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PubMedDate not supplied

Laparoscopy shortens length of stay in patients with gastric electrical stimulators.

BACKGROUND: Gastric electrical stimulation has been proven effective for drug-refractory gastroparesis. Placement of stimulator leads and device usually requires a laparotomy, although laparoscopic placement has also been used. METHODS: To compare laparotomy with laparoscopy, we examined 36 patients, 18 undergoing laparoscopy and 18 undergoing laparotomy, matched for primary diagnosis and health resource usage. We compared baseline symptoms, length of surgery, length of postoperative hospital stay, gastric emptying, and health resources in each of the 2 groups over time, to see what variables, if any, differed. RESULTS: Baseline symptoms, gastric emptying, and health resource usage were similar. Operative times were also similar, but length of stay declined from a mean of 6.4 days for laparotomy to 1.1 days for laparoscopy. Long-term outcome, via symptoms, gastric emptying, and health resource utilization were comparable between the 2 groups. CONCLUSION: Laparoscopic placement of gastric electrical stimulator leads and device is associated with shorter lengths of postoperative hospital stay. However, the patients who underwent laparotomy had higher vomiting scores and more previous abdominal surgeries at baseline, and higher long-term mortality at follow-up, suggesting that they may be more ill, as a group, than the laparoscopic patients. Laparoscopic placement of devices may be preferable when technically feasible.

Adult↗

PubMed1998

Electrical stimulation for stress incontinence.

Electrical stimulation has been reported to be effective for stress incontinence, cure and improvement rates being reported to range from 30% to 50%, and from 6% to 90%, respectively. However, clinical application of this treatment is not common because there is little physiological and technical information. Electrodes for electrical stimulation are divided into two types: external (non-implantable) and internal (implantable), and there are two methods of stimulation: chronic (long-term, continuous) and short-term. Frequencies of 20-50 Hz, with a pulse duration of 1-5 ms, have been reported to be effective for urethral closure. The effectiveness of the treatment should be verified with placebo-controlled double-blinded trials, and four such studies using an active and a sham device have been reported. Two of these verified the superiority of the active device over the sham device, but the others did not demonstrate any significant difference between the two with regard to efficacy. Electrical stimulation has been reported to result in a long-term continuation of therapeutic effect. The effect has been explained as a re-education or a reactivation of lost functions of the pelvic floor muscles. As to adverse effects, there may be some complications in relation to anesthesia or surgical procedures, such as infection, pain and bleeding with implantable electrodes. The incidence of adverse effects in short-term electrical stimulation is less than 14%. In conclusion, short-term electrical stimulation using non-implantable anal or vaginal electrodes is the most recommendable because of safety and ease of use.

Electric Stimulation Therapy↗

PubMed1994

Stimulation of residual hearing in the cat by pulsatile electrical stimulation of the cochlea.

Electrical stimulation of the cochlea may excite residual inner hair cells, either by direct electrical stimulation or through a mechanical event. Hair cell mediated responses of the auditory nerve to electrical stimulation were estimated from forward masking of the compound action potential evoked by an acoustic probe. Masking by a fixed electrical masker peaked for probes equal in frequency to the pulse repetition rate and its second harmonic, suggesting a spatially tuned profile of excitation within the cochlea. Furthermore, the tuning curves for masking of a fixed acoustic probe peaked for masker pulse rates close to the frequency of the probe. A secondary peak of masking was commonly seen for electrical stimulation at one half of the probe frequency, suggesting masking of the probe by the second harmonic of the electrical stimulus. These results suggest that pulsatile stimulation at the base of the cochlea generates a spectrally rich mechanical disturbance in which each component propagates to its place of resonance in the cochlea.

Acoustic Stimulation↗

PubMed1993

Mitogenic activity of rat salivary glands after electrical stimulation of parasympathetic nerves.

Electrical stimulation of the parasympathetic innervation to parotid or submandibular gland for 30 or 60 min resulted in increased [3H]thymidine uptake of both glands when measurements were made 18 h later. With 30 min of stimulation, the mean increase in parotid was 30% compared with unstimulated mates, and after 60 min of stimulation, the increase was 76%. Stimulation for 30 min with the adrenergic antagonists propranolol and phenoxybenzamine present showed an increase in [3H]thymidine of 76%. Stimulation of the chorda tympani for 30 min resulted in a mean increase of 59% in thymidine uptake of the sympathectomized submandibular gland compared with the unstimulated sympathectomized mate. beta-1,4-Galactosyltransferase activity of both stimulated parotid and submandibular glands also showed an increase of 71%. On the basis of the composition of the saliva in the oral cavity, we confirmed the identity of the stimulated nerve to parotid gland as the parasympathetic (auriculotemporal). Na, K, and amylase concentrations resembled closely the composition of saliva obtained directly from the duct with electrical stimulation of the parasympathetic nerve. These data provide the first evidence that electrical stimulation of the parasympathetic nerve to parotid and submandibular glands causes a mitogenic response in each of these organs; the data also provide the first evidence that electrical stimulation of the parasympathetic nerve causes an increase in levels of the enzyme beta-1,4-galactosyltransferase, known to be implicated in hyperplastic responses.

Amylases↗

PubMed1987

Effect of spatial separation of stimulation sites on ventricular refractoriness during programmed electrical stimulation.

To determine if electrical stimulation during the basic ventricular drive train introduces local effects that influence ventricular refractoriness during endocardial stimulation in humans, 10 patients were studied. With a hexapolar catheter with 3 mm interelectrode distances positioned at the right ventricular apex, the ventricular functional and effective refractory periods were determined for unipolar cathodal stimuli of 2 and 5 times diastolic threshold. Stimulation was performed with both the scanning extrastimulus (S2) and basic ventricular drive stimuli (S1) delivered to the same site and to sites separated by 6 mm. The functional refractory period was not changed by delivering the basic drive and extrastimuli to the same as opposed to separate sites (273.5 +/- 16 vs 273.5 +/- 19 msec during stimulation at 2 times threshold and 270 +/- 16 vs 270 +/- 18 msec at 5 times threshold; p = NS). The longest S1-S2 interval at which S2 failed to capture (effective refractory period) was longer by 5.5 +/- 8.2 msec at twice threshold (0.05 less than p less than 0.10) and 5.5 +/- 3.5 msec at 5 times threshold stimulation (p less than 0.01) when the basic drive and extrastimuli were delivered to separate sites. This is consistent with later activation of the extrastimulus sites during the basic drive when the stimulation sites were separate. Thus, with this method of endocardial programmed electrical stimulation, separation of the stimulation sites for the basic drive and extrastimuli does not affect ventricular refractoriness determined by the extrastimulus technique.

Adult↗

PubMed1997

[The possibility of tinnitus suppression by electrical stimulation].

The authors described the treatment of 36 patients with persistent tinnitus. In the past the patients were treated with other methods without positive results. After audiological examinations Promontory Stimulator (Cochlear Co.) for electrical stimulation was used. During the electrical stimulation one electrode was inserted in external auditory meatus and the other on planum mastoideum. Bursts of biphasic pulses of 0.1 ms duration were used during electrical stimulation. Electrical stimulation was applied 10 min. during 10 days. The patients estimated effects of treatment and results are presented in table. The authors obtained satisfactory results in 48% of the patients.

Adolescent↗

PubMed1986

A note on responses of isolated guinea-pig tracheal strip preparation to electrical stimulation.

Authors observed the mechanical response of the tracheal muscle to electrical stimulation using only one transverse strip preparation of isolated guinea-pig trachea, 4-5 mm in width, which included only one tracheal muscle strip. The effects of various pharmacological agents on these responses were also investigated. A biphasic response which is a contractile response followed by a relaxing response usually appeared when the preparation was stimulated with rectangular pulses (50 volt, 0.5 msec) at 40 Hz for a period of 5 sec. A monophasic contractile response also appeared, only rarely but this response was shifted to the biphasic response as the resting tonus level of the preparation gradually increased in the course of the experiment. When the preparation was stimulated electrically at intervals of 15 min, the resting tonus level of the preparation gradually decreased and it subsequently reached a stable state. Then the amplitude of contractile response and depth of relaxing response in the biphasic response evoked by electrical stimulation of constant condition were, respectively, almost constant, whenever the preparation was stimulated at intervals of 15 min. The amplitude of monophasic contractile response which appeared only rarely was relatively constant to every trial of electrical stimulation throughout the experiment. The amplitude of contractile response and depth of relaxing response in the biphasic response were 283 +/- 65 mg (mean +/- SD, n = 10) and 293 +/- 93 mg (mean +/- SD, n = 10), respectively. The monophasic contractile response was abolished by atropine (5 X 10(-7) g/ml) or tetrodotoxin (2 X 10(-7) g/ml). The contractile response in the biphasic response was abolished by atropine (5 X 10(-7) g/ml). In the presence of atropine (5 X 10(-7) g/ml), therefore, only the relaxing response appeared. This relaxing response was respectively reduced by guanethidine (1 X 10(-5) g/ml-1 X 10(-6) g/ml) and propranolol (1 X 10(-5) g/ml-1 X 10(-6) g/ml), but complete inhibition was never seen. These findings suggest that the excitatory innervation is cholinergic and the inhibitory innervation is both adrenergic and non-adrenergic. In addition, from the results of this work it is clear that the preparation used by the authors are good enough to observe the electrical stimulation-induced response of the preparation.

Animals↗

PubMed2001

Capsaicin stimulation of the cochlea and electric stimulation of the trigeminal ganglion mediate vascular permeability in cochlear and vertebro-basilar arteries: a potential cause of inner ear dysfunction in headache.

Trigeminal neurogenic inflammation is one explanation for the development of vascular migraine. The triggers for this inflammation and pain are not well understood, but are probably vasoactive components acting on the blood vessel wall. Migraine-related inner ear symptoms like phonophobia, tinnitus, fluctuation in hearing perception and increased noise sensitivity provide indirect evidence that cochlear blood vessels are also affected by basilar artery migraine. The purpose of this investigation was to determine if a functional connection exists between the cochlea and the basilar artery. Neuronally mediated permeability changes in the cochlea and basilar artery were measured by colloidal silver and Evans Blue extravasation, following orthodromic and antidromic stimulation of the trigeminal ganglion innervating the cochlea. Capsaicin and electrical stimulation induced both dose- and time-dependent plasma extravasation of colloidal silver and Evans Blue from the basilar artery and anterior inferior cerebellar artery. Both orthodromic and antidromic activation of trigeminal sensory fibers also induced cochlear vascular permeability changes and significant quantitative differences between the treated and control groups in spectrophotometric assays. These results characterize a vasoactive connection between the cochlea and vertebro-basilar system through the trigeminal sensory neurons. We propose that vertigo, tinnitus and hearing deficits associated with basilar migraine could arise by excitation of the trigeminal nerve fibers in the cochlea, resulting in local plasma extravasation. In addition, cochlear "dysfunction" may also trigger basilar and cluster headache by afferent input to the trigeminal system.

Animals↗

PubMedDate not supplied

Comparison of the shock artifacts induced by tripolar and bipolar electrical stimulation techniques.

Tripolar and bipolar electrical stimulation procedures were performed on the upper limbs of eight subjects. The mid-forearm was stimulated electrically (tripolar or bipolar) by surface electrodes, and the induced stimulus shock artifacts were recorded simultaneously from the wrist and elbow. During tripolar stimulation, two types of stimulating configurations were utilized: with the center electrode designated as the cathode and the two outermost electrodes connected to a common anode, and vice versa. During bipolar stimulation, the center electrode served as one pole of the stimulator, and one of the two outermost electrodes of the tripolar stimulator was disconnected. The stimulus intensity was kept constant in all stimulating procedures. Artifacts were reduced significantly during tripolar compared to bipolar stimulation, if the outermost electrodes of the tripolar stimulator (which were facing the recording electrodes) were also oriented toward the recording sites during bipolar stimulation and had the same stimulus polarity. Artifacts were slightly reduced in amplitude from tripolar stimulation, if the center electrode were oriented toward the recording sites during bipolar stimulation and had the same stimulus polarity as previously used during tripolar stimulation.

Adult↗

PubMed2005

Neuroprotective effect of epidural electrical stimulation against ischemic spinal cord injury in rats: electrical preconditioning.

BACKGROUND: Electroconvulsion therapy is likely to serve as an effective preconditioning stimulus for inducing tolerance to ischemic brain injury. The current study examines whether electrical stimuli on the spinal cord is also capable of inducing tolerance to ischemic spinal cord injury by transient aortic occlusion. METHODS: Spinal cord ischemia was induced by occlusion of the descending thoracic aorta in combination with maintaining systemic hypotension (40 mmHg) during the procedure. Animals implanted with epidural electrodes were divided into four groups according to electrical stimulation and sham. Two groups consisted of rapid preconditioning (RE group, n = 8) and sham procedure (RC group, n = 8) 30 min before 9 min of spinal cord ischemia. In the two groups that underwent delayed preconditioning, rats were exposed to 9 min of aortic occlusion 24 h after either pretreatment with epidural electrical stimulation (DE group, n = 8) or sham (DC group, n = 8). In addition, rats were exposed to 6-11 min of spinal cord ischemia at 30 min or 24 h after epidural electrical stimulation or sham stimulation. The group P50 represents the duration of spinal cord ischemia associated with 50% probability of resultant paraplegia. RESULTS: Pretreatment with electrical stimulation in the DE group but not the RE group protected the spinal cord against ischemia, and this stimulation prolonged the P50 by approximately 15.0% in the DE group compared with the DC group. CONCLUSIONS: Although the optimal setting for this electrical preconditioning should be determined in future studies, the results suggest that epidural electrical stimulation will be a useful approach to provide spinal protection against ischemia.

Animals↗

PubMed1983

Influence of electrical stimulation and deprivation on the electric organ discharge behaviour and metabolism of neuronal gangliosides of the tapirfish (Gnathonemus petersi, Mormyridae, Teleostei).

The influence of electrical stimulation ("attack"-frequency of 40 Hz, 2 V, 2 days) and of social and electrical deprivation on the metabolism of gangliosides of various brain structures and the electric organ of the weakly electric tapirfish (Gnathonemus petersi, Mormyridae) was investigated. After stimulation the daily average discharges of the electric organ increased from 9.4 to 11.1 Hz, whereas after deprivation they decreased to 7.9 Hz as compared with controls. There were significant and structure specific differences in some ganglioside-fractions (GM1, GD3, GD1a, GD1b and GP1) in concentration and in specific radioactive NeuAc-labelling between stimulated and deprived animals respectively, compared with controls.

Animals↗

PubMed1975

Electrical and mechanical activities of longitudinal muscle contraction elicited by transmural electric stimulation.

Intracellular electrical and mechanical activities were simultaneously recorded from the longitudinal muscle of isolated guinea-pig jejunum when the preparation was stimulated transmurally by square pulses of 1 msec, 10 Hz, 10-40 V. Transmural stimulation of more than 30 V induced co-ordinated peristaltic waves under intraluminal pressure at levels subthreshold for the peristaltic reflex. Transmural stimulation of less than 30 V induced various types of mechanical responses. After termination of stimulation, rebound excitation was observed. Electrical activities of the longitudinal muscle were compared with various mechanical responses. Slow depolarization without spike potential was recorded when the longitudinal muscle contracted without circular muscle contraction. However, spike potential was recorded from the longitudinal muscle when circular muscle contraction was present as a response. Hyperpolarization was observed soon after the beginning of stimulation. This hyperpolarization was persistent to atropine at 10(-6) g/ml. These electrical and mechanical responses to transmural stimulation disappeared when the preparation was treated with tetrodotoxin at 2 X 10(-7) g/ml.

Animals↗

PubMed2000

Microprocessor-controlled movement of solid gastric content using sequential neural electrical stimulation.

BACKGROUND & AIMS: Gastric electrical stimulation has been attempted for years without much success. The aim of this study was to determine if movement of solid gastric content could be achieved using microprocessor-controlled sequential electrical stimulation. METHODS: The study was performed on 9 anesthetized dogs. The dogs underwent laparotomy, pyloroplasty, and implantation of 4-6 sets of bipolar stainless-steel wire electrodes. Each set consisted of 2-6 electrodes (10 x 0.25 mm, 3 cm apart) implanted circumferentially. The stomach was filled with solid food mixed with plastic pellets, and the process of gastric emptying was monitored. Artificial contractions were produced using microprocessor-controlled phase-locked bipolar trains of 50-Hz rectangular voltage with flexible amplitudes. RESULTS: Using the above stimulating parameters, we were able to produce circumferential gastric contractions that were artificially propagated distally by embedding and phase-locking the stimulating voltage. The number of expelled pellets after the stimulation sessions was significantly higher than the number of pellets emptied during the nonstimulation sessions (P < 0.01). CONCLUSIONS: Microprocessor-controlled electrical stimulation produced artificial peristalsis and markedly accelerated the movement of solid gastric content.

Animals↗

PubMed1986

Species variations in the relaxation of tail arteries to electrical stimulation.

Relaxation in response to electrical stimulation has been studied in isolated tail arteries from rats, cats and pigs. Electrical stimulation elicited contractile responses in unstimulated strips, but caused frequency-dependent relaxations in tail arteries from all species studied, following contractile responses by various agents. The order of susceptibility to the relaxant effect of electrical stimulation in arteries from all three species was pig greater than cat greater than rat. Relaxations to electrical stimulation were unaffected by prior treatment of arteries with atropine, propranolol, tetrodotoxin, indomethacin, ouabain, pyrilamine and chemical denervation with 6-hydroxy-dopamine, but were prevented, dose-dependently, by cimetidine and aminophylline (antagonists of histamine H2-receptor and adenosine P1-receptor, respectively). The results suggest that relaxation of tail arteries from the rat, cat and pig in response to electrical stimulation is modulated by histamine and adenosine.

Animals↗

PubMed1992

Opportunities and challenges for the clinical utilization of functional electrical stimulation.

Clinical applications of electrical stimulation for effecting change in the damaged or disabled nervous system are in their infancy. This technique is extremely powerful, because any neural structure that is electrically excitable can potentially be affected. Although early attempts to apply electrical stimulation were limited by insufficient physiological knowledge and undeveloped technology, developments over the past two decades now provide a strong base for clinical applications. Clinical systems for bladder control and respiration have been in use for many years. Some applications of FES to restore hand function and walking are in multicenter testing, whereas many others are being studied for clinical feasibility at single sites. Applications are focusing on safety and efficacy, as well as on clinical outcome measures to address the issues posed by the regulatory and reimbursement processes. As clinical systems become more routine, issues of multiple system applications will need to be addressed. Present and future applications of functional electrical stimulation may be expected to significantly enhance independence and improve the quality of life for individuals with central nervous system dysfunction.

Central Nervous System Diseases↗

PubMed2001

Signal transduction in electrically stimulated bone cells.

BACKGROUND: Electrical stimulation is used to treat nonunions and to augment spinal fusions. We studied the biochemical pathways that are activated in signal transduction when various types of electrical stimulation are applied to bone cells. METHODS: Cultured MC3T3-E1 bone cells were exposed to capacitive coupling, inductive coupling, or combined electromagnetic fields at appropriate field strengths for thirty minutes and for two, six, and twenty-four hours. The DNA content of each dish was determined. Other cultures of MC3T3-E1 bone cells were exposed to capacitive coupling, inductive coupling, or combined electromagnetic fields for two hours in the presence of various inhibitors of signal transduction, with or without electrical stimulation, and the DNA content of each dish was determined. RESULTS: All three signals produced a significant increase in DNA content per dish compared with that in the controls at all time-points (p < 0.05), but only exposure to capacitive coupling resulted in a significant, ever-increasing DNA production at each time-period beyond thirty minutes. The use of specific metabolic inhibitors indicated that, with capacitive coupling, signal transduction was by means of influx of Ca(2+) through voltage-gated calcium channels leading to an increase in cytosolic Ca(2+) (blocked by verapamil), cytoskeletal calmodulin (blocked by W-7), and prostaglandin E2 (blocked by indomethacin). With inductive coupling and combined electromagnetic fields, signal transduction was by means of intracellular release of Ca(2+) leading to an increase in cytosolic Ca(2+) (blocked by TMB-8) and an increase in activated cytoskeletal calmodulin (blocked by W-7). CONCLUSIONS: The initial events in signal transduction were found to be different when capacitive coupling was compared with inductive coupling and with combined electromagnetic fields; the initial event with capacitive coupling is Ca(2+) ion translocation through cell-membrane voltage-gated calcium channels, whereas the initial event with inductive coupling and with combined electromagnetic fields is the release of Ca(2+) from intracellular stores. The final pathway, however, is the same for all three signals-that is, there is an increase in cytosolic Ca(2+) and an increase in activated cytoskeletal calmodulin.

Animals↗

PubMed1990

Foot salvage and improvement of microvascular blood flow as a result of epidural spinal cord electrical stimulation.

Epidural spinal cord electrical stimulation has been suggested as an alternative treatment in patients with limb-threatening ischemia in whom vascular reconstructive surgery is not possible anymore. We studied the effects of epidural spinal cord electrical stimulation on microcirculatory blood flow in 20 patients with ischemic rest pain and ulcers. Angiography showed occluded crural arteries technically unsuitable for reconstructive surgery. Intravital capillary microscopy was used to assess capillary density and diameter and red blood cell velocity before and after a 1-minute period of arterial occlusion. After epidural spinal cord electrical stimulation 18 patients claimed immediate pain relief, which was confirmed by intravital capillary microscopy. Capillary density increased from 10 to 19/mm2 (p less than 0.001), red blood cell velocity increased from 0.088 to 0.496 mm/sec (p less than 0.001), and peak red blood cell velocity after arterial occlusion increased from 0.092 to 0.548 mm/sec (p less than 0.001). Two patients had no immediate pain relief; they did not show improvement of microcirculatory perfusion, and amputation was necessary. During the follow-up period (3 months to 3 years, mean 27 months), six other patients had recurrent ischemic pain, and amputation was necessary. In 12 patients pain relief continued, and ischemic ulcers healed; capillary microscopy confirmed improved microcirculatory blood flow. Microcirculatory parameters were significantly higher in respondents than in nonrespondents (p less than 0.001). Life-table analysis revealed a cumulative foot salvage of 80% and 56% after 1 and 2 years, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMed1993

Degradation of two AChR populations at rat neuromuscular junctions: regulation in vivo by electrical stimulation.

The effect of electrical stimulation on the stability of junctional ACh receptors (AChR) on soleus muscles of Wistar rats was compared to that of denervation and reinnervation. Denervation causes the degradation rate of the slowly degrading AChRs (Rs) at the neuromuscular junction to accelerate and be replaced by rapidly degrading AChRs (Rr), while reinnervation restabilizes the accelerated Rs. Electrical stimulation initiated at the time of denervation prevented the acceleration of the Rs. It could not, however, reverse the effect of denervation if initiated after the AChRs became destabilized, nor could it slow the degradation rate of the Rr. We conclude that electrical stimulation of denervated muscle downregulates the expression of the Rr and prevents the destabilization of Rs.

Animals↗