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PubMed1983

[Transcutaneous electrical stimulation for the control of frequency and urge incontinence].

To control frequency, urgency and urge incontinence, transcutaneous electrical stimulation was applied to the tibial nerve, the pudendal nerve or the anal sphincter in 79 patients. All patients were refractory to any medications for the control of frequency, nocturia, urgency and urge incontinence from a variety of causes including disk protrusion, Parkinson's disease and idiopathic conditions. The parameters of stimulation were 0.1 to 0.5 msec. duration for each stimulus, frequency 10 to 40 Hz, amplitude 5 to 500 voltage. Cystometrography was repeated during and after electrical stimulation and showed increased bladder capacity, measured at first and/or at maximum desire to void, increased compliance, decreased bladder pressure and/or disappearance of uninhibited contractions in 79% of the patients examined. At least one of these changes was observed in 64, 72 and 85% of the patients who underwent stimulation of the tibial nerve, the pudendal nerve and the anal sphincter, respectively. In some patients inhibition of bladder contraction persisted for more than 2 or 3 days after stimulation. Electromyographic activity of the pelvic floor muscles increased in all of the patients during the stimulation of the pudendal nerve or the anal sphincter, but did not increase and rather decreased during stimulation of the tibial nerve. Urethral pressure measured during electrical stimulation, did not change in many cases. Clinical success was also obtained in 19 of 22 patients who underwent two electrical stimulation program; one was continuous daily use of a portable stimulator, and the other was periodic anal stimulation once or twice a week.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1975

Responses of primate spinothalamic tract neurons to electrical stimulation of hindlimb peripheral nerves.

The responses of spinothalamic tract neurons were studied by extra- and intracellular recordings from the lumbosacral spinal cord in anesthetized rhesus monkeys (Macaca mulatta). The neurons were identified by antidromic activation from the contralateral diencephalon. They were then classified by the mildest form of mechanical stimulation applied to the ipsilateral hindlimb. The effects of electrical stimulation of the nerve(s) supplying the receptive field were investigated. Graded electrical stimulation revealed that the threshold responses of spinothalamic tract neurons excited by weak mechanical stimuli occurred when the largest afferent fibers were activated. On the other hand, neurons that required intense mechanical stimulation for their excitation tended to have higher thresholds to electrical stimulation. Some spinothalamic tract cells were shown to receive monosynaptic excitatory connections from peripheral nerve fibers, although polysynaptic connections may generally be more important. An input from unmyelinated afferent fibers was demonstrated. It is concluded the primate spinothalamic tract neurons receive a rich convergent input from a variety of cutaneous receptors. The experiments provide some evidence for the most likely types of receptors.

Animals↗
PubMed1991

Protective effect of electrical stimulation in the deafened guinea pig cochlea.

The effect of chronic intrascalar electrical stimulation on the spiral ganglion cell survival of the ototoxically deafened guinea pig was investigated. Immediately after ototoxic drug administration, unilateral sinusoidal (1 kHz) charge-balanced electrical stimulation on a 50% duty cycle was administered for 2 hours per day, 5 days per week, at intensities from 0 (control) to 400 microAmp via an implanted scala tympani electrode. The relationship of electrically evoked middle latency response (EMLR) to stimulation protocol and cell survival was studied. At 9 weeks post-drug treatment, the animals were killed and temporal bones were prepared for morphometric analysis of spiral ganglion cell density. The subjects showed essentially complete elimination of outer hair sensory cells, with minimal remaining inner hair cells confined to apical turns. Variable loss of spiral ganglion cell populations was observed, which related to electrical stimulation. In animals that received daily unilaterally electrical stimulation, statistically significant increases in survival of spiral ganglion cells were observed in the stimulated ear, compared to the nonstimulated ear-particularly in basal cochlear regions near the electrode. Spiral ganglion cell density was a function of stimulation current intensity level. Moreover, the slope of the amplitude input/output (I/O) function of the EMLR was found to be dependent on stimulating current level. The effect of stimulation on induced survival may be dependent on a number of mechanisms, including metabolic effects of direct activation of "deafferented" spiral ganglion cells. These data support the suggestion that implantation may provide optimal benefits when performed shortly after deafness.

Animals↗
PubMed2000

Differential ICP responses elicited by electrical stimulation of medial preoptic area.

Recent findings indicate a complex role for the medial preoptic area (MPOA) in modulating penile erection. To further investigate this important area we measured changes in intracavernous pressure (ICP) elicited by electrical stimulation of the MPOA and evaluated the contribution of the cavernous nerve to the ICP responses after bilateral transection of the cavernous nerve (CN). In all experiments electrical stimulation was performed unilaterally in anesthetized male rats. Two distinct patterns of ICP response were seen after electrical stimulation of the MPOA: 1) increases in ICP during electrical stimulation (pattern 1, n = 10 rats) and 2) increases in ICP after electrical stimulation was terminated (pattern 2, n = 10 rats). For pattern 1, increases in ICP during stimulation exhibited a stable plateau without contraction of striated penile muscles, and bilateral transection of the CN eliminated the ICP responses. For pattern 2, increases in ICP observed after stimulation were lower, more variable, and accompanied by significant amplitude variations ("peaks"), caused by contraction of striated penile muscles. Bilateral transection of the CN eliminated the pattern 2 ICP response but did not alter striated muscle contraction. Histological studies documented that pattern 1 and pattern 2 responses occurred via electrical stimulation of the anterior and posterior areas of the MPOA, respectively. Thus both responses appear to result from activation of the CN, but the pattern 2 response apparently involves contraction of the striated penile muscles as well.

Animals↗
PubMed1996

The inferior collicular potential in acoustic and electrical stimulation of the cochlea: an experimental study of guinea pig.

We made experiments of the inferior collicular potentials in acoustic and electrical stimulation for the purpose of studying fundamental issues for cochlear implantation. Guinea pigs with normal Preyer's reflex were used for this study. The results were as follows: (1) in acoustic stimulation relatively wide and large waveforms were gained but in electrical stimulation sharp and narrow ones were gained, (2) in acoustic stimulation the input-output curve of latency and amplitude was biphasic but in electrical stimulation it was monophasic. For this reason, in acoustic stimulation by click, when the intensity is low (under 80 dB SPL) stimulus site would be comparatively low frequency fibers. When the intensity is high (over 80 dB SPL) the stimulus site would shift to high frequency fibers. Therefore, many more neighboring fibers start responding. This results in biphasic input-output curves of latecy and amplitude. By electrical stimulation, however, it would be possible to stimulate only a restricted area among the bipolar electrode. Therefore, as the intensity increases, the response amplitude increases and becomes saturated at a constant level. This results in monophasic input-output curves of latency and amplitude.

Acoustic Stimulation↗
PubMed1987

Prolactin release following electrical stimulation of the brain in female turkeys (Meleagris gallopavo).

Different regions of the hypothalamus were electrically stimulated in anesthetized adult female turkeys. Plasma levels of prolactin (Prl) were measured before (-20, 0 min), during (5, 10, 20, 30 min), and after (5, 15, 30, 60, 90 min) a 30-min period of electrical stimulation. In turkeys with electrode placements in the regions of the preoptic-anterior hypothalamus, ventromedial hypothalamus, inferior hypothalamus, and the median eminence, the onset of stimulation increased plasma Prl within 5 min (P less than 0.05) and the maximum level was reached by the end of the 30-min stimulation period. The termination of hypothalamic stimulation was followed by decreased plasma Prl to prestimulation levels. In a subsequent study plasma Prl was measured in hens at different stages of the reproductive cycle, following electrical stimulation in the ventromedial hypothalamus. Ventromedial stimulation induced increases in plasma Prl in laying, photorefractory, and incubating turkeys; however, the relative change in the maximal Prl level was greater in incubating (21-fold) than in either laying (3.5-fold) or photorefractory (5-fold) turkeys. We conclude that Prl release in the female turkey can be affected by electrical stimulation of selected hypothalamic areas and that stimulation-induced Prl release in the ventromedial hypothalamus is enhanced in incubating turkeys.

Animals↗
PubMedDate not supplied

Contralaterally elicited electrical stimulation of paralyzed facial muscles.

Functional electrical stimulation is being explored in the extremities. A major obstacle is found in programming the firing sequence. In 1976, David Zealear proposed using the activity on the normal side in axial muscle pairs that normally function symmetrically to act as a template to control the stimulator. This method was demonstrated in laryngeal muscles in dogs, and is now demonstrated in the face with future applications being proposed. The facial nerve on one side was sectioned in a series of rabbits. Implanted electrodes received electrical potentials from selected muscles on the normal side. Bursts of electrical activity on the normal side during a blink or a twitch were used to trigger a muscle stimulator, which was routed to matching muscles on the paralyzed side. This technique restored symmetric function to the hemiparalyzed side. This technique restored symmetric function to the hemiparalyzed face.

Animals↗
PubMed1991

Treatment of open-skin wounds with electric stimulation.

A randomized double blind multi-center study of electric stimulation compared with sham units enrolled 59 patients (67 wounds) with open wounds of pressure, vascular and surgical etiology at nine sites. The 14-week study consisted of a four-week phase, randomized, parallel-group, double blind, sham stimulation controlled group comparing effectiveness and tolerance of electric and sham stimulation of open wounds. Patients with wounds not completely closed at the end of the four weeks were allowed to cross over to actual treatment. After four weeks of treatment, the electric stimulation group showed a 56% decrease in size with only a 33% decrease in size with sham treatment. Available data suggest that pulsed electric stimulation should be considered by health care practitioners as an adjunct for treating open wounds.

Double-Blind Method↗
PubMed1987

Transcutaneous electrical stimulation of the normal rabbit joint.

To determine the effect of transcutaneous electrical stimulation on the rabbit joint, we studied skin and intraarticular temperatures and pressure both before and following the stimulation in nine rabbits. An elevation in skin temperature by a mean of 0.6 degrees C (p less than 0.05) and increase in intraarticular temperature by a mean of 0.8 degrees C (p less than 0.01) was noted following the electrical stimulation. Intraarticular pressure in the stimulated joints has only a trend to increase, but not significantly. In four other rabbits, synovial tissue of the stimulated joint showed blood vessels congestion and interstitial edema. These results suggest that the analgetic effect produced by electrical stimulation on joints may partially involve intraarticular temperature and pressure alterations.

Animals↗
PubMed1989

Elevation of pineal melatonin secretion by electrical stimulation of the cervical sympathetic trunk in rabbits.

The influence of electrical stimulation of the unilateral sympathetic trunk on the release patterns of plasma melatonin in the confluens sinuum of anesthetized rabbits was studied. Plasma melatonin exhibited an episodic release pattern, with pulses superimposed on a basal level. The mean concentration, mean maximum and minimum levels of plasma melatonin in the confluens sinuum were found to be significantly elevated when the sympathetic trunk was electrically stimulated. The frequency of pulse peaks of plasma melatonin sampled at 4-min intervals was not affected by electrical stimulation. Our results suggest that the diurnal rhythmic secretory pattern of pineal melatonin into the confluens sinuum of rabbits is regulated by the cervical sympathetic system.

Animals↗
PubMed1985

Plasma growth hormone responses to microinfusion of noradrenergic agents into or electrical stimulation of the hypothalamus and amygdala in baboons.

In nine baboons (Papio papio) guide cannulae and electrodes were stereotaxically implanted into the medial basal or lateral hypothalamus, the anterior hypothalamus or the dorsal amygdala. Plasma GH responses were measured after microinfusion (1 microliter) of the alpha2 adrenergic agonist, clonidine, or the beta adrenergic antagonist, propranolol, or electrical stimulation, in each of these sites. Clonidine, 100 nmol/microliter, infused into the medial basal or lateral hypothalamus elevated plasma GH levels by 5-30 ng/ml, 30-45 min post-infusion. Plasma GH responses to clonidine infused into the anterior hypothalamus or the dorsal amygdala were all less than 10 ng/ml. The prior, intravenous, administration of piperoxane, 1.0 mg/kg prevented GH responses to clonidine. Propranolol, 50 nmol/microliter, infused into the dorsal amygdala consistently increased plasma GH levels by 5-15 ng/ml. Electrical stimulation of the medial basal or lateral hypothalamus elevated plasma GH levels by 7-35 ng/ml, 15-45 min post stimulation. Electrical stimulation of anterior hypothalamus or dorsal amygdala did not alter plasma GH levels. The stimulation of alpha 2 adrenergic receptors in the medial basal or lateral hypothalamus of the baboons appears to facilitate GH release.

Amygdala↗
PubMed2002

Denervated muscles in humans: limitations and problems of currently used functional electrical stimulation training protocols.

Prior clinical work showed that electrical stimulation therapy with exponential current is able to slow down atrophy and maintain the muscle during nonpermanent flaccid paralysis. However, exponential currents are not sufficient for long-term therapy of denervated degenerated muscles (DDMs). We initiated a European research project investigating the rehabilitation strategies in humans, but also studying the underlying basic scientific knowledge of muscle regeneration from satellite cells or myoblast activity in animal experiments. In our prior study, we were able to show that high-intensity stimulation of DDMs is possible. At the beginning of training, only single muscle twitches can be elicited by biphasic pulses with durations of 120-150 ms. Later, tetanic contraction of the muscle with special stimulation parameters (pulse duration of 30-50 ms, stimulation frequency of 16-25 Hz, pulse amplitudes of up to 250 mA) can improve the structural and metabolic state of the DDMs. Because there are no nerve endings for conduction of stimuli, large-size, anatomically shaped electrodes are used. This ensures an even contraction of the whole muscle. Contrary to the current clinical knowledge, we were able to stimulate and train denervated muscle 15-20 years after denervation. The estimated amount of muscle fibers that have to be restored is about 2-4 million fibers in each m. quadriceps. To rebuild such a large number of muscle fibers takes up to 3-4 years. Despite constant stimulation parameters and training protocols, there is a high variation in the developed contraction force and fatigue resistance of the muscle during the first years of functional electrical stimulation.

Electric Stimulation Therapy↗
PubMed1997

Threshold-distance measures from electrical stimulation of human brainstem.

Threshold current levels for electrical stimulation of a single human brainstem via an auditory prosthesis are compared with postmortem measures of the distance between the electrode and stimulated structures. The results compare well with the summary of threshold-distance measures from animal experiments compiled by Ranck. The correspondence between the human and animal data gives confidence that the extent of current spread (distance to stimulable neural units) can be well estimated from the current level at threshold for 200 microseconds/phase biphasic pulses. This is of particular interest in electrical stimulation of the human central nervous system, where localization of stimulation is of paramount importance.

Animals↗
PubMed2005

Intravaginal electrical stimulation for the treatment of chronic pelvic pain.

OBJECTIVE: To evaluate the efficacy of intravaginal electrical stimulation in women with chronic pelvic pain (CPP). STUDY DESIGN: Between May 2002 and February 2004, 24 women with CPP with no apparent cause were evaluated. They underwent 10 sessions of intravaginal electrical stimulation. A program for measuring chronic diffuse pain, with a frequency of 8 Hz, variation in intensity and frequency, pulse length of 1 msec, and adjustment to the bearable intensity of each individual patient (in milliamps) was utilized. Treatment consisted of 30-minute applications, 2 or 3 times per week, and the pain was evaluated using a visual analog scale before and after each session and immediately after completion of the total treatment. The women were asked to evaluate the pain 2 weeks, 4 weeks and 7 months following the end of treatment. RESULTS: Intravaginal electrical stimulation was effective in alleviating pain in women with CPP, as evaluated at the end of treatment and 2 weeks, 4 weeks and 7 months after completion of treatment (p<0.05). There were significantly fewer complaints of dyspareunia following treatment (p = 0.0005). CONCLUSION: Intravaginal electrical stimulation is effective in the alleviation of pain in women with CPP.

Adult↗
PubMed1988

[Features of the morphofunctional state of the organs of the thymico-lymphatic system during various adaptive reactions induced by electric stimulation of emotiogenic structures of the brain].

Weak electrical stimulation of emotiogenic brain structures was found to lead to the development of different general non-specific adaptation reactions. Stimulation of nucleus lateralis septi was found to evoke mainly the development of activation reaction, while stimulation of globus pallidum caused primarily the development of training reactions. Stress reactions were considerably less frequent in electrical stimulation of both kinds of structures than in the control. This can be explained by small values of the electrical current applied. Morphofunctional activity of thymus lymphatic system depended not only on the type of non-specific reaction but also on the character of the stimulated emotiogenic structure--the functional activity was higher with the stimulation of nucleus lateralis-septi. However, the functional activity of thymus lymphatic system in rats with globus pallidum stimulation was higher than in control rats that were not subject to any stimulation.

Adaptation, Physiological↗
PubMed1987

The effect of prolonged stress-inducing electrical stimulation on cell proliferation in rat palatal epithelium.

This study examines whether blocking of cell division by stress-inducing electrical stimulation can be maintained for a prolonged period of time and whether this results in the accumulation of a large number of cells ready to divide when the block is released. A total of 96 rats was subjected to electrical stimulation at intervals of 30 min for periods of 2, 4, 6 or 12 hr. Groups of animals were killed every second hour during these stimulation periods. After 2, 4 and 6 hr groups of animals were exempted from further stimulation and killed 2 or 4 hr later. After termination of the 12 hr stimulation period, groups of animals were killed every second hour during the succeeding 24 hr. Forty-eight animals were left undisturbed and served as controls. Two and a half hours prior to death, each of the experimental and control animals was injected intraperitoneally (i.p.) with colchicine. Histological sections of the palatal mucosa were prepared and the numbers of arrested metaphases were counted. The electrical stimulation for 2, 4, 6 and 12 hr consistently resulted in a reduced number of cells entering mitosis, indicating a blockade at the G2/M transition. However, with an increase in the length of electrical stimulation, an increasing number of cells passed the block, while a decreasing number entered mitosis during the first 4 hr following cessation of the stimulation. The sum of metaphases accumulated during the various stress periods and the following 4 hr was always similar and consistently lower than the number of metaphases accumulated in the control animals within the same time periods. This observation indicates that, during stress-inducing electrical stimulation and the succeeding 4 hr, only a defined number of cells can enter the mitotic phase. Thus, in addition to the block at the G2/M transition, there appears to be another block of cell division at an earlier stage in the cell cycle.

Animals↗
PubMedDate not supplied

Comparison of isometric muscle training and electrical stimulation supplementing isometric muscle training in the recovery after major knee ligament surgery. A preliminary report.

Eight patients undergoing reconstruction of the anterior cruciate ligament were randomly allocated into two groups. The control group received a standard plaster cast and isometric muscle training. The stimulated group received a standard plaster cast, isometric training, and percutaneous electrical stimulation during the recovery period. The patients were examined clinically and with repeated muscle biopsies before surgery, 1 week after surgery, and 5 weeks after surgery at the time of removal of the cast. The electrically stimulated group had better muscle function from a clinical point of view and their succinate dehydrogenase activities were significantly higher than those in the control group. Electrical stimulation thus could prevent the fall in oxidative enzyme activity which was noted in the control group. The results suggest that percutaneous electrical stimulation may be a way of preventing muscle atrophy after major knee ligament surgery in athletes.

Adult↗