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.     

Intraoperative Monitoring of Segmental Spinal Nerve Root Function with Free-Run and Electrically-Triggered Electromyography and Spinal Cord Function with Reflexes and F-Responses

Background Context. Orthodromic ascending somatosensory evoked potentials and antidromic descending neurogenic somatosensory evoked potentials monitor spinal cord sensory function. Transcranial motor stimulation monitors spinal cord motor function but only activates 4–5% of the motor units innervating a muscle. Therefore, 95–96% of the motor spinal cord systems activating the motor units are not monitored. To provide more comprehensive monitoring, 11 techniques have been developed to monitor motor nerve root and spinal cord motor function. These techniques include: 1. neuromuscular junction monitoring, 2. recording free-run electromyography (EMG) for monitoring segmental spinal nerve root function, 3. electrical stimulation to help determine the correct placement of pedicle screws, 4. electrical impedance testing to help determine the correct placement of pedicle screws, 5. electrical stimulation of motor spinal nerve roots, 6. electrical stimulation to help determine the correct placement of iliosacral screws, 7. recording H-reflexes, 8. recording F-responses, 9. recording the sacral reflex, 10. recording intralimb and interlimb reflexes and 11. recording monosynaptic and polysynaptic reflexes during dorsal root rhizotomy. Objective. This paper is the position statement of the American Society of Neurophysiological Monitoring. It is the practice guideline for the intraoperative use of these 11 techniques. Methods. This statement is based on information presented at scientific meetings, published in the current scientific and clinical literature, and presented in previously-published guidelines and position statements of various clinical societies. Results. These 11 techniques when used in conjunction with somatosensory and transcranial motor evoked potentials provide a multiple-systems approach to spinal cord and nerve root monitoring. Conclusions. The techniques reviewed in this paper may be helpful to those wishing to incorporate these techniques into their monitoring program.     

Electrical stimulation in treating spasticity resulting from spinal cord injury

To study the efficacy of electrical stimulation in treating spasticity of six spinal cord injured patients, transcutaneous electrical nerve stimulation (TENS) was applied to the dermatomes belonging to the same spinal cord level as the selected spastic muscle group. Spasticity was assessed in knee extensors by a pendulum test in which the knee joint angle of a swinging lower leg was recorded with an electrogoniometer. TENS was found to produce a noticeable decrease of spasticity in three of the patients, but had little effect on the others.     

Transcutaneous electrical nerve stimulation: an adjunct in the pain management of Guillain-Barré syndrome.

Transcutaneous electrical nerve stimulation was applied in the pain management of a patient with Guillain-Barré Syndrome. As subjectively reported by the patient, her back and lower extremity pain was significantly decreased although her foot paresthesia was not decreased. The program was continued for an 11-day period because TENS was considered a valuable adjunct for the patient's comfort. Transcutaneous electrical nerve stimulation is a valuable addition to our repertoire of available physical therapy modalities. We hope that as clinical experience with TENS increases, fellow clinicians will volunteer the experiences of their endeavors.     

神经肌肉电刺激改善脑卒中偏瘫患者上肢功能研究进展

上肢功能障碍是脑卒中偏瘫患者最常见的后遗症之一,在物理治疗中常用的有神经肌肉电刺激（neuro-muscular electrical stimulation,NMES）、功能性电刺激（functional electrical stimulation,FES）以及经皮电神经刺激（transcuta-neous electrical nerve stimulation,TENS）。本文重点介绍NMES、FES和TENS治疗脑卒中偏瘫上肢功能障碍的临床应用。     

Clinical evaluation of computerized functional electrical stimulation after spinal cord injury: a multicenter pilot study

This study investigated the safety and effects of computerized functional electrical stimulation (FES) on spinal cord injured individuals. Nineteen subjects two to ten years postinjury, with clinically complete motor and sensory lesions between C4 and T10, participated. All subjects met the specific selection criteria. None had received lower extremity electrical stimulation before. In phase I, subjects received surface electrical stimulation to the quadriceps muscle bilaterally for resistive knee extension 3 times a week for four weeks. The resistance and number of completed lifts was recorded daily. In phase II, 36 sessions provided sequential surface electrical stimulation to the quadriceps, hamstrings, and gluteus muscles bilaterally in order for subjects to pedal a lower extremity ergometer with resistance varied depending on completed run time. For each session, heart rate, blood pressure, temperature, and work performance were recorded. Tests done before and after the training program included fasting blood chemistries, 24-hour urinalysis, arm-crank ergometer stress testing, and midthigh girth measurement. Results indicate that this form of FES is safe, that quadriceps strength and endurance is increased, that endurance for ergometer pedaling is increased, and that there may be a training effect as more work is done at a similar heart rate and systolic blood pressure and as muscle bulk is increased. The FES effect on cardiovascular conditioning and general health requires further research to precisely determine its benefits.     

Event related desynchronization-modulated functional electrical stimulation system for stroke rehabilitation: A feasibility study

ABSTRACT: BACKGROUND: We developed an electroencephalogram-based brain computer interface system to modulate functional electrical stimulation (FES) to the affected tibialis anterior muscle in a stroke patient. The intensity of FES current increased in a stepwise manner when the event-related desynchronization (ERD) reflecting motor intent was continuously detected from the primary cortical motor area. METHODS: We tested the feasibility of the ERD-modulated FES system in comparison with FES without ERD modulation. The stroke patient who presented with severe hemiparesis attempted to perform dorsiflexion of the paralyzed ankle during which FES was applied either with or without ERD modulation. RESULTS: After 20 minutes of training, the range of movement at the ankle joint and the electromyography amplitude of the affected tibialis anterior muscle were significantly increased following the ERD-modulated FES compared with the FES alone. CONCLUSIONS: The proposed rehabilitation technique using ERD-modulated FES for stroke patients was feasible. The system holds potentials to improve the limb function and to benefit stroke patients.     

Enhanced reduction in hyperalgesia by combined administration of clonidine and TENS

Transcutaneous electrical nerve stimulation (TENS) partially reduces primary hyperalgesia and is frequency dependent such that high frequency TENS produces approximately a 30% reduction in hyperalgesia whereas low frequency TENS has no effect. Both high and low frequency TENS completely reduce secondary hyperalgesia by activation of mu and delta- opioid receptors in the spinal cord and rostral-ventral medulla suggesting an opiate mediated analgesia. Clonidine in combination with opiates produces a synergistic interaction such that there is a potentiated reduction in hyperalgesia. Thus, we tested if combined application of clonidine with TENS would enhance the reduction in primary hyperalgesia. Male Sprague-Dawley rats were inflamed by subcutaneous injection of 3% carrageenan into one hindpaw. Withdrawal latency to radiant heat and withdrawal threshold to mechanical stimuli were assessed before and after inflammation and after administration of clonidine (0.002-2 mg/kg, intraperitoneal (i.p.)) with either low (4 Hz) or high (100 Hz) frequency TENS. Clonidine alone reduced both heat and mechanical hyperalgesia with ED50s of 0.02 and 1.0 mg/kg, respectively. In combination with either low or high frequency TENS, the dose-response curve shifted to the left and was significantly different from clonidine alone. The ED50s for heat and mechanical hyperalgesia following low frequency TENS with clonidine were 0.002 and 0.2 mg/kg, respectively and those following high frequency TENS with clonidine were 0.005 and 0.15 mg/kg, respectively. Thus, combined use of clonidine and TENS enhances the reduction in analgesia produced by TENS and enhances the potency of clonidine. It would thus be expected that one would reduce the side effects of clonidine and enhance analgesic efficacy with combinations of pharmaceutical and non-pharmaceutical treatments.     

Effects of transcutaneous electrical nerve stimulation on pain in patients with spinal cord injury: a randomized controlled trial

[Purpose] To investigate the effects of transcutaneous electrical nerve stimulation (TENS) on pain in patients with spinal cord injury. [Subjects and Methods] Fifty-two spinal cord injury patients with central pain were randomly allocated into two groups TENS and control with 26 subjects per group. The patients in TENS and control groups were treated with TENS and sham TENS for 20 min (three times a week) for 12 consecutive weeks, respectively. The two group’s pain was assessed using visual analog scale (VAS) and the McGill Pain Questionnaire (including pain rating index-total, pain rating index-affective, pain rating index-sensory, present pain intensity, and number of words chosen) before and after the treatment. [Results] After the intervention, we found significant differences in VAS, pain rating index-total, pain rating index-affective, pain rating index-sensory, present pain intensity, and number of words chosen between the TENS group and the control group. [Conclusion] Our results suggest that TENS effectively decreases pain in patients with spinal cord injury.Key words: Transcutaneous electrical nerve stimulation, Pain, Spinal cord injury     

Neuromodulation of thoracic intraspinal visceroreceptive transmission by electrical stimulation of spinal dorsal column and somatic afferents in rats.

Clinical studies have shown that neuromodulation therapies, such as spinal cord stimulation (SCS) and transcutaneous electrical nerve stimulation (TENS), reduce symptoms of chronic neuropathic and visceral pain. The neural mechanisms underlying SCS and TENS therapy are poorly understood. The present study was designed to compare the effects of SCS and TENS on spinal neuronal responses to noxious stimuli applied to the heart and esophagus. Direct stimulation of an intercostal nerve (ICNS) was used to simulate the effects of TENS. Extracellular potentials of left thoracic (T3) spinal neurons were recorded in pentobarbital anesthetized, paralyzed, and ventilated male rats. SCS (50 Hz, 0.2 ms, 3-5 minutes) at a clinical relevant intensity (90% of motor threshold) was applied on the C1-C2 or C8-T1 ipsilateral spinal segments. Intercostal nerve stimulation (ICNS) at T3 spinal level was performed using the same parameters as SCS. Intrapericardial injection of bradykinin (IB, 10 microg/mL, 0.2 mL, 1 minute) was used as the noxious cardiac stimulus. Noxious thoracic esophageal distension (ED, 0.4 mL, 20 seconds) was produced by water inflation of a latex balloon. C1-C2 SCS suppressed excitatory responses of 16/22 T3 spinal neurons to IB and 25/30 neurons to ED. C8-T1 SCS suppressed excitatory responses of 10/15 spinal neurons to IB and 17/23 neurons to ED. ICNS suppressed excitatory responses of 9/12 spinal neurons to IB and 17/22 neurons to ED. These data showed that SCS and ICNS modulated excitatory responses of T3 spinal neurons to noxious stimulation of the heart and esophagus. PERSPECTIVE: Neuromodulation of noxious cardiac and esophageal inputs onto thoracic spinal neurons by spinal cord and intercostal nerves stimulation observed in the present study may help account for therapeutic effects on thoracic visceral pain by activating the spinal dorsal column or somatic afferents.     

Restoration of shoulder movement in quadriplegic and hemiplegic patients by functional electrical stimulation using percutaneous multiple electrodes.

The purpose of this study is to restore the motion of the paralyzed shoulder caused by upper motor neuron disorders using functional electrical stimulation (FES). Percutaneous wire electrodes were implanted into twelve muscles of the shoulder in six patients with stroke or cervical spinal cord injury. The motion of the paralyzed shoulder was controlled by a portable FES computer system, with the three standard stimulation patterns for restoring motion of 90 degrees flexion to 90 degrees horizontal abduction, 90 degrees flexion to 20 degrees horizontal adduction, and 90 degrees abduction to 90 degrees horizontal adduction. Shoulder movements were repeatedly controlled according to the created stimulation patterns in five of the patients. The two dimensional motion analyzer also confirmed shoulder control over a satisfactorily broad range of excursion. One hemiplegic patient, who was a signboard painter, had his paretic left upper extremity improved by FES, and he drew a large picture on a board with his normal right hand and, with his affected left arm against the wall, to support his trunk. This may be a world first case of producing shoulder motion through FES.     

Relation between stimulation characteristics and clinical outcome in studies using electrical stimulation to improve motor control of the upper extremity in stroke.

OBJECTIVE: Electrical stimulation can be applied in a variety of ways to the hemiparetic upper extremity following stroke. The aim of this review is to explore the relationship between characteristics of stimulation and the effect of electrical stimulation on the recovery of upper limb motor control following stroke. METHODS: A systematic literature search was performed to identify clinical trials evaluating the effect of electrical stimulation on motor control. The reported outcomes were examined to identify a possible relationship between the reported effect and the following characteristics: duration of stimulation, method of stimulation, setting of stimulation parameters, target muscles and stage after stroke. RESULTS: Nineteen clinical trials were included, and the results of 22 patient groups were evaluated. A positive effect of electrical stimulation was reported for 13 patient groups. Positive results were more common when electrical stimulation was triggered by voluntary movement rather than when non-triggered electrical stimulation was used. There was no relation between the effect of electrical stimulation and the other characteristics examined. CONCLUSION: Triggered electrical stimulation may be more effective than non-triggered electrical stimulation in facilitating upper extremity motor recovery following stroke. It appears that the specific stimulus parameters may not be crucial in determining the effect of electrical stimulation.     

Spinal blockade of opioid receptors prevents the analgesia produced by TENS in arthritic rats

Transcutaneous electrical nerve stimulation (TENS) is commonly used for relief of pain. The literature on the clinical application of TENS is extensive. However, surprisingly few reports have addressed the neurophysiological basis for the actions of TENS. The gate control theory of pain is typically used to explain the actions of high-frequency TENS, whereas, low-frequency TENS is typically explained by release of endogenous opioids. The current study investigated the role of mu, delta, and kappa opioid receptors in antihyperalgesia produced by low- and high-frequency TENS by using an animal model of inflammation. Antagonists to mu (naloxone), delta (naltrinodole), or kappa (nor-binaltorphimine) opioid receptors were delivered to the spinal cord by microdialysis. Joint inflammation was induced by injection of kaolin and carrageenan into the knee-joint cavity. Withdrawal latency to heat was assessed before inflammation, during inflammation, after drug (or artificial cerebral spinal fluid as a control) administration, and after drug (or artificial cerebral spinal fluid) administration + TENS. Either high- (100 Hz) or low- frequency (4 Hz) TENS produced approximately 100% inhibition of hyperalgesia. Low doses of naloxone, selective for mu opioid receptors, blocked the antihyperalgesia produced by low-frequency TENS. High doses of naloxone, which also block delta and kappa opioid receptors, prevented the antihyperalgesia produced by high-frequency TENS. Spinal blockade of delta opioid receptors dose-dependently prevented the antihyperalgesia produced by high-frequency TENS. In contrast, blockade of kappa opioid receptors had no effect on the antihyperalgesia produced by either low- or high-frequency TENS. Thus, low-frequency TENS produces antihyperalgesia through mu opioid receptors and high-frequency TENS produces antihyperalgesia through delta opioid receptors in the spinal cord.     

The effects of non-painful transcutaneous electrical nerve stimulation on cutaneous pain threshold and muscular reflexes in normal men and in subjects with chronic pain

In healthy subjects and in subjects with chronic myofascial pain of one lower limb, the following was measured in both lower limbs: (i) sequential Hoffman (H) reflex, (ii) sequential Achilles tendon (T) reflex, (iii) cutaneous pain threshold determined with electrical stimuli, before, during and after transcutaneous electrical nerve stimulation (TENS).In healthy subjects no significant differences were observed between the pain thresholds of the two limbs. During and after TENS, changes of the reflexes were related to the pain thresholds.In the pathological subjects a significant difference of pain threshold was present between the affected limb and the contralateral one. An important difference between healthy and pathological subjects is not the quality but the quantity of the changes induced by TENS, in the sense that the levels of inhibition and facilitation of the reflexes are more evident in patients with pain. Indeed, TENS induces a reset of sensory and of motor system and a parallel long lasting effect both on sensory and on muscular function, with concomitant pain relief in the pathological subjects.     

Predicting muscle forces of individuals with hemiparesis following stroke

Background  

Functional electrical stimulation (FES) has been used to improve function in individuals with hemiparesis following stroke. An ideal functional electrical stimulation (FES) system needs an accurate mathematical model capable of designing subject and task-specific stimulation patterns. Such a model was previously developed in our laboratory and shown to predict the isometric forces produced by the quadriceps femoris muscles of able-bodied individuals and individuals with spinal cord injury in response to a wide range of clinically relevant stimulation frequencies and patterns. The aim of this study was to test our isometric muscle force model on the quadriceps femoris, ankle dorsiflexor, and ankle plantar-flexor muscles of individuals with post-stroke hemiparesis.     

Ambulation study of a woman with paraplegia using a reciprocating gait orthosis with functional electrical stimulation in Taiwan: A case report

Purpose. Many patients who suffer from spinal cord injuries with paraplegia cannot recover to walk independently. They need to use a special walking orthoses to support their body to walk properly. Traditionally, long leg braces (LLB) were fitted to patients for walking. Unfortunately, the results were not satisfactory as this device supplies adequate support with less than optimum mobility. This study used the latest reciprocating gait orthosis (RGO) combined with functional electrical stimulation (FES). This combination provides a greater support range while applying assistant mechanical walking structures. The FES co-ordination helps restore natural walking abilities that the paralysed patient has lost.

Method. This study developed a walking orthosis with FES, using FES to stimulate specific muscles (quadriceps, hamstring) in the paralysed patients' lower limbs. The proposed method can achieve the benefits of physical therapeutics while paralysed patients can achieve the purpose of walking. The FES is designed with control buttons on the walking orthosis. A patient can control the left or right leg in walking and speed control via the control buttons.

Results. Several practical tests were conducted on the new walking orthosis. A 25-year-old female paralysed patient (L1 complete spinal cord injury) used traditional LLB, RGO and RGO with FES to proceed with walking rehabilitation and clinical assessment. Heart rate difference (HRdifference), mean blood pressure (MBPdifference), walking speed, length of steps, number of steps and oxygen consumption comparisons were made before and after walking. The results show that RGO and RGO with FES were both better than LLB. However, the differences between RGO and RGO with FES in HRdifference, MBPdifference, and walking speed were not significant. This is because the patient's right leg reaction to the electrical stimulation was relatively low.

Discussion and conclusions. In general, RGO can help the patient achieve quicker and more independent walking. The combination of RGO and FES can increase the effectiveness of RGO for more mobile aid. These two walking orthoses are better than traditional LLB. Both methods provide patients who suffer from paraplegia with better choices.     

Non-invasive neuromuscular electrical stimulation in patients with central nervous system lesions: an educational review

The aim of this educational review is to provide an overview of the clinical application of transcutaneous electrical stimulation of the extremities in patients with upper motor neurone lesions. In general two methods of electrical stimulation can be distinguished: (i) therapeutic electrical stimulation, and (ii) functional electrical stimulation. Therapeutic electrical stimulation improves neuromuscular functional condition by strengthening muscles, increasing motor control, reducing spasticity, decreasing pain and increasing range of motion. Transcutaneous electrical stimulation may be used for neuromuscular electrical stimulation inducing repetitive muscle contraction, electromyography-triggered neuromuscular electrical stimulation, position-triggered electrical stimulation and subsensory or sensory transcutaneous electric stimulation. Functional electrical stimulation provokes muscle contraction and thereby produces a functionally useful movement during stimulation. In patients with spinal cord injuries or stroke, electrical upper limb neuroprostheses are applied to enhance upper limb and hand function, and electrical lower limb neuroprostheses are applied for restoration of standing and walking. For example, a dropped foot stimulator is used to trigger ankle dorsiflexion to restore gait function. A review of the literature and clinical experience of the use of therapeutic electrical stimulation as well as of functional electrical stimulation in combination with botulinum toxin, exercise therapy and/or splinting are presented. Although the evidence is limited we conclude that neuromuscular electrical stimulation in patients with central nervous system lesions can be an effective modality to improve function, and that combination with other treatments has an additive therapeutic effect.     

Monitoring des potentiels évoqués moteurs neurogènes lors de la chirurgie correctrice de la scoliose

Neurogenic motor evoked potentials in association with somatosensory evoked potentials were used to assess the functional integrity of spinal cord during scoliosis surgery. They were elicited by a spinal electrical stimulation and recorded from peripheral nerves in 23 patients. Reproductible responses were obtained in every patient under anesthesia. In three patients a modification of neurogenic motor evoked responses occurred: in one case, loss of potentials associated with a postoperative tetraplegia; in two cases, transient amplitude decrease without major neurological complications. Although the real origin of these potentials remains to be determined (possible involvement of antidromic sensory pathway conduction), this technique seems to be easy to perform, reproductible, fast and sensible for assessment of spinal cord during scoliosis surgery.     

Basic concepts of activity-based interventions for improved recovery of motor function after spinal cord injury

Roy RR, Harkema SJ, Edgerton VR. Basic concepts of activity-based interventions for improved recovery of motor function after spinal cord injury. Spinal cord injury (SCI) is a devastating condition that affects a large number of individuals. Historically, the recovery process after an SCI has been slow and with limited success. Recently, a number of advances have been made in the strategies used for rehabilitation, resulting in marked improved recovery, even after a complete SCI. Several rehabilitative interventions, that is, assisted motor training, spinal cord epidural stimulation, and/or administration of pharmacologic agents, alone or in combination, have produced remarkable recovery in motor function in both humans and animals. The success with each of these interventions appears to be related to the fact that the spinal cord is smart, in that it can use ensembles of sensory information to generate appropriate motor responses without input from supraspinal centers, a property commonly referred to as central pattern generation. This ability of the spinal cord reflects a level of automaticity, that is, the ability of the neural circuitry of the spinal cord to interpret complex sensory information and to make appropriate decisions to generate successful postural and locomotor tasks. Herein, we provide a brief review of some of the neurophysiologic rationale for the success of these interventions.     

Restoration of gait and motor recovery by functional electrical stimulation therapy in persons with stroke

Purpose.?To evaluate the clinical efficacy of functional electrical stimulation (FES) therapy of the tibialis anterior (TA) muscle on gait restoration and enhancing motor recovery with stroke patients.

Method.?Thirty hemiparetic participants with spastic foot-drop impairments who were at least 3 months post-stroke were recruited from a rehabilitation institute and were assigned either to a control group or a FES group. Both the groups participated in a conventional stroke rehabilitation program for 60?min per day, 5 days a week, for 12-weeks. The FES group received the electrical stimulation to the TA muscle for correction of foot-drop.

Results.?Functional electric stimulation (FES) resulted in a 26.3% (p?<?0.001) improvement of walking speed measured with 10-m walkway, whereas the improvement in the control group was only 11.5% (p?<?0.01). The FES group also showed significantly greater improvements compared to control group in other gait parameters (e.g. cadence, step length), physiological cost index (PCI), ankle range of motion, spasticity of calf muscle, Fugl–Meyer scores, and the maximum value of the root mean square (RMS_max), which reflects the capacity of the muscle output.

Conclusions.?These findings suggest that, the FES therapy combined with conventional therapy treatment more effectively improves the walking ability and enhances the motor recovery when compared with conventional therapy alone in stroke survivors.