle area without affecting the number of myelinated fibers, resulting in increased nerve fiber density. Within the pulse current stimulation protocols, stimulation frequency affected nerve fiber density, whereas current strength did not. CONCLUSIONS: Stimulation protocols had significant influences on the benefit of electrical stimulation in nerve regeneration.

Animals↗
PubMed1999

Electrical stimulation in early stroke rehabilitation of the upper limb with inattention.

Use of electrical stimulation early in stroke rehabilitation may benefit recovery of function. This case report describes the clinical outcomes following electrical stimulation for the supraspinatus of a 25-year-old patient four weeks after a right sided stroke. In this patient, use of electrical stimulation for a total of four hours in 4.5 weeks, appeared to have a number of benefits: subluxation was reduced and patient attention to the arm was increased. There was also a notable improvement in functional use of the arm when task-specific upper limb training was incorporated. Whilst not conclusive, the results of this case study reinforce the value of electrical stimulation in the early management of the upper limb in a stroke patient who clearly demonstrated inattention to his upper limb. The results also highlight the need for well controlled studies to investigate the benefits of electrical stimulation and to establish the optimal timing and parameters for this intervention. Therapists can then more effectively optimise effective upper limb rehabilitation following stroke.

Journal Article↗
PubMedDate not supplied

Therapeutic electrical stimulation for spasticity: quantitative gait analysis.

Improvement in motor function following electrical stimulation is related to strengthening of the stimulated spastic muscle and inhibition of the antagonist. A 26-year-old man with familial spastic paraparesis presented with gait dysfunction and bilateral lower limb spastic muscle tone. Clinically, muscle strength and sensation were normal. He was considered appropriate for a trial of therapeutic electrical stimulation following failed trials of physical therapy and baclofen. No other treatment was used concurrent with the electrical stimulation. Before treatment, quantitative gait analysis revealed 63% of normal velocity and a crouched gait pattern, associated with excessive electromyographic activity in the hamstrings and gastrocnemius muscles. Based on these findings, bilateral stimulation of the quadriceps and anterior compartment musculature was performed two to three times per week for three months. Repeat gait analysis was conducted three weeks after the cessation of stimulation treatment. A 27% increase in velocity was noted associated with an increase in both cadence and right step length. Right hip and bilateral knee stance motion returned to normal (rather than "crouched"). No change in the timing of dynamic electromyographic activity was seen. These findings suggest a role for the use of electrical stimulation for rehabilitation of spasticity. The specific mechanism of this improvement remains uncertain.

Adult↗
PubMed1981

Effect of electrical stimulation on human skeletal muscle.

The acute and adaptive effects of electrical stimulation of the quadriceps muscle were investigated in healthy male volunteers. The acute effects, i.e., depletion of phosphagen and glycogen stores and formation of lactate as well as decreases in certain enzyme activities, were similar to those found earlier for intense muscular exercise. Intermittent electrical stimulation for 4 to 5 weeks did not cause any significant changes in enzyme activities, muscle fiber characteristics, or mitochondrial properties. A 4-week period of electrical stimulation resulted in improvements of muscle strength comparable to the results of a corresponding program of voluntary training. However, the effects of electrical stimulation appeared more "position-specific" and less "speed-specific" than those of voluntary training with slow isokinetic contractions.

Adult↗
PubMed1997

Rapid systemic up-regulation of genes after heat-wounding and electrical stimulation.

When one leaf of a tomato plant is electrically-stimulated or heat-wounded, proteinase inhibitor genes are rapidly up-regulated in distant leaves. The identity of the systemic wound signal(s) is not yet known, but major candidates include hormones transmitted via the phloem or the xylem, the electrically-stimulated self-propagating electrical signal in the phloem (the action potential, AP), or the heat-wound-induced surge in hydraulic pressure in the xylem evoking a local change in membrane potential in adjacent living cells (the variation potential, VP). In order to discriminate between these signals we have adopted two approaches. The first approach involves applying stimuli that evoke known signals and determining whether these signals have similar effects on the "model" transcripts for proteinase inhibitors (pin) and calmodulin (cal). Here we show that a heat wound almost invariably evokes a VP, while an electrical stimulation occasionally evokes an AP, and both of these signals induce accumulation of transcripts encoding proteinase inhibitors. The second approach involves identifying the array of genes turned on by heat-wounding. To this end, we have constructed a subtractive library for heat-wounded tissue, isolated over 800 putatively up-regulated clones, and shown that all but two of the fifty that we have analyzed by Northern hybridization are, indeed, up-regulated. Here we show the early kinetics of up-regulation of three of these transcripts in the terminal (4th) leaf in response to heat-wounding the 3rd leaf, about 5 cm away. Even though these transcripts show somewhat different time courses of induction, with one peaking at 30 min, another at 15 min, and another at 5 min after flaming of a distant leaf, they all exhibit a similar pattern, i.e., a transient period of transcript accumulation preceding a period of transcript decrease, followed by a second period of transcript accumulation.

Action Potentials↗
PubMed1986

Luteinizing hormone release in the anaesthetised cat following electrical stimulation of limbic structures.

The release of luteinizing hormone (LH) in response to electrical stimulation of limbic centres, namely the medial preoptic region (MPO) medial basal hypothalamus (MBH) and the medial amygdala (AME) has been studied in the anaesthetised gonadectomized cat. Chronically gonadectomized cats were anaesthetised with pentobarbitone or Althesin and paired bipolar stimulating electrodes were aimed at the MPO, AME or MBH. The effect of electrical stimulation of these regions on the secretion of LH was studied by radio-immunoassay of LH in serial blood samples taken before, during and after stimulation. No change in plasma LH in response to electrical stimulation was ever recorded during pentobarbitone anaesthesia. During Althesin anaesthesia stimulation in the MPO more often than not resulted in a peak of LH release during stimulation. A peak release of LH during stimulation was also recorded when electrodes were placed in the arcuate-median eminence region of the MBH. The time-course of these peaks in LH secretion was similar to the time-course of the plasma LH responses recorded following a single intravenous injection of gonadotrophin-releasing hormone (GnRH). In contrast, electrodes placed in AME had no effect on plasma LH during electrical stimulation, but immediately after stopping it, a small LH peak was recorded. The time-course of these responses suggests a pulse release of GnRH, the rapid response to MPO and MBH stimulation possibly being the result of a direct action on GnRH neurons while the delayed AME response may be produced by AME projections to the GnRH release system. These responses could be likened to the surge of LH which in the cat occurs post-coitus.

Amygdala↗