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PubMed1985

Electrical stimulation of hard and soft tissues in animal models.

Studies in animals have clearly established that various forms of electrical stimulation positively affect the growth, repair, and remodeling of hard and soft tissue. Although the various electrical stimulation modalities (faradic, capacitive, and inductive) are different in their physics and biochemistry, each produces a variety of biological responses in a wide range of animal models. The level of interest in animal studies of electrical stimulation is rising rapidly, and new understanding, in parallel with studies in vitro and in the clinic, will continue to be gained. The future holds the promise of a wide range of hard and soft tissue conditions being routinely treated by electrical stimulation, based in part on progress in studies in animals.

Animals↗

PubMed1990

Effects of long-impulse electrical stimulation on atrophy and fibre type composition of chronically denervated fast rabbit muscle.

The efficacy of electrical stimulation on a chronically denervated muscle depends on stimulus parameters, which have an important influence on the development of atrophy. Stimulus frequency and/or total activity are particularly responsible for the development of some histological, biochemical and contractile features. The present study in 18 rabbits deals with a recently developed electrical stimulus, which had proved effective in maintaining muscle force following denervation. This current has (1) unusual long bidirectional rectangular impulses (20 ms) and (2) a frequency of 25 Hz, which is between the frequencies of fast- and slow-firing motor units. Electrical stimulation began 28 (in one animal 53) days after total motor and sensory denervation of the right hindleg, and was continued until the end of the experiment, up to 205 days. To mimic a therapeutic regimen, which should be agreeable to patients, daily treatment times were kept to a minimum (2 x 6 min), and surface electrodes were used. Morphometric evaluation of the fast flexor digitorum sublimis muscle showed that such electrical stimulation was able to preserve fibre diameter at a level of 72-86% of the initial values for several months, while unstimulated fibres showed the usual atrophy with a decrease of diameters below 40% of normal. The stimulation induced a "hybrid" fibre type with properties of a slow muscle (rich in mitochondria in NADH-dependent tetrazolium reductase staining and electron microscopy) as well as of a fast-twitch muscle (fibre type IIb in myofibrillar ATPase stainings).

Animals↗

PubMed2001

Effects of electrical stimulation of the sciatic nerve on background electromyography and static stretch reflex activity of the trunk muscles in rats: possible implications of neuronal mechanisms in the development of sciatic scoliosis.

STUDY DESIGN: The effects of electrical stimulation of the sciatic nerve on background electromyographic and static stretch reflex activity of the trunk muscles were studied. OBJECTIVES: To verify the hypotheses that sciatic scoliosis is induced reflexively by radiculopathic pain, and that scoliosis might be maintained by prolonged asymmetric alteration of the trunk muscle tonus caused by central sensitization of the spinal neurons that constitute the postural reflex pathways. SUMMARY OF BACKGROUND DATA: Sciatic scoliosis usually occurs with convexity to the side of the herniated disc. The neuronal mechanism of sciatic scoliosis has not been well clarified. Recently, prolonged alteration of motor function in the hindlimbs of animals caused by central sensitization has been reported. METHODS: In spinalized rats (transection of the spinal cord), the sciatic nerve was stimulated electrically as a conditioning stimulus. Muscle stretch elicited by bending of the lumbar spine was applied as a test stimulus. Background and stretch reflex activities of the bilateral oblique abdominal, psoas, and quadratus lumborum muscles were recorded. Rats in which MK-801, an N-methyl-d-aspartate antagonist, was preadministered also were used. RESULTS: The conditioning stimulus enhanced background electromyographic activity in bilateral oblique abdominal, contralateral psoas, and quadratus lumborum muscles. Furthermore, the conditioning stimulus induced prolonged facilitation and depression of stretch reflex activity of the contralateral psoas and quadratus lumborum, and ipsilateral psoas and quadratus lumborum muscles, respectively. Preadministration of MK-801 reduced these excitatory and inhibitory effects. CONCLUSION: It was found that the pattern of electromyographic activity of the trunk muscles evoked by sciatic nerve stimulation coincided with the typical direction of sciatic scoliosis in patients with lumbar disc herniation. It was supposed that the prolonged asymmetric alteration of the trunk muscle tonus was caused by central sensitization, and that central sensitization of spinal neurons may underlie the neuronal mechanism of sciatic scoliosis.

Animals↗

PubMed1986

[Histochemical studies on skeletal muscle atrophy, with reference to the relationship between atrophy and muscle tension, and to the effect of electrical stimulation].

To clarify the significance of muscle tension and the effect of electrical stimulation on the immobilized muscle, two experiments were performed. First, the ankle joint of rat was fixed by a Kirschner-wire in two ways. After fixation at a strained position for one to twelve weeks, wet weight of soleus had decreased less than after fixation at a relaxed position. Histochemical investigation revealed the fiber type transformation of soleus from type 1 to type 2 at relaxed position, which was not observed at a strained position. The result confirmed the importance of muscle tension not only in the nutrition but also in the differentiation of the muscle. Secondly, electrical stimulation was given to the immobilized soleus for two weeks. Under the experimental procedure, the electrical stimulation prevented the transformation of muscle fiber type, but not muscle atrophy. This result suggested that the nutrition and the differentiation of muscle could be regulated independently.

Animals↗

PubMed2002

Electrical stimulation for the treatment of bladder dysfunction: current status and future possibilities.

Electrical stimulation of peripheral nerves can be used to cause muscle contraction, to activate reflexes, and to modulate some functions of the central nervous system (neuromodulation). If applied to the spinal cord or nerves controlling the lower urinary tract, electrical stimulation can produce bladder or sphincter contraction, produce micturition, and can be applied as a medical treatment in cases of incontinence and urinary retention. This article first reviews the history of electrical stimulation applied for treatment of bladder dysfunction and then focuses on the implantable Finetech-Brindley stimulator to produce bladder emptying, and on external and implantable neuromodulation systems for treatment of incontinence. We conclude by summarizing some recent research efforts including: (a) combined sacral posterior and anterior sacral root stimulator implant (SPARSI), (b) selective stimulation of nerve fibers for selective detrusor activation by sacral ventral root stimulation, (c) microstimulation of the spinal cord, and (d) a newly proposed closed-loop bladder neuroprosthesis to treat incontinence caused by bladder overactivity.

Animals↗

PubMed1990

Partial pressure of oxygen in brain and peripheral nerve during damaging electrical stimulation.

The studies were performed to elucidate the mechanism underlying the neural damage which may occur during prolonged electrical stimulation of either brain tissue or peripheral nerve. The partial pressure of oxygen (pO2) was measured in the sciatic nerve and the cerebral cortex of adult cats before and during direct, local electrical stimulation of these neural tissues, using stimulus parameters capable of inducing neural injury. pO2 was monitored by the polarographic method, employing a platinum microelectrode inserted into the tissue adjacent to or beneath the stimulating electrode. In the sciatic nerve there was no marked change in intrafascicular pO2 in three cats upon initiation of the electrical stimulation. In a fourth animal intraneural pO2 increased briefly upon initiation of the stimulation. In no case did the intrafascicular compartment of nerves become significantly hypoxic. In the cerebral cortex, the start of stimulation was accompanied by a significant increase (approximately 12-15 Torr) in intracortical pO2 beneath the stimulating electrode, and pO2 remained at or above the pre-stimulus value for the duration of the stimulation. These results show that extracellular hypoxia is unlikely to be a significant factor in the neural injury induced in brain or peripheral nerve by prolonged electrical stimulation.

Animals↗

PubMed1988

Muscle strengthening through electric stimulation combined with low-resistance weights in patients with neuromuscular disorders.

Ten patients with gradually progressive neuromuscular disorders underwent (1) unilateral electric stimulation of anterior tibialis muscles and (2) unilateral stimulation of quadriceps femoris muscles, in combination with voluntary knee extension against ankle weights. After electric stimulation two hours/day, five days/week for two to 14 months, the mean maximum force (muscle strength) of knee extension increased significantly (p less than 0.005), by 108% +/- 56%. The contralateral nonexercised knee extensors also showed some increase in muscle strength. Electric stimulation of ankle dorsiflexors was ineffective; the maximum force of ankle dorsiflexion increased by only 11% +/- 27% (p greater than 0.3). In general, severely weak muscles (less than 10% normal strength) did not improve with either stimulation program. Electric neuromuscular stimulation combined with low-resistance weights can significantly increase muscle strength in patients with neuromuscular disorders if disease progression is gradual and initial muscle strength is greater than 15% normal.

Adolescent↗

PubMed1999

A controlled prospective outcome study of implantable electrical stimulation with spinal instrumentation in a high-risk spinal fusion population.

STUDY DESIGN: A series of 65 instrumented patients without stimulation were compared with a later series of 65 patients with instrumentation and implantable electrical stimulation. The groups were evaluated for risk factors, age, diagnostic groups, levels fused, and radiographic and clinical success. OBJECTIVES: To test the efficacy of electrical stimulation in instrumented high-risk lumbar fusions. SUMMARY OF BACKGROUND DATA: Spinal instrumentation and implantable electrical stimulation have been shown to improve fusion success rates. METHODS: All patients were instrumented via pedicle screws and autologous bone graft. Diagnostic groups were evaluated, and the risk factors in each group were identified and compared. Postoperation management and follow-up regimen were similar in each group. Radiographs were evaluated via Dawson's criteria and confirmed by an independent radiologist. Clinical success was evaluated via the Modified Smiley-Webster Scale and confirmed by a second orthopedic surgeon. RESULTS: Fusion success was 95.6% in the stimulated group compared with 87% in the nonstimulated group (P = 0.05). Clinical success was 91% in the stimulated group and 79% in the nonstimulated group (P = 0.02). In a workers' compensation subset, fusion success was 93% in the stimulated group and 81% in the nonstimulated group. Clinical success was 57% in the stimulated group and 46% in the nonstimulated group. CONCLUSIONS: The results from using both instrumentation and electrical stimulation in a high-risk pool of patients show a statistically significant difference, with higher rates of fusion and clinical success than in a similar pool that did not receive stimulation.

Bone Screws↗

PubMed1995

The treatment of osteoarthritis of the knee with pulsed electrical stimulation.

OBJECTIVE: The safety and effectiveness of pulsed electrical stimulation was evaluated for the treatment of osteoarthritis (OA) of the knee. METHODS: A multicenter, double blind, randomized, placebo controlled trial that enrolled 78 patients with OA of the knee incorporated 3 primary efficacy variables of patients' pain, patients' function, and physician global evaluation of patients' condition, and 6 secondary variables that included duration of morning stiffness, range of motion, knee tenderness, joint swelling, joint circumference, and walking time. Measurements were recorded at baseline and during the 4 week treatment period. RESULTS: Patients treated with the active devices showed significantly greater improvement than the placebo group for all primary efficacy variables in comparisons of mean change from baseline to the end of treatment (p < 0.05). Improvement of > or = 50% from baseline was demonstrated in at least one primary efficacy variable in 50% of the active device group, in 2 variables in 32%, and in all 3 variables in 24%. In the placebo group improvement of > or = 50% occurred in 36% for one, 6% for 2, and 6% for 3 variables. Mean morning stiffness decreased 20 min in the active device group and increased 2 min in the placebo group (p < 0.05). No statistically significant differences were observed for tenderness, swelling, or walking time. CONCLUSION: The improvements in clinical measures for pain and function found in this study suggest that pulsed electrical stimulation is effective for treating OA of the knee. Studies for longterm effects are warranted.

Adult↗

PubMed1994

Modulation of thresholds to acoustical and electrical stimulation of the intact ear in guinea pig by furosemide and noise.

Middle latency responses (MLR) to acoustical stimulation (AS) and to electrical stimulation (ES) of the intact inner ear were recorded in guinea pigs. ES threshold curve decreased in the frequency range 2-16 kHz with a slope 5.4 dB/octave. Immediately after 50 mg/kg intravenous injection of the furosemide, which resulted in a temporary suppression of the cochlear function, the ES thresholds increased and resembled thresholds found in gentamicin-treated animals. Whereas temporary threshold shift (TTS) at 1 kHz ES was negligible at this time, maximum TTS at 8 kHz and 20 kHz ES was limited to 27 dB and 37 dB resp. TTS to acoustical stimulation was larger than TTS to ES (in some cases exceeded 50 dB) and it was similar at all frequencies. Amplitude-intensity functions (AIF) to high-frequency ES stimuli (20 kHz) consisted of two parts--a flat part at low intensities and a steep part at high intensities of the ES. High-frequency noise exposure (third-octave band noise, centered at 16 kHz, intensity 105 dB for 1 h) reduced or abolished only the flat part of the AIF, the steep part, as well as the responses to low-frequency ES, were not substantially changed. TTS at high frequencies, elicited by the noise exposure, were similar for ES and AS. However, amplitudes of acoustically evoked MLR significantly increased after the noise exposure while MLR amplitudes to ES did not change. The results characterize the frequency-intensity domain of the electrophonic effect in the guinea pig and its changes after influencing the inner ear function by furosemide and noise.

Acoustic Stimulation↗

PubMed1987

Electrical stimulation of the endothelial surface of pressurized cat middle cerebral artery results in TTX-sensitive vasoconstriction.

The purpose of this study was to examine the electrical and mechanical responses of cat middle cerebral arteries to electrical stimulation of the adventitial vs. intimal surface of the vessels and to determine the responses as a function of transmural pressure. Middle cerebral arteries were cannulated at both ends. Within each cannula was a stimulating electrode. Electrical stimulation (0.5-msec square current pulses at 0.5 Hz yielding 160 microA of current between electrodes) resulted in significant reduction in diameter that was greater at both 40 and 80 mm Hg vs. 100 or 140 mm Hg. Conversely, adventitial stimulation of perivascular nerves with transmural platinum stimulating electrodes resulted in significant vasodilation. The constrictor response to intimal stimulation, as well as the dilatory response to adventitial stimulation, was blocked by tetrodotoxin. The constrictor response to luminal stimulation was enhanced by scorpion toxin demonstrating a functional role for tissues containing fast Na+ channels. Perfusion with collagenase to disrupt the endothelium also abolished the constrictor response to luminal stimulation. The divergence of responses between adventitial and luminal surface stimulation may suggest that different cell layers within a blood vessel serve different functions, one to increase resistance and another to decrease resistance. For example, in cat middle cerebral arteries, the adventitial nerves (i.e., via reflexes) may increase flow, while blood-borne substances may mediate release of agents that reduce flow.

Animals↗

PubMed2001

99mTc-sestamibi muscle scintigraphy to assess the response to neuromuscular electrical stimulation of normal quadriceps femoris muscle.

OBJECTIVES: Neuromuscular electrical stimulation (NMES) is widely used for improving muscle strength by simultaneous contraction in the prevention of muscle atrophy. Although there exist many clinical methods for evaluating the therapeutic response of muscles, 99mTc-sestamibi which is a skeletal muscle perfusion and metabolism agent has not previously been used for this purpose. The aim of our work was to ascertain whether 99Tc-sestamibi muscle scintigraphy is useful in the monitoring of therapeutic response to NMES in healthy women. METHODS: The study included 16 women aged between 21 and 45, with a mean age of 32.7 +/- 6.4. Both quadriceps femoris muscles (QFM) of each patient were studied. After randomization to remove the effect of the dominant side, one QFM of each patient was subjected to the NMES procedure for a period of 20 days. NMES was performed with an alternating biphasic rectangular current, from a computed electrical stimulator daily for 23 minutes. After measurement of skinfold thickness over the thigh, pre- and post-NMES girth measurements were assessed in centimeters. Sixty minutes after injections of 555 MBq 99mTc-sestamibi, static images of the thigh were obtained for 5 minutes. The thigh-to-knee uptake ratio was calculated by semiquantitative analysis and normalized to body surface area (NUR = normalized uptake ratio). RESULTS: The difference between the pre and post NMES NUR values was significant (1.76 +/- 0.31 versus 2.25 +/- 0.38, p = 0.0000). The percentage (%) increase in NUR values also well correlated with the % increase in thigh girth measurements (r = 0.89, p = 0.0000). CONCLUSION: These results indicated that 99mTc-sestamibi muscle scintigraphy as a new tool may be useful in evaluating therapeutic response to NMES.

Adult↗

PubMed2000

[The position of submaxillary transcutaneous electrical stimulation for obstructive sleep apnea syndrome].

OBJECTIVE: To investigate the effective position of submaxillary transcutaneous electrical stimulation for obstructive sleep apnea syndrome (OSAS). METHODS: With fixed provocative locus of genioglossus and its controlling nerve, 11 normal healthy men and 9 patients with OSAS during awakening were studied to disclose the effect of submaxillary constant-current stimulation under different stimulative radius or intensity and thickness of submaxillary skin. The effects of electric stimulation in 9 OSAS patients with narrowing of the retrotongue-base-pharynx level were compared with the control during sleep. RESULTS: The submental and internal side of mandibular angle was effective loci for stimulating genioglossus. Stimulative radius and intensity of both loci were not significantly different (P < 0.05) and no influence of the skin thickness was found. During sleep, indices of breath disorder (P < 0.05), oxygen saturation (P < 0.05) and clinical symptoms had significantly improved. CONCLUSION: Submaxillary electrical stimulation with fixed provocative locus is effective for the treatment of OSAS. The mechanism is perhaps stimulation of genioglossus pushes the tongue ahead and opens the pharyngeal cavity.

Adult↗

PubMed1985

[Electric stimulation of the human olfactory nerve--an approach to short-term memory?].

Electrical stimulation of the human olfactory mucosa was performed by means of an electrode, which was attached to a rhinoscope. Stimulations of the nasal mucosa did not evoke the sensation of smell, but suppressed smell sensations of presented odorants. When electrical stimulation followed the exposure to an odorant within a certain interval, the stimulus recalled the faded sensation of the preceding odorant. Electrical stimulation without prior natural stimulation produced unpleasant sensations in three patients with a history of temporal lobe seizures and olfactory auras, but not in patients with primary generalized or focal epilepsy.

Electric Stimulation↗

PubMed2004

Effect of an electric stimulation facilitation program on quadriceps motor unit recruitment after stroke.

OBJECTIVE: To compare maximum voluntary isometric torque (MVIT) and motor unit recruitment of the quadriceps after an electric stimulation facilitation program in persons affected by cerebrovascular accident (CVA). DESIGN: Three-week, randomized controlled trial with an electric stimulation facilitation program added to standard care. SETTING: Inpatient rehabilitation center. PARTICIPANTS: Twenty patients receiving rehabilitation for first-time CVA (51.8+/-15.2 y; days post-CVA, 38.4+/-40.0 d). Patients were randomly assigned to study and control groups. INTERVENTIONS: All patients received standard physical therapy (PT) care. In addition, the study group received an electric stimulation facilitation program during weight-bearing and ambulatory activities of the PT program. MAIN OUTCOME MEASURES: MVIT and motor unit recruitment measured by interpolated twitch testing. A 2 x 4 repeated-measures analysis of variance was performed on measurements at 4 intervals: pretest, 1 week, 2 weeks, and 3 weeks. RESULTS: MVIT increased by 77% in patients receiving electric stimulation, compared with a 31% increase for the control group. There was a significant effect for assessment time only. Motor unit recruitment increased from 35% to 53% for the study group, whereas the control group recorded no change in recruitment ability. A significant interaction was recorded, indicating improved motor unit recruitment for the study group. CONCLUSIONS: A brief and dynamic electric stimulation facilitation program significantly improved motor unit recruitment in persons after CVA.

Adult↗

PubMed1989

ACTH-(1-24) enhances the electrically stimulated release of [3H]dopamine from rat septal slices via a dopamine D2 receptor-independent mechanism.

ACTH-(1-24) enhanced the basal as well as the electrically stimulated release of [3H]dopamine from rat septal slices in vitro. In the absence of Ca2+ from the superfusion medium the effect of ACTH-(1-24) on the electrically stimulated release of [3H]dopamine was abolished. The stimulus-evoked release of [3H]dopamine from septal slices appeared to be modulated through dopamine receptors of the D2 subtype: the dopamine D2 receptor agonists 2-(N-propyl-N-2-thienylethylamino)-5-hydroxytetralin (N-0437) and quinpirole reduced, whereas the dopamine D2 receptor antagonist sulpiride enhanced the electrically stimulated release of [3H]dopamine. The magnitude of the effect of ACTH-(1-24) on [3H]dopamine release was the same in the presence or absence of N-0437, quinpirole and sulpiride. ACTH-(1-24) had no effect on either the basal or the electrically stimulated release of [3H]noradrenaline. Also when the electrically stimulated release of [3H]noradrenaline was reduced by the alpha 2-adrenoceptor agonist clonidine, the peptide was without effect. These results show that ACTH-(1-24) selectively enhances the release of [3H]dopamine from septal slices. The effect of the peptide is independent of the degree of activation of dopamine D2 receptors which modulate the stimulus-evoked release of [3H]dopamine. These results suggest that ACTH-(1-24) enhances the stimulus-evoked release of dopamine in the septum via a mechanism not associated with dopamine D2 autoreceptors.

Adrenocorticotropic Hormone↗

PubMed2003

Activation of activator protein-1 in cells exposed to electrical stimulation of various parameters used in electroacupuncture therapy.

The aim of this study was to investigate the effect of electrical stimulation on activator protein-1 (AP-1) in recombinant liver cells. In order to elucidate the molecular effects of electrical stimulation on cells, AP-1 expression was detected by a luciferase assay. The parameters used were taken from clinical electroacupuncture (EA) therapy as follows: biphasic rectangular symmetrical pulses (frequency: 2, 10 and 100 Hz; pulse width: 50, 80, 130 and 250 microsec; intensity: 1, 2, 5 and 10 mA; time: 5, 10, 20 and 30 minutes). S (10% fetal bovine serum in medium), SF (serum free medium) and 12-O-tetradecanoylphorbol-13-acetate (TPA) treatment represented the experimental, negative and positive groups, respectively. We found that electrical stimulation with 10 Hz, a pulse width of 130 microsec, and a duration of 30 minutes gave a significant increase in AP-1 activity. In contrast, the intensity of the stimulation had no significant effect on AP-1 activity. In conclusion, our data suggest that electrical stimulation with an appropriate frequency, duration and pulse width could cause an increase in AP-1 activity in cells.

Cells, Cultured↗

PubMed1994

Electrical stimulation effect on extensor lag and length of hospital stay after total knee arthroplasty.

The effects of electrical stimulation in conjunction with traditional physical therapy, on knee extensor lag and length of hospital stay among patients recovering from total knee arthroplasty were assessed. Forty patients who underwent total knee replacement (TKR) were randomly assigned to either an electrical stimulation group (16 females, 5 males), or a control group (15 females, 4 males). Both groups received conventional physical therapy including continuous passive motion (CPM) to the affected limb, ambulation training, range of motion exercises, and activities of daily living (ADL) training. The experimental group additionally received electrical stimulation during CPM treatment. Experimental group subjects reduced their extensor lag from 7.5 to 5.7 degrees, whereas control group extensor lag increased from 5.3 to 8.3 degrees. These trends were significantly different (p < .01). Rehabilitation discharge criteria were reached in 6.7 days in the experimental group and 7.4 days in the control group. These differences were also significant (p < .05). The results of this study indicate that the application of electrical stimulation during recovery from TKR can effectively reduce extensor lag and decrease the length of hospital stay.

Activities of Daily Living↗