[Electric ophthalmologic stimulator Fosfen-1]

The paper describes a [sequence: see text] electric eye stimulator which works on the principle of transcutaneous electric stimulation of a peripheral part of the eye analyzer. The device is both diagnostic and therapeutical, exerting a positive therapeutical effect in the treatment of ocular nerve atrophy in patients treated in the ophthalmological, neurological, and neurosurgical units.

Effect of TENS on pain, medications, and pulmonary function following coronary artery bypass graft surgery

The efficacy of transcutaneous electrical nerve stimulation (TENS) as an adjunct to narcotic medications for the management of postoperative pain was assessed in a prospective, randomized, controlled study of patients following coronary artery bypass graft (CABG) surgery with the right or left internal thoracic artery (ITA). Forty-five male patients (mean age, 57 +/- 6 years) were randomly assigned to (1) TENS, (2) placebo TENS, or (3) control treatments (n = 15 each), following extubation and during the 24- to 72-h postoperative period. Two-way analysis of variance tests indicated no significant differences among treatment groups for (1) pain with cough, (2) narcotic medication intake, (3) FVC, (4) FEV1, and (5) PEFR (p > 0.05). However, pain at rest reported by the TENS group was significantly lower than that reported by the control group (treatment main effect; p < 0.04), although no significant differences were observed between the TENS and placebo or between the placebo and control groups (p > 0.05). All six criterion measures were characterized by significant changes over time for the entire group (n = 45; time main effect; p < 0.01), as follows: pain and medication intake were similar on days 1 and 2, but were significantly less on day 3, and pulmonary functions were significantly lower than preoperatively on day 1, decreased further on day 2, and despite an improvement on day 3, remained significantly lower than preoperative values (p < 0.01). This study suggests that the addition of TENS, applied continuously during the immediate postoperative period following CABG with ITA, may not be advantageous in pain management or the prevention of pulmonary dysfunction.

The effect of electronic dental analgesia during sonic scaling

The aim of the present study was to investigate the effects of electronic dental analgesia (EDA) during sonic scaling. The clinical trial included 30 healthy adult subjects and was conducted as a randomised single-blind split-mouth design. The applied procedure consisted of periodontal scaling by means of a sonic scaler, while using the EDA device either in an active or placebo state. Rather similar results were obtained for the subjective pain rating in both the active and the placebo trials. When patients rated their discomfort on a scale 0-4 from no pain to very severe pain, the mean (s.d.) score for both the EDA and the placebo was 1.2 (0.6). The subjective pain estimate was positively correlated to the electrical current intensity provided. This implied that with a stronger pain experience, patients tried to administer more anaesthesia by turning the dial of the control box to an increased intensity of the electrical current. This remained insufficient to eliminate pain sensation. It was concluded that application of electronic dental anaesthesia in periodontal treatment remains questionable.

Augmentation of transfers for a quadriplegic patient using an implanted FNS system. Case report

A 22 year old man with incomplete quadriplegia (C6-7) was unable to perform either a sliding or a pivot transfer. He was instrumented with an implanted functional neuromuscular stimulation (FNS) system, radio frequency-linked to a belt-worn controller. The system activated eight muscles selected from among quadriceps, hamstrings, posterior portion of the adductor magnus, gluteus maximus, and erector spinae, bilaterally. The two-stage implantation procedure included electrode implantation with percutaneous leads followed by stimulator implantation and removal of the percutaneous leads. All implants were well tolerated with no adverse effects. The subject was able independently to put on the external controller portion of the system and to perform a standing pivot transfer with only standby assistance. An unexpected outcome of the FNS system use was increased voluntary upper body strength that resulted in improvement of the sliding transfer from 'inability' to 'independent'.

A nonlinear finite element model of the electrode-electrolyte-skin system

This study presents a two-dimensional finite element model of the electrode-electrolyte-skin system which takes into account the nonlinear behavior of the skin with respect to the amplitude of the voltage. The nonlinear modeling approach has practical value for studies related to transcutaneous stimulation (e.g. maximizing the dynamic range of sensory substitution systems, optimization of TENS, optimization of transcutaneous cardiac pacing, etc.). The model has three main regions: 1) the electrolyte; 2) the skin; and 3) the body. The model consists of 364 nodes, 690 elements and was generated on a MacIntosh II using a version of FEHT (Finite Element for Heat Transfer) adapted for electromagnetics. The electrodes are equipotential lines and the electrolyte is modeled as a pure resistive region with constant conductivity. Although the electrode-electrolyte interface can introduce nonlinearities, we did not take them into account because the skin displays a much higher impedance. The skin is modeled as a nonlinear material with the conductivity dependent on the applied voltage. To account for the mosaic structure of the skin, we used ten different nonlinear subregions of five different values of breakdown voltage. The region designated "body" models the effects of the resistance associated with the dermis and the tissues underneath the skin, and has a constant high conductivity. We studied the effects of two different electrolytes on the comfort of stimulation and found that there was less potential pain delivered when high-resistivity electrolytes were used. This was due to the larger nonuniformities in the current density distribution which appeared for low-resistivity electrolytes.(ABSTRACT TRUNCATED AT 250 WORDS)

[The efficacy of transcutaneous electrostimulation of the visual system in partial optic atrophy]

Effects of transcutaneous electric stimulation of the eyes on vision acuity, visual field, electric sensitivity, electric lability, Hanzfeld ERG and macular ERG were studied in 260 patients with partial atrophy of the optic nerve of various origins and with different degrees of visual function loss. Dispersion analysis of random samples showed that changes in each characteristic after electric stimulation depended on the initial value of this parameter: in general, the more manifest were deviations from the norm, the more marked was the improvement of this or that function. A conclusion is made on physiological nature of electric stimulation method used for the treatment of optic nerve atrophy.

Management of incontinent SCI patients with penile stimulation: preliminary results

We investigated dorsal penile stimulation for control of incontinence in nine spinal cord impaired (SCI) patients, using a battery-powered home-use stimulator connected to surface electrodes (Unipatch). The efficacy of the penile stimulation was assessed by urodynamic evaluation (NL-2, LifeTech) and surface electrodes (Unipatch); baseline and repeat cystometries (CMG) with and without stimulation were done. Stimulation for home use was begun at threshold parameters for inducing perineal contractions and, after two weeks, was adjusted based upon results. Two subjects successfully completed the study and became continent. One of these patient's CMG demonstrated hyperreflexia and his volume increased from 110 ml to 150 ml after the stimulation protocol. The most effective stimulating parameters were 5 pps, 250 microsec, pulse width and 40 ma current. The other patient also had a hyperreflexic bladder and improved on the protocol. The remaining seven patients did not complete the study for several reasons. Three patients had CMG's that demonstrated areflexia. Stimulation did not alter their bladder function and they dropped out of the program. Three other subjects withdrew because of bothersome sensations even at subthreshold levels and they complained that the technique was cumbersome. Finally, one patient with significant hyperreflexia and incontinence withdrew after trying unsuccessfully and diligently for 10 days. Our encouraging results in two patients with hyperreflexic bladders and decreased sensation suggest that this modality may be effective in this patient group.

Transcutaneous electrical nerve stimulation in classic and nonulcer interstitial cystitis

Long-term treatment of interstitial cystitis by transcutaneous electrical stimulation provides a conservative means of bringing the disease to remission. The overall results are better in the classic than in the nonulcer subtype of interstitial cystitis. These findings are considered in relation to the role of neutral factors in the disease.

Computer-controlled portable stimulator for paraplegic patients

A six-channel lightweight, portable and computer-controlled stimulator for the functional activation of paraplegic patients is described. To enable programming of the various functions, the stimulator was designed to work in a remote-control mode hosted by an IBM PC or compatible computer, in addition to its normally used local mode. The stimulus parameters, including current intensity, stimulus frequency and pulse width, are individually adjustable and programmable for each channel. The power source is 12 V 500 m Ah-1, from 10 rechargeable nickel cadmium batteries, with a run time of 1.5 h for a load of 200 mA in four channels. Various training programmes for the activation of paraplegics in the sitting, standing and walking positions are described. The final design of the stimulator is based on experience gained from 25 patients, treated and evaluated during the course of development. Ongoing work including clinical, biomechanical and physiological studies is carried out to evaluate performance of the activated patients and to optimize stimulation.

Acupuncture-like stimulation with codetron for rehabilitation of patients with chronic pain syndrome and osteoarthritis

Acupuncture is one of the oldest healing methods which is used in traditional medicine. In the modern medicine, we are witnessing a renaissance of this ancient treatment applied mainly in the management of chronic pain. A number of modern technological changes are being applied to replace, or modify, the classical needle treatment. Among many modalities used today is the novel addition in Transcutaneous Electrical Nerve Stimulation (TENS) called CODETRON which delivers acupuncture-like stimulation in a random order. CODETRON was developed by a Canadian Scientist and had been evaluated in a clinical trial in a multidisciplinary pain clinic on patients who came for acupuncture therapy over a period of two years. Indications, effectiveness and experiences with this form of treatment are presented. In addition, results obtained from a six week double-blind randomized placebo controlled pilot trial of osteoarthritis of the hip/knee with CODETRON which was conducted later. The results were highly suggestive of the beneficial effect of this nonhabituating mode of therapy and confirmed our initial uncontrolled trial results.

[Efficacy of mini-TENS in the treatment of primary dysmenorrhea]

Recent knowledge on the pathogenetic mechanisms which are thought to be responsible for primary dysmenorrhea in most young females allow us to abandon old therapeutical approaches for several medical solutions with high effectiveness rates. But a number of patients remain for whom these treatments are not suitable or not effective. Mainly for these patients, today we can offer a valid alternative, a new kind of electroanalgesy, TENS, now easier to use owing to the miniaturization of the machine. In fact, in two groups of patients resistant or insensitive to modern medical therapies, we obtained good analgesia during the menstrual period, without important side effects and with high compliance by the patients.

[Transcutaneous electrostimulation of the primary elements of the visual system in children after the extraction of a congenital cataract]

Courses of transcutaneous electrostimulation of the visual analyzer periphery according to E. B. Kompaneets were administered to 31 children (56 eyes) aged 4 to 12 because of low vision acuity after congenital cataract extraction. The amplitude of stimulating pulses was from 150 to 400 microA. The first course consisted of 5-8 sessions, repeated courses of 4 sessions. The results were assessed by vision acuity check-ups and recordings of visual [correction of auditory] evoked potentials (AEP). Vision acuity improved from 0.1 to 0.9 after a course of treatment. AEP amplitude was reduced in all the patients to 15.4 microV on an average, the time of the pulse conduction in the auditory system was normal (113.2 ms). Electrostimulation effects on the AEP were negligible. Electrostimulation may be recommended to children with low vision acuity and low values of the AEP amplitude after congenital cataract extraction.

Closed-loop class E transcutaneous power and data link for microimplants

Magnetic transcutaneous coupling is frequently used for power and data transfer to implanted electronic devices. The proposed development of MicroImplants, small enough to be injected through a hypodermic needle suggest the need for a high-efficiency magnetic transcutaneous link. This paper describes the use of a multifrequency transmitter coil driver based upon the Class E topology. The development of a "high-Q approximation" which simplifies the design procedure is presented. A closed-loop controller to compensate for transmitter and receiver variations, and a method of data modulation, using synchronous frequency shifting are described. The closed-loop Class E circuit shows great promise, especially for circuits with unusually low coefficients of coupling. Currents of several amperes, at radio frequencies, can easily and efficiently be obtained.

[Indirect electric stimulation of the auditory neural structures in the complex treatment of sensorineural hearing loss and subjective noise in the ears]

Indirect or transdermal electrostimulation (ES) was used in 62 patients suffering from neurosensory hypoacusis stage II-III. The procedure was conducted with the help of an +electric stimulator made on the country and a device providing an automatic change of the polarity. Disappearance of noise in the ears, better hearing, 10-15 dB shifts in auditory thresholds were achieved in 20 patients (32.3%). Noise in the ears declined, hearing improved subjectively in 25 (40.3%) of the patients. 17 (27.4%) of the patients did not respond. ES is recommended as a method of choice in combined treatment of neurosensory hypoacusis and subjective noise in the ears.

Epidural spinal electrical stimulation for severe angina: a study of its effects on symptoms, exercise tolerance and degree of ischaemia

The effectiveness of epidural spinal electrical stimulation has been studied in 14 patients with severe intractable angina unresponsive to standard therapies including bypass grafting. After implantation of the neurostimulator units the patients were assessed by a symptom questionnaire, treadmill exercise testing and right atrial pacing. There was a significant improvement of symptoms and GTN consumption fell markedly. With the neurostimulator on, exercise duration increased from a mean (CI) of 414 (153) to 478 (149) s, and total ST segment depression was less both at maximum exercise (7.1 (4.5) vs 5.6 (4.2) mm) and at 90% of the maximum control heart rate (3.5 (3.7) vs 2.6 (4.3) mm), with similar rate-pressure product at maximum exercise. With right atrial pacing the maximum heart rate reached before onset of angina was increased (143 (14) to 150 (7) b.min-1) and total ST segment depression was less at all heart rates. Benefit has persisted in some patients for over 2 years without any apparent adverse sequelae. Epidural spinal electrical stimulation is, therefore, an alternative therapy for some patients with intractable angina which has not responded to standard therapies.

The use of functional electrical stimulation to assist gait in patients with incomplete spinal cord injury

The use of FES (functional electrical stimulation) for gait reproduction in six patients with spinal cord injury is described. Following a detailed neuromuscular assessment the patients commenced a muscle conditioning programme using electrical stimulation applied via surface electrodes. Once patients were strong enough to stand, gait synthesis was initiated in the laboratory utilizing a programmable electrical stimulator. When a satisfactory gait pattern had been achieved, patients used their portable stimulator at home. All six patients became able to stand and walk using the FES system and completed the home phase of the programme. Three patients continue to use the system at home for exercise and walking; the other patients have discontinued using the system, preferring a wheelchair or their original orthoses. We conclude that FES-assisted walking is feasible in patients with incomplete spinal cord injury, even with severe motor loss. Further advances in technology are needed for the system to become applicable to a larger number of patients.

[Comparative evaluation of equipment: the problem of false evidence. Remarks on the paper by P. März: In electric nerve stimulation is it possible to judge the status of the nerve from the intensity of muscle contraction?]

In a recent comparative evaluation of electric nerve stimulators, data were published for the device of a certain manufacturer that disqualified this stimulator for the claimed application. For this reason, an extensive follow-up examination has been executed. The results of this follow-up examination convincingly show that the data of the stimulator are significantly better than published in the comparative study. It was not possible with this follow-up examination, however, to supply an explanation for the totally erroneous results in the first study. If after all any trustworthiness can be given to that comparative study, it can be emphasized that the examined stimulator compares favourably with those devices that had been declared as especially qualified in the comparative study. In this context, the problem is discussed that is related with the potential of influencing and manipulation as part of comparative evaluation studies.

Conductive differences in electrodes used with transcutaneous electrical nerve stimulation devices

The purpose of this study was to document conductive differences among commercially available electrodes used with transcutaneous electrical nerve stimulation (TENS) devices. Impedance within a model system involving a human subject was calculated from oscilloscopic tracings of the pulse waveform for each of 25 different electrode types. Impedance values ranged from 1,000 to 7,800 omega Possible reasons for these differences are discussed. The observation that electrodes vary in their impedance and can thereby affect the stimulus applied to the skin raises the question of whether electrode choice might affect the clinical effectiveness of TENS. Attention is drawn to the skin electrodes as a variable that may affect the results of clinical and basic studies involving TENS.

Factors influencing quadriceps femoris muscle torque using transcutaneous neuromuscular electrical stimulation

Quadriceps femoris muscle torque was measured in 40 subjects during transcutaneous neuromuscular electrical stimulation (NMES). Three different electrode types (carbonized rubber, sponge, and adhesive) were used on each subject, permitting determination of the factors that influenced the magnitude of quadriceps femoris muscle torque induced by NMES. This goal was accomplished by entering the various factors into a multiple-regression model. The electrodes differed significantly in their characteristics. The carbonized-rubber electrode delivered the greatest current with the lowest impedance, resulting in the highest knee extension torque. We found that the most important factor in determining torque generation level was the quadriceps femoris muscle's intrinsic ability to be activated (as opposed to electrode size, current, current density, or skin impedance). These data suggest that NMES efficacy is primarily determined by the intrinsic tissue properties of the individual (defined in this study as "efficiency") and is not dramatically changeable by using high stimulation currents or large electrode sizes. The precise physiological basis for interindividual differences in efficiency is not known.

Popliteal sciatic nerve block aided by a nerve stimulator: a reliable technique for foot and ankle surgery

The reliability of popliteal sciatic nerve blocks was prospectively assessed in 625 blocks performed in 507 patients. The sciatic nerve was approached at the apex of the popliteal fossa, in the midline, with an insulated needle connected to a peripheral nerve stimulator partially designed by one of the authors. When needed, an inguinal paravascular femoral nerve block was also performed. The drugs used were 1% mepivacaine or 0.5% bupivacaine with or without 1:200,000 epinephrine. The sciatic and femoral nerves were blocked with 30 ml and 10 ml of local anesthetic, respectively. The block was sufficient to provide surgical anesthesia in 92%; supplemental analgesia was necessary in 5% and general anesthesia was required in 3% of the cases. Discomfort associated with the block procedure was found to be minimal by 89% of the patients, moderate by 9% and severe by 2%. Overall satisfaction with perioperative analgesia was evaluated by 466 patients: 444 (95%) were completely satisfied, 20 (4%) expressed moderate reservations and two (1%) expressed major reservations. The authors conclude that the technique is a safe and reliable alternative to more common forms of anesthesia for surgery below the knee. They attribute the great success rate to a high popliteal approach, the use of insulated needles, a discriminating mode of nerve stimulation and the systematic search for optimal response to needle stimulation.

[Electric stimulation of the muscles using the CHENS-2M apparatus in spinal osteochondrosis]

The authors of the article established that the application of electrostimulation by means of the apparatus CHENS--2M allows to remove the pain syndrome and to improve the amplitude of motion in the spine. The reovasography examination data confirm the efficiency of the applied treatment. The proposed method of treatment of the spine osteochondrosis should be recommended for practice due to its simplicity and accessibility.

The consistency of pulse frequencies and pulse patterns of transcutaneous electrical nerve stimulation (TENS) used by chronic pain patients

This study records the consistency of transcutaneous electrical nerve stimulation (TENS) pulse frequency and pulse pattern used by 13 chronic patients over a 1 year period. The results show that patients prefer specific pulse frequencies and pulse patterns unique to the individual and that they turn to such frequencies and patterns on subsequent treatment sessions. Pulse frequencies and pulse patterns were not related to the cause and site of pain, a finding consistent with previous study in this laboratory. This observation, coupled with the large variability in pulse frequencies and pulse patterns used between individuals, implies that patients prefer such frequencies and patterns for reasons of comfort which may not be related to mechanisms specific to the pain system.

[Reflex analgesia in the combined treatment of pregnant women with a pathological preliminary period]

The impact of reflex analgesia via transcutaneous electrical neurostimulation and electrical acupuncture was studied in 46 patients with an abnormal preliminary period by using tests of pain sensations and personal and reactive anxiety, ECG, hysterography, and computer-aided prediction of labor complications. Reflex analgesia was found to contribute to effective abolishment of preliminary pain sensations, to normalization of central nervous system function, autonomic reactions, uterine contractility, to reduction in pharmacological agent use and treatment duration, and to better delivery.

Effects of cranial transcutaneous electrical nerve stimulation in normal subjects at rest and during psychological stress

Some effects of sub-threshold sine-wave transcutaneous electrical nerve stimulation (TENS), passed between earlobe electrodes at a constant alternating current (AC) frequency of 100 Hertz (Hz), were investigated in 90 normal subjects after 30 minutes of treatment, and after 3 minutes of standardized mental stress (mental arithmetic) which immediately followed the 30 minute treatment. In a double-blind protocol, five groups received 1) active TENS during treatment and active TENS during stress; 2) active TENS during treatment and placebo TENS during stress; 3) placebo TENS during treatment and placebo TENS during stress; 4) placebo TENS during treatment and active TENS during stress; and 5) no treatment during both treatment and stress. Results showed significant reductions in systolic blood pressure, pulse rate and anxiety, but not in diastolic blood pressure or peripheral vascular tension, after 30 minutes of active TENS as compared to no treatment. No placebo TENS effect was observed. No significant differences were observed between active TENS; placebo TENS and no treatment in physiological or psychological response to the stress procedure. Results are discussed in terms of the applicability of this technique to the management of stress.

Stimulus-response latencies of two instruments delivering transcutaneous electrical neuromuscular stimulation (TENS)

Stimulus-response latencies of low-frequency transcutaneous electrical neuromuscular stimulation (TENS) were studied in 15 healthy subjects, applying the two different pulse configurations delivered by the Biotens and the Myomonitor instruments. Latencies, in milliseconds, were determined on bipolar raw surface electromyograms (EMG) of the suprahyoid muscles, using the skin surface over the sigmoid notches of the mandible as the site of stimulation. Stimulus-response times were measured from the onset of the stimulus artefact to the first response peak on EMG, and their mean values showed ranges of 3.79-4.49 ms for Biotens and 5.10-5.34 ms for Myomonitor. It was concluded that low-frequency TENS caused direct stimulation of motor nerves, and that the timing of the contraction response was not affected by altered electrode placement, lead-wire reversal or unbalanced (right/left) stimulation.

Fifteen years of transcutaneous electrical stimulation for pain control

Transcutaneous electrical stimulation was reintroduced into medical practice in the early 1970s. Since that time, numerous studies, both controlled and uncontrolled, have suggested its utility for the treatment of pain related to acute musculoskeletal injury, postoperative pain, pain of peripheral vascular origin, pain of myocardial ischemia and chronic pain of a variety of causes. Pain of labor in delivery is affected equivocally. Pain complicating cancer has not been reliably relieved. A small number of controlled studies fail to demonstrate benefit, but the preoponderance of evidence suggests that electrical stimulation of the peripheral nervous system is a useful adjunct in the management of many pain states. Most studies indicate that the resultant analgesia is not opioid-dependent. Pain threshold and perception both appear to be reduced. The physiological mechanism by which pain is affected is not defined; local neural blockade, branch block in the dorsal horn and activation of a central inhibitory system have all been postulated.

Lack of influence of acupuncture and transcutaneous stimulation on the immunoglobulin levels and leucocyte counts following upper-abdominal surgery

The changes in immunoglobulins (IgA, IgG and IgM) and total and differential leucocyte counts in the peripheral blood during, and for 6 days after, surgery were evaluated in 29 male patients submitted to standardized upper-abdominal surgery performed under two different anaesthetic techniques. Group 1 received stimulation of ear and paravertebral points, supplemented by small doses of fentanyl (mean 1.2 micrograms kg-1, range 0.0-5.7) and Group 2 received moderate-dose fentanyl (mean 22.9 micrograms kg-1, range: 17.5-29.8). All were induced with thiopentone 5 mg kg-1, intubated after vecuronium 0.1 mg kg-1 and ventilated with 67% nitrous oxide in oxygen. Inhalation anaesthesia was not used. Surgery was followed by a fall in immunoglobulins, lymphocyte and eosinophil counts and a rise in leucocyte and neutrophil counts in both groups (P less than 0.01). No recovery was observed until the last assessment on Day 6 after surgery in IgA, IgG, leucocyte, neutrophil and lymphocyte counts in both groups, whereas IgM and eosinophil counts recovered by Day 4. Monocyte and basophil counts were unchanged in either group. Acupuncture and transcutaneous stimulation analgesia performed for major abdominal surgery did not influence the body's immune system either during or after surgery as measured by the concentrations of immunoglobulin and total and differential WBC counts.

[The quality of life of the patient with unstable angina treated by spinal cord electrical stimulation]

Quality of life was evaluated in patients with unstable angina before and after surgical therapy with spinal cord electrical stimulation (SCES). Overall 12 patients were evaluated, with quantification of the mean weekly number of anginal attacks, the degree of effort provoking them and the Nottingham Health Profile (NHP). The criteria of inclusion in the study were: angina grade IV, resistant to drug therapy and without indication of surgery. The mean follow-up period was 9.8 +/- 8.2 months. A significant reduction in the weekly number of anginal attacks (preoperative 30.9 +/- 14.5; postoperative 9.6 +/- 8.2; p less than 0.01); improvement in functional class (p less than 0.001), and significant improvement (p greater than 0.05) in the pain, energy, sleep, social isolation and emotional reactions areas of NHP were observed. It was concluded that SCES is a useful procedure in patients with unstable angina untreatable by other medical or surgical methods, as it reduces the number of anginal attacks and increases quality of life of the patients without additional risk.

Restoration of volitional limb movement of hemiplegics following patterned functional electrical stimulation

24 hemiplegic patients completed patterned functional electrical stimulation (PFES) upon the afflicted arm and leg. The multichannel PFES program was mathematically derived from the EMG agonist/antagonist pattern recorded from each subject's unaffected limbs during a series of monitored, voluntary movements. The average improvement in volitional range of motion for the group's paralyzed limbs was 90% for the upper extremities and 69% for the lower extremities. For partially paralyzed limbs, there was an average increase in range of movement of 68% for the upper extremities and 26% for the lower extremities. These findings support the relearning-based, PFES open-loop theory which uses individualized therapeutic PFES-derived from EMG coordination patterns modeled from specific, ballistic limb movements to rehabilitate patients who have been immobilized after stroke.

[Reflex correction of the tocolytic activity in premature labor]

Reflex relaxation using transcutaneous electroneurostimulation (TENS) has been employed in premature labor. Low-frequency TENS proved helpful in the prevention and therapy of un-coordinated uterine contractions and thus in the reduction of perinatal mortality.

[The function of peripheral nerve stimulators in the implementation of nerve and plexus blocks]

A selection of nine instruments supplied by eight different manufacturers for carrying out peripheral nerve stimulation were checked for their suitability, safety and ease of operation, and were compared and contrasted with reference to a spectrum of characteristics that appear desirable in theoretical and practical terms. Measurements at Ohm's resistance showed that in the clinically relevant range of impulse amplitudes (0.1-1.0 mA) the quality of adjustment of the instruments varied widely. The actual electrical impulse delivered by some of the instruments deviated so widely from the adjusted theoretical value that they must be regarded as unsuitable. The duration of the impulse corresponded to the manufacturer's specifications for only two instruments. Four instruments did not generate a monophasic square-wave signal despite assertions to the contrary in the instructions for use, and one instrument did generate such a signal although a "special biphasic asymmetrical" impulse is described by the manufacturer. Impulse-like overshooting at the beginning of the signal, oscillations into the positive range at the end of the signal and fall in current during the course of the signal were the form variants indicating technically inadequate design in the other instruments. Resistance to the square-wave current impulse engendered by the complex body resistance (impedance), a good approximation to the mathematical e-function to be expected, could be demonstrated for the rising signal flank, whereas the signal curve in the lower part of the descending flank was flatter than expected owing to polarization effects in the body tissue. The characteristic voltage and time values calculated for the signal curves are shown in tables.(ABSTRACT TRUNCATED AT 250 WORDS)

[In electric nerve stimulation can the distance from the nerves be inferred from the intensity of muscle contraction? Possible parameters and sources of error]

Electrical nerve stimulation is a useful tool in regional anesthesia; it assists in locating the nerves. This investigation deals with electrical resistances at adhesive electrodes attached to the skin. The influence of external electrical resistance on the stimulating impulse is demonstrated. A new type of nerve stimulator is described; which integrates a measuring device that indicates the electrical impulse actually flowing in the patient. With this device, relationships between stimulating impulse, intensity of muscle contraction, and distance of the puncture cannula from the nerve can be assessed. MATERIALS AND METHODS. The electrical curve I = f (R) was determined using 3 different nerve stimulators (R = 1 - 15k omega). On each of five test persons, five adhesive electrodes were attached to the skin 10 cm apart. The resistance was assessed between these electrodes and a subcutaneously inserted puncture needle. The right and left brachial plexuses of the 5 subjects were punctured, using the axillary approach. A synchronized video camera simultaneously recorded the following values: (1) electrical impulse; (2) corresponding muscle contraction; and (3) the position of the puncture cannula. A scale ranging from 0-5 was applied to define the strength of the muscle contractions. RESULTS. The external resistance as measured under clinical conditions may limit the output impulse of nerve stimulators. In this case, the exerting impulse is lower than that indicated by the appliance. This error can only be identified using an impulse-measuring device. Nerve stimulators not equipped with a measuring device increase the risk of malpuncture, potentially resulting in nerve lesions. Skin resistance at adhesive electrodes varied from patient to patient within a range of 1.1 to 8.2 K omega. Preparing the skin appropriately (wiping with sandpaper) decreased the resistance by only 6% during the first 30 min. Within a distance of 50 cm to the puncture needle, the position of the adhesive electrode did not play a significant role. Axillary puncture of the brachial plexus resulted in the following values: (1) A stimulating impulse (cross-wave) of 1 mA and 1 ms exerted at a distance of 4 mm to the nerve induced a contraction of strength 3. (2) Reducing the impulse at this site by one-half (0.55 mA) resulted in just-visible contractions (strength 1). (3) Advancing the cannula at a stimulating impulse of 0.55 mA inside the neurovascular sheath again produced contractions of strength 3. (4) Performing the puncture with a blunt needle and tracing a distinct resistance, the impulse of 0.6 mA elicited contractions of strength 2. The needle tip was still outside the vascular nerve sheath. If this resistance was overcome and the needle tip lay inside the neurovascular sheath, the impulse could be reduced by one-half (0.32 mA) to produce contractions of strength 2.

[Fundamentals and requirements of peripheral electric nerve stimulation. A contribution to the improvement of safety standards in regional anesthesia]

The use of a nerve stimulator allows an injection cannula to be located without the cooperation of the patient. Regional anesthesia thus becomes safer because the basic condition "no paresthesia, no anesthesia" becomes irrelevant. In accordance with the basic electrophysiological conditions, a stimulator should have the following properties: (1) adjustable constant current at resistances of 0.5-10 kOhm; (2) monophasic square-wave initial impulse; (3) impulse duration selectable (0.1 ms + 1 ms, and exactly adjustable; (4) impulse amplitude (0-5 mA) exactly adjusted, unequivocal scale graduation or current indicator, in particular in the range of 0.05-1.0 mA; (5) impulse frequency 1-2 (-3) Hz; (6) alarm at high impedance and check on electrical circuit; (7) battery test (indication of battery voltage); (8) unequivocal assignment of load end; (9) high-quality connecting cable and plug; and availability of (10) instructions for use with relevant parameters (tolerated variations, steady-state characteristic curves, etc.).

[Kinesiographic neuromuscular orthognathodontics: kinesiographic method after the Attinas]

The Authors, after a brief mention to the historical evolution of the stream of thought and of the several operative approaches towards the gnatological problem, illustrate the main principles of Attina's new kinesiographic methodology. They underline the integrative value regarding the one adopted at present and its capacity to be able to enlarge the power of kinesiographic instrument.