["Stimul-1" apparatus for electric stimulation of the muscles].
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Electric Stimulation Therapy↗
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Research note: Functionality of electrically stimulated broiler breast meat.
Postmortem electrical stimulation (ES) tenderizes meat by acceleration of adenosine triphosphate (ATP) depletion, pH decline, and physical disruption of muscle fibers. It has been demonstrated that rigor development at elevated temperatures, as with slow chilling, can cause meat to develop pale color and poor water-holding capacity. The objective of this study was to compare the functionality of broiler breast meat from control and electrically stimulated carcasses with and without normal rapid chilling. Broilers were either electrically stimulated (450 mA, 450 V, 2 s on, 2 s off for 7 pulses) immediately after bleeding or used as nonstimulated controls. The ES birds were either chilled immediately (ES2) or had chilling delayed for 2 h at room temperature (ESD2). All ES breast fillets were harvested at 2 h postmortem. The control carcasses were chilled immediately and had fillets harvested at 2 h postmortem (C2) or at 8 h postmortem (C8). Electrical stimulation accelerated pH decline and prevented toughening when breast meat was deboned at 2 h postmortem, regardless of chilling rate. The water released from the gels during cooking was higher for the ESD2 than the ES2 group, which was not different from the C2 group, suggesting that ES followed by slow chilling reduced water-holding capacity compared with the ES2 and C2 groups. There were no differences in expressible moisture, gel strength, or lightness among the ES2, ESD2, and C2 treatments. These results indicated that high voltage ES followed by normal chilling did not impair protein functionality or cause pale, soft, exudative meat. However, there was some evidence that slow chilling after ES may negatively affect some water-holding properties of the meat.
Adenosine Triphosphate↗
Phagocytic and metabolic reactions to intracerebral electrical stimulation of rat brain.
Electrical stimulation of the brain has been used with a variety of different electrode types and different stimulating intensities. Few studies have explored neural damage resulting from electrical stimulation that may render the experiment unreliable. The present study used conventional intracerebral bipolar metal stimulating electrodes, delivered a range of defined charge levels, and systematically measured "acute" metabolic effects on glucose (2-deoxy[14C]glucose) metabolism as well as "chronic" (96 h poststimulation) neuronal death and phagocytosis at the electrode surfaces. Neither charge density per phase (QD) nor total charge density per phase (TQD) were independent predictors of "safe" or damaging stimulation; however, together they provided ranges of clearly safe or damaging stimulating conditions that lasted 1 to 2 h. The lowest QD (11.11 microC/cm2/ph) was safe even at 9.1 TQD but not when the pulses totaled 9.6 TQD in 4 h. The middle QD (22.22) was safe even at 9.3 TQD but not when the 2-h pulsing totaled 11.0 TQD. The highest QD (44.44) was safe at 0.4 and 0.8 TQD but irreversibly damaging at 1.6 and 9.6 TQD. These comparisons demonstrated conditions suitable for 1 to 2 h of safe stimulation, but did not provide evidence on the cumulative effects of longer periods or higher frequencies.
Animals↗
Treatment of urinary incontinence in men with electrical stimulation: is practice evidence-based?
Electrical stimulation is frequently recommended for the treatment of urinary incontinence in men. However, few randomized, controlled trials allow practitioners to evaluate the evidence base for this practice. The purpose of this article is to determine, based on a review of the literature, whether adequate evidence exists to support the use of electrical stimulation as a treatment of male urinary incontinence. Urge, stress, and overflow incontinence are evaluated separately. This review led to 3 conclusions: (1) theoretical and urodynamic evidence exists to support the use of electrical stimulation for urge incontinence, (2) conflicting evidence exists in the use of electrical stimulation for stress urinary incontinence, and (3) treatment of overflow incontinence in men has not been evaluated in a systematic way. For both stress urinary or overflow incontinence, practitioners should consider the existing research before recommending electrical stimulation as a first line of treatment. For urge incontinence, electrical stimulation may be an effective first-line treatment strategy.
Electric Stimulation Therapy↗
Electrical stimulation of small intestinal electrical control activity.
The small intestinal electrical control activity (ECA) was driven by an electrical stimulus and the resultant effects on the frequency and the phase relationships of control waves recorded. The small intestinal ECA can be driven from all sites from which it could be recorded. The mean maximum driven frequency (MDF) was the highest near the pylorus and it decreased distally, but at any given site it was the same before and after dividing the small intestine into small segments. The length of the frequency plateau decreased and phase lag per cm increased with an increase in plateau frequency. The direction of phase lag was orad proximal to a stimulation site and aborad distal to it. Intravenous atropine (up to 100 mug per kg) or reserpinization of dogs before an experiment had no effect on the MDF in the frequency plateau region. The study confirms the validity of an array of bidirectionally coupled relaxation oscillators as a model of small intestinal ECA and shows that the frequency and the phase relationship of small intestinal control waves can be altered by electrical stimulation. The study also points out some differences between the small intestinal and gastric ECA's at the cellular level.
Animals↗
Morphological differentiation of rat pheochromocytoma cells (PC12 cells) by electric stimulation.
The effects of electric stimulation on the morphological differentiation of PC12 cells are described. PC12 cells were stimulated with the 'theta' (4-7 Hz electroencephalogram (EEG) rhythm) pattern-electric stimulation, which was known to elicit stable long-term potentiation (LTP) in the CA1 region of the hippocampus. The stimulation induced the neurite outgrowth of PC12 cells, as well as nerve growth factor (NGF). This result suggests that the electric signal has a differentiating potential equivalent to the receptor-ligand interaction.
Animals↗
Reduction in excitability of the auditory nerve following acute electrical stimulation at high stimulus rates: III. Capacitive versus non-capacitive coupling of the stimulating electrodes.
Safe electrical stimulation of neural tissue is typically achieved using charge-balanced biphasic current pulses, which are designed to minimize the generation of direct current (DC) and the production of harmful electrochemical products. However, due to the kinetics of the charge injection process, neural stimulators must also use capacitive coupling or electrode shorting techniques, to ensure DC levels are minimal. Previous studies have reported a reduction in excitability of the auditory nerve following acute simulation at high rates and intensities. Elevated levels of DC were reported in these studies despite using charge-balanced biphasic pulses and electrode shorting. The present study was designed to investigate the extent to which DC contributed to these stimulus induced reductions in auditory nerve excitability. Adult guinea pigs were bilaterally implanted and unilaterally stimulated for two hours using charge-balanced biphasic current pulses and stimulus rates of 200, 400 or 1000 pulses/s (pps) at a stimulus intensity well above clinical levels (0.34 microC/phase). DC levels were controlled using either electrode shorting, or electrode shorting with capacitive coupling. Electrically evoked auditory brainstem responses (EABRs) were recorded before and periodically following the acute stimulation. It was found that the extent of reduction in the EABR amplitude was a function of stimulus rate. While there was little change in the EABR following stimulation at 200 pps, significant post-stimulus reductions in the EABR amplitude were observed at stimulus rates of 400 and 1000 pps during the three hour post-stimulus monitoring period. Stimulation using capacitively coupled electrodes, which eliminated all DCs, showed reductions in EABR amplitudes similar to those observed following stimulation using electrode shorting alone. While there was no significant difference in the extent of reduction in EABR amplitudes for capacitive coupling versus electrode shorting at stimulus rates of 200 pps (P > 0.05) and 400 pps (P > 0.05), there was a significant difference at 1000 pps (P< 0.001). The present findings indicate that the major component of the stimulus induced reductions observed in auditory nerve excitability appear to be associated with stimulus induced neuronal activity, although elevated levels of DC ( > 2.5 microA) can also contribute to these changes. However, although statistically significant, the effects of DC are very small compared to the effects of high rate, high intensity stimulation per se.
Animals↗
Development of brain stimulation reward in the medial prefrontal cortex: facilitation by prior electrical stimulation of the sulcal prefrontal cortex.
Electrical stimulation of the medial prefrontal cortex (MC) in rats delivered daily for seven days causes a marked improvement in the rate of acquisition of a self-stimulation response. In the present experiment, we looked at whether we could get the same facilitatory effect on self-stimulation of the MC by delivering pre-training stimulation to other points in the brain anatomically related to the MC. Electrical stimulation of the lateral hypothalamus was without effect. However, electrical stimulation of the sulcal prefrontal cortex (SC) either contralateral or ipsilateral to the MC electrode did facilitate acquisition of self-stimulation of the MC. Thus the Sc and MC would appear to be part of the same substrate controlling the development of positive reinforcement in the MC.
Animals↗
Toward the optimal waveform for electrical stimulation of human muscle.
Electrical stimulation of the quadriceps muscle was used to elicit 4-min isometric contractions at 10% of the maximal voluntary contraction (MVC) in four male and three female subjects. The effect of four waveforms, including Russian, interferential, sine, and square, on the mean stimulation current required to achieve the desired contraction force, subjective comfort, and physiological responses was studied. Interferential stimulation, even at full power, could not elicit a sustained contraction at 10% MVC. The contractions elicited by electrical stimulation utilizing the sine waveform required significantly less mean stimulation current to maintain the desired force of contraction with consistently lower verbal rating scale scores and greater increases in oxygen consumption than either the Russian or square waveform stimulations. Russian waveform stimulation produced a significantly greater rise in galvanic skin resistance than the sine or square waveform while the changes in respiratory quotient were similar between waveforms. The data support sine wave stimulation as working the best by producing the desired muscle tension with the least mean stimulation current and therefore, the least tissue trauma while providing the most subjective comfort.
Adult↗
Standing up with denervated muscles in humans using functional electrical stimulation.
The use of electrical stimulation for denervated muscles is still considered to be a controversial issue by many rehabilitation facilities and medical professionals because prior clinical experience has shown that treating denervated muscle tissue using exponential current over a long time period constitutes an impossible task. Despite this fact, we managed to evoke tetanic contractions in denervated muscle using a long duration stimulation with anatomically shaped electrodes and sufficiently high amplitudes. The pulse amplitudes, which were being used for this purpose, exceeded by far the MED-GV and EC regulations (300 mJ/impulse). For this reason, an application has recently been submitted to have the EC regulations changed accordingly. It takes a tetanic contraction to achieve the desired muscle fiber tension, constituting a hypertrophic stimulus. It is also an appropriate means of exercise, which is capable of creating the metabolic and structural conditions needed (e.g, increased mitochondrial volume and capillary density) to obtain satisfactory muscle performance. With patients suffering from a complete spinal cord injury at level D12/L1, having motor and sensory loss in both lower extremities, we were able to train denervated muscle using long-duration stimulation, evoking single muscle contractions at first, soon followed by tetanic contractions against gravity. To increase the efficacy of this functional electrical stimulation (FES) strengthening program, we used ankle weights. With daily FES training over a period of 1-2 years, denervated muscle was exercised until it produced torques between 16 and 38 Nm in the m. quadriceps. With that muscle force, it is possible to stand up from a sitting position in parallel bars. Our results show that denervated muscle in humans is indeed trainable and can perform functional activities with FES. Furthermore, this method of stimulation can assist in decubitus prevention and significantly improve the mobility of paraplegics.
Capillaries↗
Experimental study of denervated rat muscle. Part II: The effects of electrical stimulation on the denervated rat muscles.
Electrical stimulation has been widely employed for the treatment of peripheral nerve lesion, however, its effects are not well known. Effects of electrical stimulation on denervated muscles were studied by measuring the weight of anterior crural muscles and the diameter of muscle fibers of the extensor digitorum longus muscle of the rat. The muscle fibers were classified by myofibrillar ATPase reaction. The denervated muscle showed loss of weight, a marked decrease in diameter of type 1 fibers and a small increase in diameter of type 2 fibers. Electrical stimulation suppressed weight loss of the denervated muscles. Electrical stimulation with high frequency cycle, like phasic motoneuron discharges, significantly suppressed the increase in diameter of type 2 muscle fibers. Electrical stimulation with low frequency cycle, like tonic motoneuron discharge, significantly suppressed the decrease in diameter of type 1 muscle fibers.
Adenosine Triphosphatases↗
Electrical stimulation restores the specificity of sensory axon regeneration.
Electrical stimulation at the time of nerve repair promotes motoneurons to reinnervate appropriate pathways leading to muscle and stimulates sensory neurons to regenerate. The present experiments examine the effects of electrical stimulation on the specificity of sensory axon regeneration. The unoperated rat femoral cutaneous branch is served by 2-3 times more DRG neurons than is the muscle branch. After transection and repair of the femoral trunk, equal numbers of DRG neurons project to both branches. However, 1 h of electrical stimulation restores the normal proportion of DRG neurons reinnervating skin and muscle. To ask if the redistribution of stimulated neurons results from enhanced specificity of target reinnervation, we developed a new technique of sequential double labeling. DRG neurons projecting to the femoral muscle branch were prelabeled with Fluoro Gold 2 weeks before the nerve was transected proximally and repaired with or without 1 h of 20-Hz electrical stimulation. Three weeks after repair, the muscle nerve was labeled a second time with Fluororuby. The percentage of regenerating neurons that both originally served muscle and returned to muscle after nerve repair increased from 40% without stimulation to 75% with stimulation. Electrical stimulation thus dramatically alters the distribution of regenerating sensory axons, replacing normally random behavior with selective reinnervation of tissue-specific targets. If the enhanced regeneration specificity resulting from electrical stimulation is found to improve function in a large animal model, this convenient and safe technique may be a useful adjunct to clinical nerve repair.
Animals↗
Burns in functional electric stimulation: two case reports.
Electric stimulation of nerve and muscle is a widely used procedure for diagnosis and therapy in spinal cord injured patients. Damage from such stimulation can occur in the form of tissue burns. Two cases of burns in spinal cord patients receiving functional electric stimulation are presented. It is concluded that to avoid burning of tissue: a stimulating electrode with a large surface should be used; uniform contact between the electrode and the skin should be insured; a good conducting-material interface between the electrode and skin is required; adequate ventilation for heat dissipation should be provided; sharply cut electrode corners, wire insulation damage, and cuts in lead wires must be avoided.
Adult↗
Gastric electrical stimulation for gastroparesis improves nutritional parameters at short, intermediate, and long-term follow-up.
BACKGROUND: Nutritional depletion, either macronutrient- or micronutrient-related, is common in patients with drug-refractory gastroparesis (GP) for which there is often no effective treatment. We studied a group of 12 patients (4 men, 8 women; mean age, 35.7 years) who had symptoms of GP and were a subset of the Gastric ElectroMechanical Stimulation trial of gastric electrical stimulation. Patients' symptoms were of long duration (7.3 years) and associated with diabetes mellitus (3 patients) or were idiopathic (9 patients) as etiology. METHODS: The patients had permanent gastric electrical stimulation devices surgically implanted after a positive trial of temporary stimulation. Patients had baseline measures of gastrointestinal total symptom score (TSS), laboratory (albumin and related) measures, weight (kg), body mass index, and route of nutrition: oral feeding, enteral tubes, or hyperalimentation, repeated at 3, 6, and 12 months. Intermediate-term follow-up was done at 1 to 2 years, and long-term follow-up was done at 5 years and included gastrointestinal TSS, weekly vomiting frequency score, and nutrition and overall health-related quality-of-life measures. RESULTS: Gastric electrical stimulation was associated with rapid improvement over the short-term in TSS (35.6 at baseline to 16.6 at month 12; p < .05), body weight, body mass index, and serum albumin over the short term with most parameters improving by 3 to 6 months. Intermediate (1 to 2 years) and long-term (5 year) data showed continued improvement in TSS, vomiting frequency (weekly vomiting frequency score 3.9 at baseline to 1.7 at 5 years; p < .01), quality-of-life measures, and maintenance of weight gain. CONCLUSIONS: Gastric electrical stimulation implantation resulted in improvement of nutritional parameters throughout the first 12 months, as nausea and vomiting decreased and oral intake increased. This improvement in nutritional measures is maintained long-term and is associated with improvements in quality of life. Gastric electrical stimulation should be considered as a therapeutic option for any patients with refractory GP and nutritional compromise.
Adult↗
Randomized, controlled trial of anal electrical stimulation for fecal incontinence.
PURPOSE: Anal electric stimulation has been described as effective for fecal incontinence in several case series, but no study has addressed possible mechanism of benefit. We wished to examine whether anal electric stimulation, using an anal probe electrode, used on a daily basis at home for eight weeks, in the absence of any adjunctive exercises or advice, would improve symptoms of fecal incontinence and anal sphincter pressures when compared with "sham" electric stimulation. METHODS: Ninety patients (9 males, 81 females), with median age of 55 (range, 30-77) years were randomized, 47 to active anal stimulation at 35 Hz and 43 to "sham" stimulation at 1 Hz. Outcome measures included a one-week bowel diary, symptom questionnaire, manometry, and patients' evaluation of outcome. RESULTS: Seventy patients completed the study. On an intention-to-treat analysis, there was no difference between the two groups on any of the outcome measures after eight weeks. Of those who completed stimulation, 44 (63 percent) felt the stimulation had improved their continence. Those with intact anal sphincters were not likely to rate their change more positively than those with sphincter disruption (P=0.71). Median patient rating of bowel control increased from 3 of 10 before stimulation to 5 of 10 after stimulation (P=0.001). CONCLUSIONS: Eight weeks of anal electric stimulation was rated by patients as having improved their bowel control to a modest extent. There was no statistically significant difference detected between the groups, suggesting that 1 Hz was as effective as 35 Hz. This raises the possibility that the main effect is not sphincter contraction but sensitization of the patient to the anal area, or simply the effect of intervening per se. Home electric stimulation is a relatively cheap and generally well-tolerated therapy in the conservative treatment of fecal incontinence.
Adult↗
Relief of pain by subcutaneous electrical stimulation after ocular surgery.
Electrical stimulation in the treatment of postoperative ophthalmologic pain was applied in 25 patients. In 21, stimulation was applied by means of subcutaneously implanted wires and in four patients the therapy was administered by externally placed electrodes. The subcutaneous electrodes were introduced near the supraorbital and infraorbital nerves at the end of the surgical procedures, and stimulation was immediately begun. Duration of treatment varied between one and three days. The nerve stimulator is a portable, battery-operated apparatus. The implanted electrodes avoid skin resistance and are extremely stable, thus affording uniform current intensity that does not change during sudden movements. As a result, the stimuli are perceived as a pleasant sensation. Complete pain relief was attained in nine patients, and in 13 patients the pain was diminished. The therapy is appropriate and effective in postoperative ocular pain, because the pain is restricted to a limited area, innervated by superficial nerves that are easily accessible to electrical stimulation.
Adolescent↗
[Dependence of nutritive value of canned meat on the thermal of the raw materials and electric stimulation].
Research of influence electric stimulation and different thermal condition of raw material on meat protein breaking down by proteinases of gastrointestinal tract (pepsin, trypsin and chymotrypsin) was carried out. It was shown that electric stimulation increased the rate of meat protein proteolysis significantly, i.e. from the point of view of breaking down of meat protein by enzymes it gave effect, similar meat ripening in the cool condition.
Chymotrypsin↗
Intracellular calcium deposition in brain following electrical stimulation.
The effects of electrical stimulation of the cat cerebral cortex have been evaluated by light and electron microscopy following a wide variety of stimulation parameters (QD/ph of 10 - 300 muC/cm2/ph). Platinum or rhodium disc electrode arrays were bilaterally implanted subdurally on the parietal cortex and subjected to 36-hour stimulations (9 hrs./day for 4 days). Prominent among the degenerative changes shown by electron microscopy were dense crystalline inclusions that were identified as calcium hydroxyapatite (CHA) crystals by electron diffraction and energy dispersive X-ray analysis. The appearance of intracellular calcification generally paralleled the onset of other degenerative changes in stimulated tissue, including gliosis, mitochondrial swelling, lipid inclusions, degenerating cells, neuronal loss, and phagocytic activity. A preferential deposition of calcium was noted in mitochondria of several cell types and in postsynaptic dendrites. The mechanism of the apparently electroresponsive calcium deposition is obscure; however, a plausible explanation is that increased cyclic AMP levels, known to occur with electrical stimulation of nervous tissue, result in enhanced calcium plasmalemmal permeability.
Animals↗