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Functional electrical stimulation (FES) techniques progress by adopting the developments in computers and engineering, but complete functional reconstruction is not yet possible to be achieved. The attachment of the devices to the body can be complex, and training to handle FES is not easy. FES systems are expensive and their coverage by medical insurance is limited with the exception of a few systems. Hence, recognition of FES by the medical community is limited and as a result, it is not a common therapy. However, FES is the main method available for reconstruction of motor function, at present. The improvement in activities of daily living (ADL) of patients using FES may not only improve the patient’s quality of life (QOL) but also reduce the burden to persons who look after them, and hence, secure a valuable work force. The medical insurance should support the use of FES and reduce the patients’ financial burden. Studies and developments based on a close collaboration of users (patients and care-givers), persons involved in therapy (doctors and nurses), and manufactures (engineers and technicians) are necessary. In addition to FES, other methods such as therapeutic electrical stimulation (TES) for prevention of atrophy and spasms of paralytic limbs show the therapeutic potential of neuromodulation.

Functional electrical stimulation (FES) is a rehabilitative technique where low level electrical voltages and currents are applied to an individual in order to improve or restore function lost to injury or disease. In its broadest definition, FES includes electrical stimulation technologies that, for example, are aimed at restoration of a sense of hearing for the deaf, vision for the blind, or suppression of seizures in epilepsy or tremors for people with Parkinson's disease. Most FES devices and systems are known then as “neuroprostheses” because through electrical stimulation they artificially modulate the excitability of neural tissue in order to restore function. While sometimes used synonymously with FES, the term functional neuromuscular stimulation (FNS) is most commonly used to describe only those FES technologies that are applied to the neuromuscular system in order to improve quality of life for people disabled by stroke, spinal cord injury, or other neurological conditions that result in impaired motor function (e.g., the abilities to move or breathe). Another technology closely related to FES is that of therapeutic electrical stimulation (TES), wherein electrical stimulation is applied to provide healing or recovery of tissues (e.g., muscle conditioning and strengthening, wound healing). As will be seen, some FES and FNS technologies concurrently provide or rely upon such therapeutic effects in order to successfully restore lost function. For illustrative purposes, much of this article is centered on FNS and related TES devices and technologies. Keywords: functional electrical stimulation; FES; therapeutic electrical stimulation; TES

We have been using microminiature, single-channel, leadless, RF-powered stimulators called BIONs/sup TM/, in three clinical trials to strengthen muscles weakened by disuse atrophy. Two of these studies are aimed at preventing and reversing shoulder subluxation in post-stroke patients. The third study is aimed at increasing knee function in patients with knee osteoarthritis. Results from these studies (a total of 14 patients implanted) have shown that BIONs are easy for the physicians to implant and easy for the patients to use. Thresholds for recruitment have been stable over time periods as long as 20 months. Significant improvement was seen in the small number of patients under treatment.

A portable percutaneous, intramuscular-electrode-type, 30-channel electrical stimulation system has been developed which has the capability of both functional electrical stimulation (FES) and therapeutic electrical stimulation (TES). This system was developed with an emphasis on flexibility, which makes it easily adaptable to various patients, easy to operate, and durable. The control sensors will be further enhanced in order to make effective use of the patients's remaining functions. >

이명은 외부의 자극 없이 머리와 귀에서 음을 느끼는 현상 으로 라틴어의 ring을 뜻하는 tinnire에서 유래되었다. 전인구 의 약 10~15%의 높은 유병률을 보이고 연령이 증가될수록 많이 발생하나 소아를 포함하여 전 연령대에서 발생할 수 있 다. 이명의 발생은 청각계뿐만 아니라 중추신경계 및 정서와 도 깊은 연관성을 가지고 있는 것으로 알려져 있지만 아직까 지 뚜렷한 원인과 기전에 대해 확실히 밝혀지지 않아 정확한 진단과 치료가 어려운 실정이다. 일반적으로 이명의 치료에는 약물치료, 이명재훈련치료, 소리치료, 인지치료 등이 시도되고 있으나 아직 누구나 인정하는 근본적인 치료는 없다. 전기자극치료는 일반적으로 통증을 완화하는 목적이나 골 절의 회복을 돕는 치료로 많이 이용되고 있으며, 이명의 치료 에 있어서도 최근에 새로 시도되는 치료는 아니고 오래 전부 터 사용되어 왔지만 그 기전이나 효과에 대해서는 아직 명확 하지 않으며 논란이 많다. 이명치료 목적의 전기자극치료는 1800년대 Volta가 자신의 내이에 직류전류로 자극을 시도한 이래 1976년 House 등이 인공 와우 이식 후 부수적인 효과 로 이명의 감소를 보고하였고, 1979년 Portmann 등이 직류 전류 자극을 고실갑각에 주어 이명을 치료하고자 하였으며 1981년 Chouard 등이 경피적 자극을 이용한 치료를 처음 보 고하였다. 이외에도 Graham과 Hazell 등에 의해 전기자극 치료의 이명 억제 효과가 보고되었으며, Shulman이 경피적으 로 유양돌기에 전기자극을 가하는 기기인 Audimax Theraband의 적용시도 등 이명의 치료의 한 축으로 다양한 방법 이 시도되어 왔다. 그 외에도 뇌 자극, 와우 자극 등 다양한 자극방법이 연구 되었으나, 전기자극에 의한 이명 억제 효과는 자극조건과 자 극경로에 따라 연구자들마다 80%의 이명감소결과부터 효과 없음까지 다양하고 이명감소의 지속기간에 대하여도 다양한 결과가 보고되어 아직까지 치료효과에 대해서는 명확하지 않 다. 하지만 이명을 억제할 수 있는 작은 단서도 이명치료의 큰 시작이 될 수 있고 최근 전기공학의 발달은 이명에서 전기 자극치료를 보다 효과적으로 적용할 수 있게 되어 최근 전기 자극치료에 대한 관심이 높아지고 있다. 따라서 이명치료로 Electrical Stimulation for the Treatment of Tinnitus

To improve walking ability, therapeutic electrical stimulation (TES) was applied, through percutaneous implantable electrodes, to the lower extremities of five hemiplegics with cerebrovascular accidents and three quadriplegics with cervical cord injury. Seven out of the eight cases increased 10 meter maximum walking speed. All the hemiplegics showed improvements in standing balance. Since electrode implantation required one week of quiet for the muscle, the muscular strength of the knee decreased during the first two weeks compared to the level before applying TES, then it increased and exceeded this level after the next four weeks.

A randomized controlled trial was carried out to determine the effectiveness of therapeutic electrical stimulation (TES) in improving the function of children with spastic cerebral palsy (CP), who had undergone selective posterior lumbosacral rhizotomy more than a year previously. Children were randomly assigned to groups to receive TES for 1 year, or to have no TES. The primary outcome was the change in the Gross Motor Function Measure (GMFM), a quantitative and validated measure for use in children with spastic CP. There was a statistically significant and clinically important improvement in outcome for the treated children, with the mean change in the GMFM score at one year being 5.5% compared with 1.9% in the untreated group (P = 0.001). TES was simple to use, had no significant complications, and was well accepted by the children and their caregivers, as indicated by an average compliance of 93% for the application of TES on a nightly basis over the course of the study. It was concluded that TES may be beneficial in children with spastic CP who have undergone a selective posterior rhizotomy procedure more than 1 year previously.

One of the most used methods to perform artificial control of muscles is based on functional electrical stimulation (FES), which enables restoration of movement (e.g. arm, knee). FES-based devices use electric current pulses to stimulate and excite the (intact) peripheral nerves. Therapeutic electrical stimulation for paralyzed, orparetic muscles, or damaged ligament in the knee, has proved to be an efficacious rehabilitation tooI in clinical trials on humans (Richmond et al. 2001).

Supraspinal modulation and phase-related sensory input play an important role for the functional recovery of locomotion among patients with central nervous system (CNS) lesions. Reciprocal inhibition (RI) modulates reciprocating lower extremity movements such as locomotion and pedaling. The effects of therapeutic electrical stimulation (TES) on reciprocal inhibition are limited. Pedaling is widely used for rehabilitation of locomotion because it induces similar muscle activity to that observed during locomotion. We, therefore, applied pedaling and TES simultaneously and examined the effects on RI in healthy persons. Pedaling + TES induced stronger after-effects on RI compared with either intervention alone. Furthermore, we combined anodal transcranial direct current stimulation (anodal tDCS) with patterned electrical stimulation (PES) on the peroneal nerve. We applied anodal tDCS + PES to patients with incomplete spinal cord injury. Combination of anodal tDCS with PES significantly modulated RI and improved ankle movements. Combination of TES with pedaling or anodal tDCS could be effective for the functional recovery of locomotion among patients with CNS lesions.

Therapeutic electrical stimulation for spasticity. Quantitative gait analysis [American Journal of Physical Medicine & Rehabilitation 1998;77(4):351-5]

The aim of this study was to evaluate the effect of therapeutic electrical stimulation (TES) applied to antagonists of spastic leg muscles on gross motor function in children with spastic diplegic cerebral palsy. Twelve children between 5 and 12 years of age completed a 24-month crossover study in which six were randomly assigned to receive TES for the first 12 months and the remaining six for the last 12 months. Physiotherapy and a home training program were not altered. All were evaluated blindly in terms of tests of motor function and video recordings at the start and at 12 and 24 months. At the end of the study parents/carers gave a subjective assessment of the effect of TES. No significant effect of TES on motor or ambulatory function was found on the blinded evaluation, but parents of 11 of the 12 children stated that TES had a significant effect. We conclude that it is unlikely that TES has a significant effect on motor and ambulatory function in spastic diplegia.

Disuse muscle atrophy is a significant component of the long-term disability in cerebral palsy and other childhood neurologic disorders. Traditional methods of electrical stimulation, which include neuromuscular electrical stimulation (NMES) and functional electrical stimulation (FES), produce active muscle contraction to strengthen and produce functional gain. Therapeutic electrical stimulation (TES) is a new form of stimulation that uses subcontraction stimulus to promote muscle growth. The presumed mechanism is increased blood flow during a time of trophic hormone secretion during sleep. The TES technique is considered a technologic adjunct to ongoing therapy. TES-stimulated muscle growth requires that ongoing therapy be conducted to strengthen the muscle and to channel the added strength into useful function.

Possible effective sites in the central nervous system for therapeutic electrical stimulation in muscular hypertonus are presented. The tonic vibration reflex (TVR) was used as a suitable model of a hypertonic muscular mechanism. Using cats, vibration of 225 Hz was applied to the tendon of the gastrocnemius and soleus muscles. During TVR, stimuli of 200 Hz were applied at various sites within the brain. Results showed that stimulation of the contralateral precruciate cortex, the medial part of the internal capsule, the ventralis anterior nucleus of the thalamus, and the ipsilateral anterior lobe of the cerebellum produced an intense inhibitory effect on TVR,but no significant effect by stimulation alone. Therefore, it is suggested that stimulation of these structures should be suitable for clinical application.

After a survey of therapeutic electrical stimulation a model is proposed which could explain some of the phenomena observed when stimulating patients with deficits of the locomotor system. Introducing non-linear characteristics of synaptic efficacies, the afferent diffuse barrage of signals due to electrical stimulation is selectively ‘channelled’ to synapses which are not at their saturation points. Electrical therapy thus either improves the balance between general excitation and inhibition or it does not exert any therapeutic effect. The model also shows why stimulation could not increase the unbalanced state and thus impair the clinical picture of the patient.

The problem of inadequate hip stability prevents many patients with head trauma, stroke, or spinal injury from balancing on one limb in order to take a step. There is no adequate orthotic substitute for hip instability, and electrical stimulation with surface electrodes cannot effectively activate the deep hip muscles. This report describes a clinical program in which electrical stimulation via surgically placed electrodes is combined with routine tendon lengthening and transfers and physical therapy. The electrodes are fixed to the epimysium and the leads directed subcutaneously to exit the skin at a common site for attachment to a commercially available stimulator. Preliminary results indicate that functional muscle contractions of the deep hip muscles can be obtained with epimysial electrodes and that stimulation can be used to augment walking ability. The results demonstrate the safety and effectiveness of percutaneous electrical stimulation and contribute to the development of a practical, implanted stimulation system for patients who do not regain hip instability after an upper motor neuron lesion.